id
int64 0
203k
| input
stringlengths 66
4.29k
| output
stringlengths 0
3.83k
|
|---|---|---|
6,900 | Suppose that you have an abstract for a scientific paper: through an investigation of photoemission properties of highly - photoexcited single - walled carbon nanotubes , we demonstrate that there is an upper limit on the achievable excitonic density . as the intensity of optical excitation increases , all photoluminescence emission peaks arising from different chirality single - walled carbon nanotubes showed clear saturation in intensity .
each peak exhibited a saturation value that was independent of the excitation wavelength , indicating that there is an upper limit on the excitonic density for each nanotube species .
we propose that this saturation behavior is a result of efficient exciton - exciton annihilation through which excitons decay non - radiatively . in order to explain the experimental results and obtain excitonic densities in the saturation regime ,
we have developed a model , taking into account the generation , diffusion - limited exciton - exciton annihilation , and spontaneous decays of one - dimensional excitons . using the model
, we were able to reproduce the experimentally obtained saturation curves under certain approximations , from which the excitonic densities were estimated .
the validity of the model was confirmed through comparison with monte carlo simulations .
finally , we show that the conventional rate equation for exciton - exciton annihilation without taking into account exciton diffusion fails to fit the experimentally observed saturation behavior , especially at high excitonic densities . .
And you have already written the first three sentences of the full article: the optical and electronic properties of low - dimensional materials have been an important subject of study in the field of condensed matter physics . in particular ,
one - dimensional ( 1-d ) materials are predicted to possess unique properties that are distinctly different from those at higher dimensions,@xcite primarily due to the enhanced coulomb interactions among the quantum confined charge carriers .
one common feature of optically - excited low - dimensional systems is the formation of strongly bound electron - hole ( @xmath0-@xmath1 ) pairs , or excitons,@xcite which dominate interband optical spectra ..
Please generate the next two sentences of the article | 1-d semiconductors are expected to show an almost complete suppression of optical absorption at the band edges , with a significant fraction of the total oscillator strength taken by the lowest excitonic state.@xcite early reports of lasing from semiconductor quantum wires ( qwrs)@xcite invoked much interest in the physics of _ high density _ 1-d excitons .
a number of studies have thus far been performed on such qwr systems during the last two decades to understand many - body phenomena ( e.g. , lasing , band - gap renormalization , biexciton formation , and the mott transition),@xcite but many aspects are still under debate and not well understood . |
6,901 | Suppose that you have an abstract for a scientific paper: we have performed monte carlo studies of the 3d @xmath0 model with random uniaxial anisotropy , which is a model for randomly pinned spin - density waves .
we study @xmath1 simple cubic lattices , using @xmath2 values in the range 16 to 64 , and with random anisotropy strengths of @xmath3 = 1 , 2 , 3 , 6 and @xmath4 .
there is a well - defined finite temperature critical point , @xmath5 , for each these values of @xmath3 .
we present results for the angle - averaged magnetic structure factor , @xmath6 at @xmath5 for @xmath7 .
we also use finite - size scaling analysis to study scaling functions for the critical behavior of the specific heat , the magnetization and the longitudinal magnetic susceptibility .
good data collapse of the scaling functions over a wide range of @xmath8 is seen for @xmath3 = 6 and @xmath4 . for our finite values of @xmath3
the scaled magnetization function increases with @xmath2 below @xmath5 , and appears to approach an @xmath2-independent limit for large @xmath2 .
this suggests that the system is ferromagnetic below @xmath5 . .
And you have already written the first three sentences of the full article: the harris - plischke - zuckermann model@xcite has long been used to study the effects of random uniaxial anisotropy on ferromagnetism .
the hamiltonian of this random anisotropy model ( ram ) is @xmath9 where each @xmath10 , the dynamical on site @xmath11 , is usually taken to be a classical three - component spin of unit length .
each @xmath12 is a time - independent unit vector ..
Please generate the next two sentences of the article | the @xmath13 on different sites are assumed to be uncorrelated random variables .
@xmath14 is a sum over nearest neighbors on some lattice . in this work |
6,902 | Suppose that you have an abstract for a scientific paper: background : : : the most significant source of background in direct dark matter searches are neutrons that scatter elastically from nuclei in the detector s sensitive volume .
experimental data for the elastic scattering cross section of neutrons from argon and neon , which are target materials of interest to the dark matter community , were previously unavailable .
purpose : : : measure the differential cross section for elastic scattering of neutrons from argon and neon in the energy range relevant to backgrounds from ( @xmath0 ) reactions in direct dark matter searches .
method : : : cross - section data were taken at the triangle universities nuclear laboratory ( tunl ) using the neutron time - of - flight technique .
these data were fit using the spherical optical model .
results : : : the differential cross section for elastic scatting of neutrons from neon at 5.0 and 8.0 mev and argon at 6.0 mev was measured . optical - model parameters for the elastic scattering reactions were determined from the best fit to these data . the total elastic scattering cross section for neon was found to differ by 6% at 5.0 mev and 13% at 8.0 mev from global optical - model predictions . compared to a local optical - model for @xmath1ar ,
the elastic scattering cross section was found to differ from the data by 8% at 6.0 mev .
conclusions : : : these new data are important for improving monte - carlo simulations and background estimates for direct dark matter searches and for benchmarking optical models of neutron elastic scattering from these nuclei . .
And you have already written the first three sentences of the full article: the next generation of low - background physics experiments , including direct detection of weakly interacting massive particle ( wimp ) dark matter may provide significant insight to physics beyond the standard model and the nature of the dominant matter constituent of the universe @xcite .
the successful detection of wimps will provide valuable information about the nature of dark matter .
several current and next generation large - scale detectors designed to search for wimp dark matter make use of liquified noble gas ( ne , ar , xe ) ..
Please generate the next two sentences of the article | descriptions of several experiments of this type may be found in refs.@xcite .
these experiments will search for the scintillation light and in some cases the ionization charges generated from the recoiling nucleus after a putative wimp - nucleus scatter . on the other hand , |
6,903 | Suppose that you have an abstract for a scientific paper: even though the technology of adaptive optics ( ao ) is rapidly maturing , calibration of the resulting images remains a major challenge . the ao point - spread function ( psf ) changes quickly both in time and position on the sky . in a typical observation
the star used for guiding will be separated from the scientific target by 10 to 30 .
this is sufficient separation to render images of the guide star by themselves nearly useless in characterizing the psf at the off - axis target position .
a semi - empirical technique is described that improves the determination of the ao off - axis psf .
the method uses calibration images of dense star fields to determine the change in psf with field position .
it then uses this information to correct contemporaneous images of the guide star to produce a psf that is more accurate for both the target position and the time of a scientific observation .
we report on tests of the method using natural - guide - star ao systems on the canada - france - hawaii telescope and lick observatory shane telescope , augmented by simple atmospheric computer simulations . at 25 off - axis , predicting the psf full width at half maximum using only information about the guide star results in an error of 60% . using an image of a dense star field
lowers this error to 33% , and our method , which also folds in information about the on - axis psf , further decreases the error to 19% . .
And you have already written the first three sentences of the full article: a key ingredient to successful analysis of images produced with the aid of an adaptive optics ( ao ) system is the determination of the point - spread function ( psf ) .
the application dictates how precisely the psf must be determined .
for example , limiting the uncertainty in psf - fitting photometry in a crowded star field to only a few percent will demand very high accuracy in knowledge of the strehl ratio ..
Please generate the next two sentences of the article | another example , but a case where a good reference star is less likely to be found , is the subtraction of the point - like core from the image of a quasar - host or radio galaxy @xcite . in this case
strehl ratio may be low , and the ao psf approximately gaussian . for a fixed volume , |
6,904 | Suppose that you have an abstract for a scientific paper: the radial velocity spectrometer ( rvs ) on board of gaia will perform a large spectroscopic survey to determine the radial velocities of some @xmath0 stars .
we present the status of ground - based observations of a sample of 1420 candidate standard stars designed to calibrate the rvs .
each candidate star has to be observed several times before gaia launch ( and at least once during the mission ) to ensure that its radial velocity remains stable during the whole mission .
observations are performed with the high - resolution spectrographs sophie , narval and coralie , completed with archival data of the elodie and harps instruments .
the analysis shows that about 7% of the current catalogue exhibits variations larger than the adopted threshold of 300 m s@xmath1 .
consequently , those stars should be rejected as reference targets , due to the expected accuracy of the gaia rvs .
emphasis is also put here on our observations of bright asteroids to calibrate the ground - based velocities by a direct comparison with celestial mechanics .
it is shown that the radial velocity zero points of sophie , narval and coralie are consistent with each other , within the uncertainties . despite some scatter ,
their temporal variations remain small with respect to our adopted stability criterion .
galaxy : kinematics and dynamics galaxy : structure stars : kinematics and dynamics minor planets , asteroids : general surveys techniques : radial velocities .
And you have already written the first three sentences of the full article: the rvs is a slitless spectrograph whose spectral domain is 847 - 874 nm and resolving power @xmath2 .
the expected accuracy is 1 km s@xmath1 for f0 to k0 stars brighter than v@xmath3 , and for k1 to k4 stars brighter than v@xmath4 .
the main scientific objectives of rvs are the chemistry and dynamics of the milky way , the detection and characterisation of multiple systems and variable stars ( for more details , see * ? ? ?.
Please generate the next two sentences of the article | those objectives will be achieved from a spectroscopic survey of : * radial velocities ( @xmath5 objects , v @xmath6 ) * rotational velocities ( @xmath7 objects , v @xmath8 ) * atmospheric parameters ( @xmath7 objects , v @xmath8 ) * abundances ( @xmath9 objects , v @xmath10 ) each star will be observed @xmath11 times on average by rvs over the 5 years of the mission .
because the rvs has no calibration module on board , the zero point of its radial velocities has to be determined from reference sources . |
6,905 | Suppose that you have an abstract for a scientific paper: red giants offer a good opportunity to study the interplay of magnetic fields and stellar evolution . using the spectro - polarimeter narval of the telescope bernard lyot ( tbl ) , pic du midi , france and the lsd technique we began a survey of magnetic fields in single g - k - m giants .
early results include 6 mf - detections with fast rotating giants , and for the first time a magnetic field was detected directly in an evolved m - giant : ek boo .
our results could be explained in the terms of @xmath0@xmath1 dynamo operating in these giants . .
And you have already written the first three sentences of the full article: magnetic fields ( mf ) in single evolved stars are still poorly studied .
most of the g
k m giants presently been known as active are fast rotators ..
Please generate the next two sentences of the article | ( fekel&balachandran , 1993 ; huensch et al . ,
angular momentum dredge - up has been suggested to provide the fast rotation , driven by the convective zone reaching near the stellar core ( simon&drake , 1989 ) . in this way |
6,906 | Suppose that you have an abstract for a scientific paper: massive high - redshift quiescent compact galaxies ( nicknamed _ red nuggets _ ) have been traditionally connected to present - day elliptical galaxies , often overlooking the relationships that they may have with other galaxy types .
we use large bulge - disk decomposition catalogues based on the sloan digital sky survey ( sdss ) to check the hypothesis that red nuggets have _ survived _ as compact cores embedded inside the haloes or disks of present - day massive galaxies . in this study , we designate a _ compact core _ as the bulge component that satisfies a prescribed compactness criterion .
photometric and dynamic mass - size and mass - density relations are used to show that , in the inner regions of galaxies at @xmath0 , there are _ abundant _ compact cores matching the peculiar properties of the red nuggets , an abundance comparable to that of red nuggets at @xmath1 .
furthermore , the morphology distribution of the present - day galaxies hosting compact cores is used to demonstrate that , in addition to the standard channel connecting red nuggets with elliptical galaxies , a comparable fraction of red nuggets might have ended up embedded in disks .
this result generalises the inside - out formation scenario ; present - day massive galaxies can begin as dense spheroidal cores ( red nuggets ) , around which either a spheroidal halo or a disk are formed later .
[ firstpage ] galaxies : evolution galaxies : formation galaxies : stellar content galaxies : structure galaxies : bulges . .
And you have already written the first three sentences of the full article: an approximate census of massive galaxies at redshift @xmath1 provides a morphological classification into 40% disks , 15% extended spheroids , 25% compact spheroids and 20% peculiar objects ( e.g. * ? ? ?
more than 9 gyrs later , in the present - day universe , a similar census of massive galaxies gives 30% disks , 65% extended spheroids and 5% peculiar morphologies .
strikingly , compact spheroids are virtually absent in the present - day universe ( e.g. * ? ? ?.
Please generate the next two sentences of the article | * ; * ? ? ?
* ; * ? ? ? |
6,907 | Suppose that you have an abstract for a scientific paper: among many physical processes involved in star formation , radiation transfer is one of the key processes since it dominantly controls the thermodynamics . because metallicities control opacities , they are one of the important environmental parameters which affect star formation processes . in this work ,
i investigate protostellar collapse in solar - metallicity and low - metallicity ( @xmath0 ) environments using 3d radiation hydrodynamic and magnetohydrodynamic simulations . because radiation cooling is more effective in the low - metallicity environments , first cores are colder and have lower entropies . as a result ,
first cores are smaller , less massive and have shorter lifetimes in the low - metallicity clouds .
therefore , first cores would be less likely to be found in low - metallicity star forming clouds .
this also implies that first cores tend to be more gravitationally unstable and susceptible to fragmentation .
the evolution and structure of protostellar cores formed after the second collapse weakly depend on metallicities in the spherical and magnetized models despite the large difference in the metallicities . because this is due to the change of the heat capacity by dissociation and ionization of hydrogen
, it is a general consequence of the second collapse as long as the effects of radiation cooling are not very large during the second collapse . on the other hand ,
the effects of different metallicities are more significant in the rotating models without magnetic fields , because they evolve slower than other models and therefore more affected by radiation cooling . .
And you have already written the first three sentences of the full article: stars are formed in various environments with different density , temperature , rotation , turbulence , magnetic fields , metallicities , and so on . to take account of these effects , computational simulations including many physical processes have been extensively performed and played leading roles in understanding star formation processes . among these physical processes , metallicities are one of the important parameters which control thermal evolution through radiation transfer .
thermodynamics is of critical importance in dynamics of collapsing clouds ; for instance , the effective adiabatic index @xmath1 is an important criterion whether a gas sphere collapses dynamically by self - gravity .
it is well accepted that the early phase of star formation , from molecular clouds cores to protostellar cores , proceeds through two distinctive stages @xcite ..
Please generate the next two sentences of the article | initially a dense cloud core collapses almost isothermally because radiation cooling is highly efficient .
when the gas gets dense enough and radiation cooling becomes inefficient , the gas pressure balances with gravity and a quasi hydrostatic object , a so - called first core , is formed . |
6,908 | Suppose that you have an abstract for a scientific paper: using inverse statistical - mechanical optimization techniques , we have discovered isotropic pair interaction potentials with strongly repulsive cores that cause the tetrahedrally - coordinated diamond and wurtzite lattices to stabilize , as evidenced by lattice sums , phonon spectra , positive - energy defects , and self - assembly in classical molecular dynamics simulations .
these results challenge conventional thinking that such open lattices can only be created via directional covalent interactions observed in nature .
thus , our discovery adds to fundamental understanding of the nature of the solid state by showing that isotropic interactions enable the self - assembly of open crystal structures with a broader range of coordination number than previously thought .
our work is important technologically because of its direct relevance generally to the science of self - assembly and specifically to photonic crystal fabrication . .
And you have already written the first three sentences of the full article: the science of self - assembly " , as introduced by george whitesides and coworkers about fifteen years ago @xcite as a promising research direction , is a large and rapidly growing field of tremendous technological potential and fundamental interest .
its motivating factor is simple : direct micro- and nano - fabrication of circuitry ( electronic , optoelectronic , or others ) becomes prohibitively time - consuming and/or expensive below a certain length scale , and as a result , scientists and engineers are searching for particles on the mesoscopic scale that by themselves assemble into potentially useful structures by virtue of their mutual interactions ; hence the term ` self - assembly ' .
there is a large number of examples of theoretical , experimental , and computational studies on this topic @xcite ..
Please generate the next two sentences of the article | colloidal systems command particular interest , as interaction potentials in these systems have become increasingly tailorable with the advent of new ways to functionalize the colloidal surface .
these systems have tremendous capacity to assemble exotic lattices and hence to yield photonic bandgap structures . |
6,909 | Suppose that you have an abstract for a scientific paper: we use heegaard splittings to give a criterion for a tunnel number one knot manifold to be non - fibered and to have large cyclic covers .
we also show that such a knot manifold ( satisfying the criterion ) admits infinitely many virtually haken dehn fillings . using a computer
, we apply this criterion to the 2 generator , non - fibered knot manifolds in the cusped snappea census . for each such manifold @xmath0 ,
we compute a number @xmath1 , such that , for any @xmath2 , the @xmath3-fold cyclic cover of @xmath0 is large . .
And you have already written the first three sentences of the full article: this paper continues the project , begun in @xcite , of using heegaard splittings to construct closed essential surfaces in finite covers of 3-manifolds .
the idea , based on the work of casson and gordon @xcite , is to lift a heegaard splitting of a 3-manifold to a finite cover in which there are disjoint compressing disks on each side . by compressing the lifted heegaard surface along an appropriate choice of such disks ,
we hope to arrive at an essential surface . by a _ knot manifold _.
Please generate the next two sentences of the article | we mean a connected , compact , orientable 3-manifold whose boundary is a single torus .
a _ tunnel system _ for a knot manifold @xmath0 is a collection @xmath4 where the @xmath5 s are disjoint , properly embedded arcs in @xmath0 , such that @xmath6 is homeomorphic to a handlebody . |
6,910 | Suppose that you have an abstract for a scientific paper: we propose a new method of gravitational wave detection using a modified form of higher criticism , a statistical technique introduced by @xcite .
higher criticism is designed to detect a group of sparse , weak sources , none of which are strong enough to be reliably estimated or detected individually .
we apply higher criticism as a second - pass method to synthetic @xmath0-statisticand @xmath1-statisticdata for a monochromatic periodic source in a binary system and quantify the improvement relative to the first - pass methods .
we find that higher criticism on @xmath1-statisticdata is more sensitive by @xmath2% than the @xmath1-statisticalone under optimal conditions ( i.e. binary orbit known exactly ) and the relative advantage increases as the error in the orbital parameters increases .
higher criticism is robust even when the source is not monochromatic ( e.g. phase wandering in an accreting system ) .
applying higher criticism to a phase - wandering source over multiple time intervals gives a @xmath3% increase in detectability with few assumptions about the frequency evolution .
by contrast , in all - sky searches for unknown periodic sources , which are dominated by the brightest source , second - pass higher criticism does not provide any benefits over a first pass search . .
And you have already written the first three sentences of the full article: direct detection of gravitational waves appears likely in the near future .
existing terrestrial long - baseline interferometers , such as the laser interferometer gravitational - wave observatory ( ligo ) and virgo , have achieved their design sensitivity @xcite .
next - generation interferometers now under construction are expected to detect tens of events per year , if contemporary estimates of compact binary coalescence rates are correct @xcite ..
Please generate the next two sentences of the article | searches for periodic sources have the advantage of integrating over long observation times to increase the signal - to - noise ratio .
the most likely periodic sources detectable by terrestrial interferometers are rapidly rotating , slightly deformed neutron stars @xcite . |
6,911 | Suppose that you have an abstract for a scientific paper: it is well known that in an exact covering system in @xmath0 , the biggest modulus must be repeated .
very recently , s. kim proved an analogous result for certain quadratic fields . in this paper , we prove that s. kim s result holds for any algebraic number field .
* keywords : * exact covering systems , lattice parallelotopes , chinese remainder theorem .
And you have already written the first three sentences of the full article: for an integer @xmath1 and a positive integer @xmath2 , let @xmath3 denote the set of integers @xmath4 . a finite collection of congruence classes @xmath5
is called a covering system in @xmath0 if each integer belongs to at least one congruence class .
this concept was first introduced by erds @xcite in 1950 , who constructed an infinite arithmetic sequence of odd integers not representable as @xmath6 ( @xmath7 a prime ) using a covering system ..
Please generate the next two sentences of the article | if moreover , each integer belongs to exact one congruence class , we say it is an exact covering system .
given a number field @xmath8 , denoting the ring of algebraic integers of @xmath8 by @xmath9 . |
6,912 | Suppose that you have an abstract for a scientific paper: we explore the physics potential of the numi beamline with a detector located 10 km off - axis at a distant site ( @xmath0 km ) .
we study the sensitivity to @xmath1 and to the cp - violating parameter @xmath2 as well as the determination of the neutrino mass hierarchy by exploiting the @xmath3 and @xmath4 appearance channels .
the results are illustrated for three different experimental setups to quantify the benefits of increased detector sizes , proton luminosities and @xmath5 detection efficiencies .
july 25 , 2005 1.4 cm neutrino oscillations have been observed and robustly established by the data from solar @xcite , atmospheric @xcite , reactor @xcite and long - baseline neutrino experiments @xcite .
these results indicate the existence of non - zero neutrino masses and mixings .
the new parameters can be accommodated via the three neutrino pmns mixing matrix , the leptonic analogue to the ckm matrix in the quark sector .
neutrino oscillations within this scenario are described by six parameters : two mass squared differences throughout the paper . ]
( @xmath6 and @xmath7 ) , three euler angles ( @xmath8 , @xmath9 and @xmath10 ) and one dirac cp phase @xmath11 .
the standard way to connect the solar , atmospheric , reactor and accelerator data with the six oscillation parameters listed above is to identify the two mass splittings and the two mixing angles which drive the solar and atmospheric transitions with ( @xmath6 , @xmath8 ) and ( @xmath12 , @xmath13 ) , respectively .
the sign of the atmospheric mass splitting @xmath7 with respect to the solar doublet is one of the unknowns within the neutrino sector , i.e. we do not know if the neutrino mass spectrum is normal ( @xmath14 ) or inverted ( @xmath15 ) . the best fit point for the combined analysis of solar neutrino data @xcite together with kamland reactor data @xcite is at @xmath16 ev@xmath17 and @xmath18 . the 90% c.l .
allowed ranges of the atmospheric neutrino oscillation parameters obtained by the super -....
And you have already written the first three sentences of the full article: since we are exploiting the @xmath3 and @xmath4 appearance channels , the observables that we use in our numerical analysis are the number of expected electron neutrino and antineutrino events . for the central values of the already measured oscillation parameters ,
we have thus computed the expected number of electron and positron events @xmath38 and @xmath39 at the far detector located @xmath40 km off - axis at @xmath41 km , assuming positive or negative hierarchies , which are given by : @xmath42 where @xmath43 and @xmath44 are taken as perfectly known , @xmath45 denote the neutrino fluxes , and @xmath46 the cross sections .
the neutrino ( antineutrino ) flux , which peaks at @xmath47 , is integrated over a narrow @xmath48 energy window ( @xmath49 and @xmath50 ) ..
Please generate the next two sentences of the article | the @xmath3 ( @xmath51 ) appearance probabilities in long baseline neutrino oscillation experiments , assuming the normal mass hierarchy , read @xcite : @xmath52 in the last expressions , @xmath53 and the coefficients @xmath54 and @xmath55 are determined by @xmath56 where @xmath57 , and @xmath58 denotes the index of refraction in matter , @xmath59 being the fermi constant and @xmath60 is a constant electron number density in the earth .
we denote the first , second and third terms in eqs . |
6,913 | Suppose that you have an abstract for a scientific paper: commonplace at every evolutionary stage , multiple protostellar systems ( mpss ) are thought to be formed through fragmentation , but it is unclear when and how .
the youngest mpss , which have not yet undergone much evolution , provide important constraints to this question .
it is then of interest to disentangle early stage mpss . in this letter we present the results of our work on vla1623 using our observations and archival data from the submillimeter array ( sma ) .
our continuum and line observations trace vla1623 s components , outflow and envelope , revealing unexpected characteristics .
we construct the sed for each component using the results of our work and data from literature , as well as derive physical parameters from continuum and perform a simple kinematical analysis of the circumstellar material .
our results show vla1623 to be a triple non - coeval system composed of vla1623a , b & w , with each source driving its own outflow and unevenly distributed circumstellar material . from the sed , physical parameters and ir emission
we conclude that vla1623a & w are class 0 and i protostars , respectively , and together drive the bulk of the observed outflow .
furthermore , we find two surprising results , first the presence of a rotating disk - like structure about vla1623a with indications of pure keplerian rotation , which , if real , would make it one of the first evidence of keplerian disk structures around class 0 protostars .
second , we find vla1623b to be a bonafide extremely young protostellar object between the starless core and class 0 stages . .
And you have already written the first three sentences of the full article: multiple protostellar systems ( mpss ) are common among every stage of protostellar evolution , but are tricky to decipher .
fragmentation is believed to be the main mechanism for forming mpss @xcite , but how and when fragmentation occurs is still a major question . to constrain the fragmentation process , information about the system s multiplicity , coevality , environment and outflows are needed . since older systems have suffered dynamical evolution @xcite , young early stage mpss , having many of the initial conditions almost intact , are the best targets for the task . in this letter we present the results of our work on
the much debated vla1623 , located in @xmath0 ophiuchus and generally considered the prototypical class 0 source ( @xcite , hereafter awb93 ) ..
Please generate the next two sentences of the article | first detected through red- and blueshifted overlapped outflows @xcite , vla1623 s multiplicity has long been suspected from observation of multiple continuum sources ( @xcite ; @xcite ; @xcite , hereafter lmw00 ) , outflow misalingment ( @xcite ; @xcite , hereafter yc97 ) and two discreet precessing jets originating from the same region @xcite .
in contrast , the multiple continuum sources are argued to constitute a monopolar jet driven by vla1623a ( @xcite , hereafter ba97 ; @xcite ; @xcite , hereafter moa12 ) . |
6,914 | Suppose that you have an abstract for a scientific paper: phase retrieval refers to a classical nonconvex problem of recovering a signal from its fourier magnitude measurements .
inspired by the compressed sensing technique , signal sparsity is exploited in recent studies of phase retrieval to reduce the required number of measurements , known as compressive phase retrieval ( cpr ) . in this paper , @xmath0
minimization problems are formulated for cpr to exploit the signal sparsity and alternating direction algorithms are presented for problem solving . for
real - valued , nonnegative image reconstruction , the image of interest is shown to be an optimal solution of the formulated @xmath0 minimization in the noise free case .
numerical simulations demonstrate that the proposed approach is fast , accurate and robust to measurements noises . .
And you have already written the first three sentences of the full article: many imaging techniques reconstruct a signal from its frequency or fourier measurements .
but in practice the phase information of the data in the frequency domain may not be available to the detecting and sensing devices , e.g. , in x - ray crystallography @xcite .
it therefore arises the problem of recovering a signal from its fourier magnitude only measurements , known as phase retrieval ..
Please generate the next two sentences of the article | other applications of phase retrieval include optics @xcite , diffraction imaging @xcite , astronomical imaging @xcite and magnetic resonance imaging @xcite , to name just a few .
since more than one signal can result in the same fourier magnitude measurements , the phase retrieval problem is ill - posed . |
6,915 | Suppose that you have an abstract for a scientific paper: this paper presents the discovery and timing parameters for five millisecond pulsars ( msps ) , four in binary systems with probable white dwarf companions and one isolated , found in ongoing processing of the high time resolution universe pulsar survey ( htru ) .
we also present high quality polarimetric data on four of them .
these further discoveries confirm the high potential of our survey in finding pulsars with very short spin periods .
at least two of these five msps are excellent candidates to be included in the pulsar timing array projects .
thanks to the wealth of msp discoveries in the htru survey , we revisit the question of whether the luminosity distributions of isolated and binary msps are different . using the cordes and lazio distance model and our new and catalogue flux density measurements , we find that 41 of the 42 most luminous msps in the galactic disk are in binaries and a statistical analysis suggests that the luminosity functions differ with 99.9% significance .
we conclude that the formation process that leads to solitary msps affects their luminosities , despite their period and period derivatives being similar to those of pulsars in binary systems .
[ firstpage ] stars : pulsars : individual : psrj14315740 , psrj15454550 , psrj18250319 , psrj18320836 , psrj22365527 .
And you have already written the first three sentences of the full article: according to the _ recycling _ model ( e.g. @xcite ) millisecond - or recycled - pulsars ( msps ) are formed in binary systems where the companion star transfers mass , and hence angular momentum , onto the neutron star ( ns ) .
extended mass transfer from low mass companions can cause the ns to be spun up to rotational periods of at least 1.5 milliseconds .
higher mass systems , transferring mass over shorter time scales and mostly via a wind @xcite , can not push the recycling process down to periods below @xmath0 20 milliseconds . at the same time , due to still unclear mechanisms , possibly linked to the accreted mass itself , the magnetic field b is decreased down to @xmath1 g. about 75% of all known msps in the galactic field ( i.e. outside globular clusters , where exchange interactions can change the final outcome of the evolution of an msp ) are found in binary systems ( data from the atnf pulsar catalogue[multiblock footnote omitted ] ; @xcite ) , supporting the above scenario . the formation path of isolated msps ,.
Please generate the next two sentences of the article | though , is still a matter of debate : those with spin periods of few tens of ms or more could derive from double neutron star systems disrupted during the second supernova explosion ( disrupted recycled pulsars , drps ; @xcite ) while the shorter period pulsars could be the result of a binary system where the companion was so light that the interaction with the pulsar wind was able to completely destroy it @xcite
. there are now a few examples of the so called _ black widow _ |
6,916 | Suppose that you have an abstract for a scientific paper: we study the dimension spectrum of lyapunov exponents for rational maps on the riemann sphere .
this research was supported by the eu fp6 marie curie programmes spade2 and cody .
the research of f.p and m.r . were supported by the polish mnisw grant nn201 0222 33 ` chaos , fraktale i dynamika konforemna ' .
k.g .
was partially supported by the deutsche forschungsgemeinschaft and by the humboldt foundation .
k.g . and m.r .
thank for the hospitality of mpi pks dresden and i m pan warsaw where part of this research was done . .
And you have already written the first three sentences of the full article: let @xmath0 be a rational function of degree @xmath1 on the riemann sphere and let @xmath2 be its julia set .
our goal is to study the spectrum of lyapunov exponents of @xmath3 . given @xmath4 we denote by @xmath5 and @xmath6 the _ lower _ and _ upper lyapunov exponent _ at @xmath7 , respectively , where @xmath8 if both values coincide then we call the common value the _ lyapunov exponent _ at @xmath7 and denote it by @xmath9 .
for given numbers @xmath10 we consider also the following level sets @xmath11 we denote by @xmath12 the set of _ lyapunov regular points _ with exponent @xmath13 . if @xmath14 then @xmath15 is contained in the set of so - called _ irregular points _ @xmath16 recall that it follows from the birkhoff ergodic theorem that @xmath17 for any @xmath18-invariant probability measure @xmath19 ..
Please generate the next two sentences of the article | while the first results on the multifractal formalism go already back to besicovitch @xcite , its systematic study has been initiated by work of collet , lebowitz and porzio @xcite .
the case of spectra of lyapunov exponents for conformal uniformly expanding repellers has been covered for the first time in @xcite building also on work by weiss @xcite ( see @xcite for more details and references ) . to our best knowledge |
6,917 | Suppose that you have an abstract for a scientific paper: early type massive stars drive thin , dense shells whose edges often show evidence of star - formation . the possibility of fragmentation of these shells , leading to the formation of putative star - forming clumps
is examined with the aid of semi - analytic arguments .
we also derive a mass - spectrum for clumps condensing out of these shells by performing monte - carlo simulations of the problem . by extending on results from our previous work on the stability of thin , dense shells
, we argue that clump - mass estimated by other authors in the past , under a set of simplifying assumptions , are several orders of magnitude smaller than those calculated here . using the expression for the fastest growing unstable mode in a shock - confined shell ,
we show that fragmentation of a typical shell can produce clumps with a typical mass @xmath0 m@xmath1 .
it is likely that such clumps could spawn a second generation of massive and/or intermediate - mass stars which could in turn , trigger the next cycle of star - formation .
we suggest that the ratio of shell thickness - to - radius evolves only weakly with time .
calculations have been performed for stars of seven spectral types , ranging from b1 to o5 .
we separately consider the stability of supernova remnants .
star formation , hiiregions , supernova remnants , instabilities .
And you have already written the first three sentences of the full article: partial or full ring - like structures , which apparently are projections of shells , are often found in the interstellar medium ( ism ) .
these dense shells could possibly be driven by one of the numerous sources like , ionising radiation from young star - clusters , early type massive stars , blast - waves from supernovae , or energetic stellar winds . detailed observations of these shells in various bands of the infrared wavelength have also revealed isolated sites of massive star formation ( e.g. deharveng , zavagno & caplan 2005 ) . in the recent past a number of such sites have been reported , for instance in the hii region rcw79 ( zavagno _ et al .
_ 2006 ) , and rcw120 ( anderson _ et al ..
Please generate the next two sentences of the article | a catalogue of 600 such shells in the galactic disk was drawn up by churchwell _
( 2006 ) as part of the glimpse survey . |
6,918 | Suppose that you have an abstract for a scientific paper: recent numerical work on the fate of plasma instabilities in weakly - coupled non - abelian gauge theory has shown the development of a cascade of energy from long to short wavelengths .
this cascade has a steady - state spectrum , analogous to the kolmogorov spectrum for turbulence in hydrodynamics or for energy cascades in other systems . in this paper
, we theoretically analyze processes responsible for this cascade and find a steady - state spectrum @xmath0 , where @xmath1 is the phase - space density of particles with momentum @xmath2 .
the exponent @xmath3 is consistent with results from numerical simulations .
we also discuss implications of the emerging picture of instability development on the `` bottom - up '' thermalization scenario for ( extremely high energy ) heavy ion collisions , emphasizing fundamental questions that remain to be answered .
l ss v c .
And you have already written the first three sentences of the full article: it is important to understand theoretically the mechanisms by which quark - gluon plasmas can locally equilibrate in heavy ion collisions such as those at rhic . since the path - breaking work of baier , mueller , schiff and son @xcite on `` bottom - up '' thermalization
, one modest theoretical goal has been to understand the process of equilibration in the simplifying theoretical limit of arbitrarily high - energy collisions , where the running strong coupling @xmath4 can be treated as small .
typically , theorists expect to be able to solve weakly - coupled problems , but equilibration of weakly - coupled non - abelian plasmas has proven to be a very rich and challenging problem . in particular , the original attempt by baier did not account for the physics of plasma instabilities , which are now believed to play a crucial role during some of the early stages of thermalization @xcite ..
Please generate the next two sentences of the article | early in a heavy - ion collision , particles have an anisotropic distribution of momenta , as measured in local frames moving with the expanding plasma @xcite .
later , they scatter and equilibrate to locally isotropic distributions , giving rise to hydrodynamic behavior . generically , anisotropic distributions of particles produce collective plasma instabilities known as weibel or filamentary instabilities . |
6,919 | Suppose that you have an abstract for a scientific paper: one of the cornerstones of special relativity is the postulate that all observers measure exactly the same photon speeds independently of the photon energies .
however , a hypothesized structure of spacetime may alter this conclusion at ultra - small length scales .
even a tiny energy - dependent variation in the speed of light may be revealed , when accumulated over cosmological light - travel times , by high temporal - resolution measurements of sharp features in gamma - ray burst ( grb ) lightcurves .
we report the results of a study of the emission from grb 090510 as detected by _ fermi _
s lat and gbm instruments that set unprecedented limits on the dependence of the speed of light on its energy . .
And you have already written the first three sentences of the full article: one of the predicted manifestations of lorentz invariance violation ( liv ) is a dependence of the speed of light in vacuo on its energy ( see refs . and references therein ) .
according to postulated liv effects , two photons of energies @xmath0 emitted simultaneously from a distant astrophysical source at redshift @xmath1 will travel with different velocities and will arrive with a time delay @xmath2 equal to@xcite : @xmath3 where @xmath4 is the ` quantum - gravity ( qg ) mass , ' a parameter that sets the energy scale at which the qg effects that cause liv start to become important .
its value is assumed to be near the planck mass ( @xmath5 gev/@xmath6 ) and most likely smaller than it ..
Please generate the next two sentences of the article | the model - dependent parameter @xmath7 is assumed to be one or two , corresponding to linear ( @xmath8 , with @xmath9 ) and quadratic ( @xmath10 ) liv respectively .
the model - dependent parameter @xmath11 is equal to plus or minus one , corresponding to a speed retardation or acceleration with an increasing photon energy respectively . in ref . and using the above parametrization for @xmath2 |
6,920 | Suppose that you have an abstract for a scientific paper: the production at central rapidity of , , @xmath0 and @xmath1 particles in pb - pb collisions at 158 @xmath2 gev/@xmath3 has been measured by the na57 experiment over a centrality range corresponding to the most central 53% of the inelastic pb - pb cross section . in this paper
we present the rapidity distribution of each particle in the central rapidity unit as a function of the event centrality .
the distributions are analyzed based on hydrodynamical models of the collisions . .
And you have already written the first three sentences of the full article: lattice quantum chromodynamic calculations predict a new state of matter of deconfined quark and gluons ( quark gluon plasma , qgp ) at an energy density exceeding @xmath4 1 gev/@xmath5 @xcite
. nuclear matter at high energy density has been extensively studied through ultra - relativistic heavy ion collisions ( for recent developements , see reference @xcite ) . within the experimental programme with heavy - ion beams at cern sps
, na57 is a dedicated experiment for the study of the production of strange and multi - strange particles in pb - pb collisions at mid - rapidity @xcite ..
Please generate the next two sentences of the article | the measurement of strange particle production provides one of the most powerful tools to study the dynamics of the reaction .
in particular , an enhanced production of strange particles in nucleus nucleus collisions with respect to proton |
6,921 | Suppose that you have an abstract for a scientific paper: with a core - periphery structure of networks , core nodes are densely interconnected , peripheral nodes are connected to core nodes to different extents , and peripheral nodes are sparsely interconnected .
core - periphery structure composed of a single core and periphery has been identified for various networks .
however , analogous to the observation that many empirical networks are composed of densely interconnected groups of nodes , i.e. , communities , a network may be better regarded as a collection of multiple cores and peripheries .
we propose a scalable algorithm to detect multiple non - overlapping groups of core - periphery structure in a network .
we illustrate our algorithm using synthesised and empirical networks .
for example , we find distinct core - periphery pairs with different political leanings in a network of political blogs and separation between international and domestic subnetworks of airports in some single countries in a world - wide airport network . .
And you have already written the first three sentences of the full article: many complex systems can be expressed as networks in which a node represents an object ( e.g. , person , web page , protein ) and an edge represents the relationship between two objects ( e.g. , friendship , hyperlink , physical interaction )
. a network can be characterised by microscale , mesoscale and macroscale structural patterns such as the degree ( i.e. , the number of edges that a node has ) , clustering coefficient , and diameter @xcite . among various structural properties of networks ,
community structure is a representative mesoscale structure of networks @xcite ..
Please generate the next two sentences of the article | a community is a group of densely interconnected nodes while different communities are sparsely interconnected .
a community often corresponds to a group of nodes sharing a role , and identifying communities aids classification of nodes and visualisation of networks @xcite . |
6,922 | Suppose that you have an abstract for a scientific paper: let @xmath0 be a connected component of a stratum in the moduli space of abelian or quadratic differentials for a non - exceptional riemann surface @xmath1 of finite type .
we show that the probability measure on @xmath0 in the lebesgue measure class which is invariant under the teichmller flow is obtained by bowen s construction . .
And you have already written the first three sentences of the full article: the _ teichmller flow _ @xmath2 acts on components of strata in the moduli space of area one abelian or quadratic differentials for a non - exceptional surface @xmath1 of finite type .
this flow has many properties which resemble the properties of an anosov flow .
for example , there is a pair of transverse invariant foliations , and there is an invariant mixing borel probability measure @xmath3 in the lebesgue measure class which is absolutely continuous with respect to these foliations , with conditional measures which are uniformly expanded and contracted by the flow @xcite ..
Please generate the next two sentences of the article | this measure is even exponentially mixing , i.e. exponential decay of correlations for hlder observables holds true @xcite .
the entropy @xmath4 of the lebesgue measure @xmath3 is the supremum of the topological entropies of the restriction of @xmath2 to compact invariant sets @xcite . for strata of abelian differentials |
6,923 | Suppose that you have an abstract for a scientific paper: recent results of meson photo - production at the existing electron machines with polarized real photon beams and the measurement of polarization observables of the final state baryons have provided high precision data that led to the discovery of new excited nucleon and @xmath0 states using multi - channel partial wave analyses procedures .
the internal structure of several prominent excited states has been revealed employing meson electroproduction processes . on the theoretical front
, lattice qcd is now predicting the baryon spectrum with very similar characteristics as the constituent quark model , and continuum qcd , such as is represented in the dyson - schwinger equations approach and in light front relativistic quark models , describes the non - perturbative behavior of resonance excitations at photon virtuality of @xmath1 . in this
talk i discuss the need to continue a vigorous program of nucleon spectroscopy and the study of the internal structure of excited states as a way to reveal the effective degrees of freedom underlying the excited states and their dependence on the distance scale probed .
example.eps gsave newpath 20 20 moveto 20 220 lineto 220 220 lineto 220 20 lineto closepath 2 setlinewidth gsave .4 setgray fill grestore stroke grestore .
And you have already written the first three sentences of the full article: the excited states of the nucleon have been studied experimentally since the 1950 s @xcite .
they contributed to the discovery of the quark model in 1964 by gell - mann and zweig @xcite , and were critical for the discovery of `` color '' degrees of freedom as introduced by greenberg @xcite .
the quark structure of baryons resulted in the prediction of a wealth of excited states with underlying spin - flavor and orbital symmetry of @xmath2 , and led to a broad experimental effort to search for these states ..
Please generate the next two sentences of the article | most of the initially observed states were found with hadronic probes .
however , of the many excited states predicted in the quark model , only a fraction have been observed to date . |
6,924 | Suppose that you have an abstract for a scientific paper: new integral field spectroscopy has been obtained for izw18 , the nearby lowest - metallicity galaxy considered our best local analog of systems forming at high - z . here
we report the spatially resolved spectral map of the nebular heii@xmath04686 emission in izw18 , from which we derived for the first time its total heii - ionizing flux .
nebular heii emission implies the existence of a hard radiation field .
heii - emitters are observed to be more frequent among high - z galaxies than for local objects .
so investigating the heii - ionizing source(s ) in izw18 may reveal the ionization processes at high - z .
heii emission in star - forming galaxies , has been suggested to be mainly associated with wolf - rayet stars ( wrs ) , but wrs can not satisfactorily explain the heii - ionization at all times , in particular at lowest metallicities .
shocks from supernova remnants , or x - ray binaries , have been proposed as additional potential sources of heii - ionizing photons .
our data indicate that conventional heii - ionizing sources ( wrs , shocks , x - ray binaries ) are not sufficient to explain the observed nebular heii@xmath04686 emission in izw18 .
we find that the heii - ionizing radiation expected from models for either low - metallicity super - massive o stars or rotating metal - free stars could account for the heii - ionization budget measured , while only the latter models could explain the highest values of heii@xmath04686/h@xmath1 observed .
the presence of such peculiar stars in izw18 is suggestive and further investigation in this regard is needed .
this letter highlights that some of the clues of the early universe can be found here in our cosmic backyard . .
And you have already written the first three sentences of the full article: heii recombination emission indicates the presence of very hard ionizing radiation with photon energies @xmath2 54ev .
star - forming galaxies with lower metallicities tend to have larger nebular heii@xmath04686 line intensities compared to those with higher metallicities ( e.g. guseva et al .
2000 ; schaerer 2003 ) ..
Please generate the next two sentences of the article | while nebular heii emission has been observed in some local low metallicity ( z ) starbursts ( e.g. schaerer et al .
1999 ; guseva et al . |
6,925 | Suppose that you have an abstract for a scientific paper: as an extension of the project in @xcite , we collected times of superhump maxima for 61 su uma - type dwarf novae mainly observed during the 20092010 season .
the newly obtained data confirmed the basic findings reported in @xcite : the presence of stages a c , as well as the predominance of positive period derivatives during stage b in systems with superhump periods shorter than 0.07 d. there was a systematic difference in period derivatives for systems with superhump periods longer than 0.075 d between this study and @xcite .
we suggest that this difference is possibly caused by the relative lack of frequently outbursting su uma - type dwarf novae in this period regime in the present study .
we recorded a strong beat phenomenon during the 2009 superoutburst of iy uma .
the close correlation between the beat period and superhump period suggests that the changing angular velocity of the apsidal motion of the elliptical disk is responsible for the variation of superhump periods .
we also described three new wz sge - type objects with established early superhumps and one with likely early superhumps .
we also suggest that two systems , vx for and el uma , are wz sge - type dwarf novae with multiple rebrightenings . the @xmath0 variation in ot j213806.6@xmath1261957 suggests that the frequent absence of rebrightenings in very short-@xmath2 objects can be a result of sustained superoutburst plateau at the epoch when usual su uma - type dwarf novae return to quiescence preceding a rebrightening .
we also present a formulation for a variety of bayesian extension to traditional period analyses . .
And you have already written the first three sentences of the full article: in paper @xcite , we surveyed period variations of superhumps in su uma - type dwarf novae ( for general information of su uma - type dwarf novae and superhumps , see @xcite ) .
@xcite indicated that evolution of superhump period ( @xmath3 ) is generally composed of three distinct stages : early evolutionary stage with a longer superhump period ( stage a ) , middle stage with systematically varying periods ( stage b ) , final stage with a shorter , stable superhump period ( c ) .
it was also shown that the period derivatives ( @xmath4 ) during stage b is correlated with @xmath3 , or binary mass - ratios ( @xmath5 ) ..
Please generate the next two sentences of the article | although this relation commonly applies to classical su uma - type dwarf novae , wz sge - type dwarf novae , a subtype of su uma - type dwarf novae with very infrequent superoutbursts , tend to deviate from this picture : they rarely show a distinct stage b c transition , and
some objects show relatively small period derivatives , and they frequently exhibit unusual multiple post - superoutburst rebrightenings . the origin of these relations is not yet well understood . |
6,926 | Suppose that you have an abstract for a scientific paper: this proceeding briefly summarizes our recent vishnu hybrid model investigations on the chemical and thermal freeze - out of various hadrons species in 2.76 a tev pb+pb collisions .
detailed analysis on the evolution of particle yields and the last elastic collisions distributions during the hadronic evolution reveals that the two multi - strange hadrons , @xmath0 and @xmath1 , experience early chemical and thermal freeze - out when compared with other hadron species . .
And you have already written the first three sentences of the full article: in relativistic heavy - ion collisions at top rhic and the lhc energies , a hot and dense matter the quark - gluon plasma ( qgp ) has been created . during its expansion ,
the qgp fireball quickly cools down , which then undergos the phase transition and produces a large amount of hadrons .
these hadrons subsequently experience frequent inelastic and elastic collisions during the hadronic evolution . with the termination of inelastic and elastic collisions ,.
Please generate the next two sentences of the article | the evolving system reach the chemical and thermal freeze - out , respectively . traditionally , the chemical freeze - out temperature @xmath2 and the baryon chemical potential @xmath3 are extracted from the particle yields of various hadrons using the statistical model @xcite , which gives a uniform @xmath2 and @xmath3 for all hadrons species .
similarly , pure hydrodynamic simulations implement a uniform thermal freeze - out temperature to construct the freeze - out hyper - surface , which decouples various hadrons from the bulk matter @xcite . |
6,927 | Suppose that you have an abstract for a scientific paper: results from a 60 ks hetgs observation of the nearby seyfert 2 are presented .
the spectrum shows a wealth of emission lines at both soft and hard x - rays , including lines of ne , mg , si , s , ar , ca , and fe , and a prominent line at 6.4 kev .
we identify several of the he - like components and measure several of the lyman lines of the h - like ions .
the lines profiles are unresolved at the limited signal - to - noise ratio of the data . our analysis of the zeroth - order image in a companion paper constrains the size of the emission region to be 2060 pc , suggesting that emission within this volume is almost entirely due to the reprocessing of the obscured central source . here we show that a model containing two distinct components can reproduce almost all the observed properties of this gas .
the ionized component can explain the observed intensities of the ionized species , assuming twice - solar composition and an @xmath0 density distribution .
the neutral component is highly concentrated , well within the 0.8 point source , and is responsible for almost all of the observed k@xmath1 ( 6.4 kev ) emission
. seems to be different than mkn 3 in terms of its gas distribution . .
And you have already written the first three sentences of the full article: recent x - ray studies of seyfert 2 galaxies with and have shown that the 0.110 kev spectra of these sources are rich in emission lines at both soft and hard energies ( e.g. , guainazzi et al . 1999 ; turner et al .
the interpretation of the emission lines is problematic because of ambiguities about line blending , line profiles , and line flux distribution that are all poorly constrained by and .
the data are consistent with emission from gas in photoionization equilibrium ( e.g. , netzer , turner , & george 1998 and references therein ) , but there are also attempts to fit the spectra by a two - temperature gas in collisional equilibrium ( ueno et al . 1994 ) , presumably due to starburst emission ..
Please generate the next two sentences of the article | x - ray observations at high resolution both spatially and spectrally are crucial to determining the origin of the x - ray lines in seyfert 2s , a task for which is uniquely suited . here
we present a 60 ks hetgs spectrum of the seyfert 2 galaxy . |
6,928 | Suppose that you have an abstract for a scientific paper: in the paper the epr - bohm scenario will be reproduced in an algebraic quantum field theoretical setting with locally finite degrees of freedom .
it will be shown that for a set of spatially separated correlating events ( projections ) maximally violating the clauser
horne inequality there can be given a common causal explanation _ if _ commutativity is abandoned between the common cause and the correlating events .
moreover , the noncommuting common cause will be local and supported in the common past of the correlating events .
* key words : * clauser horne inequality , common cause , noncommutativity , algebraic quantum field theory . .
And you have already written the first three sentences of the full article: the central idea of algebraic quantum field theory is the representation of observables by a net of local @xmath0-algebras associated to bounded regions of a spacetime ( see ( haag , 1992 ) ) .
this correspondence is established _ via _ the standard axioms of the theory such as isotony , locality ( also called einstein causality or microcausality ) and covariance .
a state @xmath1 in such a local quantum theory is defined as a normalized positive linear functional on the quasilocal observable algebra @xmath2 which is an inductive limit of local observable algebras ..
Please generate the next two sentences of the article | the representation @xmath3 corresponding to the state @xmath1 converts the net of @xmath0-algebras into a net of von neumann observable algebras by closures in the weak topology .
since von neumann algebras are rich in projections , they offer a nice representation of _ quantum events _ : projections can be interpreted as 0 - 1valued observables and their expectation value defines the probability of the event that the observable takes on the value 1 in the appropriate quantum state . |
6,929 | Suppose that you have an abstract for a scientific paper: we propose dijkstra s algorithm with bounded list size after qr decomposition for decreasing the computational complexity of near maximum - likelihood ( ml ) detection of signals over multiple - input - multiple - output ( mimo ) channels .
after that , we compare the performances of proposed algorithm , qr decomposition m - algorithm ( qrd - mld ) , and its improvement . when the list size is set to achieve the almost same symbol error rate ( ser ) as the qrd - mld , the proposed algorithm has smaller average computational complexity . .
And you have already written the first three sentences of the full article: the channel capacity of multiple - input - multiple - output ( mimo ) channels linearly increases with the number of antennas @xcite .
maximum - likelihood ( ml ) detection provides the minimum error rate .
however , the computational complexity of the simple ml detection algorithm grows exponentially with the number of transmit antennas ..
Please generate the next two sentences of the article | thus , we need an efficient algorithm that achieves similar error rate to the ml detection .
the qr decomposition m - algorithm ( qrd - mld ) @xcite and sphere decoding ( sd ) @xcite are possibly the most promising algorithms . in @xcite , to reduce the computational complexity , dijkstra s algorithm is applied to sd which achieves same error rate as ml detection . both the qrd - mld and dijkstra s algorithm are tree search based algorithms . |
6,930 | Suppose that you have an abstract for a scientific paper: we present interferometric observations of the be star 51 ophiuchi .
these observations were obtained during the science demonstration phase of the midi instrument at the very large telescope interferometer ( vlti ) .
using midi , a michelson 2 beam combiner that operates at the n band ( 8 to 13 @xmath0 m ) , we obtained for the first time observations of 51 oph in the mid - infrared at high - angular resolution .
it is currently known that this object presents a circumstellar dust and gas disk that shows a very different composition from other herbig ae disks .
the nature of the 51 oph system is still a mystery to be solved .
does it have a companion ?
is it a protoplanetary system ? we still do nt know .
observations with midi at the vlti allowed us to reach high - angular resolution ( 20 mas).we have several uv points that allowed us to constrain the disk model .
we have modeled 51 oph visibilities and were able to constrain the size and geometry of the 51 oph circumstellar disk . .
And you have already written the first three sentences of the full article: 51 ophiuchi is a be ( b9.5iiie ) star , located at 131 pc with a rotational velocity @xmath1 = 267 @xmath2 5 km / s @xcite .
51 oph shows a large infrared excess , that was first noticed by waters et al .
1988 @xcite ..
Please generate the next two sentences of the article | this infrared excess was explained as being originated by the circumstellar dust around the star .
the 51 oph circumstellar gas and dust origin is still unknown . |
6,931 | Suppose that you have an abstract for a scientific paper: characterising tractable fragments of the constraint satisfaction problem ( csp ) is an important challenge in theoretical computer science and artificial intelligence .
forbidding patterns ( generic sub - instances ) provides a means of defining csp fragments which are neither exclusively language - based nor exclusively structure - based .
it is known that the class of binary csp instances in which the broken - triangle pattern ( btp ) does not occur , a class which includes all tree - structured instances , are decided by arc consistency ( ac ) , a ubiquitous reduction operation in constraint solvers . we provide a characterisation of simple partially - ordered forbidden patterns which have this ac - solvability property .
it turns out that btp is just one of five such ac - solvable patterns .
the four other patterns allow us to exhibit new tractable classes .
[ defn]definition [ exmp]example supported by epsrc grant ep / l021226/1 ] supported by epsrc grant ep / l021226/1 and a royal society university research fellowship .
part of this work was done while the second author was visiting the simons institute for the theory of computing at uc berkeley ] ( 20,40 ) ( 20,40)(0,0 ) ( 10,20)(18,38 ) ( 10,10)(0,0)@xmath0 ( 10,30)(0,0)@xmath0 ( 20,40 ) ( 20,40)(0,0 ) ( 10,20)(18,28 ) ( 10,20)(0,0)@xmath0 .
And you have already written the first three sentences of the full article: the _ constraint satisfaction problem _ ( csp ) provides a common framework for many theoretical problems in computer science as well as for many real - life applications .
a csp instance consists of a number of variables , a domain , and constraints imposed on the variables with the goal to determine whether the instance is satisfiable , that is , whether there is an assignment of domain values to all the variables in such a way that all the constraints are satisfied .
the general csp is np - complete and thus a major research direction is to identify restrictions on the csp that render the problem _ tractable _ , that is , solvable in polynomial time ..
Please generate the next two sentences of the article | a substantial body of work exists from the past two decades on applications of universal algebra in the computational complexity of and the applicability of algorithmic paradigms to csps .
moreover , a number of celebrated results have been obtained through this method ; see @xcite for a recent survey . however , the algebraic approach to csps is only applicable to _ language - based _ csps , that is , classes of csps defined by the set of allowed constraint relations but with arbitrary interactions of the constraint scopes . |
6,932 | Suppose that you have an abstract for a scientific paper: we prove that the outer automorphism group @xmath0 is residually finite when the group @xmath1 is virtually compact special ( in the sense of haglund and wise ) or when @xmath1 is isomorphic to the fundamental group of some compact @xmath2-manifold . to prove these results we characterize commensurating endomorphisms of acylindrically hyperbolic groups .
an endomorphism @xmath3 of a group @xmath1 is said to be commensurating , if for every @xmath4 some non - zero power of @xmath5 is conjugate to a non - zero power of @xmath6 .
given an acylindrically hyperbolic group @xmath1 , we show that any commensurating endomorphism of @xmath1 is inner modulo a small perturbation .
this generalizes a theorem of minasyan and osin , which provided a similar statement in the case when @xmath1 is relatively hyperbolic .
we then use this result to study pointwise inner and normal endomorphisms of acylindrically hyperbolic groups . .
And you have already written the first three sentences of the full article: a group @xmath1 is said to be _ residually finite _ if for any distinct @xmath7 there is a finite group @xmath8 and a homomorphism @xmath9 such that @xmath10 in @xmath8 . informally speaking this means that @xmath1 can be approximated by its finite quotients , in which case these quotients can be used to study the group @xmath1 .
for example , two classical theorems of malcev state that finitely presented residually finite groups have solvable word problem @xcite , and finitely generated residually finite groups are hopfian @xcite .
thus residual finiteness is a very basic property , so given any infinite group @xmath1 , one of the first questions we could ask about @xmath1 is whether it is residually finite ..
Please generate the next two sentences of the article | the goal of this work is to prove residual finiteness of the outer automorphism group @xmath11 , where @xmath1 belongs to one of the following large classes of groups : * the class of virtually compact special groups ( in the sense of f. haglund and d. wise @xcite ) , * the class of fundamental groups of compact @xmath2-manifolds . before formulating the main results ,
let us recall some background of the problem . |
6,933 | Suppose that you have an abstract for a scientific paper: dimensional regularization is used to derive the equations of motion of two point masses in harmonic coordinates . at the third post - newtonian ( 3pn ) approximation
, it is found that the dimensionally regularized equations of motion contain a pole part [ proportional to @xmath0 which diverges as the space dimension @xmath1 tends to @xmath2 .
it is proven that the pole part can be renormalized away by introducing suitable shifts of the two world - lines representing the point masses , and that the same shifts renormalize away the pole part of the `` bulk '' metric tensor @xmath3 .
the ensuing , finite renormalized equations of motion are then found to belong to the general parametric equations of motion derived by an extended hadamard regularization method , and to uniquely determine the 3pn ambiguity parameter @xmath4 to be : @xmath5 .
this value is fully consistent with the recent determination of the equivalent 3pn `` static ambiguity '' parameter , @xmath6 , by a dimensional - regularization derivation of the hamiltonian in arnowitt - deser - misner coordinates .
our work provides a new , powerful check of the consistency of the dimensional regularization method within the context of the classical gravitational interaction of point particles . .
And you have already written the first three sentences of the full article: the problem of motion , one of the cardinal problems of einstein s gravitation theory , has received continuous attention over the years .
the early , classic works of lorentz - droste , eddington - clark , einstein - infeld - hoffmann , fock , papapetrou and others led to a good understanding of the equations of motion of @xmath7 bodies at the first post - newtonian ( 1pn ) approximationpn order refers to the terms of order @xmath8 in the equations of motion . ]
e.g. _ , @xcite for a general review of the problem of motion ) . in the 1970 s , an important series of works by a japanese group @xcite led to a nearly complete control of the problem of motion at the second post - newtonian ( 2pn ) approximation ..
Please generate the next two sentences of the article | then , in the early 80 s , motivated by the observation of secular orbital effects in the hulse - taylor binary pulsar psr1913 + 16 , several groups solved the two - body problem at the 2.5pn level ( while completing on the way the derivation of the 2pn dynamics ) ( for more recent work on the 2.5pn dynamics see @xcite ) . in the late 90 s , motivated by the aim of deriving high - accuracy templates for the data analysis of the upcoming international network of interferometric gravitational - wave detectors
, two groups embarked on the derivation of the equations of motion at the third post - newtonian ( 3pn ) level . |
6,934 | Suppose that you have an abstract for a scientific paper: we use density - functional theoretical methods to examine the recent prediction , based on a mean - field solution of the zener model , that diamond doped by mn ( with spin @xmath0=5/2 ) would be a dilute magnetic semiconductor that remains ferromagnetic well above room temperature .
our findings suggest this to be unlikely , for four reasons : ( 1 ) substitutional mn in diamond has a low - spin @xmath0=1/2 ground state ; ( 2 ) the substitutional site is energetically unfavorable relative to the much larger `` divacancy '' site ; 3 ) mn in the divacancy site is an acceptor , but with only hyperdeep levels , and hence the holes are likely to remain localized ; ( 4 ) the calculated heisenberg couplings between mn in nearby divacancy sites are two orders of magnitude smaller than for substitutional mn in germanium . .
And you have already written the first three sentences of the full article: a large class of dilute magnetic semiconductors ( dms ) is based on manganese doping of iii - v or group - iv hosts having the zincblende , wurzite , or diamond structure .
formally , mn is either a single or double acceptor , depending on whether it substitutes for a group - iii or -iv atom , respectively.@xcite aside from this difference , there are no simple guidelines for predicting how the magnetic behavior of the resulting dms depends on the choice of host semiconductor . elucidating such guidelines would be of great practical interest for efforts to control and optimize the magnetic properties of dms materials . in particular
, it would be very helpful to understand how the resulting curie temperatures depend on the choice of host semiconductor ..
Please generate the next two sentences of the article | an important and early contribution was made by , who used a mean - field solution of the zener model to predict the curie temperatures for mn doping of a wide range of ii - vi , iii - v , and group - iv host semiconductors.@xcite mn ions with localized spin @xmath0=5/2 were assumed to substitute on the cation site , and to interact by an indirect exchange interaction mediated by holes .
curie temperatures were calculated for fixed mn content @xmath1 and hole concentration @xmath2 @xmath3 using the mean - field result @xmath4 in this equation , the most direct dependence of @xmath5 on the host semiconductor comes from the density per unit volume of cation sites @xmath6 , which varies with the host lattice constant as @xmath7 . a much weaker dependence on the host arises from the density - of - states effective mass @xmath8 and the fermi wavevector @xmath9 . |
6,935 | Suppose that you have an abstract for a scientific paper: though it is generally assumed that massive molecular clouds are the progenitors of globular clusters , their detailed formation mechanism is still unclear .
standard scenarios based on the collapse of a smooth matter distribution suffer from strong requirements with respect to cluster formation time scale , binding energy and star formation efficiency . an alternative model assuming cluster formation due to the recollapse of
a supernova - induced , fragmented shell can relax these difficulties . in this paper the final collapse stages of the different scenarios
are compared by n - body simulations for shells and spheres .
it is shown that fragmentation is much more pronounced for shells . taking a galactic tidal field into account shells preferably
form twin ( or multiple ) systems , whereas spheres end up as single clusters .
the twins are characterized by identical metallicities , and stellar mass functions ; some of them show counter - rotating cores .
their orbital evolution can result in both , a final merger or well separated twins sharing a common galactic orbit . .
And you have already written the first three sentences of the full article: most formation scenarios of globular clusters commence with giant molecular clouds ( gmcs ) undergoing a phase of rapid star formation .
this star formation can be triggered by several processes , e.g. a thermal instability ( fall & rees 1985 ; murray & lin 1990 ) , a radiative shock ( kang et al . 1990 ; shapiro 1993 ) or other perturbations like collisions of clouds ( fujimoto & kumai 1997 ; lee , schramm , & mathews 1995 ) or galaxy interactions ( ashman & zepf 1992 ) .
a common characteristic of all these scenarios is , that globulars are formed from smooth gaseous distributions ( if we neglect the clumpy structure of the gmcs for the moment ) which are transformed into stars ..
Please generate the next two sentences of the article | this assumption leads to several difficulties : first , the gravitational binding energy of a homogeneous gmc with @xmath0 and a radius of 30 pc is about @xmath1 ergs , whereas it decreases for a @xmath2 cloud of 10 pc to less than @xmath3 ergs .
thus , already a single supernova injects sufficient energy to destroy a small cloud completely , and a few ob stars can even disrupt a @xmath0 cloud . |
6,936 | Suppose that you have an abstract for a scientific paper: an analytical expression for the self coherence function of a microcavity and partially coherent source is derived from first principles in terms of the component self coherence functions .
excellent agreement between the model and experimental measurements of two resonant cavity leds ( rcleds ) is evident .
the variation of coherence length as a function of numerical aperture is also described by the model .
this is explained by a microcavity s angular sensitivity in filtering out statistical fluctuations of the underlying light source .
it is further demonstrated that the variable coherence properties of planar microcavities can be designed by controlling the underlying coherences of microcavity and emitter whereby coherence lengths ranging over nearly an order of magnitude could be achieved .
the last two decades have seen widespread use of optical microcavities , both for experimental physics and commercial applications .
microcavities redistribute emission from an underlying source and depending on the ensuing radiation pattern allow light collection for use elsewhere . commercially available microcavity devices such as
resonant cavity light emitting diodes ( rcleds ) use the planar microcavity geometry to increase the extraction efficiency of spontaneous emission from materials with high dielectric constants .
@xcite more recently microcavities have been used to spectrally and spatially isolate quantum dot emitters to increase the efficiency of single photon production .
@xcite recent work on planar microcavities has identified the dependence of numerical aperture ( na ) on emission properties such as spectral linewidth @xcite and coherence length,@xcite the latter of which is the focus of the following paper . note that , migration of these results to the spectral domain are trivial due to the implicit fourier relationship with the coherence domain .
in addition to the choice of domain , the name _ coherence _ has been used , instead of _
time_. coherence highlights the....
And you have already written the first three sentences of the full article: fig . [ fig1 ] .
comparison of experimental and model results for coherence length variation with observation angle for ( a ) a tuned rcled and ( b ) a detuned rcled . fig . [ fig2 ] .
coherence length variation as a function of numerical aperture generated using empirical model data in the coherence model for tuned and detuned rcleds ..
Please generate the next two sentences of the article | markers at na extrema denote experimental points determine by measurements at low na and from an integrating sphere .
predictions of maximum and minimum coherence as a function of microcavity finesse and detuning with respect to the emission source across the useful emission na ( see text ) . |
6,937 | Suppose that you have an abstract for a scientific paper: the habitable zone concept is important because it focuses the scientific search for extraterrestrial life and aids the planning of future telescopes .
recent work has shown that planets near the outer edge of the habitable zone might not actually be able to stay warm and habitable if co@xmath0 outgassing rates are not large enough to maintain high co@xmath0 partial pressures against removal by silicate weathering . in this paper
i use simple equations for the climate and co@xmath0 budget of a planet in the habitable zone that can capture the qualitative behavior of the system . with these equations
i derive an analytical formula for an effective outer edge of the habitable zone , including limitations imposed by the co@xmath0 outgassing rate .
i then show that climate cycles between a snowball state and a warm climate are only possible beyond this limit if the weathering rate in the snowball climate is smaller than the co@xmath0 outgassing rate ( otherwise stable snowball states result ) .
i derive an analytical solution for the climate cycles including a formula for their period in this limit .
this work allows us to explore the qualitative effects of weathering processes on the effective outer edge of the habitable zone , which is important because weathering parameterizations are uncertain . .
And you have already written the first three sentences of the full article: the habitable zone is defined as the region around a star where a planet with co@xmath0 and h@xmath0o as its main greenhouse gases can support liquid water at its surface @xcite .
the habitable zone is relatively wide because of the silicate - weathering feedback @xcite .
silicate - weathering is a geological process that removes co@xmath0 from the atmosphere and a negative ( stabilizing ) feedback is possible because this process is believed to run faster at higher temperatures and higher co@xmath0 partial pressures @xcite ..
Please generate the next two sentences of the article | the inner edge of the habitable zone is set by the moist or runaway greenhouse @xcite , which should not be influenced by the details of the silicate - weathering feedback since the co@xmath0 should have been drawn down to low levels when they occur .
on the other hand , calculations of the outer edge of the habitable zone generally assume that the silicate - weathering feedback can maintain co@xmath0 at arbitrarily high levels . the outer edge |
6,938 | Suppose that you have an abstract for a scientific paper: we use multiwavelength data from space and ground based instruments to study the solar flares and coronal mass ejections ( cmes ) on january 23 , 2012 that were responsible for one of the largest solar energetic particle ( sep ) events of solar cycle 24 .
the eruptions consisting of two fast cmes ( @xmath01400 km s@xmath1 and @xmath02000 km s@xmath1 ) and m - class flares that occurred in active region 11402 located at @xmath0n28 w36 .
the two cmes occurred in quick successions , so they interacted very close to the sun .
the second cme caught up with the first one at a distance of @xmath011 - 12 @xmath2 .
the cme interaction may be responsible for the elevated sep flux and significant changes in the intensity profile of the sep event .
the compound cme resulted in a double - dip moderate geomagnetic storm ( @xmath3 ) .
the two dips are due to the southward component of the interplanetary magnetic field in the shock sheath and the icme intervals .
one possible reason for the lack of a stronger geomagnetic storm may be that the icme delivered a glancing blow to earth .
sun , solar flares , coronal mass ejections , solar energetic particles , geomagnetic storm .
And you have already written the first three sentences of the full article: solar flares and coronal mass ejections ( cmes ) involve a sudden release of magnetic energy stored in complex active regions through magnetic reconnection @xcite .
the several mechanisms may compel the energy build - up in the flaring and eruptive regions that later released in form of bulk mass motion , heating , as well as acceleration of the energetic particles .
these processes may involve magnetic instabilities , flux and helicity emergence , building of the magnetic field complexity , etc ..
Please generate the next two sentences of the article | * ; * ? ? ?
* ; * ? ? ? |
6,939 | Suppose that you have an abstract for a scientific paper: we obtain second and higher order corrections to the shift of the bose - einstein critical temperature due to finite - size effects .
the confinement is that of a harmonic trap with general anisotropy .
numerical work shows the high accuracy of our expressions .
we draw attention to a subtlety involved in the consideration of experimental values of the critical temperature in connection with analytical expressions for the finite - size corrections .
bose - einstein condensation , bose gas , finite - size effects 03.75.hh , 05.30.jp .
And you have already written the first three sentences of the full article: in the first realizations of bose - einstein condensation ( bec ) in the laboratory @xcite and in many experiments ever since , the bose gas is trapped in a potential that can be considered as parabolic to a very good approximation . in the thermodynamic limit , within the ideal gas approximation , the critical temperature for such a system is given by @xmath0 , where @xmath1 is the geometric mean of the trap frequencies and all the other symbols have their usual meaning ( see e.g. @xcite ) .
soon after the first experiments , corrections to this expression , @xmath2 , were found . on the one hand , experiments do not take place in the thermodynamic limit .
hence , finite - size corrections are required . on the other hand ,.
Please generate the next two sentences of the article | the gases are not ideal , having a non - vanishing scattering length .
hence , interaction effects must be taken into account . |
6,940 | Suppose that you have an abstract for a scientific paper: in this paper , we investigate the one - dimensional derivative nonlinear schrdinger equations of the form @xmath0 with non - zero @xmath1 and any real number @xmath2 .
we establish the local well - posedness of the cauchy problem with any initial data in @xmath3 by using the gauge transformation and the littlewood - paley decomposition .
chengchun hao ( communicated by gigliola staffilani ) .
And you have already written the first three sentences of the full article: in the present paper , we consider the following cauchy problem for the derivative nonlinear schrdinger equation @xmath4 where @xmath5 is a complex - valued wave function , both @xmath6 and @xmath2 are real numbers . a great deal of interesting research has been devoted to the mathematical analysis for the derivative nonlinear schrdinger equations @xcite . in @xcite , c. e. kenig , g. ponce and l. vega studied the local existence theory for the cauchy problem of the derivative nonlinear schrdinger equations @xmath7 with small data @xmath8 in @xmath9 where @xmath10 is a polynomial having no constant or linear terms with the lowest order term of degree being greater than or equal to @xmath11 .
subsequently , it was improved to @xmath12 by n. hayashi and t. ozawa @xcite .
if the nonlinearity consists mostly of the conjugate wave @xmath13 , then it can be done much better . in the case.
Please generate the next two sentences of the article | @xmath14 , a. grenrock , in @xcite , obtained local well - posedness when @xmath15 , @xmath16 , and @xmath17 was an integer .
in particular , the global well - posedness in @xmath18 is obtained when @xmath19 with the help of the bourgain spaces ( cf . |
6,941 | Suppose that you have an abstract for a scientific paper: in a remarkable paper from 1852 , gotthilf heinrich ludwig hagen measured and explained two fundamental aspects of granular matter : the first effect is the saturation of pressure with depth in a static granular system confined by silo walls generally known as the _ janssen effect_. the second part of his paper describes the dynamics observed during the flow out of the container today often called the _ beverloo law _ and forms the foundation of the _ hourglass theory_. the following is a translation of the original german paper from 1852 . .
And you have already written the first three sentences of the full article: gotthilf heinrich ludwig hagen is most renowned for his contributions to the study on laminar flow in pipes ; his measurements published in 1839 studied what is now well - known as the ( hagen-)poiseuille law @xcite .
less well - known is hagen s work on granular systems . while janssen , with his 1895 paper , typically receives credit for the saturation effect in granular silos @xcite , it was hagen in his paper _ ber den druck und die bewegung des trocknen sandes _
@xcite who measured this effect earlier but also not for the first time , cf ..
Please generate the next two sentences of the article | @xcite and offered a first model that provided a qualitative understanding of the effect .
hagen proposes a quadratic law ( with some cutoff ) for the pressure instead of the exponential form put forward by janssen more than 40 years later @xcite . |
6,942 | Suppose that you have an abstract for a scientific paper: at sufficiently low temperatures , the configurational phase space of a large spin - glass system breaks into many separated domains , each of which is referred to as a macroscopic state .
the system is able to visit all spin configurations of the same macroscopic state , while it can not spontaneously jump between two different macroscopic states .
ergodicity of the whole configurational phase space of the system , however , can be recovered if a temperature - annealing process is repeated an infinite number of times . in a heating - annealing cycle , the environmental temperature is first elevated to a high level and then decreased extremely slowly until a final low temperature @xmath0 is reached .
different macroscopic states may be reached in different rounds of the annealing experiment ; while the probability of finding the system in macroscopic state @xmath1 decreases exponentially with the free energy @xmath2 of this state . for finite - connectivity spin glass systems , we use this free energy boltzmann distribution to formulate the cavity approach of mzard and parisi [ eur .
phys .
j. b * 20 * , 217 ( 2001 ) ] in a slightly different form . for the @xmath3 spin - glass model on a random regular graph of degree @xmath4
, the predictions of the present work agree with earlier simulational and theoretical results . .
And you have already written the first three sentences of the full article: spin - glasses are simple models for disordered systems .
they can be defined very easily in mathematical terms ; on the hand , the properties of such simple models usually are quite rich .
statistical physics of spin - glasses has been studied for more than thirty years since the concept of spin - glasses was first presented by edwards and anderson @xcite in 1975 , but there are still many unsolved and heavily debated issues . in the last decades.
Please generate the next two sentences of the article | there have been a lot of theoretical investigations concerning models defined on a finite - connectivity random graph .
these later models are more realistic than conventional spin - glass models ( e.g. , the sherrington - kirkpatrick model @xcite ) on a complete graph , in the sense that each spin interacts only with a finite number of other spins . as direct analytical studies of spin - glass models on three - dimensional ( regular ) lattices are still beyond reach , people hope that a deep understanding of ( mean - field ) models on finite - connectivity random graphs will shed much light on the properties of 3d systems . for a spin - glass system of very large size |
6,943 | Suppose that you have an abstract for a scientific paper: we discuss model building in tribrid inflation , which is a framework for realising inflation in the matter sector of supersymmetric particle physics models .
the inflaton is a d - flat combination of matter fields , and inflation ends by a phase transition in which some higgs field obtains a vacuum expectation value .
we first describe the general procedure for implementing tribrid inflation in realistic models of particle physics that can be applied to a wide variety of bsm particle physics models around the gut scale .
we then demonstrate how the procedure works for an explicit lepton flavour model based on an @xmath0 family symmetry .
the model is both predictive and phenomenologically viable , and illustrates how tribrid inflation connects cosmological and particle physics parameters . in particular
, it predicts a relation between the neutrino yukawa coupling and the running of the spectral index @xmath1 .
we also show how topological defects from the flavour symmetry breaking can be avoided automatically . + stefan antusch@xmath2 and david nolde@xmath3 @xmath3 _ department of physics , university of basel ,
_ _ klingelbergstr .
82 , ch-4056 basel , switzerland _
@xmath4 _ max - planck - institut fr physik ( werner - heisenberg - institut ) , _ _ fhringer ring 6 , d-80805 mnchen , germany _ .
And you have already written the first three sentences of the full article: the field of flavour physics is experiencing rapid experimental progress , e.g. increasingly precise measurements of the leptonic mixing angles and perspectives to measure currently unknown parameters , such as the leptonic dirac cp phase and the neutrino mass ordering .
this progress provides both a challenge for some of the existing models explaining the flavour structure of the standard model , and an opportunity to constrain and test such models with increasing precision .
for example , the measurement of @xmath5 by t2k @xcite , double chooz @xcite , reno @xcite , and in particular daya bay @xcite , has put tensions on popular models that predict tribimaximal mixing , and has encouraged the search for new models that are compatible with the experimental values @xcite ..
Please generate the next two sentences of the article | a sufficiently complete particle physics model should also provide a consistent cosmological evolution .
many processes in the early universe happen at high energy scales , which makes these processes very sensitive to particle physics beyond the standard model . |
6,944 | Suppose that you have an abstract for a scientific paper: we present a @xmath0 20 ks _ chandra _ acis - s observation of the strongly lensed ultra - luminous infrared galaxy fsc 10214 + 4724 .
although this observation achieves the equivalent sensitivity of an up - to @xmath0 4 ms _ chandra _ exposure ( when corrected for gravitational lensing ) , the rest - frame 1.626.3 kev emission from fsc 10214 + 4724 is weak ( @xmath1 2@xmath2 erg s@xmath3 for a lensing boost of @xmath4 ) ; a significant fraction of this x - ray emission appears to be due to vigorous star - formation activity . if fsc 10214 + 4724 hosts a quasar , as previously suggested , then it must be obscured by compton - thick material .
we compare fsc 10214 + 4724 to high - redshift galaxies and discuss the x - ray identification of compton - thick agns at high redshift .
[ firstpage ] x - rays : individual : fsc 10214 + 4724 galaxies : active gravitational lensing .
And you have already written the first three sentences of the full article: the @xmath5 galaxy fsc 10214 + 4724 was one of the most remarkable objects detected by the survey .
originally proposed to be the most luminous galaxy known ( rowan - robinson 1991 ) , multi - wavelength observations subsequently showed that it is lensed by an intervening @xmath6 galaxy , boosting its intrinsic emission by a factor of @xmath7 10100 ( depending on the location and extent of the unlensed emission with respect to the caustic ; e.g.,broadhurst & lehar 1995 ; downes 1995 ; trentham 1995 ; eisenhardt 1996 ; evans 1999 ) .
optical and near - ir spectroscopic / polarimetric observations have unambiguously shown that fsc 10214 + 4724 hosts an obscured active galactic nucleus ( agn ; e.g.,elston 1994 ; soifer 1995 ; goodrich 1996 ) ..
Please generate the next two sentences of the article | multi - wavelength analyses have suggested that the agn is powerful ( e.g. , goodrich 1996 ; granato 1996 ; green & rowan - robinson 1996 ) , although it is generally accepted that star - formation activity dominates the bolometric output ( e.g.,rowan - robinson 1993 ; rowan - robinson 2000 ) .
the lensing - corrected properties of fsc 10214 + 4724 are similar to those of galaxies ( e.g. , blain 2002 ; ivison 2002 ; smail 2002 ; chapman 2003 ; neri 2003 ) : it lies at @xmath8 , is optically faint with @xmath9 25 , has an 850@xmath10 m flux density of a few mjy and a 1.4 ghz flux density of @xmath0 25 @xmath10jy , is massive ( a molecular gas mass of @xmath11@xmath12 @xmath13 ) , and has a bolometric luminosity of @xmath14 l@xmath15 ( e.g. , rowan - robinson 1993 ; downes 1995 ; eisenhardt 1996 ) . |
6,945 | Suppose that you have an abstract for a scientific paper: in this work , we have theoretically analyzed and numerically evaluated the accuracy of high - order lattice boltzmann ( lb ) models for capturing non - equilibrium effects in rarefied gas flows . in the incompressible limit ,
the lb equation is proved to be equivalent to the linearized bhatnagar - gross - krook ( bgk ) equation .
therefore , when the same gauss - hermite quadrature is used , lb method closely assembles the discrete velocity method ( dvm ) . in addition
, the order of hermite expansion for the equilibrium distribution function is found not to be correlated with the approximation order in terms of the knudsen number to the bgk equation , which was previously suggested by @xcite .
furthermore , we have numerically evaluated the lb models for a standing - shear - wave problem , which is designed specifically for assessing model accuracy by excluding the influence of gas molecule / surface interactions at wall boundaries .
the numerical simulation results confirm that the high - order terms in the discrete equilibrium distribution function play a negligible role .
meanwhile , appropriate gauss - hermite quadrature has the most significant effect on whether lb models can describe the essential flow physics of rarefied gas accurately .
for the same order of the gauss - hermite quadrature , the exact abscissae will also modestly influence numerical accuracy .
using the same gauss - hermite quadrature , the numerical results of both lb and dvm methods are in excellent agreement for flows across a broad range of the knudsen numbers , which confirms that the lb simulation is similar to the dvm process .
therefore , lb method can offer flexible models suitable for simulating continuum flows at navier stokes level and rarefied gas flows at the linearized boltzmann equation level .
[ firstpage ] .
And you have already written the first three sentences of the full article: rarefied gas flows have recently attracted significant research interest due to the rapid development of micro / nano - fluidic technologies . gaseous transport in micro / nano devices is often found to be non - equilibrium , and non - equilibrium phenomena have not yet been well understood @xcite . the conventional theory to describe gas flows is the navier stokes equations , which assume that the fluid is in a quasi - equilibrium state .
however , for non - equilibrium flows , the navier stokes equations break down because that the molecular nature of the gas strongly affects the bulk flow behavior i.e. the gas can no longer be regarded as a fluid continuum . whether gas flows are in local equilibrium or not can be classified by the non - dimensional knudsen number , kn , defined as the ratio of mean free path and the device characteristic length scale .
the navier stokes equations with no - velocity - slip wall boundary condition are only appropriate when @xmath0 . however , gas flows in micro / nano - fluidic devices are often in the slip flow regime ( @xmath1 ) or the transition flow regime ( @xmath2 ) . in these regimes ,.
Please generate the next two sentences of the article | the gas flow can not properly be described as a continuous flow , nor as a free molecular flow . in practice , most devices operate with a range of knudsen numbers in different parts of the device ; this makes it even more difficult to develop a generalized flow model .
direct simulation monte carlo ( dsmc ) methods and direct numerical simulation of the boltzmann equation can provide accurate solutions for rarefied gas flows . however , these are computationally intractable for 3d flow systems , and impractical with the current computer technology , especially for the low speed gas flows usually encountered in micro / nano - systems . |
6,946 | Suppose that you have an abstract for a scientific paper: we propose an efficient method for monte carlo simulation of quantum lattice models .
unlike most other quantum monte carlo methods , a single run of the proposed method yields the free energy and the entropy with high precision for the whole range of temperature .
the method is based on several recent findings in monte carlo techniques , such as the loop algorithm and the transition matrix monte carlo method . in particular , we derive an exact relation between the dos and the expectation value of the transition probability for quantum systems , which turns out to be useful in reducing the statistical errors in various estimates . .
And you have already written the first three sentences of the full article: the monte carlo method for classical and quantum lattice models has been improved dramatically since the proposal of the metropolis method@xcite .
the introduction of the extended ensemble , being one of the ideas that enhanced the monte carlo method , is characterized by a random walker traveling in the energy space .
the most well - known methods among the ones based on the extended ensemble is the multicanonical method @xcite . in this method ,.
Please generate the next two sentences of the article | one can obtain the density of states ( dos ) from the histogram of visiting frequency at each value of the energy . since the random walk in the extended ensemble methods
is typically biased in a complicated way , the scaling property of the the traveled distance of the walker deviates from that of the free random walk , i.e. , @xmath0 . |
6,947 | Suppose that you have an abstract for a scientific paper: based on our recent work on tidal tails of star clusters @xcite we investigate star clusters of a few @xmath0 by means of velocity dispersion profiles and surface density profiles .
we use a comprehensive set of @xmath1-body computations of star clusters on various orbits within a realistic tidal field to study the evolution of these profiles with time , and ongoing cluster dissolution .
+ from the velocity dispersion profiles we find that the population of potential escapers , i.e. energetically unbound stars inside the jacobi radius , dominates clusters at radii above about 50% of the jacobi radius . beyond 70% of the jacobi radius
nearly all stars are energetically unbound .
the velocity dispersion therefore significantly deviates from the predictions of simple equilibrium models in this regime .
we furthermore argue that for this reason this part of a cluster can not be used to detect a dark matter halo or deviations from newtonian gravity . + by fitting templates to the about @xmath2 computed surface density profiles we estimate the accuracy which can be achieved in reconstructing the jacobi radius of a cluster in this way .
we find that the template of king ( 1962 ) works well for extended clusters on nearly circular orbits , but shows significant flaws in the case of eccentric cluster orbits .
this we fix by extending this template with 3 more free parameters . our template can reconstruct the tidal radius over all fitted ranges with an accuracy of about 10% , and is especially useful in the case of cluster data with a wide radial coverage and for clusters showing significant extra - tidal stellar populations .
no other template that we have tried can yield comparable results over this range of cluster conditions .
all templates fail to reconstruct tidal parameters of concentrated clusters , however .
+ moreover , we find that the bulk of a cluster adjusts to the mean tidal field which it experiences and not to the tidal field at perigalacticon as has often been assumed in other....
And you have already written the first three sentences of the full article: velocity dispersion profiles and surface density profiles are among the most basic tools for investigating the structure of star clusters .
however , such investigations indicate that the region around the tidal radius , at which the internal acceleration of a star cluster is similar to the tidal acceleration due to the galactic tidal field , is particularly poorly understood .
+ velocity dispersion profiles sometimes show peculiarities which have been discussed in the literature ..
Please generate the next two sentences of the article | @xcite , for example , observed a flattening in the outer parts of the velocity dispersion profile of the galactic globular cluster m15 which they interpreted as an effect of tidal heating by the general galactic tide or by tidal shocks .
@xcite also found a flattening of the velocity dispersion profile for @xmath3 cen and more recently for other galactic globular clusters like ngc6171 , ngc7099 and ngc288 @xcite . |
6,948 | Suppose that you have an abstract for a scientific paper: a consistent description of shear flow and the accompanied viscous heating as well the associated entropy balance is given in the framework of a deterministic dynamical system .
a laminar shear flow is modeled by a hamiltonian multibaker map which drives velocity and temperature fields . in an appropriate macroscopic limit one
recovers the navier - stokes and heat conduction equations along with the associated entropy balance .
this indicates that results of nonequilibrium thermodynamics can be described by means of an abstract , sufficiently chaotic and mixing dynamics .
a thermostating algorithm can also be incorporated into this framework . 2 .
And you have already written the first three sentences of the full article: shear flows provide one of the paradigms of transport processes @xcite .
the importance of chaos in the equations underlying macroscopic shearing has recently been addressed by various numerical studies @xcite , which to some extent were supported by kinetic theory @xcite and rigorous mathematical work @xcite .
in contrast , however , a simple , exactly solvable model based on a low - dimensional chaotic dynamics whose mixing property would be the cause of irreversibility has not yet been established . for material and heat transport such type of models.
Please generate the next two sentences of the article | have helped to understand the physical content of thermostating schemes used in numerical simulations @xcite ( cf .
however @xcite for open questions ) . in the present article |
6,949 | Suppose that you have an abstract for a scientific paper: we construct a sample of 3,516 radio - loud host galaxies of active galactic nuclei ( agn ) from the optical sloan digital sky survey ( sdss ) and faint images of the radio sky at twenty cm ( first ) .
these have 1.4ghz luminosities in the range @xmath0whz@xmath1 , span redshifts @xmath2 , are brighter than @xmath3mag and are constrained to ` early - type ' morphology in colour space ( @xmath4mag ) . optical emission line ratios ( at @xmath5 ) are used to remove type 1 agn and star - forming galaxies from the radio sample using bpt diagnostics . for comparison
, we select a sample of 35,160 radio - quiet galaxies with the same @xmath6-band magnitude - redshift distribution as the radio sample .
we also create comparison radio and control samples derived by adding the nrao vla sky survey ( nvss ) to quantify the effect of completeness on our results .
we investigate the effective radii of the surface brightness profiles in the sdss @xmath7 and @xmath8 bands in order to quantify any excess of blue colour in the inner region of radio galaxies .
we define a ratio @xmath9 and use maximum likelihood analysis to compare the average value of @xmath10 and its intrinsic dispersion between both samples .
@xmath10 is larger for the radio - loud agn sample as compared to its control counterpart , and we conclude that the two samples are not drawn from the same population at @xmath11 significance .
given that star formation proceeds over a longer time than radio activity , the difference suggests that a subset of galaxies has the predisposition to become radio loud .
we discuss host galaxy features that cause the presence of a radio - loud agn to increase the scale size of a galaxy in red relative to blue light , including excess central blue emission , point - like blue emission from the agn itself , and/or diffuse red emission .
we favour an explanation that arises from the stellar rather than the agn light .
[ firstpage ] .
And you have already written the first three sentences of the full article: considerable uncertainties remain as to what controls the apparent link between the activity of active galactic nuclei ( agn ) during the time that a black hole is fed and star formation .
the accretion disk surrounding a super - massive black hole ( smbh ) emits highly energetic radiation and particles , and can form powerful winds and/or collimated , relativistic jets ( e.g. , * ? ? ?
. the radiation and outflows might then affect the interstellar medium , triggering star formation which might be detectable as an excess of blue light from the central regions of galaxies ..
Please generate the next two sentences of the article | alternatively , the activity of the agn may be sparked by specific events in the galaxy s past .
for example , there is morphological evidence that activity in radio galaxies might be triggered by mergers and galaxy interactions ( e.g. , * ? ? ? * ) , which in turn could contribute to central blue light through enhanced star formation . in either case |
6,950 | Suppose that you have an abstract for a scientific paper: this paper provides two families of flexible and simple galaxy models .
many representatives of these families possess important cosmological cusps , with the density behaving like @xmath0 , @xmath1 , or @xmath2 at small radii .
the density falls off between @xmath3 and @xmath4 at large radii .
we provide analytic and anisotropic distribution functions for all the models . unlike many existing methods ,
our algorithm can yield tangentially anisotropic velocity dispersions in the outer parts , and so is useful for modeling populations of satellite galaxies and substructure in host galaxy halos . as an application , we demonstrate the degeneracy between mass and anisotropy for the satellite galaxy population of the milky way .
this can introduce a factor of @xmath53 uncertainty in the mass of the milky way as inferred from the kinematics of the satellite population . .
And you have already written the first three sentences of the full article: one of eddington s famous discoveries is that the isotropic distribution function ( df ) of a spherical stellar system can be calculated from the density using an abel transform pair @xcite : @xmath6 here , @xmath7 is the binding energy per unit mass , and @xmath8 is the relative potential . however , galaxy halos produced in cosmological simulations are held up by anisotropic velocity dispersions ( see e.g. , * ? ? ?
the recovery of an anisotropic df for a spherical system is a more difficult problem @xcite .
now , the steady state df can depend not only on @xmath9 but also on the magnitude of the specific angular momentum @xmath10 through jeans theorem . here.
Please generate the next two sentences of the article | @xmath11 is the two - dimensional velocity component projected on the tangential plane . at least in the comparison of observational data with models ( e.g. , * ? ? ?
* ; * ? ? ? |
6,951 | Suppose that you have an abstract for a scientific paper: we calculate contributions to @xmath0 mixing through tree - level sneutrino exchange in the framework of the minimal supersymmetric standard model with r - parity violation , including the next - to - leading - order qcd corrections .
we compare our results with the updated bounds on the @xmath0 mass difference reported by cdf collaborations , and present new constraints on the relevant combinations of parameters of the minimal supersymmetric standard model with r - parity violation .
our results show that upper bound on the relevant combination of couplings of @xmath0 mixing is of the order @xmath1 .
we also calculate the @xmath2 and @xmath3 mass differences , and show that the upper bounds on the relevant combinations of couplings are two and four orders of magnitude stronger than ones reported in the literatures , respectively .
we also discuss the case of complex couplings and show that how the relevant combinations of couplings are constrained by the updated experiment data of @xmath0 , @xmath4 mixing and time - dependent cp asymmetry @xmath5 , and future possible observations of @xmath6 at lhcb , respectively . .
And you have already written the first three sentences of the full article: very recently , the d collaboration and the cdf collaboration at the fermilab tevatron reported their updated measurements of the mass difference between @xmath7 and @xmath8 mesons ( @xmath9 ) .
the new bounds on the mass difference are @xcite : @xmath10 it was the first time that both the lower bound and the upper bound for the @xmath0 mixing are presented .
especially the cdf result has reached an accuracy of about 1% ..
Please generate the next two sentences of the article | the new results are important for the precision test of the standard model ( sm ) , especially for the determination of the unitary triangle . moreover ,
if the sm predictions are consistent with the above results , these data will put severe constraints on the flavor structure of the possible new physics models beyond the sm . in the literature , there have already been many discussions about the implications of the new measurements . in ref . |
6,952 | Suppose that you have an abstract for a scientific paper: some years ago aerts _ et al . _
@xcite presented a macroscopic model in which the amount of non - locality and indeterminism could be continuously varied , and used it to show that by increasing non - locality one increases , as expected , the degree of violation of bell s inequality ( bi ) , whereas , more surprisingly , by increasing indeterminism one decreases the degree of the violation of bi . in this note
we propose a different macroscopic model in which the amount of non - locality and indeterminism can also be parameterized , and therefore varied , and we find that , in accordance with the model of aerts _ et al .
_ , an increase of non - locality produces a stronger violation of bi .
however , differently from their model , we also find that , depending on the initial state in which the system is prepared , an increase of indeterminism can either strengthen or weaken the degree of violation of bi . .
And you have already written the first three sentences of the full article: in @xcite aerts constructed an remarkable macroscopic model in which he could operationally define coincidence experiments violating ( the chsh version of ) bell s inequality ( bi ) , with exactly the same numerical value @xmath0 as the one obtained in typical coincidence experiments with entangled microscopic entities in a singlet state @xcite ( which corresponds to the maximal violation obtainable in quantum mechanics @xcite ) .
subsequently , the model was generalized in @xcite , with the introduction of two parameters , @xmath1 $ ] , quantifying the degree of indeterminism and of non - locality present in the model , respectively .
more precisely , @xmath2 corresponds to the classical situation of absence of indeterminism , whereas @xmath3 to the situation of maximum indeterminism , typical of pure quantum systems . on the other hand.
Please generate the next two sentences of the article | , @xmath4 corresponds to the situation of maximum locality , when the two pairs forming the double - system are totally disconnected , whereas @xmath5 corresponds to the opposite situation of perfect correlation .
the authors of @xcite obtain that bi can only be violated if @xmath6 , and that the violation takes its maximal numerical value @xmath7 when @xmath5 ( maximum correlation ) and @xmath2 ( minimum indeterminism ) . also , they find that for any @xmath8 , it is always possible to restore the validity of bi by increasing @xmath9 , whereas this is not any more possible if @xmath10 . to sum up , the study of the model described in @xcite has showed that the source of the violation of bi is the existence of a non zero correlation between the two pairs forming the double - system ( @xmath6 ) , whereas the only effect of increasing the level of indeterminism ( increasing @xmath9 ) is to decrease the value the inequality can take . |
6,953 | Suppose that you have an abstract for a scientific paper: this paper presents an adaptive version of the hill estimator based on lespki s model selection method .
this simple data - driven index selection method is shown to satisfy an oracle inequality and is checked to achieve the lower bound recently derived by @xcite . in order to establish the oracle inequality , we derive non - asymptotic variance bounds and concentration inequalities for hill estimators . these concentration inequalities are derived from talagrand s concentration inequality for smooth functions of independent exponentially distributed random variables combined with three tools of extreme value theory : the quantile transform , karamata s representation of slowly varying functions , and rnyi s characterisation for the order statistics of exponential samples .
the performance of this computationally and conceptually simple method is illustrated using monte - carlo simulations . .
And you have already written the first three sentences of the full article: the basic questions faced by extreme value analysis consist in estimating the probability of exceeding a threshold that is larger than the sample maximum and estimating a quantile of an order that is larger than 1 minus the reciprocal of the sample size . in words , they consist in making inferences on regions that lie outside the support of the empirical distribution . in order to face these challenges in a sensible framework , extreme value theory ( ) assumes that the sampling distribution @xmath0 satisfies a regularity condition .
indeed , in heavy - tail analysis , the tail function @xmath1 is supposed to be regularly varying that is , @xmath2 exists for all @xmath3 .
this amounts to assume the existence of some @xmath4 such that the limit is @xmath5 for all @xmath6 ..
Please generate the next two sentences of the article | in other words , if we define the _ excess distribution above the threshold @xmath7 _ by its survival function : @xmath8 for @xmath9 , then @xmath10 is regularly varying if and only if @xmath11 converges weakly towards a pareto distribution .
the sampling distribution @xmath0 is then said to belong to the _ max - domain of attraction _ of a frchet distribution with index @xmath12 ( abbreviated in @xmath13 ) and @xmath14 is called the _ extreme value index_. the main impediment to large exceedance and large quantile estimation problems alluded above turns out to be the estimation of the extreme value index . since the inception of extreme value analysis , many estimators have been defined , analysed and implemented into software . |
6,954 | Suppose that you have an abstract for a scientific paper: in the approximate integration some inequalities between the quadratures and the integrals approximated by them are called _
extremalities_. on the other hand , the set of all quadratures is convex .
we are trying to find possible connections between extremalities and extremal quadratures ( in the sense of extreme points of a convex set ) .
of course , the quadratures are the integrals discrete measures and , moreover , a quadrature is extremal if and only if the associated measure is extremal .
hence the natural problem arises to give some description of extremal measures with prescribed moments in the general ( not only discrete ) case . in this paper
we deal with symmetric measures with prescribed first four moments . the full description ( with no symmetry assumptions , and/or not only four moments are prescribed and so on ) is far to be done . .
And you have already written the first three sentences of the full article: the second - named author considered in @xcite so - called _ extremalities _ in the approximate integration .
let @xmath0 be the @xmath1-th degree legendre polynomial given by the rodrigues formula @xmath2 then @xmath0 has @xmath1 distinct roots @xmath3 .
the @xmath1-point gauss .
Please generate the next two sentences of the article | legendre quadrature is the positive linear functional on @xmath4}$ ] given by @xmath5=\sum_{i=1}^nw_if(x_i)\ ] ] with the weights @xmath6 the @xmath7-point lobatto quadrature is the functional @xmath8=v_1f(-1)+v_{n+1}f(1)+\sum_{i=2}^n v_if(y_i)\,,\ ] ] where @xmath9 are ( distinct ) roots of @xmath10 and @xmath11 for these forms of quadratures as well as for another quadratures appearing in this paper see for instance @xcite .
recall that a continuous function @xmath12\to\r$ ] is @xmath1-_convex _ ( @xmath13 ) , if and only if @xmath14 is of the class @xmath15 and the derivative @xmath16 is convex ( ( * ? ? ? |
6,955 | Suppose that you have an abstract for a scientific paper: we present a new approach to financial returns based on an infinite family of statistics called _ slide statistics _ that we introduce .
the evidence these statistics provide suggests that certain distributions such as the stable distributions are not good models for the financial returns from various securities or indexes like the s@xmath0p @xmath1 and the dow jones .
formally , we associate with any finite subset of a metric space an infinite sequence of scale invariant numbers @xmath2 derived from a variant of differential entropy called the genial entropy .
we give explicit formulas for @xmath3 and @xmath4 that are easily evaluated by a computer and make this theory particularly suitable for applications . as statistics for point processes , these numbers often appear to converge in simulations and we give examples where @xmath5 converges to the hausdorff dimension and we prove that @xmath6 . for a uniform random variable @xmath7 on @xmath8^n$ ] , the evidence from simulations suggests that @xmath9 and @xmath10 which yields new tests for spatial randomness .
the slide statistics describe continuous random variables in an entirely new way . for example , if @xmath11 is any normal variable then simulations suggest that @xmath12 and @xmath13 which provides new goodness of fit tests for normality . .
And you have already written the first three sentences of the full article: we develop new entropy based statistics @xmath2 called _ slide statistics _ which can be computed from any sample data in a metric space . as an application
, we use these statistics to test whether financial returns are independent observations from a particular distribution .
for example , figure [ fig : fig1 ] shows plots of @xmath3 against @xmath14 for data @xmath15 consisting of n - tuples of consecutive returns regarded as a subset of the metric space @xmath16 with the usual metric ..
Please generate the next two sentences of the article | as can be seen , the lower curve corresponding to the s@xmath0p @xmath1 is very different from the ones obtained for either the normal or laplace distributions . any potential model for
the returns of the s@xmath0p @xmath1 must be able simulate the @xmath3 curve in figure [ fig : fig1 ] which is a new requirement that is apparently difficult to meet . |
6,956 | Suppose that you have an abstract for a scientific paper: collapsars are fast - spinning , massive stars , whose core collapse liberates an energy , that can be channeled in the form of ultrarelativistic jets .
these jets transport the energy from the collapsed core to large distances , where it is dissipated in the form of long - duration gamma - ray bursts . in this paper
we study the dynamics of ultrarelativistic jets produced in collapsars .
also we extrapolate our results to infer the angular energy distribution of the produced outflows in the afterglow phase .
our main focus is to look for global energetical properties which can be imprinted by the different structure of different progenitor stars .
thus , we employ a number of pre - supernova , stellar models ( with distinct masses and metallicities ) , and inject in all of them jets with fixed initial conditions .
we assume that at the injection nozzle , the jet is mildly relativistic ( lorentz factor @xmath0 ) , has a finite half - opening angle ( @xmath1 ) , and carries a power of @xmath2ergs@xmath3 . in all cases ,
well collimated jets propagate through the progenitor , blowing a high pressure and high temperature cocoon .
these jets arrive intact to the stellar surface and break out of it .
a large lorentz factor region @xmath4 develops well before the jet reaches the surface of the star , in the unshocked part of the beam , located between the injection nozzle and the first recollimation shock .
these high values of @xmath5 are possible because the finite opening angle of the jet allows for free expansion towards the radial direction .
we find a strong correlation between the angular energy distribution of the jet , after its eruption from the progenitor surface , and the mass of the progenitors .
the angular energy distribution of the jets from light progenitor models is steeper than that of the jets injected in more massive progenitor stars .
this trend is also imprinted in the angular distribution of isotropic equivalent energy . .
And you have already written the first three sentences of the full article: recent observations of gamma - ray bursts ( grbs ) suggest that long duration grbs and type ib / c supernova ( sn ) explosions are tightly connected .
for example , sn1998bw was observed in the positional error box of grb980425 @xcite . in this case
the grb / sn association was based on the spatial and temporal coincidence of both events ..
Please generate the next two sentences of the article | the most remarkable example of long grb / sn link came in 2003 , when the spectra of both the grb030329 afterglow and of the sn2003dh were measured , since the burst happened closeby and it was quite bright .
the supernova spectrum , which includes many complex lines , gradually appeared from the decaying afterglow spectrum after a few tens of days from the burst . |
6,957 | Suppose that you have an abstract for a scientific paper: adopting the framework of the halo occupation distribution ( hod ) , we investigate the ability of galaxy clustering measurements to simultaneously constrain cosmological parameters and galaxy bias . starting with a fiducial cosmological model and galaxy hod , we calculate spatial clustering observables on a range of length and mass scales , dynamical clustering observables that depend on galaxy peculiar velocities , and the galaxy - matter cross - correlation measurable by weak lensing .
we then change one or more cosmological parameters and use @xmath0-minimization to find the galaxy hod that best reproduces the original clustering .
our parameterization of the hod incorporates a flexible relation between galaxy occupation numbers and halo mass and allows spatial and velocity bias of galaxies within dark matter halos . despite this flexibility , we find that changes to the hod can not mask substantial changes to the matter density @xmath1 , the matter clustering amplitude @xmath2 , or the shape parameter @xmath3 of the linear matter power spectrum cosmology and bias are not degenerate . with the conservative assumption of 10% fractional errors , the set of observables considered here can provide @xmath4 ( @xmath5 ) constraints on @xmath2 , @xmath1 , and @xmath3 , using galaxy clustering data _ alone_. the combination @xmath6 is constrained to @xmath7 . in combination with traditional methods that focus on large - scale structure in the `` perturbative '' regime , hod modeling can greatly amplify the cosmological power of galaxy redshift surveys by taking advantage of high - precision clustering measurements at small and intermediate scales ( from sub - mpc to @xmath8 ) . at the same time
, the inferred constraints on the galaxy hod provide valuable tests of galaxy formation theory . .
And you have already written the first three sentences of the full article: from the 1970s through the early 1990s , studies of galaxy clustering drove much of the progress in cosmology .
measurements of steadily improving dynamic range and precision demonstrated good agreement with the predictions of a cosmological model incorporating scale - invariant , gaussian primeval fluctuations modulated by the transfer function expected in a universe dominated by cold dark matter ( cdm ) with @xmath9 ( where @xmath1 is the matter density parameter and @xmath10 ) .
the advent of multi - fiber galaxy redshift surveys and improved photometric input catalogs has dramatically improved the precision of clustering measurements over the last decade , beginning with the las campanas redshift survey ( lcrs ; @xcite ) and continuing with the two - degree field galaxy redshift survey ( 2dfgrs ; @xcite ) and the sloan digital sky survey ( sdss ; @xcite ) . in parallel , numerical simulations and.
Please generate the next two sentences of the article | numerically tested analytic approximations have turned the task of calculating non - linear dark matter clustering from specified initial conditions into an essentially solved problem .
the principal obstacle to drawing cosmological inferences from galaxy clustering measurements is now the uncertainty in the relation between the distribution of observable galaxies and the underlying distribution of dark matter , the problem known as galaxy bias . |
6,958 | Suppose that you have an abstract for a scientific paper: an experiment that measured the parity - violating asymmetries in deep inelastic scattering was completed at the thomas jefferson national accelerator facility in experimental hall a. from these asymmetries , a combination of the quark weak axial charge could be extracted with a factor of five improvement in precision over world data . to achieve this , asymmetries at the @xmath0 level needed to be measured at event rates up to 600 khz and the high pion background typical to deep inelastic scattering experiments needed to be rejected efficiently . a specialized data acquisition ( daq ) system with intrinsic particle identification ( pid )
was successfully developed and used : the pion contamination in the electron samples was controlled at the order of @xmath1 or below with an electron efficiency of higher than 91% during most of the production period of the experiment , the systematic uncertainty in the measured asymmetry due to daq deadtime was below 0.5% , and the statistical quality of the asymmetry measurement agreed with the gaussian distribution to over five orders of magnitudes .
the daq system is presented here with an emphasis on its design scheme , the achieved pid performance , deadtime effect and the capability of measuring small asymmetries . , , , , , , , , jefferson lab ; hall a ; pvdis ; daq .
And you have already written the first three sentences of the full article: the parity - violating deep inelastic scattering ( pvdis ) experiment e08 - 011 was completed in december 2009 at the thomas jefferson national accelerator facility ( jlab ) .
the goal of this experiment @xcite was to measure with high precision the parity - violating asymmetry in deep inelastic scattering of a polarized 6 gev electron beam on an unpolarized liquid deuterium target .
this asymmetry is sensitive to the quark weak axial charge @xmath2 which corresponds to a helicity dependence in the quark coupling with the @xmath3 boson . for electron inclusive scattering from an unpolarized target ,.
Please generate the next two sentences of the article | the electromagnetic interaction is parity conserving and is insensitive to the spin flip of the incoming electron beam .
only the weak interaction violates parity and causes a difference between the right- and the left - handed electron scattering cross - sections @xmath4 and @xmath5 . |
6,959 | Suppose that you have an abstract for a scientific paper: tropical algebraic geometry is the geometry of the tropical semiring @xmath0 .
the theory of total positivity is a natural generalization of the study of matrices with all minors positive . in this paper
we introduce the totally positive part of the tropicalization of an arbitrary affine variety , an object which has the structure of a polyhedral fan .
we then investigate the case of the grassmannian , denoting the resulting fan @xmath1 .
we show that @xmath2 is the stanley - pitman fan , which is combinatorially the fan dual to the ( type @xmath3 ) associahedron , and that @xmath4 and @xmath5 are closely related to the fans dual to the types @xmath6 and @xmath7 associahedra .
these results are strikingly reminiscent of the results of fomin and zelevinsky , and scott , who showed that the grassmannian has a natural cluster algebra structure which is of types @xmath3 , @xmath6 , and @xmath7 for @xmath8 , @xmath9 , and @xmath10 .
we suggest a general conjecture about the positive part of the tropicalization of a cluster algebra . .
And you have already written the first three sentences of the full article: tropical algebraic geometry is the geometry of the tropical semiring @xmath0 .
its objects are polyhedral cell complexes which behave like complex algebraic varieties .
although this is a very new field in which many basic questions have not yet been addressed ( see @xcite for a nice introduction ) , tropical geometry has already been shown to have remarkable applications to enumerative geometry ( see @xcite ) , as well as connections to representation theory ( see @xcite , @xcite , @xcite ) . the classical theory of total positivity concerns matrices in which all minors are positive ..
Please generate the next two sentences of the article | however , in the past decade this theory has been extended by lusztig ( see @xcite and @xcite ) , who introduced the totally positive variety @xmath11 in an arbitrary reductive group @xmath12 and the totally positive part @xmath13 of a real flag variety @xmath14 . in the process , lusztig discovered surprising connections between his theory of canonical bases for quantum groups and the theory of total positivity . in this paper
we introduce the totally positive part ( or positive part , for short ) of the tropicalization of an arbitrary affine variety over the ring of puiseux series , and then investigate what we get in the case of the grassmannian @xmath15 . |
6,960 | Suppose that you have an abstract for a scientific paper: the optical properties of single crystals of the high - temperature superconductor la@xmath0ba@xmath1cuo@xmath2 have been measured over a wide frequency and temperature range for light polarized in the _ a - b _ planes and along the _ c _ axis .
three different ba concentrations have been examined , @xmath3 with a critical temperature @xmath4 k , @xmath5 where the superconductivity is dramatically weakened with @xmath6 k , and @xmath7 with @xmath8 k. the in - plane behavior of the optical conductivity for these materials at high temperature is described by a drude - like response with a scattering rate that decreases with temperature . below @xmath9 in the @xmath3 and 0.145 materials
there is a clear signature of the formation of a superconducting state in the optical properties allowing the superfluid density ( @xmath10 ) and the penetration depth to be determined . in the anomalous 1/8 phase , some spectral weight shifts from lower to higher frequency ( @xmath11 @xmath12 ) on cooling below the spin - ordering temperature @xmath13 k , associated with the onset of spin - stripe order ; we discuss alternative interpretations in terms of a conventional density - wave gap versus the response to pair - density - wave superconductivity .
the two dopings for which a superconducting response is observed both fall on the universal scaling line @xmath14 , which is consistent with the observation of strong dissipation within the _ a - b _ planes .
the optical properties for light polarized along the _ c _ axis reveal an insulating character dominated by lattice vibrations , superimposed on a weak electronic background .
no josephson plasma edge is observed in the low - frequency reflectance along the _ c _ axis for @xmath15 ; however , sharp plasma edges are observed for @xmath3 and 0.145 below @xmath9 . .
And you have already written the first three sentences of the full article: the discovery of superconductivity at elevated temperatures in the copper - oxide materials a quarter of a century ago sparked an intense effort to understand the mechanism of the superconductivity in these compounds . despite the wealth of information from the accumulation of hundreds of thousands of scientific papers , there is still no consensus on the pairing mechanism .
while superconductivity was originally observed in the single - layer la@xmath0ba@xmath1cuo@xmath2 system,@xcite single crystals of this material proved difficult to grow and attention quickly shifted to the related la@xmath0sr@xmath1cuo@xmath2 materials where large single crystals were available .
further investigations into systems with more than two copper - oxygen layers in the unit cell led to rapid increases in the critical temperature ( @xmath9 ) , with the current maximum @xmath16 k observed at ambient pressure in the hgba@xmath17ca@xmath17cu@xmath18o@xmath19 system.@xcite the physical properties of this class of correlated electron materials and the nature of the superconductivity have been described in numerous review articles.@xcite while most high - temperature superconductors display a doping - dependent dome - shaped superconducting phase boundary,@xcite an anomalous weakening of the superconductivity is observed at a doping of @xmath20 per copper atom in the related la@xmath0sr@xmath1cuo@xmath2 system,@xcite and more recently in the bi@xmath17sr@xmath17cacu@xmath17o@xmath19 and yba@xmath17cu@xmath18o@xmath21 materials.@xcite this so - called `` @xmath22 anomaly '' increases dramatically in la@xmath0ba@xmath1cuo@xmath2 for @xmath15 and results in the almost total destruction of the bulk three - dimensional ( 3d ) superconductivity.@xcite there is also a structural transition over much of the phase diagram from a low - temperature orthorhombic ( lto ) to a low - temperature tetragonal ( ltt ) symmetry@xcite that is not observed in pure la@xmath0sr@xmath1cuo@xmath2 crystals ; the lto@xmath23ltt transition is also accompanied....
Please generate the next two sentences of the article | the 1/8 phase exhibits a pseudogap@xcite in the lto phase,@xcite similar to what is observed in the underdoped cuprates.@xcite the remaining fermi arc ( or pocket ) in the nodal region becomes gapped in the ltt phase close to the spin - ordering temperature .
the gap in the nodal region is momentum - dependent with a _ |
6,961 | Suppose that you have an abstract for a scientific paper: we study the influence of a strong agn outburst on the surrounding galaxies .
the agn is assumed to reside in a group of galaxies , and an outburst excites a shock wave in the hot gas in the group .
we calculate the impact of the shock wave on the galaxies .
we find that if the energy of the outburst is extremely large ( @xmath0 erg ) as the one recently observed in clusters , the impact is strong enough to strip the cold interstellar medium in the disc of the galaxies in the inner region of the group .
moreover , even in the outer region of the group , the warm gas in the halo of the galaxies would be stripped , even if the energy of the outburst is @xmath1 erg .
these would decrease star formation activity of the galaxies .
if these galaxies fall into the group centre through dynamical friction and their interstellar medium is the fuel of the supermassive black hole in the agn , the outburst would serve as feedback . while this mechanism works only when @xmath2 is extremely large , such outbursts
have not been observed in groups at low redshift ; it would work at high redshift rather than at low redshift .
[ firstpage ] galaxies : active galaxies : clusters : general galaxies : interactions galaxies : intergalactic medium . .
And you have already written the first three sentences of the full article: x - ray observations have shown that hot gas in groups and clusters of galaxies has been heated by some sources in addition to gravity .
this was shown by the fact that the luminosity and temperature of a group or cluster follow a scaling relationship ( the @xmath3@xmath4 relation ) , @xmath5 , @xcite , which is at odds with that expected for groups and clusters formed by gravitational structure formation , with @xmath6 @xcite .
more recently , it was shown that the entropies of the hot gas in groups and clusters , especially groups , are higher than those predicted by models of gravitational structure formation @xcite ..
Please generate the next two sentences of the article | supernova - driven galactic winds have been considered the heating source @xcite .
however , the energy from supernovae alone seems to be insufficient to heat the hot gas to the observed level @xcite . |
6,962 | Suppose that you have an abstract for a scientific paper: we present a first - principles - based coronal mass ejection ( cme ) model suitable for both scientific and operational purposes by combining a global magnetohydrodynamics ( mhd ) solar wind model with a flux rope - driven cme model .
realistic cme events are simulated self - consistently with high fidelity and forecasting capability by constraining initial flux rope parameters with observational data from gong , soho / lasco , and stereo / cor .
we automate this process so that minimum manual intervention is required in specifying the cme initial state . with the newly developed data - driven eruptive event generator gibson - low ( eeggl ) , we present a method to derive gibson - low ( gl ) flux rope parameters through a handful of observational quantities so that the modeled cmes can propagate with the desired cme speeds near the sun . a test result with cmes launched with different carrington rotation magnetograms are shown .
our study shows a promising result for using the first - principles - based mhd global model as a forecasting tool , which is capable of predicting the cme direction of propagation , arrival time , and icme magnetic field at 1 au ( see companion paper by @xcite ) . .
And you have already written the first three sentences of the full article: coronal mass ejections ( cmes ) are a major source of potentially destructive space weather conditions ( e.g. , geomagnetic storms , solar energetic particles ) . due to our increasing dependence on advanced technology , which is vulnerable to severe space weather conditions
, there is a high national priority to establish a reliable space weather forecasting capability .
however , available cme observations that may provide a basis for forecasts are very limited . in particular , erupting magnetic fields can not be directly observed in the solar corona , which is of critical importance given that interplanetary magnetic field ( imf ) is a major driver of the geomagnetic storms . for these reasons , there is a great need to be able to predict cme magnetic fields based on photospheric observations , both for scientific understanding and for forecasting purposes . in the past two decades.
Please generate the next two sentences of the article | , many cme forecasting models have been developed , which can be divided mainly into three different categories .
the first category is empirical forecasting models , which use near - sun cme observations to estimate the arrival time of cmes at 1 au through empirical relations built through a large number of observations ( e.g. , @xcite ) . |
6,963 | Suppose that you have an abstract for a scientific paper: we report extensive photometry of the dwarf nova v419 lyr throughout its 2006 july superoutburst till quiescence . the superoutburst with amplitude of @xmath0 magnitude lasted at least 15 days and was characterized by the presence of clear superhumps with a mean period of @xmath1 days ( @xmath2 min ) . according to the stolz - schoembs relation
, this indicates that the orbital period of the binary should be around 0.086 days i.e. within the period gap . during the superoutburst the superhump period was decreasing with
the rate of @xmath3 , which is one of the highest values ever observed in su uma systems . at the end of the plateau phase ,
the superhump period stabilized at a value of 0.08983(8 ) days .
the superhump amplitude decreased from 0.3 mag at the beginning of the superoutburst to 0.1 mag at its end . in the case of v419 lyr
we have not observed clear secondary humps , which seems to be typical for long period systems .
* key words : * stars : individual : v419 lyr binaries : close novae , cataclysmic variables .
And you have already written the first three sentences of the full article: dwarf novae a subclass of cataclysmic variable stars
are quite well studied interacting binary systems composed of late - type red dwarf secondary and white dwarf primary stars ( warner 1995 , hellier 2001 ) .
matter transferred from the red dwarf forms an accretion disc around the white dwarf ..
Please generate the next two sentences of the article | although in the last decade significant progress has been made in explaining the behaviour of dwarf novae light curves , some physical processes ongoing in these systems are still not fully understood ( see for example smak 2000 , schreiber and lasota 2007 ) . in particular , the thermal - tidal instability model of osaki ( 1996 , 2005 ) describing the phenomenon of superoutbursts and superhumps may be tested by examination of su uma - type dwarf novae light curves .
additionally , objects near and inside the so called period gap are very important from an evolutionary point of view . |
6,964 | Suppose that you have an abstract for a scientific paper: we report new spectroscopic observations performed in 2010 and 2011 for luminous radio - quite quasar pg1416 - 129 .
our new spectra with high quality cover both h@xmath0 and h@xmath1 regions , and show negligible line profile variation within a timescale of one year .
the two spectra allow us to study the variability of the balmer line profile by comparing the spectra with the previous ones taken at 10 and 20 years ago . by decomposing the broad balmer emission lines into two gaussian profiles , our spectral analysis suggests a strong response to the continuum level for the very broad component , and significant variations in both bulk blueshift velocity / fwhm and flux for the broad component .
the new observations additionally indicate flat balmer decrements ( i.e. , too strong h@xmath0 emission ) at the line wings , which is hard to be reproduced by recent optically thin models . with these observations
we argue that a separate inner optically thin emission - line region might not be necessary in the object to reproduce the observed line profiles . .
And you have already written the first three sentences of the full article: because of the limited spatial resolutions of the currently available instruments , the geometry and kinematics of broad - line region ( blr ) in active galactic nucleus ( agn ) is still an important and unresolved problem .
this poor understanding results in an uncertainty for the virial coefficient @xmath2 that depends not only on the kinematics , structure and orientation of the blr , but also on the virial width estimator used .
@xmath2 is equal to 3 for a spherical isotropic velocity distribution , while @xmath2 can be several times larger if the blr can be described as a circular rotation disk ..
Please generate the next two sentences of the article | the poor determination of @xmath2 finally causes an uncertainty in the estimation of the mass of central supermassive black hole ( smbh ) of an agn in the virial assumption ( e.g. , onken et al .
2004 ; kaspi et al . 2005 ; marconi et al . 2008 |
6,965 | Suppose that you have an abstract for a scientific paper: we have observed the central 45@xmath0 region of the galaxy at 620 mhz band of the giant metrewave radio telescope ( gmrt ) in radio continuum , and measured the polarisation properties of 64 small diameter background extragalactic sources seen through the @xmath16@xmath2@xmath36@xmath2 , @xmath12@xmath2@xmath42@xmath2 region with the australia telescope compact array ( atca ) and the very large array ( vla ) .
our 620 mhz observations show that sgr a * is located behind the hii region sgr a west . using the atca and the vla observations
, we measured the faraday rotation measure ( rm ) of the polarised sources .
the measured rms are mostly positive , and show no reversal of sign across the rotation axis of the galaxy .
this rules out any circularly symmetric model of magnetic field in the region .
we estimate the magnetic field strength in the region to be @xmath5 g , which raises doubts against an all pervasive mg field in the central few hundred pc of the galaxy . galaxy : centre galaxy : nucleus ism : magnetic fields hii regions .
And you have already written the first three sentences of the full article: being located two orders of magnitude closer than the nearest large galaxy , the galactic centre ( gc ) can be studied with much higher spatial resolution and sensitivity than is possible for other galaxies .
because of this advantage , we can identify unique objects like the radio - arc consisting of linear parallel filaments ( yusef - zadeh et al .
1984 ) , or the 2.6@xmath6 m@xmath7 black hole most probably associated with the compact radio source sgr a * ( ghez et al . 1998 ) ..
Please generate the next two sentences of the article | these studies have also established a concentration of gas , mostly in the form of molecular clouds characterised by densities @xmath810@xmath9 molecules @xmath10 , velocity dispersions @xmath810 km s@xmath11 , temperatures @xmath870 k and apparent magnetic fields @xmath81 mg in the region .
most of these quantities are one to two orders of magnitude larger than those found in the disk of our galaxy . |
6,966 | Suppose that you have an abstract for a scientific paper: the @xmath0 semileptonic decay is analyzed in the framework of heavy quark effective theory to the order of @xmath1 and @xmath2 .
the qcd sum rule and large @xmath3 predictions to the decay form factors are applied .
it argues that the subleading baryonic isgur - wise function in the large @xmath3 limit vanishes .
the decay rates , distributions and asymmetry parameters are calculated numerically .
some of the nonleptonic decay modes are discussed in the end . .
And you have already written the first three sentences of the full article: the weak decays of heavy baryons provide testing ground for the standard model .
they reveal some important features of the physics of heavy quarks . from the study of the heavy quark physics , some important parameters of the standard model , for instance
, the cabbibo - kobayashi - maskawa ( ckm ) matrix element @xmath4 can be extracted by comparing experiments with theoretical calculations from the decay mode @xmath5 ..
Please generate the next two sentences of the article | the main difficulties in the standard model calculations , however , are due to the poor understanding of the nonperturbative aspects of the strong interactions ( qcd ) . for the heavy hadrons containing a single heavy quark , an effective theory of qcd based on the heavy quark symmetry in the heavy quark limit @xcite , the so - called heavy quark effective theory ( hqet ) , has been proposed @xcite .
the classification of the weak decay form factors of heavy baryons has been simplified greatly in hqet @xcite . at the leading order of heavy quark expansion , only one universal form factor , the isgur - wise function , |
6,967 | Suppose that you have an abstract for a scientific paper: supermassive black hole binaries ( smbhbs ) are expected by the hierarchical galaxy formation model in @xmath0cdm cosmology .
there is some evidence in the literature for smbhbs in agns , but there are few observational constraints on the evolution of smbhbs in inactive galaxies and gas - poor mergers . on the theoretical front , it is unclear how long is needed for a smbhb in a typical galaxy to coalesce . in this paper
we investigate the tidal interaction between stars and binary bhs and calculate the tidal disruption rates of stellar objects by the bh components of binary .
we derive the interaction cross sections between smbhbs and stars from intensive numerical scattering experiments with particle number @xmath1 and calculate the tidal disruption rates by both single and binary bhs for a sample of realistic galaxy models , taking into account the general relativistic effect and the loss cone refilling because of two - body interaction .
we estimate the frequency of tidal flares for different types of galaxies using the bh mass function in the literature . we find that because of the three - body slingshot effect , the tidal disruption rate in smbhb system is more than one order of magnitude smaller than that in single smbh system .
the difference is more significant in less massive galaxies and does not depend on detailed stellar dynamical processes .
our calculations suggest that comparisons of the calculated tidal disruption rates for both single and binary bhs and the surveys of x - ray or uv flares at galactic centers could tell us whether most smbhs in nearby galaxies are single and whether the smbhbs formed in gas - poor galaxy mergers coalesce rapidly . .
And you have already written the first three sentences of the full article: in cold dark matter ( cdm ) cosmology , galaxies form hierarchically and present - day galaxies are the products of successive mergers @xcite .
recent observations show that almost all galaxies harbor supermassive black holes ( smbhs ) at their centers @xcite and the black hole ( bh ) masses tightly correlate with the properties of their host galaxies such as the mass of stellar bulge @xcite , the bulge luminosity @xcite , and the nuclear stellar velocity dispersion @xcite .
the correlations between bh mass and galaxy properties imply that the growth of smbhs and the formation and evolution of galaxies are closely linked ..
Please generate the next two sentences of the article | the correlation is likely induced by galaxy major mergers ( merging of galaxies with comparable mass ) in which both rapid star formation and gas accretion onto smbhs are triggered and the feedback from the central active galactic nuclei ( agns ) regulates the growth of both smbhs and galaxy bulges .
the coevolution scenario can successfully explain not only the correlations between smbhs and their host galaxies but also many of the observed evolutions of galaxies and agns @xcite . |
6,968 | Suppose that you have an abstract for a scientific paper: issues that are specific for formulating fermions in light - cone quantization are discussed .
special emphasis is put on the use of parity invariance in the non - perturbative renormalization of light - cone hamiltonians .
# 1#2#3#4#1 * # 2 * , # 3 ( # 4 ) light - front ( lf ) quantization is the most physical approach to calculating parton distributions on the basis of qcd @xcite . before one can formulate qcd with quarks ,
it is necessary that one understands how to describe fermions in this framework .
this in turn requires that one addresses the following issues how is spontaneous symmetry breaking ( chiral symmetry ! ) manifested in the lf framework , where the vacuum appears to be trivial ?
is it possible to preserve current conservation and parity invariance in this framework ?
how does one formulate fermions on the transverse lattice , which seems to be a very promising approaches to pure glue lfqcd @xcite ? .
And you have already written the first three sentences of the full article: the first of the above issues has been addressed very often in the past and we will restrict ourselves here to a brief summary . in the lf framework ,
non - trivial vacuum structure can reside only in zero - modes ( @xmath0 modes ) . since these are high - energy modes ( actually infinite energy in the continuum ) one often does not include them as explicit degrees of freedom but assumes they have been integrated out , leaving behind an effective lf - hamiltonian .
the important points here are the following ..
Please generate the next two sentences of the article | if the zero - mode sector involves spontaneous symmetry breaking , this manifests itself as explicit symmetry breaking for the effective hamiltonian . in general
, these effective lf hamiltonians thus have a much richer operator structure than the canonical hamiltonian . |
6,969 | Suppose that you have an abstract for a scientific paper: a novel approach that enables the study of parallel transport in magnetized plasmas is presented .
the method applies to general magnetic fields with local or nonlocal parallel closures .
temperature flattening in magnetic islands is accurately computed . for a wave number @xmath0 , the fattening time scales as @xmath1 where @xmath2 is the parallel diffusivity , and @xmath3 ( @xmath4 ) for non - local ( local ) transport .
the fractal structure of the devil staircase temperature radial profile in weakly chaotic fields is resolved . in fully chaotic fields ,
the temperature exhibits self - similar evolution of the form @xmath5 $ ] , where @xmath6 is a radial coordinate . in the local case
, @xmath7 is gaussian and the scaling is sub - diffusive , @xmath8 . in the non - local case , @xmath7 decays algebraically , @xmath9 , and the scaling is diffusive , @xmath10 .
the study of transport in magnetized plasmas is a problem of fundamental interest in controlled fusion , space plasmas , and astrophysics research .
three issues make this problem particularly challenging : ( i ) the _ extreme anisotropy _ between the parallel ( i.e. , along the magnetic field ) , @xmath11 , and the perpendicular , @xmath12 , conductivities ( @xmath13 may exceed @xmath14 in fusion plasmas ) ; ( ii ) magnetic _ field lines chaos _ which in general complicates ( and may preclude ) the construction of magnetic field line coordinates ; and ( iii ) _ nonlocal parallel transport _ in the limit of small collisionality . as a result of these challenges ,
standard finite difference and finite elements numerical methods suffer from a number of ailments .
chief among them are the pollution of perpendicular dynamics due to truncation errors in the discrete representation of the parallel heat flux , and the lack of a discrete maximum principle ( to enforce temperature positivity ) . despite the severity of these issues
, recent studies have succeeded in partially addressing some of them , and important progress has been....
And you have already written the first three sentences of the full article: this work was sponsored by the oak ridge national laboratory , managed by ut - battelle , llc , for the u.s.department of energy under contract de - ac05 - 00or22725 ..
Please generate the next two sentences of the article | |
6,970 | Suppose that you have an abstract for a scientific paper: we give some closed formulas for certain vectors of the canonical bases of the fock space representation of @xmath0 . as a result
, a combinatorial description of certain parabolic kazhdan - lusztig polynomials for affine type @xmath1 is obtained . 0.6 cm .
And you have already written the first three sentences of the full article: let @xmath2 be the fock space representation of @xmath0 introduced by hayashi @xcite and further studied by misra and miwa @xcite , stern @xcite , and kashiwara , miwa and stern @xcite .
it has a standard basis @xmath3 indexed by the set @xmath4 of all integer partitions . in @xcite two canonical bases @xmath5 and @xmath6 of @xmath2 have been constructed .
the subset of @xmath7 consisting of the @xmath8 s for which @xmath9 is @xmath10-regular coincides with kashiwara s lower global basis ( or lusztig s canonical basis ) of the irreducible sub - representation of @xmath2 generated by the highest weight vector @xmath11 . the main motivation for introducing the bases @xmath7 and @xmath12 was their conjectural relation with the decomposition matrices of the @xmath13-schur algebras @xmath14 defined by dipper and james @xcite in connection with the modular representation theory of the finite groups @xmath15 in non - describing characteristic ..
Please generate the next two sentences of the article | conjecture 5.2 of @xcite was proved by varagnolo and vasserot @xcite , who established that the coefficients of the expansion of @xmath16 on the basis @xmath17 are equal to the kazhdan - lusztig polynomials appearing in lusztig s character formula for @xmath18 , where @xmath19 is a complex primitive @xmath10th root of 1 .
let @xmath20 be a prime number coprime to @xmath13 and such that the multiplicative order of @xmath13 in @xmath21 is equal to @xmath10 . |
6,971 | Suppose that you have an abstract for a scientific paper: we study charmless pure annihilation type radiative @xmath0 decays within the qcd factorization approach . after adding the vertex corrections to the naive factorization approach
, we find that the branching ratios of @xmath1 , @xmath2 and @xmath3 within the standard model are at the order of @xmath4 , @xmath5 and @xmath6 , respectively .
the smallness of these decays in the standard model makes them sensitive probes of flavor physics beyond the standard model . to explore their physics potential ,
we have estimated the contribution of @xmath7 boson in the decays . within the allowed parameter space ,
the branching ratios of these decay modes can be enhanced remarkably in the non - universal @xmath7 model : the branching ratios can reach to @xmath8 for @xmath9 and @xmath5 for the @xmath10 , which are large enough for lhc - b and/or super b - factories to detect those channels in near future .
moreover , we also predict large cp asymmetries in suitable parameter space .
the observation of these modes could in turn help us to constrain the @xmath11 mass within the model . .
And you have already written the first three sentences of the full article: rare @xmath0 decays induced by flavor changing neutral currents ( fcnc ) play important roles in particle physics , where they are always regarded as ideal places for probing signals of new physics .
the gim suppression of fcnc amplitude is absent in many new physics scenarios beyond the standard model ( sm ) , which could give large enhancement of fcnc contributions over the sm predictions .
however , due to our poor knowledge of non - perturbative qcd , predictions for many interesting exclusive decays are polluted by large hadronic uncertainties ..
Please generate the next two sentences of the article | therefore , it would be of great interest to explore rare @xmath0 decays , which are induced with few hadronic parameters as well as only by fcnc currents .
two body radiative @xmath0 decays involve simple hadronic dynamics with only one hadron in the final states , so they suffer much less pollution than non - leptonic decays . in studying |
6,972 | Suppose that you have an abstract for a scientific paper: the compactified jacobian of any projective curve @xmath0 is defined as the simpson moduli space of torsion free rank one degree @xmath1 sheaves that are semistable with respect to a fixed polarization @xmath2 on @xmath0 . in this paper
we give explicitly the structure of this compactified simpson jacobian in the case where @xmath0 is a generalized tree - like curve , i.e. , a projective , reduced and connected curve such that the intersection points of its irreducible components are disconnecting ordinary double points .
we prove that it is isomorphic to the product of the compactified jacobians of a certain degree @xmath3 of its components @xmath4 , where the degrees @xmath3 depend on @xmath1 , @xmath2 and on the particular structure of the curve .
we find also necessary and sufficient conditions for the existence of stable points which allow us to study the variation of these simpson jacobians as the polarization @xmath2 changes . .
And you have already written the first three sentences of the full article: the problem of compactifying the generalized jacobian of a singular curve has been studied since igusa s work @xcite around 1950 .
he constructed a compactification of the jacobian of a nodal and irreducible curve @xmath0 as the limit of the jacobians of smooth curves approaching @xmath0 .
igusa also showed that his compactification does not depend on the considered family of smooth curves ..
Please generate the next two sentences of the article | an intrinsic characterization of the boundary points of the igusa s compactification as the torsion free , rank 1 sheaves which are not line bundles is due to mumford and mayer .
the complete construction for a family of integral curves over a noetherian hensel local ring with residue field separably closed was carried out by dsouza @xcite . |
6,973 | Suppose that you have an abstract for a scientific paper: in our recent paper ( solar physics * 261 * , 233 ) we investigated quasi - periodic oscillations of hard x - rays during impulsive phase of solar flares .
we have come to conclusion that they are caused by magnetosonic oscillations of magnetic traps within the volume of hard - x - ray ( hxr ) loop - top sources . in the present paper
we investigate four flares which show clear quasi - periodic sequences of hxr pulses .
we also describe our phenomenological model of oscillating magnetic traps to show that it can explain observed properties of hxr oscillations .
main results are the following : 1 . we have found that low - amplitude quasi - periodic oscillations occur before impulsive phase of some flares .
2 .
we have found that quasi - period of the oscillations can change in some flares .
we interpret this as being due to changes of the length of oscillating magnetic traps .
3 . during impulsive phase a significant part of the energy of accelerated ( non - thermal ) electrons
is deposited within the hxr loop - top source .
4 .
our analysis suggests that quick development of impulsive phase is due to feedback between pulses of the pressure of accelerated electrons and the amplitude of magnetic - trap oscillation .
5 .
we have also determined electron number density and magnetic filed strength for hxr loop - top sources of several flares .
the values fall within the limits of @xmath0 @xmath1 , @xmath2 gauss . .
And you have already written the first three sentences of the full article: in hard x - ray ( hxr ) emission of many flares quasi - periodic variations were observed with time - intervals between pulses , @xmath3s [ see ; see also review of and references therein ] . in our previous paper ( , paper i )
we attempted to investigate relationship between hxr loop - top ( lt ) sources and the quasi - periodic variations .
main difficulty was that sequences of pulses are usually short , so that it is difficult to carry out comprehensive analysis of their quasi - periodicity . therefore we used time - interval , @xmath4 , between the strongest pulses as a simple estimate of the quasi - period @xmath5 . in the present paper.
Please generate the next two sentences of the article | we have selected four flares which have longer sequences of hxr pulses , so that it was possible to carry out detailed analysis of their quasi - periodicity ( section [ qper ] ) .
section [ 16jan ] contains detailed analysis of 16 january 1994 flare . in section [ det ] |
6,974 | Suppose that you have an abstract for a scientific paper: based on our recent findings regarding ( non-)renormalizability of non - commutative @xmath0 gauge theories @xcite we present the construction of a new type of model . by introducing a soft breaking term in such a way that only the bilinear part of the action is modified , no interaction between the gauge sector and auxiliary fields occurs .
demanding in addition that the latter form brst doublet structures , this leads to a minimally altered non - commutative @xmath0 gauge model featuring an ir damping behavior .
moreover , the new breaking term is shown to provide the necessary structure in order to absorb the inevitable quadratic ir divergences appearing at one - loop level in theories of this kind . in the present paper
we compute feynman rules , symmetries and results for the vacuum polarization together with the one - loop renormalization of the gauge boson propagator and the three - point functions .
institute for theoretical physics , vienna university of technology + wiedner hauptstrasse 8 - 10 , a-1040 vienna ( austria ) + faculty of physics , university of vienna + boltzmanngasse 5 , a-1090 vienna ( austria ) + .
And you have already written the first three sentences of the full article: when considering quantum field theories on non - commutative spaces , e.g. by employing the so - called groenewold - moyal star product , one inevitably has to deal with the infamous uv / ir mixing problem ( see @xcite for reviews of the topic ) : new kinds of non - local ir divergences prevent the model from being renormalizable .
in fact , so far only some modified scalar field theories on euclidean non - commutative spaces have been found to be renormalizable by adding new types of terms in the action .
the first successful approach was introduced by grosse and wulkenhaar @xcite , and proofs of renormalizability have been achieved mainly by utilizing multiscale analysis @xcite , or formally in the matrix base @xcite . recently , and quite independent of former developments , gurau _ et al . _.
Please generate the next two sentences of the article | @xcite introduced a term of the type @xmath1 into the lagrangian which modifies the theory in the infrared region and , in this way , renders it renormalizable .
this was in fact proven to all orders by the authors using multiscale analysis . |
6,975 | Suppose that you have an abstract for a scientific paper: possibilities of turning intrinsically n - type oxide semiconductors like zno and zn@xmath0mg@xmath1o into p - type materials are investigated .
motivated by recent experiments on zn@xmath0mg@xmath1o doped with nitrogen we analyze the electronic defect levels of point defects n@xmath2 , v@xmath3 , and n@xmath2-v@xmath4 pairs in zno and zn@xmath0mg@xmath1o by means of self - interaction - corrected density functional theory calculations .
we show how the interplay of defects can lead to shallow acceptor defect levels , although the levels of individual point defects n@xmath2 are too deep in the band gap for being responsible for p - type conduction .
we relate our results to p - type conduction paths at grain boundaries seen in polycrystalline zno and develop an understanding of a p - type mechanism which is common to zno , zn@xmath0mg@xmath1o , and related materials . .
And you have already written the first three sentences of the full article: zinc oxide is a prominent example of an intrinsically n - type semiconductor .
its abundant availability , its low - cost production , and its wide electronic band gap of approximately 3.4 ev make zno attractive for transparent and conducting oxide layers in consumer - electronics devices . however , a break - through of zno - based transparent electronics has not been achieved so far due to the lack of sufficiently conductive and long - term stable zno layers .
the problem of p - type doping of zno has by now been a scientific challenge for more than two decades . besides the doping with single elements like n , p , as , or sb , substituting o and li ,.
Please generate the next two sentences of the article | na , k , cu , ag or au , substituting zn@xcite co - doping was discussed as well.@xcite apparently , the most promising candidate so far is still nitrogen .
however , it was shown theoretically@xcite that the substitutional defect of n on o sites ( n@xmath2 ) can not be responsible for the p - type conduction which has been observed in some experiments,@xcite since it creates a defect level which is located too high above the valence band ( vb ) edge with respect to thermal excitation energies . |
6,976 | Suppose that you have an abstract for a scientific paper: motivated by the diversity and complexity of two - dimensional crystals formed by triangular proteins and protein trimers , we have investigated the structures and phase behavior of hard - disk trimers . in order to mimic specific binding interactions ,
each trimer possesses on ` attractive ' disk which can interact with similar disks on other trimers _ via _ an attractive square - well potential . at low density and low temperature ,
the fluid phase mainly consists of tetramers , pentamers , or hexamers .
hexamers provide the structural motif for a high - density , low - temperature periodic solid phase , but we also identify a metastable periodic structure based on a tetramer motif . at high density there is a transition between orientationally ordered and disordered solid phases .
the connections between simulated structures and those of 2d protein crystals as seen in electron microscopy are briefly discussed . .
And you have already written the first three sentences of the full article: two - dimensional ( 2d ) materials present some fascinating challenges to condensed - matter theory , with even the most simple 2d systems harboring surprises .
one of the most famous problems involves the precise description of melting in 2d solids made up of hard , disk - like particles with short - range repulsive interactions.@xcite specifically , does the fluid undergo a weak first - order transition to the solid , or is there an intermediate hexatic phase linked by two continuous phase transitions ? related avenues of research concern the existence of exotic phases in systems made up of more complex particles , such as ( non)periodic solids of hard - disk dimers,@xcite pentamers and hexamers,@xcite tetratic phases of hard squares@xcite and hard rectangles,@xcite and orientationally ordered solids of hard pentagons and heptagons.@xcite the effects of additional interactions on the phase behavior and dynamics of 2d systems are also of interest , as evidenced by recent studies on dipolar potentials in the context of magnetic colloids.@xcite such models provide an ideal testing ground for condensed - matter theories , and in some cases challenge our most fundamental understanding of the properties of matter . despite their simplicity
, 2d models can provide reliable descriptions of some real , and rather complex , experimental situations ..
Please generate the next two sentences of the article | for example , in a number of recent studies , 2d models have been employed to help interpret and understand the clustering and crystallization of proteins at interfaces .
the conformations and interactions of proteins are central to biological activity , and ideally one would like to investigate these properties _ in vivo_. unfortunately , structural information is most commonly obtained from x - ray diffraction studies on crystals . |
6,977 | Suppose that you have an abstract for a scientific paper: we test a hypothesis for the origin of dynamical heterogeneity in slowly relaxing systems , namely that it emerges from soft ( goldstone ) modes associated with a broken continuous symmetry under time reparametrizations .
we do this by constructing coarse grained observables and decomposing the fluctuations of these observables into transverse components , which are associated with the postulated time - fluctuation soft modes , and a longitudinal component , which represents the rest of the fluctuations .
our test is performed on data obtained in simulations of four models of structural glasses .
as the hypothesis predicts , we find that the time reparametrization fluctuations become increasingly dominant as temperature is lowered and timescales are increased .
more specifically , the ratio between the strengths of the transverse fluctuations and the longitudinal fluctuations grows as a function of the dynamical susceptibility , @xmath0 , which represents the strength of the dynamical heterogeneity ; and the correlation volumes for the transverse fluctuations are approximately proportional to those for the dynamical heterogeneity , while the correlation volumes for the longitudinal fluctuations remain small and approximately constant . .
And you have already written the first three sentences of the full article: the rapidly increasing relaxation timescales , the presence of non - exponential relaxation , as well as the violation of stokes - einstein relations between viscosity and diffusivity are some features observed close to the glass transition in glassy systems @xcite .
the appearance of these features suggests that relaxation dynamics is heterogeneous , i.e. that it is faster in some regions and slower in others @xcite .
direct microscopic evidence for this behavior has been found both in simulations @xcite and in experiments @xcite ..
Please generate the next two sentences of the article | the understanding of dynamical heterogeneity is believed to be crucial to explain anomalous behavior of materials near the glass transition , and even possibly to explain the very presence of the glass transition itself @xcite . despite many efforts trying to address the origin of dynamical heterogeneity
, this question still remains open @xcite . in recent years |
6,978 | Suppose that you have an abstract for a scientific paper: we calculate the @xmath0 transition rate of @xmath1he by the hybrid picture , the @xmath2 and @xmath3 exchanges plus the direct quark processes . it is found that the hyperon - induced decay is weaker than the nucleon - induced decay , but the former may reveal the short - range mechanism of the weak transition and also give a clear signal of the strong @xmath4 transition .
the @xmath5 transition in double-@xmath6 hypernucleus is complement to the @xmath7 transition as it occurs only in the @xmath8 channel , while the @xmath9 transition is dominant in the @xmath7 case . , , and hypernuclei , nonmesonic decay , direct quark process 21.80.+a , 12.39.-x .
And you have already written the first three sentences of the full article: recent analyses of hypernuclear nonmesonic decay reveal the importance of short - range interaction of baryonic weak transition @xcite .
it is , in fact , realized that the momentum transfer is large due to the @xmath10 mass difference , and therefore the short range interaction becomes important .
we proposed to treat the short range part of @xmath7 interaction using the valence quark picture of the baryon and the effective four - quark weak hamiltonian @xcite ..
Please generate the next two sentences of the article | we found that the direct quark ( dq ) process gives significantly large contribution and shows qualitatively different features from the meson exchange contribution , especially in its isospin structure .
the kaon exchange contribution also largely enhance the @xmath11 ratio due to its spin structure @xcite . there remains , however , another problem , i.e. , experimental values of the proton asymmetry from polarized hypernucleus are incompatible with the theoretical values , which is closely related to the @xmath8 transition amplitudes @xcite . |
6,979 | Suppose that you have an abstract for a scientific paper: we quantify the extent to which naturalness is lost as experimental lower bounds on the higgs boson mass increase , and we compute the natural upper bound on the lightest supersymmetric higgs boson mass .
we find that it would be unnatural for the mass of the lightest supersymmetric higgs boson to saturate it s maximal upper bound . in the absence of significant fine - tuning
, the lightest higgs boson mass should lie below @xmath0 gev , and in the most natural cases it should be lighter than @xmath1 gev . for modest @xmath2 ,
these bounds are significantly lower .
our results imply that a failure to observe a light higgs boson in pre - lhc experiments could provide a serious challenge to the principal motivation for weak - scale supersymmetry . fermilab - pub-96/147-t + hep - ph/9609463 + .5 in * naturalness lowers the upper bound + on the lightest higgs boson mass + in supersymmetry + * 1.cm greg w. anderson@xmath3 , diego j. castao@xmath4 , and antonio riotto@xmath3 + .25 cm _ @xmath3 fermi national accelerator laboratory + p.o .
box 500 , batavia ,
illinois 60510 + .25 cm _ @xmath4dept . of physics , florida state university + tallahassee , fl 32306 usa .
+ _ _ .5 cm .
And you have already written the first three sentences of the full article: the higgs boson is the last remaining ingredient of a complete standard model .
it s persistent elusiveness is perhaps not surprising . within the framework of the standard model
, there are no symmetries which can be invoked to make a fundamental scalar light ..
Please generate the next two sentences of the article | the existence of a light scalar degree of freedom which remains fundamental above the weak - scale would argue for supersymmetry since supersymmetry provides the only explicitly known solution to the naturalness problem which accompanies fundamental scalars @xcite .
of course , the higgs boson may not be fundamental at all , and the only testament to its existence may be the eventual unitarization of the longitudinal @xmath5 scattering cross section at tev scale energies . |
6,980 | Suppose that you have an abstract for a scientific paper: the connections between the @xmath0models ( the original @xmath1 using an infinite square well , @xmath2 , @xmath3 and @xmath4 ) , based on particular solutions of the geometrical bohr hamiltonian with @xmath5-unstable potentials , and the interacting boson model ( ibm ) are explored . for that purpose ,
the general ibm hamiltonian for the @xmath6 transition line is used and a numerical fit to the different @xmath0models energies is performed , later on the obtained wavefunctions are used to calculate b(e2 ) transition rates .
it is shown that within the ibm one can reproduce very well all these @xmath0models .
the agreement is the best for @xmath2 and reduces when passing through @xmath3 , @xmath4 and @xmath1 , where the worst agreement is obtained ( although still very good for a restricted set of lowest lying states ) .
the fitted ibm hamiltonians correspond to energy surfaces close to those expected for the critical point . a phenomenon similar to the quasidynamical symmetry
is observed . .
And you have already written the first three sentences of the full article: both , the bohr - mottelson ( bm ) collective model @xcite and the interacting boson model ( ibm ) @xcite have thoroughly been used to study the same kind of nuclear structure problems .
although very different in their formulation , both models present clear relationships . in an approximate way
, the ibm can be interpreted as the second quantization of the bm shape variables @xcite ..
Please generate the next two sentences of the article | more detailed connections between both models were studied during the eighties by several authors @xcite and , more recently , by rowe and collaborators @xcite .
both models have three particular cases that can be easily solved and for which a clear correspondence can be done . |
6,981 | Suppose that you have an abstract for a scientific paper: in this paper , following the work of chen , l and pope , we present the general metric for kerr-(a)ds black holes with two rotations .
the corresponding klein - gordon equation is separated explicitly , from which we develop perturbative expansions for the angular eigenvalues in powers of the rotation parameters with @xmath0 . .
And you have already written the first three sentences of the full article: after the advent of the brane world scenario @xcite and the ads / cft correspondence @xcite , there has been an increase in interest in the study of higher - dimensional black holes .
the kerr metric was first generalized to higher dimensions in the seminal paper by myers and perry @xcite .
one of the unexpected results is that for some rotating black holes event horizons exist for arbitrarily large values of the rotation parameters ..
Please generate the next two sentences of the article | the stability of such black holes are certainly in question @xcite . these are asymptotically flat black holes .
the first asymptotically non - flat higher - dimensional kerr metric was given by hawking _ |
6,982 | Suppose that you have an abstract for a scientific paper: we study the interplay between different models of the same irreducible representation of the @xmath0-points of a reductive group over a local field . .
And you have already written the first three sentences of the full article: let @xmath1 be a locally compact group .
an important notion in representation theory is that of a _
model_. broadly speaking , a model is a representation space of @xmath1 ( usually defined geometrically ) which contains any irreducible constituent with multiplicity one ..
Please generate the next two sentences of the article | consider the case where @xmath1 is the @xmath0-points of a reductive group @xmath2 defined over a local field @xmath0 .
there are many examples of models which are realized on induces spaces @xmath3 where @xmath4 is a character of a closed subgroup @xmath5 of @xmath1 i.e. , on the space of smooth functions on @xmath1 which are left @xmath6-equivariant with the right @xmath1-action . |
6,983 | Suppose that you have an abstract for a scientific paper: due to the commonly known impossibility results , information theoretic security is considered impossible for oblivious transfer ( ot ) in both the classical and the quantum world . in this paper , we proposed a weak version of the all - or - nothing ot . in our protocol
the honest parties do not need long term quantum memory , entanglements , or sophisticated quantum computations .
we observe some difference between the classical and quantum ot impossibilities .
* keywords : * quantum oblivious transfer , information theoretic security .
And you have already written the first three sentences of the full article: oblivious transfer ( ot ) is an important two - party cryptographic protocol , as a building block for many general cryptographic primitives . in the first ot system introduced by rabin @xcite ,
a message is received with probability 1/2 and the sender does not know whether the message reaches the receiver .
this is later called the all - or - nothing ot or simply the rabin ot . even et al ..
Please generate the next two sentences of the article | @xcite defined the 1-out - of-2 ot , where the sender has two secrets and the receiver can choose one and only one of them in an oblivious manner .
that is , the sender can not know the receiver s choice and the receiver can not know anything more than one secret . |
6,984 | Suppose that you have an abstract for a scientific paper: we consider a car - following model described by a delay difference equation and give its exact solutions that present propagation of a traffic jam .
this model is a discrete - time version of the delayed optimal - velocity model ; in the continuum limit , we recover the delay differential equation for this model and the exact solutions as well .
we then work in the ultra - discrete limit , obtaining a delay cellular - automaton model , which successfully inherits the solutions .
also the dispersion relation for the present solutions suggests that a quick response of drivers does not always result in fast dissolution of a traffic jam .
_ keywords _ : delay difference equation , exact solution , ultra - discrete limit , cellular automaton , nonlinear waves , car - following model , traffic flow + .
And you have already written the first three sentences of the full article: study of traffic flow relies in no small part on theoretical / mathematical modeling because of the difficulty in extensive measurements and designed experiments , and predictions from simulation and analytical study have particular importance in this field @xcite .
a car - following model is described in general by an equation of the form : @xmath0 @xmath1 denotes the position of the @xmath2th car at time @xmath3 and a positive constant @xmath4 is a delay in time , which corresponds to the driver s reaction time . after this latency , each car reaches the velocity @xmath5 determined by the headway @xmath6 , i.e. , a distance to the next car in front ; hence @xmath7 is nowadays referred to as _ the optimal - velocity ( ov ) function_. in the earlier studies of traffic flow , g. f. newell proposed the car - following model with @xmath8 where @xmath9 , @xmath10 and @xmath11 are positive constants , and found an exact solution for @xmath12 @xcite . in this case , the equation can be transformed into a linear equation and thus allows for superposition of the shocks each of which present a traffic jam propagating upstream at different speeds . subsequently , g. b. whitham obtained an elliptic solution for newell s model in the generic case @xmath13 @xcite .
this presents nonlinear waves beyond newell s _ linear _ solutions , including a solitary - wave in the case that the modulus of the elliptic function goes to 1 ..
Please generate the next two sentences of the article | he also suggested that the solitary - wave solution be stable in the range of parameters for stable linear waves .
both newell s model and the kac van moerbeke system reduce to the same equation if one assumes a steady - profile solution with the phase velocity @xmath14 ; the kac |
6,985 | Suppose that you have an abstract for a scientific paper: we report fluorescence investigations and raman spectroscopy on colloidal nanodiamonds ( nds ) obtained via bead assisted sonic disintegration ( basd ) of a polycrystalline chemical vapor deposition film .
the basd nds contain _ in situ _ created silicon vacancy ( siv ) centers .
whereas many nds exhibit emission from siv ensembles , we also identify nds featuring predominant emission from a single bright siv center .
we demonstrate oxidation of the nds in air as a tool to optimize the crystalline quality of the nds via removing damaged regions resulting in a reduced ensemble linewidth as well as single photon emission with increased purity .
we furthermore investigate the temperature dependent zero - phonon - line fine - structure of a bright single siv center as well as the polarization properties of its emission and absorption . .
And you have already written the first three sentences of the full article: recently , narrowband fluorescent nanodiamonds ( nds ) harnessing the photoluminescence of silicon vacancy ( siv ) centers have attracted research interest due to their promising applications as single photon sources as well as fluorescence labels for in vivo imaging.@xcite for the application as single photon sources , siv centers stand out owing to high brightness , narrow bandwidth single photon emission : single photon rates up to 6 mcps have been reported .
simultaneously , the fluorescence predominantly concentrates in the narrow purely electronic transition , i.e. , the zero - phonon - line ( zpl ) with down to 0.7 nm width at room temperature.@xcite for the application as fluorescence labels , siv centers are promising as they enable optical excitation using red laser light ( e.g. , at 671 nm ) combined with fluorescence in the near - infrared spectral range at approx . 738 nm.@xcite both properties aid to minimize absorption in biological tissue as well as tissue autofluorescence;@xcite additionally , the narrow bandwidth enables efficient spectral filtering of fluorescence and background signal . in ref .
, we reported the production of an aqueous , colloidal solution of siv containing nds from polycrystalline chemical vapor deposition ( cvd ) diamond films using the bead assisted sonic disintegration ( basd ) method ( see refs . ) ..
Please generate the next two sentences of the article | these siv containing nds in solution are promising for applications as fluorescence labels as well as single photon sources .
however , some essential characteristics of the siv fluorescence in basd nds have not been investigated to date . in the context of single photon sources , |
6,986 | Suppose that you have an abstract for a scientific paper: we consider a normal - superconducting junction in order to investigate the effect of new physical ingredients on waiting times .
first , we study the interplay between andreev and specular scattering at the interface on the distribution of waiting times of electrons or holes separately . in that case the distribution is not altered dramatically compared to the case of a single quantum channel with a quantum point contact since the interface acts as an andreev mirror for holes .
we then consider a fully entangled state originating from spliting of cooper pairs at the interface and demonstrate a significant enhancement of the probability to detect two consecutive electrons in a short time interval .
finally , we discuss the electronic waiting time distribution in the more realistic situation of partial entanglement .
normal - superconducting junction , andreev reflection , waiting time distribution , entanglement 02.50.ey , 72.70.+m , 73.23.hk .
And you have already written the first three sentences of the full article: markus bttiker was certainly one of the most influential scientists in the field of mesoscopic physics . among all his important contributions ,
time in quantum mechanics has a peculiar flavor since it occupied his mind at the right beginning and at the end of his carrier .
intrigued at first by the traversal time of an electron through a tunnel barrier @xcite , he came back to this topic after the emergence of `` on - demand single electron sources '' @xcite , which he greatly contributed to develop @xcite , via the concept of waiting time distribution ( wtd ) @xcite ..
Please generate the next two sentences of the article | charge transport at the nanoscale is known to be stochastic due to the quantum nature of particles @xcite .
therefore , going beyond the knowledge of average quantities , such as the average electronic current , appears to be unavoidable and extremely fruitful at the same time . |
6,987 | Suppose that you have an abstract for a scientific paper: the small instanton transition of a five - brane colliding with one end of the @xmath0 interval in heterotic @xmath1-theory is discussed , with emphasis on the transition moduli , their potential function and the associated non - perturbative superpotential . using numerical methods ,
the equations of motion of these moduli coupled to an expanding friedmann - robertson - walker spacetime are solved including non - perturbative interactions .
it is shown that the five - brane collides with the end of the interval at a small instanton .
however , the moduli then continue to evolve to an isolated minimum of the potential , where they are trapped by gravitational damping .
the torsion free sheaf at the small instanton is `` smoothed out '' into a vector bundle at the isolated minimum , thus dynamically completing the small instanton phase transition .
radiative damping at the origin of moduli space is discussed and shown to be insufficient to trap the moduli at the small instanton point . .
And you have already written the first three sentences of the full article: in @xcite , witten studied @xmath2 heterotic string theory on @xmath3 with an @xmath4 , @xmath5 gauge instanton supported on @xmath6 with instanton number @xmath7 .
the effective @xmath8 theory manifests @xmath9 supersymmetry and has gauge symmetry @xmath10 .
the boundary of instanton moduli space contains singular points , at each of which one unit of instanton number is concentrated ..
Please generate the next two sentences of the article | these are called `` small '' instantons and the local moduli space @xmath11 was shown to be @xmath12 dimensional . it was demonstrated in @xcite that @xmath11 can be described as the flat directions of a potential energy function .
this is constructed from @xmath13 hypermultiplets , each transforming as a fundamental @xmath13 representation of @xmath4 and as a doublet under an additional @xmath14 gauge symmetry . at the origin of field space , |
6,988 | Suppose that you have an abstract for a scientific paper: nonequilibrium states induced by an applied bias voltage @xmath0 and the corresponding current - voltage characteristics of one - dimensional models describing band and mott insulators are investigated theoretically by using nonequilibrium green s functions .
we attach the models to metallic electrodes whose effects are incorporated into the self - energy .
modulation of the electron density and the scalar potential coming from the additional long - range interaction are calculated self - consistently within the hartree approximation . for both models of band and mott insulators with length @xmath1 ,
the bias voltage induces a breakdown of the insulating state , whose threshold shows a crossover depending on @xmath1 .
it is determined basically by the bias @xmath2 for @xmath1 smaller than the correlation length @xmath3 where @xmath4 denotes the bandwidth and @xmath5 the energy gap . for systems with @xmath6 ,
the threshold is governed by the electric field , @xmath7 , which is consistent with a landau - zener - type breakdown , @xmath8 .
we demonstrate that the spatial dependence of the scalar potential is crucially important for this crossover by showing the case without the scalar potential , where the breakdown occurs at @xmath2 regardless of the length @xmath1 . .
And you have already written the first three sentences of the full article: nonlinear conduction in correlated electron systems such as one - dimensional mott insulators@xcite and two - dimensional charge - ordered materials@xcite has been of great interest in the past few decades .
they offer intriguing subjects of nonequilibrium physics in condensed matter and possibility for novel functions of electronic devices .
for example , in a typical quasi - one - dimensional mott insulator , sr@xmath9cuo@xmath10,@xcite a dielectric breakdown has been observed experimentally by applying a strong electric field ..
Please generate the next two sentences of the article | a dielectric breakdown has been reported also in an organic spin - peierls insulator , k - tcnq@xcite [ tcnq = tetracyanoquinodimethane ] .
for another organic compound , ( bedt - ttf)(f@xmath9tcnq ) [ bedt - ttf = bis(ethylenedithio)tetrathiafulvalene ] , which is a quasi - one - dimensional mott insulator , metal - insulator - semiconductor field - effect transistor device structures have been reported,@xcite where its field - effect characteristics are different from those of band insulators.@xcite so far , theoretical investigations on nonlinear conduction for interacting electron systems that are initially insulating in their equilibrium states have been done by several authors.@xcite in general , these studies are classified into two approaches depending on whether an external force is written as an electric field@xcite or a bias voltage.@xcite the former approach is to consider electron systems without electrodes . the electric field is usually applied with open boundary condition,@xcite or equivalently with periodic boundary condition by using a time - dependent magnetic flux.@xcite in one dimension , oka and aoki studied the hubbard model under a strong electric field by the time - dependent density - matrix - renormalization - group method.@xcite one of their important results is that the dielectric breakdown of mott insulators is interpreted as a many - body counterpart of the landau - zener ( lz ) breakdown.@xcite this is known to describe the breakdown of band insulators where the one - particle picture holds . |
6,989 | Suppose that you have an abstract for a scientific paper: many complex systems can be represented as networks of dynamical elements whose states evolve in response to interactions with neighboring elements , noise and external stimuli .
the collective behavior of such systems can exhibit remarkable ordering phenomena such as _ chimera order _ corresponding to coexistence of ordered and disordered regions .
often , the interactions in such systems can also evolve over time responding to changes in the dynamical states of the elements . link adaptation inspired by hebbian learning
, the dominant paradigm for neuronal plasticity , has been earlier shown to result in structural balance by removing any initial frustration in a system that arises through conflicting interactions . here
we show that the rate of the adaptive dynamics for the interactions is crucial in deciding the emergence of different ordering behavior ( including chimera ) and frustration in networks of ising spins .
in particular , we observe that small changes in the link adaptation rate about a critical value result in the system exhibiting radically different energy landscapes , viz . , smooth landscape corresponding to balanced systems seen for fast learning , and rugged landscapes corresponding to frustrated systems seen for slow learning . .
And you have already written the first three sentences of the full article: many natural and technological complex systems can be described as networks connecting a large number of elements whose states evolve in time @xcite .
the collective behavior of a system resulting from interactions between its components can exhibit non - trivial features , including critical phenomena @xcite .
for instance , a system of binary - state elements ( e.g. , representing individuals having opposing opinions on an issue ) connected through a network having modular organization can exhibit ordering dynamics at very distinct time - scales @xcite and under certain circumstances , self - organize into locally aligned clusters that correspond to the communities of the network ( i.e. , subnetworks characterized by a significantly higher connection density compared to the overall density of the network ) @xcite . in many situations , the links of the network ( representing the interactions ) can also evolve over time as a result of the changes in the states of the components that they connect ..
Please generate the next two sentences of the article | such connections may not only be characterized by weights ( indicating the strength of interaction ) but also sign ( representing the nature of the interaction ) .
for instance , in the context of a network of synaptically - connected model neurons , positive links may correspond to excitatory interactions ( whereby activation of one element can result in activation of other connected elements ) while negative links can give rise to inhibition ( i.e. , activation of an element tends to suppress subsequent activation of neighboring elements ) @xcite . |
6,990 | Suppose that you have an abstract for a scientific paper: we present a theory of quantum circuits based on logical qubits encoded in chirality of electron spin complexes in lateral gated semiconductor triple quantum dot molecules with one electron spin in each dot . using microscopic hamiltonian
we show how to initialize , coherently control and measure the quantum state of a chirality based coded qubit using static in - plane magnetic field and voltage tuning of individual dots .
the microscopic model of two interacting coded qubits is established and mapped to an ising hamiltonian , resulting in conditional two - qubit phase gate . .
And you have already written the first three sentences of the full article: there is currently interest in exploiting electron spin for nano - spintronic@xcite and quantum information processing@xcite .
this is partly motivated by electron spin long coherence times @xcite and availability of scalable semiconductor technology . in the simplest approach ,
a physical qubit is identified with the two states of an electron spin , which can be manipulated by applying local magnetic fields ..
Please generate the next two sentences of the article | much progress has been achieved using micro - magnet@xcite technology with electron spin qubits .
an alternative approach is to encode a logical qubit in a two level system constructed with spin complexes@xcite . |
6,991 | Suppose that you have an abstract for a scientific paper: an analytical study of discrete and resonant impurity quasi - coulomb states in a narrow gaped armchair graphene nanoribbon ( gnr ) is performed .
we employ the adiabatic approximation assuming that the motions parallel ( `` slow '' ) and perpendicular ( `` fast '' ) to the boundaries of the ribbon are separated adiabatically .
the energy spectrum comprises a sequence of series of quasi - rydberg levels relevant to the `` slow '' motion adjacent from the low energies to the size - quantized levels associated with the `` fast '' motion .
only the series attributed to the ground size - quantized sub - band is really discrete , while others corresponding to the excited sub - bands consist of quasi - discrete ( fano resonant ) levels of non - zero energetic widths , caused by the coupling with the states of the continuous spectrum branching from the low lying sub - bands . in the two- and three - subband approximation the spectrum of the complex energies of the impurity electron is derived in an explicit form .
narrowing the gnr leads to an increase of the binding energy and the resonant width both induced by the finite width of the ribbon . displacing the impurity centre from the mid - point of the gnr causes the binding energy to decrease while the resonant width of the first excited rydberg series increases . as for
the second excited series their widths become narrower with the shift of the impurity .
a successful comparison of our analytical results with those obtained by other theoretical and experimental methods is presented .
estimates of the binding energies and the resonant widths taken for the parameters of typical gnrs show that not only the strictly discrete but also the some resonant states are quite stable and could be studied experimentally in doped gnrs . .
And you have already written the first three sentences of the full article: the electron properties of two - dimensional ( 2d ) graphene , a single - layer carbon sheet , has attracted much attention by both theoreticians and experimentalists ( see @xcite and references therein ) . along with this related structures , namely graphene nanoribbons ,
are also under intensive investigation @xcite .
one of the reason for this is that the long electron mean free path in graphene up to 1@xmath0 m opens a field of carbon - based nanoelectronics , where gnrs are used as interconnects in nanodevices ..
Please generate the next two sentences of the article | the unique electron mobility in graphene structures is caused by the strong bonding between the carbon atoms in the honeycomb lattice of graphene .
this in turn prevents the replacing of the carbon atoms by alien ones . |
6,992 | Suppose that you have an abstract for a scientific paper: we present a class of models that describe self - diffusion on fcc(001 ) metal substrates within a common framework .
the models are tested for cu(001 ) , ag(001 ) , au(001 ) , ni(001 ) and pd(001 ) , and found to apply well for all of them . for each of these metals
the models can be used to estimate the activation energy of any diffusion process using a few basic parameters which may be obtained from experiments , ab - initio or semi - empirical calculations . to demonstrate the approach , the parameters of the models are optimized to describe self - diffusion on the ( 001 ) surface , by comparing the energy barriers to a full set of barriers obtained from semi - empirical potentials via the embedded atom method ( eam ) .
it is found that these models with at most four parameters , provide a good description of the full landscape of hopping energy barriers on fcc(001 ) surfaces .
the main features of the diffusion processes revealed by eam calculations are quantitatively reproducible by the models . .
And you have already written the first three sentences of the full article: thin film growth processes involve complicated kinetics giving rise to a rich variety of surface morphologies . within this vast domain ,
the study of the growth in the submonolayer regime is of particular interest due to the large impact of the initial kinetics on the resulting film structure .
experiments on thin film growth on well characterized substrates using molecular - beam epitaxy ( mbe ) have provided a large body of information about growth kinetics and morphology , and revealed that for a variety of systems and a broad temperature range , island nucleation is the dominant mechanism for crystal growth @xcite ..
Please generate the next two sentences of the article | diffraction methods such as helium beam scattering @xcite , low energy electron diffraction @xcite and other techniques @xcite , provide information on the collective behavior and the statistical properties of the surface .
these techniques have been used to measure the island size distribution , the island density , and their scaling properties with respect to the coverage and the flux @xcite . |
6,993 | Suppose that you have an abstract for a scientific paper: in the context of mod - gaussian convergence , as defined previously in our work with j. jacod , we obtain asymptotic formulas and lower bounds for local probabilities for a sequence of random vectors which are approximately gaussian in this sense , with increasing covariance matrix .
this is motivated by the conjecture concerning the density of the set of values of the riemann zeta function on the critical line .
we obtain evidence for this fact , and derive unconditional results for random matrices in compact classical groups , as well as for certain families of @xmath0-functions over finite fields . .
And you have already written the first three sentences of the full article: it is well - known ( see , e.g. , ( * ? ? ?
* th . 11.9 ) ) that , for @xmath1 , the set of values @xmath2 , @xmath3 , is dense in the complex plane .
in fact , much more is true : it was proved by bohr and jessen that there exists a borel probability measure @xmath4 on @xmath5 , such that the support of @xmath4 is the whole complex plane , and such that the convergence in law @xmath6 holds for @xmath7 continuous and bounded ..
Please generate the next two sentences of the article | the corresponding density question for @xmath8 is , however , still open ( it was apparently first raised by ramachandra during the 1979 durham conference , but seems to appear in print only in heath - brown s note in @xcite ) : the difficulty is that the values @xmath9 , @xmath10 , do not have a limiting distribution , as evidenced already by the hardy - littlewood asymptotic @xmath11 or by selberg s result that @xmath12 , @xmath10 , is asymptotically normal with variance _ growing to infinity _
( see also the work of ghosh @xcite for the imaginary part , and @xcite for a recent proof ) . |
6,994 | Suppose that you have an abstract for a scientific paper: multi - photon interference results in modulations of output probabilities with phase shift periods that are much shorter than @xmath0 . here , we investigate the physics behind these statistical patterns in the case of well - defined photon numbers in the input and output modes of a two - path interferometer .
we show that the periodicity of the multi - photon interference is related to the weak value of the unobserved intensity difference between the two arms of the interferometer .
this means that the operator relations between the photon number differences in input , path , and output can be used to determine the periodicity of the experimentally observed quantum interference , establishing an important link between the classical causality of random phase interference and quantum effects that depend on the superposition of classically distinct possibilities . .
And you have already written the first three sentences of the full article: one of the most basic operations of linear optics is the interference between two optical modes in a two - path interferometer . in quantum optics
, this scenario has been widely studied in the context of quantum metrology , where it serves to illustrate the role of non - classical correlations in the phase sensitivity of multi - photon interference @xcite .
unfortunately , these arguments about phase sensitivity often leave out the details of the physics , focusing merely on the perceived figures of merit and not on the mechanisms by which multi - photon interference patterns emerge ..
Please generate the next two sentences of the article | recent experiments on multi - photon interference are providing a much more detailed picture of non - classical effects in two - mode interferences @xcite , and it might be time to ask what these experimental observation of multi - photon fringes can tell us about the nature and origin of quantum interference . to properly address this question ,
it is necessary to distinguish carefully between classical wave interference and quantum interference . in typical experiments , |
6,995 | Suppose that you have an abstract for a scientific paper: in the heavy - quark limit , the hadronic matrix elements entering nonleptonic @xmath0-meson decays into two light mesons can be calculated from first principles including `` nonfactorizable '' strong - interaction corrections .
the @xmath1 decay amplitudes are computed including electroweak penguin contributions , su(3 ) violation in the light - cone distribution amplitudes , and an estimate of power corrections from chirally - enhanced terms and annihilation graphs .
the results are then used to reduce the theoretical uncertainties in determinations of the weak phases @xmath2 and @xmath3 . in that way ,
new constraints in the @xmath4 plane are derived .
predictions for the @xmath5 branching ratios and cp asymmetries are also presented .
a good global fit to the ( in part preliminary ) experimental data on the branching fractions is obtained without taking recourse to phenomenological models .
cern - th/2001 - 107 + clns 01/1728 + pitha 01/01 + shep 01/11 + hep - ph/0104110 + april 11 , 2001 * qcd factorization in @xmath5 decays and + extraction of wolfenstein parameters * m. beneke@xmath6 , g. buchalla@xmath7 , m. neubert@xmath8 and c.t .
sachrajda@xmath9 + .
And you have already written the first three sentences of the full article: the study of nonleptonic two - body decays of @xmath0 mesons is of primary importance for the exploration of cp violation and the determination of the flavour parameters of the standard model . because of the interference of several competing amplitudes , these processes allow for the presence of different weak and strong - interaction phases , which play a crucial role for cp violation . in the standard model ,
all cp - violating observables are related to the complex phase of the quark mixing matrix , which in turn implies nontrivial angles in the `` unitarity triangle '' @xmath10 . with the standard choice of phase conventions
, one defines the weak phases @xmath11 and @xmath12 , as well as @xmath13 . in the standard model.
Please generate the next two sentences of the article | , @xmath14 can be extracted in a theoretically clean way by measuring the time - dependent rates for the decays @xmath15 .
the measurement of @xmath2 ( or @xmath3 ) is more difficult , since it requires controlling the hadronic dynamics in nonleptonic @xmath0 decays . |
6,996 | Suppose that you have an abstract for a scientific paper: spontaneous parametric down conversion ( spdc ) has been largely exploited as a tool for absolute calibration of photon - counting detectors , i.e detectors registering very small photon fluxes . in @xcite
we derived a method for absolute calibration of analog detectors using spdc emission at higher photon fluxes , where the beam is seen as a continuum by the detector .
nevertheless intrinsic limitations appear when high - gain regime of spdc is required to reach even larger photon fluxes . here
we show that stimulated parametric down conversion allow one to avoid this limitation , since stimulated photon fluxes are increased by the presence of the seed beam
. 99 h.a .
bachor , _ a guide to experimental quantum optics _ , ( wiley - vch , new york , 1998 ) .
m. genovese , `` research on hidden variable theories : a review on recent progresses , '' phys . rep . * 413*/6 , 319 - 398 ( 2005 ) and references therein .
see , for a general review , n. gisin , g. ribordy , w. tittel and h. zbinden , quantum cryptography , rev .
mod .
phys .
* 74 * , 145 - 195 ( 2000 ) , and references therein .
giorgio brida , maria chekhova , marco genovese , alexander penin , ivano ruo - berchera , `` the possibility of absolute calibration of analog detectors by using parametric down - conversion : a systematic study , '' j. opt
. soc . am .
b * 23 * , 2185 - 2193 ( 2006 ) .
b.y . zeldovich and d.n .
klyshko , `` statistics of field in parametric luminescence , '' sov . phys .
jetp lett .
* 9 * 40 - 44 ( 1969 ) .
d.c .
burnham and d.l .
weinberg , `` observation of simultaneity in parametric production of optical photon pairs , '' phys .
rev .
lett . * 25 * , 84 - 87 ( 1970 ) .
d.n .
klyshko , `` use of two - photon light for absolute calibration of photoelectric detectors , '' sov .
j. quant .
elect .
* 10 * , 1112 - 1116 ( 1980 ) .
a. a. malygin , a. n. penin and a. v. sergienko , `` absolute calibration of the sensitivity of photodetectors....
And you have already written the first three sentences of the full article: prompted by the necessity of a precise calibration of photo - detectors both in the analog and photon - counting regime @xcite , we presented recently @xcite a detailed theoretical analysis on the possibility to use the correlations of spontaneous parametric down conversion ( spdc ) light @xcite for calibrating analog detectors , as an extension of the technique developed in photon counting regime @xcite . however , while the method is suitable for analog calibration at relatively low gain , which means a photon flux lower than @xmath0 photon / s , in higher - gain regime it is limited by the difficulty of collecting the same correlated modes in the two branches @xcite . in this paper
we present a detailed theoretical analysis of a scheme based on the stimulated pdc ( on the other hand a discussion of the uncertainty budget is left to a specifically addressed paper @xcite ) .
we show that this scheme allow to overcome the problem mentioned above ..
Please generate the next two sentences of the article | indeed , in this case the photon fluxes can be varied by varying the power of the coherent seed beam , without increasing the parametric gain @xmath1 . on the other hand , the spdc non - classical correlation at single - photon level which enables the absolute calibration of counting detectors survives , in some form , when a coherent seed is injected and the photon flux becomes macroscopic .
the schematic set - up for calibration of photodetectors by using pdc is shown in fig . |
6,997 | Suppose that you have an abstract for a scientific paper: we report synchrotron x - ray powder diffraction measurements of ce@xmath0la@xmath1th@xmath1 subject to pulsed magnetic fields as high as 28 tesla .
this alloy is known to exhibit a continuous volume collapse on cooling at ambient pressure , which is a modification of the @xmath2 transition in elemental cerium .
recently , it has been suggested on the basis of field - cooled resistivity and pulsed field magnetization measurements that the volume collapse in this alloy can be suppressed by the application of magnetic fields .
conversely , our direct diffraction measurements show a robust collapsed phase , which persists in magnetic fields as high as 28 tesla .
we also observe nanoscale disorder in the collapsed phase , which increasingly contaminates the high temperature phase on thermal cycling . .
And you have already written the first three sentences of the full article: elemental cerium is stark example of the complicating effects of magnetism in metals . in principle
a simple system , cerium at room temperature and ambient pressure presents a monatomic bravais lattice ( the face - centered - cubic @xmath3 phase ) .
however , under the application of modest pressures , cerium undergoes a spectacular first - order transition to a low temperature @xmath4 phase ..
Please generate the next two sentences of the article | both @xmath4 and @xmath3 are isostructural f.c.c
. phases , but differ by @xmath5 in volume , and have markedly different magnetic susceptibilities and resistivities.@xcite there are competing explanations for the transition , which variously invoke a `` kondo volume collapse''@xcite mechanism , a `` mott transition'',@xcite or some entropic mechanism@xcite . in all cases however , it is generally agreed that the large volume @xmath3 phase contains relatively larger localized magnetic moments ( evinced by the higher susceptibility ) and relatively less itinerant electrons ( evinced by the higher resistivity ) . beyond that |
6,998 | Suppose that you have an abstract for a scientific paper: we report fully quantum simulations of realistic models of boron - doped graphene - based field effect transistors , including atomistic details based on dft calculations .
we show that the self - consistent solution of the three - dimensional ( 3d ) poisson and schrdinger equations with a representation in terms of a tight - binding hamiltonian manages to accurately reproduce the dft results for an isolated boron - doped graphene nanoribbon . using a 3d poisson / schrdinger solver within the non - equilibrium green s functions ( negf ) formalism ,
self - consistent calculations of the gate - screened scattering potentials induced by the boron impurities have been performed , allowing the theoretical exploration of the tunability of transistor characteristics .
the boron - doped graphene transistors are found to approach unipolar behavior as the boron concentration is increased , and by tuning the density of chemical dopants the electron - hole transport asymmetry can be finely adjusted . correspondingly , the onset of a mobility gap in the device is observed .
although the computed asymmetries are not sufficient to warrant proper device operation , our results represent an initial step in the direction of improved transfer characteristics and , in particular , the developed simulation strategy is a powerful new tool for modeling doped graphene nanostructures .
the discovery of graphene has opened a promising alternative to silicon - based electronics .
@xcite reported charge mobilities in undoped graphene layers are actually orders of magnitude larger than those measured in silicon , but the unfortunate zero - gap semiconductor nature of this material severely limits the achievable @xmath0/@xmath1 ratio @xcite ( ratio infinite for an ideal switch of the current flowing through the device in the conducting state to that flowing in the nonconducting state ) for graphene transistors , making them not yet able to compete with mainstream silicon technologies .
@xcite another adverse feature....
And you have already written the first three sentences of the full article: parameters for our calculations have been obtained from a first - principle approach , as we detail in the following . as an initial step ,
first - principle density functional theory ( dft ) calculations were undertaken for a single substitutional boron impurity in two - dimensional ( 2d ) graphene and in gnrs , @xcite by means of the siesta code , @xcite within the local density approximation and using a double-@xmath4 basis set .
following the methodology in refs ..
Please generate the next two sentences of the article | @xcite , the onsite energies of the @xmath5 orbitals for the ( bulk ) 2d case were extracted . their variation with the distance from the boron atom
is shown in fig . |
6,999 | Suppose that you have an abstract for a scientific paper: the lagrange - mesh method is an approximate variational approach having the form of a mesh calculation because of the use of a gauss quadrature .
although this method provides accurate results in many problems with small number of mesh points , its accuracy can be strongly reduced by the presence of singularities in the potential term . in this paper , a new regularized lagrange - laguerre mesh , based on _ exactly _
orthonormal lagrange functions , is devised .
it is applied to two solvable radial potentials : the harmonic - oscillator and coulomb potentials . in spite of the singularities of the coulomb and centrifugal potentials ,
accurate bound - state energies are obtained for all partial waves .
the analysis of these results and a comparison with other lagrange - mesh calculations lead to a simple rule to predict in which cases a singularity does induce or not a significant loss of accuracy in lagrange - mesh calculations .
in addition , the lagrange - laguerre - mesh approach is applied to the evaluation of phase shifts via integral relations .
small numbers of mesh points suffice to provide very accurate results .
_ keywords _ : lagrange - mesh method , gauss quadrature , potential model , bound states and continuum .
And you have already written the first three sentences of the full article: the lagrange - mesh method @xcite is a simple and often accurate method for solving quantum - mechanical problems .
it can be seen as an approximate variational calculation using a basis of lagrange functions associated with a mesh and the gauss quadrature associated with this mesh to evaluate most of the matrix elements . for reasons
not perfectly understood @xcite , the lagrange - mesh method is in many applications as accurate as the corresponding variational approach ..
Please generate the next two sentences of the article | however , the success of the lagrange - mesh method relies ultimately on the validity of the gauss quadrature .
therefore , when the quality of the gauss - quadrature approximation is poor , the lagrange - mesh method is inaccurate . in particular |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.