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3,400 | Suppose that you have an abstract for a scientific paper: since 2010 the large hadron collider ( lhc ) is the accelerator with the highest stored energy per beam , with a record of 140 mj at a beam energy of 4 tev , almost a factor of 50 higher than other accelerators . with such a high stored energy , machine protection aspects set the boundary conditions for operation during all phases of the machine cycle .
only the low - intensity commissioning beams can be considered as relatively safe .
this document discusses the interplay of machine operation and machine protection at the lhc , from commissioning to regular operation .
+ + * keywords * + operation ; machine protection ; beam loss ; lhc . .
And you have already written the first three sentences of the full article: the large hadron collider ( lhc ) is the last in the series of hadron colliders after the isr ( intersecting storage ring ) , sps ( super proton synchrotron ) , tevatron , hera and rhic ( relativistic heavy ion collider ) .
the machine elements are installed on average 100 m below the surface in the 26.7 km long accelerator tunnel that housed the large electron positron collider ( lep ) between 1989 and 2000 @xcite .
the ring consists of eight arcs and of eight long straight sections ( lsss ) ..
Please generate the next two sentences of the article | the large particle physics experiments alice , atlas , cms and lhcb are installed at interaction points ( ips ) in the middle of four lsss , while the other lsss house the collimation ( or beam cleaning ) system , the radio - frequency ( rf ) system , the beam instrumentation and the beam dumping system .
the layout of the lhc is shown in fig . |
3,401 | Suppose that you have an abstract for a scientific paper: we assess the performance of a recently proposed renormalized adiabatic local density approximation ( ralda ) for _ ab initio _ calculations of electronic correlation energies in solids and molecules .
the method is an extension of the random phase approximation ( rpa ) derived from time - dependent density functional theory and the adiabatic connection fluctuation - dissipation theorem and contains no fitted parameters .
the new kernel is shown to preserve the accurate description of dispersive interactions from rpa while significantly improving the description of short range correlation in molecules , insulators , and metals . for molecular atomization energies
the ralda is a factor of 7(4 ) better than rpa(pbe ) when compared to experiments , and a factor of 3(1.5 ) better than rpa(pbe ) for cohesive energies of solids . for transition metals the inclusion of full shell semi - core states
is found to be crucial for both rpa and ralda calculations and can improve the cohesive energies by up to 0.4 ev .
finally we discuss straightforward generalizations of the method , which might improve results even further . .
And you have already written the first three sentences of the full article: the adiabatic - connection fluctuation - dissipation theorem ( acfdt ) provides an exact representation of the electronic correlation energy in term of the interacting density response function , within density functional theory ( dft).@xcite a major advantage of this method , is that it naturally accounts for dispersive interactions through the non - locality of the response function .
furthermore , in contrast to semi - local approximations , the acfdt correlation energy is naturally combined with the exact exchange energy and does not rely on error cancellation between the exchange and correlation contributions to the total energy .
the accuracy of correlation energies within the acfdt , then depends on the quality of the interacting response function which needs to be approximated ..
Please generate the next two sentences of the article | the most famous approximation for the response function is the random phase approximation ( rpa ) , which is obtained when a non - interacting approximation is used for the irreducible polarizability . for metallic systems ,
the rpa provides a qualitative account of screening in and cures the pathological divergence of second order perturbation theory for the homogeneous electron gas . in 2001 |
3,402 | Suppose that you have an abstract for a scientific paper: current ongoing stellar spectroscopic surveys ( rave , galah , gaia - eso , lamost , apogee , gaia ) are mostly devoted to studying galactic archaeology and structure of the galaxy .
but they allow for important auxiliary science :
( i ) galactic interstellar medium can be studied in four dimensions ( position in space @xmath0 radial velocity ) through weak but numerous diffuse insterstellar bands and atomic absorptions seen in spectra of background stars , ( ii ) emission spectra which are quite frequent even in field stars can serve as a good indicator of their youth , pointing e.g. to stars recently ejected from young stellar environments , ( iii ) astrometric solution of the photocenter of a binary to be obtained by gaia can yield accurate masses when joined by spectroscopic information obtained serendipitously during a survey .
these points are illustrated by first results from the first three surveys mentioned above .
these hint at the near future : spectroscopic studies of the dynamics of the interstellar medium can identify and quantify galactic fountains which may sustain star formation in the disk by entraining fresh gas from the halo ; rave already provided a list of @xmath1 14,000 field stars with chromosperic emission in ca ii lines , to be supplemented by many more observations by gaia in the same band , and by galah and gaia - eso observations of balmer lines ; several millions of astrometric binaries with periods up to a few years which are being observed by gaia can yield accurate masses when supplemented with measurements from only a few high - quality ground based spectra . .
And you have already written the first three sentences of the full article: last decade has seen a major shift in stellar spectroscopy : a slow collection of individual spectra has been accelerated by massive surveys , mostly using fiber - fed spectrographs with hundreds of spectra observed simultaneously .
the past and ongoing efforts include rave @xcite , gaia - eso @xcite , segue @xcite , apogee @xcite , lamost @xcite , galah @xcite , and of course gaia @xcite .
up - to - date overviews of the state and results of these surveys are given elsewhere in this volume ..
Please generate the next two sentences of the article | the main goal of stellar spectroscopic surveys is to study galactic structure and evolution . but the collected spectra allow for a significant auxiliary science .
the three examples discussed below are an illustration of a vast range of posibilities and are by no means exhaustive . |
3,403 | Suppose that you have an abstract for a scientific paper: we evaluate the casimir energy and force for a massive scalar field with general curvature coupling parameter , subject to robin boundary conditions on two codimension - one parallel plates , located on a @xmath0-dimensional background spacetime with an arbitrary internal space . the most general case of different robin coefficients on the two separate plates is considered . with independence of the geometry of the internal space ,
the casimir forces are seen to be attractive for special cases of dirichlet or neumann boundary conditions on both plates and repulsive for dirichlet boundary conditions on one plate and neumann boundary conditions on the other . for robin boundary conditions ,
the casimir forces can be either attractive or repulsive , depending on the robin coefficients and the separation between the plates , what is actually remarkable and useful .
indeed , we demonstrate the existence of an equilibrium point for the interplate distance , which is stabilized due to the casimir force , and show that stability is enhanced by the presence of the extra dimensions
. applications of these properties in braneworld models are discussed . finally , the corresponding results are generalized to the geometry of a piston of arbitrary cross section .
pacs numbers : 03.70.+k , 11.10.kk .
And you have already written the first three sentences of the full article: many of the high - energy theories of fundamental physics are formulated in higher - dimensional spacetimes . in particular , the idea of extra dimensions has been extensively used in supergravity and superstring theories .
it is commonly assumed that the extra dimensions are compactified . from the inflationary point of view , universes with compact spatial dimensions , under certain conditions , should be considered a rule rather than an exception @xcite .
models involving a compact universe with non - trivial topology play a very important role by providing proper initial conditions for inflation . and compactification of spatial dimensions leads to a number of interesting quantum field theoretical effects , which include instabilities in interacting field theories , topological mass generation , and symmetry breaking . in the case of non - trivial topology ,.
Please generate the next two sentences of the article | the boundary conditions imposed on fields give rise to a modification of the spectrum for vacuum fluctuations and , as a result , to casimir - type contributions in the vacuum expectation values of physical observables ( for the topological casimir effect and its role in cosmology see @xcite and references therein ) . in models of the kaluza - klein type
, the casimir effect has been used as a stabilization mechanism for moduli fields and as a source for dynamical compactification of the extra dimensions , in particular , for quantum kaluza - klein gravity ( see ref . |
3,404 | Suppose that you have an abstract for a scientific paper: in a general two - scalar - doublet model without fermions , there is a unique source of cp violation , @xmath0 , in the gauge interactions of the scalars .
it arises in the mixing of the three neutral physical scalars @xmath1 , @xmath2 and @xmath3 .
cp violation may be observed via different decay rates for @xmath4 and @xmath5 ( or , alternatively , for @xmath6 and @xmath7 depending on which decays are kinematically allowed ) .
i compute the part of those cp - violating decay - rate differences which is proportional to @xmath0 .
the cp - invariant final - state - interaction phase is provided by the absorptive parts of the one - loop diagrams .
i check the gauge invariance of the whole calculation .
-15 mm .
And you have already written the first three sentences of the full article: there are general reasons for the interest in the possibility of cp violation in the scalar sector .
cp violation is a necessary ingredient for the generation of the baryon asymmetry of the universe @xcite .
it is believed that cp violation in the kobayashi .
Please generate the next two sentences of the article | maskawa matrix is not large enough to explain that asymmetry @xcite .
it has been speculated @xcite that the scalar sector might provide the missing cp violation . |
3,405 | Suppose that you have an abstract for a scientific paper: minimal absent words ( maw ) of a genomic sequence are subsequences that are absent themselves but the subwords of which are all present in the sequence . the characteristic distribution of genomic maws as a function of their length has been observed to be qualitatively similar for all living organisms , the bulk being rather short , and only relatively few being long .
it has been an open issue whether the reason behind this phenomenon is statistical or reflects a biological mechanism , and what biological information is contained in absent words . in this work
we demonstrate that the bulk can be described by a probabilistic model of sampling words from random sequences , while the tail of long maws is of biological origin .
we introduce the novel concept of a core of a minimal absent word , which are sequences present in the genome and closest to a given maw .
we show that in bacteria and yeast the cores of the longest maws , which exist in two or more copies , are located in highly conserved regions the most prominent example being ribosomal rnas ( rrnas ) .
we also show that while the distribution of the cores of long maws is roughly uniform over these genomes on a coarse - grained level , on a more detailed level it is strongly enhanced in 3 untranslated regions ( utrs ) and , to a lesser extent , also in 5 utrs .
this indicates that maws and associated maw cores correspond to fine - tuned evolutionary relationships , and suggest that they can be more widely used as markers for genomic complexity .
enomic sequences are texts in languages shaped by evolution .
the simplest statistical properties of these languages are short - range dependencies , ranging from single - nucleotide frequencies ( gc content ) to @xmath0-step markov models , both of which are central to gene prediction and many other bioinformatic tasks @xcite .
more complex characteristics , such as abundances of @xmath0-mers , sub - sequences of length @xmath0 , have applications to classification of genomic sequences ....
And you have already written the first three sentences of the full article: let us consider a random sequence @xmath27 of total length @xmath28 with alphabet @xmath29 .
each position of @xmath27 is independently assigned the letter @xmath30 , @xmath31 , @xmath32 , or @xmath33 with corresponding probabilities @xmath34 , @xmath35 , @xmath36 and @xmath37 ( @xmath38 ) .
a word of length @xmath13 has the generic form of @xmath39 , where @xmath40 is the letter at the @xmath41-th position ..
Please generate the next two sentences of the article | the total number of such words is @xmath42 .
this number exceeds @xmath28 when @xmath13 increases to order @xmath43 , therefore most of the words of length @xmath44 will never appear in @xmath27 |
3,406 | Suppose that you have an abstract for a scientific paper: the inner regions of barred galaxies contain substructures such as off - axis shocks , nuclear rings , and nuclear spirals .
these substructure may affect star formation , and control the activity of a central black hole ( bh ) by determining the mass inflow rate .
we investigate the formation and properties of such substructures using high - resolution , grid - based hydrodynamic simulations .
the gaseous medium is assumed to be infinitesimally - thin , isothermal , and non - self - gravitating .
the stars and dark matter are represented by a static gravitational potential with four components : a stellar disk , the bulge , a central bh , and the bar . to investigate various galactic environments , we vary the gas sound speed @xmath0 as well as the mass of the central bh @xmath1 .
once the flow has reached a quasi - steady state , off - axis shocks tend to move closer to the bar major axis as @xmath0 increases .
nuclear rings shrink in size with increasing @xmath0 , but are independent of @xmath1 , suggesting that ring position is not determined by the lindblad resonances .
rings in low-@xmath0 models are narrow since they are occupied largely by gas on @xmath2-orbits and well decoupled from nuclear spirals , while they become broad because of large thermal perturbations in high-@xmath0 models .
nuclear spirals persist only when either @xmath0 is small or @xmath1 is large ; they would otherwise be destroyed completely by the ring material on eccentric orbits .
the shape and strength of nuclear spirals depend sensitively on @xmath0 and @xmath1 such that they are leading if both @xmath0 and @xmath1 are small , weak trailing if @xmath0 is small and @xmath1 is large , and strong trailing if both @xmath0 and @xmath1 are large . while the mass inflow rate toward the nucleus is quite small in low-@xmath0 models because of the presence of a narrow nuclear ring , it becomes larger than @xmath3 when @xmath0 is large , providing a potential explanation of nuclear activity in seyfert galaxies . .
And you have already written the first three sentences of the full article: stellar bars play an important role in the dynamical evolution of gas in galaxies . by introducing a non - axisymmetric torque
, they produce interesting morphological substructures in the gaseous medium , including a pair of dust lanes at the leading side of the bar , a nuclear ring near the center , and nuclear spirals inside the ring ( e.g. , @xcite ) .
they also transport gas inward which can trigger starbursts in the rings ( e.g. , @xcite ) and if the mass inflow extends all the way to the center , they may help power active galactic nuclei ( agn ) ( e.g. , @xcite ) ..
Please generate the next two sentences of the article | since bar substructures represent a nonlinear response of the gas to a non - axisymmetric gravitational potential , their formation and evolution is best studied using direct numerical simulations .
there have been a number of numerical studies on the gas dynamics in barred galaxies . based on the numerical scheme employed |
3,407 | Suppose that you have an abstract for a scientific paper: a feshbach resonance arises in cold atom scattering due to the complex interplay between several coupled channels .
however , the essential physics of the resonance may be encapsulated in a simplified model consisting of just two coupled channels . in this paper
we describe in detail how such an effective feshbach model can be constructed from knowledge of a few key parameters , characterizing the atomic born - oppenheimer potentials and the low energy scattering near the resonance .
these parameters may be obtained either from experiment or full coupled channels calculations . using r - matrix theory
we analyze the bound state spectrum and the scattering properties of the two - channel model , and find it to be in good agreement with exact calculations . .
And you have already written the first three sentences of the full article: a feshbach resonance can occur in collision events , when a closed channel bound state of a specific electronic level of an atom is coupled to the scattering continuum of an open channel of another electronic level of the atom @xcite .
if the energy of the discrete closed channel state is very close to that of the scattering particles , the cross section is resonantly enhanced , due to the temporary capture of the particles in the quasi - bound state .
feshbach resonances would be of limited importance in cold atom scattering if not for the ability to control the energy of the bare resonance state , and hence the resonance position , through the application of a static magnetic field @xcite . in this context the open and closed channels , in the separated atom limit ,.
Please generate the next two sentences of the article | correspond to pairs of alkali atoms in different combinations of eigenstates of the hyperfine and zeeman hamiltonian with total angular momentum projection quantum numbers @xmath0 and @xmath1 .
the entrance channel is in an @xmath2-wave orbital state ( relative angular momentum quantum number @xmath3 ) , while the closed channels may be in any partial wave , with @xmath4 indicating the projection of the relative orbital angular momentum . |
3,408 | Suppose that you have an abstract for a scientific paper: hot subluminous stars lying up to 0.7 mag below the extreme horizontal branch ( ehb ) are found in the ultraviolet ( uv ) color - magnitude diagrams of both @xmath0 cen ( dcruz et al .
2000 ) and ngc 2808 ( brown et al . 2001 ) . in order to explore the evolutionary status of these subluminous stars ,
we have evolved a set of low - mass stars continuously from the main sequence through the helium - core flash to the hb for a wide range in the mass loss along the red - giant branch ( rgb ) .
stars with the largest mass loss evolve off the rgb to high effective temperatures before igniting helium in their cores .
our results indicate that the subluminous ehb stars , as well as the gap within the ehb of ngc 2808 , can be explained if these stars undergo a late helium - core flash while descending the white - dwarf cooling curve . under these conditions
the convection zone produced by the helium flash will penetrate into the stellar envelope , thereby mixing most , if not all , of the envelope hydrogen into the hot helium - burning interior , where it is rapidly consumed ( sweigart 1997 ) .
this phenomenon is analogous to the `` born - again '' scenario for producing hydrogen - deficient stars following a very late helium - shell flash .
this `` flash mixing '' of the stellar envelope greatly enhances the envelope helium and carbon abundances and , as a result , leads to a discontinuous jump in the hb effective temperature .
we argue that the ehb gap in ngc 2808 is associated with this theoretically predicted dichotomy in the hb morphology . using new helium- and carbon - rich stellar atmospheres , we show that these changes in the envelope abundances of the flash - mixed stars will suppress the uv flux by the amount needed to explain the hot subluminous ehb stars in @xmath0 cen and ngc 2808 .
moreover , we demonstrate that models without flash mixing lie , at most , only @xmath1 mag below the ehb , and hence fail to explain the observations .
flash mixing may also provide a new....
And you have already written the first three sentences of the full article: extreme horizontal - branch ( ehb ) stars occupy the hot end of the horizontal branch ( hb ) in globular clusters with extended blue hb tails .
the envelope masses of these stars are too small ( @xmath2 @xmath30.02 @xmath4 ) to sustain hydrogen - shell burning , and thus nearly all of their luminosity comes from helium burning in the core .
recent observations have discovered an unexpected population of hot stars lying below the canonical ehb in the uv color - magnitude diagram ( cmd ) of @xmath0 cen ( dcruz et al ..
Please generate the next two sentences of the article | 2000 and references therein ) . in the present paper
we will use new uv observations of the globular cluster ngc 2808 to explore the origin of these subluminous ehb stars and will suggest that these stars may be the progeny of stars which underwent extensive mixing during a delayed helium flash on the white - dwarf ( wd ) cooling curve ( brown et al . |
3,409 | Suppose that you have an abstract for a scientific paper: we introduce a new lattice growth model , which we call boundary sandpile . the model amounts to potential - theoretic redistribution of a given initial mass on @xmath0 ( @xmath1 ) onto the boundary of an ( a priori ) unknown domain .
the latter evolves through sandpile dynamics , and has the property that the mass on the boundary is forced to stay below a prescribed threshold .
since finding the domain is part of the problem , the redistribution process is a discrete model of a free boundary problem , whose continuum limit is yet to be understood .
we prove general results concerning our model . these include canonical representation of the model in terms of the smallest super - solution among a certain class of functions , uniform lipschitz regularity of the scaled odometer function , and hence the convergence of a subsequence of the odometer and the visited sites , discrete symmetry properties , as well as directional monotonicity of the odometer function .
the latter ( in part ) implies the lipschitz regularity of the free boundary of the sandpile . as a direct application of some of the methods developed in this paper , combined with earlier results on classical abelian sandpile
, we show that the boundary of the scaling limit of abelian sandpile is locally a lipschitz graph . .
And you have already written the first three sentences of the full article: recent years have seen a surge of modelling particle dynamics from a discrete potential theoretic perspective .
the models , which usually run under the heading _ aggregation models _ , in particular cases boil down to ( harmonic / poisson ) redistribution of a given initial mass ( sandpile ) according to some prescribed governing rules .
the most famous and well - known model is the poincar s balayage , where a given initial mass distribution @xmath2 ( in a given domain @xmath3 ) is to be redistributed ( or mapped ) to another distribution @xmath4 on the boundary of the domain @xmath5 where @xmath4 is uniquely defined through @xmath2 , and @xmath3 ..
Please generate the next two sentences of the article | this model uses continuous amounts of mass instead of discrete ones ; the latter is more common in chip firing on graphs ( see @xcite for instance ) . a completely different model called _ partial - balayage _ ( see @xcite ) aims at finding a body ( domain ) that is gravi - equivalent with the given initial mass .
this problem , in turn , is equivalent to variational inequalities and the so - called obstacle problem . |
3,410 | Suppose that you have an abstract for a scientific paper: observations of four comets made with the _ far ultraviolet spectroscopic explorer _ show the rotational envelope of the ( 0,0 ) band of the co hopfield - birge system ( @xmath0 @xmath1 ) at 1088 to consist of both `` cold '' and `` hot '' components , the `` cold '' component accounting for @xmath275% of the flux and with a rotational temperature in the range 5575 k. we identify the `` hot '' component as coming from the dissociation of into rotationally `` hot '' co , with electron impact dissociation probably dominant over photodissociation near the nucleus .
an additional weak , broad satellite band is seen centered near the position of the p(40 ) line that we attribute to co fluorescence from a non - thermal high @xmath3 rotational population produced by photodissociation of formaldehyde into co and .
this process also leaves the preferentially populated in excited vibrational levels which are identified by fluorescent lines in the spectrum excited by solar @xmath41031.9 and solar lyman-@xmath5 .
the amount of produced by dissociation is comparable to the amount produced by photodissociation of .
electron impact excitation of co , rather than resonance fluorescence , appears to be the primary source of the observed @xmath6 @xmath1(0,0 ) band at 1151 . .
And you have already written the first three sentences of the full article: in previous papers @xcite , we reported on the spectra of four comets observed by the _ far ultraviolet spectroscopic explorer _ ( _ fuse _ ) . launched in june 1999 , _ fuse _ operated through october 2007 providing an orbiting capability with a spectral resolution better than 0.4 in the wavelength range 9051187 together with very high sensitivity to weak emissions making possible both the search for minor coma species and extensive temperature and density diagnostics for the dominant species . our initial reports on the three comets observed in 2001 focused on three hopfield - birge band systems of co not previously observed in comets , the @xmath6 @xmath1(0,0 ) band at 1150.5 , the @xmath0 @xmath1(0,0 ) band at 1087.9 , and the weak @xmath7 @xmath1(0,0 ) band at 1076.1 , three lines of h@xmath8 fluorescently pumped by solar lyman-@xmath9 radiation , and upper limits to emission from and .
the rotational envelopes of the co bands are resolved and appear to consist of both cold and warm components , the cold component , with a rotational temperature in the range 5575 k , accounting for over 75% of the flux and presumably due to native co released by the nucleus .
the warm ( @xmath2500 k ) component suggested a photodissociation source but this was considered unlikely because the low rate for this process in the solar radiation field would have required a very high relative abundance of ..
Please generate the next two sentences of the article | emission at 1031.9 and 1037.6 was searched for but only the 1031.9 line was marginally detected in c/2000 wm1 at about the level predicted by a model used to explain the x - ray emission from comets as being produced by charge exchange between solar wind ions and cometary neutrals @xcite .
the higher signal / noise ratio in the spectrum of comet c/2001 q4 , observed in april 2004 , enabled an accurate determination of the wavelength of this feature which suggested that it was the ( 1,1 ) q(3 ) werner ( @xmath10 ) line , which can be fluorescently pumped by either solar @xmath4989.8 or @xmath41031.9 . |
3,411 | Suppose that you have an abstract for a scientific paper: the inclusive cross sections of the @xmath0-particles produced in the reaction @xmath1li+@xmath2 tb have been measured at energies around the coulomb barrier .
the measured cross sections are found to be orders of magnitude larger than the calculated cross sections of @xmath1li breaking into @xmath0 and @xmath3 fragments , thus indicating contributions from other processes .
the experimental cross sections of @xmath4-stripping and @xmath4-pickup processes have been determined from an entirely different measurement , reported earlier .
apart from incomplete fusion and/ @xmath3-transfer processes , the @xmath4-stripping process is found to be a significant contributor to the inclusive @xmath0-particle cross sections in this reaction . .
And you have already written the first three sentences of the full article: investigation of reactions involving weakly bound projectiles and the influence of their low binding energies on various reaction channels has received a fillip in recent years , especially in the context of the increasing number of radioactive ion beam facilities . to have a proper understanding of the influence of breakup of loosely bound projectiles on the fusion process , one needs to understand the mechanisms of all the competing reaction channels .
measurements involving weakly bound projectiles , both stable and unstable , with @xmath0+x cluster structures show substantially large production cross sections for @xmath0-particles [ 1 - 9 ] , which indicate the presence of mechanisms other than the @xmath0+x breakup .
_ showed that for the reaction @xmath5li+@xmath2 tb @xcite , about half of the @xmath0 and triton yield originates from the breakup - fusion process , which is more commonly referred to as the incomplete fusion ( icf ) process ..
Please generate the next two sentences of the article | evidence of transfer - induced breakup producing @xmath0-particles in the reaction @xmath5li+@xmath6cu has also been reported @xcite .
our recent works on the systematic measurements of complete and incomplete fusion excitation functions for the reactions @xmath7li+@xmath2 tb and @xmath8b+@xmath2 tb @xcite have shown that the complete fusion ( cf ) cross sections at above - barrier energies are suppressed for reactions with weakly bound projectiles , and the extent of suppression is correlated with the @xmath0-breakup threshold of the projectile . |
3,412 | Suppose that you have an abstract for a scientific paper: a structured mixed phase consisting of quark and hadron phases is numerically studied with the coulomb screening effect and the surface effect .
we carefully introduced the coulomb potential , so that a geometrical structure becomes mechanically unstable when the surface tension is large .
charge densities are largely rearranged by the screening effect , and thereby the equation of state shows the similar behavior to that given by the maxwell construction .
therefore , although bulk calculations with the gibbs conditions show that the mixed phase may exist in a wide density region , we can see it is restricted to a narrow density region by the surface effect and the coulomb screening effect .
* hadron - quark matter phase transition in neutron stars * tomoki endo@xmath0 , toshiki maruyama@xmath1 , satoshi chiba@xmath1 and toshitaka tatsumi@xmath2 @xmath2 department of physics , kyoto university , kyoto 606 - 8502 , japan + @xmath1 advanced science research center , japan atomic energy research institute , tokai , ibaraki 319 - 1195 , japan + .
And you have already written the first three sentences of the full article: it has been believed that hadron matter changes to quark matter at high - density region by way of the `` deconfinement phase transition '' .
unfortunately the deconfinement phase transition have not been well understood up to now , and many authors have studied it by model calculations or by first - principle calculations like lattice qcd .
these studies are now developing , and many exciting results have been reported ..
Please generate the next two sentences of the article | properties of quark matter have been actively studied theoretically in quark - gluon plasma , color superconductivity @xcite or magnetism @xcite , and experimentally in relativistic heavy - ion collision ( rhic ) , hera or early universe and compact stars @xcite .
when we calculate uniform hadron matter ( nuclear matter ) and quark matter at zero temperature separately , by using the mit bag model , we can expect the first - order phase transition as seen in figs . |
3,413 | Suppose that you have an abstract for a scientific paper: we propose a scheme to transfer the quantum state of light fields to the collective density excitations of a bose einstein condensate ( bec ) in a cavity .
this scheme allows to entangle two becs in a double cavity setup by transferring the quantum entanglement of two light fields produced from a nondegenerate parametric amplifier ( nopa ) to the collective density excitations of the two becs .
an epr state of the collective density excitations can be created by a judicious choice of the system parameters . .
And you have already written the first three sentences of the full article: it is widely accepted that quantum entanglement is an essential ingredient for the implementation of quantum information processing devices @xcite .
creating highly entangled multi - particle states is therefore one of the most challenging goals of modern experimental quantum mechanics .
quantum entanglement of two or more systems leads to correlations between observables of the systems that can not be explained on the basis of local realistic theories ..
Please generate the next two sentences of the article | quantum entanglement lies at the heart of the difference between the quantum and the classical world . due to its vast application
, quantum entanglement has been studied in different systems such as optomechanical systems@xcite , bose einstein condensates ( bec ) trapped in double quantum well @xciteand in optical lattices @xcite . |
3,414 | Suppose that you have an abstract for a scientific paper: we demonstrate that local modulations of magnetic couplings have a profound effect on the temperature dependence of the relaxation rate of optical magnons in a wide class of antiferromagnets in which gapped excitations coexist with acoustic spin waves . in a two - dimensional collinear antiferromagnet with an easy - plane anisotropy ,
the disorder - induced relaxation rate of the gapped mode , @xmath0 , greatly exceeds the magnon - magnon damping , @xmath1 , negligible at low temperatures .
we measure the lifetime of gapped magnons in a prototype @xmath2 antiferromagnet bani@xmath3(po@xmath4)@xmath3 using a high - resolution neutron - resonance spin - echo technique and find experimental data in close accord with the theoretical prediction .
similarly strong effects of disorder in the three - dimensional case and in noncollinear antiferromagnets are discussed . _
introduction._the recent development of the neutron - resonance spin - echo technique has led to dramatic improvement of the energy resolution in neutron - scattering experiments @xcite . when applied to elementary excitations in magnetic insulators
, this technique allows one to measure magnon linewidth with the @xmath5ev accuracy compared to the mev resolution of a typical triple - axis spectrometer .
damping of quasiparticles depends fundamentally on the strength of their interactions with each other and with impurities , information not accessible directly by other measurements .
although theoretical studies of magnon damping in antiferromagnets ( afs ) go back to the 1970s @xcite , a comprehensive comparison between theory and experiment is still missing , mainly due to the lack of experimental data .
magnon - magnon scattering is traditionally viewed as the leading source of temperature - dependent magnon relaxation rates in afs @xcite .
another common relaxation mechanism in solids is the lattice disorder , which is responsible for a variety of the low - temperature effects , such as residual resistivity of metals....
And you have already written the first three sentences of the full article: here we briefly outline basic steps and main results of the spin - wave calculations for the energy spectrum and the magnon relaxation rates of the @xmath143@xmath144 antiferromagnet on a honeycomb lattice .
the harmonic spin - wave analysis of the nearest - neighbor heisenberg honeycomb - lattice antiferromagnet can be found , for example , in @xcite .
geometry of exchange bonds of the considered model is schematically shown in fig ..
Please generate the next two sentences of the article | [ suppl : lattice ] .
the unit cell of the antiferromagnetic structure coincides with the crystal unit cell and contains two oppositely aligned spins @xmath145 and @xmath146 in positions @xmath147 and @xmath148 . |
3,415 | Suppose that you have an abstract for a scientific paper: sn 1885 was a probable subluminous type ia supernova which occurred in the bulge of the andromeda galaxy , m31 , at a projected location 16@xmath0 from the nucleus .
here we present and analyze _ hubble space telescope _ images of the sn 1885 remnant seen in absorption against the m31 bulge via the resonance lines of , , , and .
viewed in h & k line absorption , the remnant appears as a nearly black circular spot with an outermost angular radius of @xmath1 , implying a maximum linear radius of @xmath2 pc at m31 s estimated distance of @xmath3 kpc and hence a 120 yr average expansion velocity of @xmath4 .
the strongest absorption is organized in a broken ring structure with a radius of @xmath5 (= @xmath6 km s@xmath7 ) with several apparent absorption ` clumps ' of an angular size around that of the image pixel scale of @xmath8 (= 1500 km s@xmath7 ) . and absorption structures appear similar except for a small absorption peak displaced @xmath9 off - center of the structure by a projected velocity of about @xmath10 km s@xmath7 .
analyses of these images using off - center , delayed - detonation models suggest a low @xmath11ni production similar to the subluminous sn ia explosion of sn 1986 g .
the strongly lopsided images of of and can be understood as resulting from an aspherical chemical distribution , with the best agreement found using an off - center model viewed from an inclination of @xmath12 60@xmath13 .
the detection of small scale ca ii clumps is the first direct evidence for some instabilities and the existence of a deflagration phase in sne ia or , alternatively , mixing induced by radioactive decay of @xmath11ni over time scales of seconds or days
. however , the degree of mixing allowed by the observed images is much smaller than current 3d calculations for rayleigh - taylor dominated deflagration fronts .
moreover , the images require a central region of no or little ca but iron group elements indicative for burning under sufficiently high densities for electron capture....
And you have already written the first three sentences of the full article: the ` bright nova ' s andromedae ( s and ) was discovered in the central bulge of m31 ( ngc 224 ) during late august of 1885 .
it is believed to have been a type ia supernova ( sn ia ) on the basis of an apparent absence of hydrogen balmer lines @xcite and a close match of nearly all reported spectral features to those of sne ia @xcite .
however relative to normal sn ia events , sn 1885 was subluminous with an unusually rapid initial decline and a somewhat redder @xmath14 color @xcite . a recent analysis of sn 1885 observations by @xcite suggests a decline rate of @xmath15 mag and a maximum brightness of @xmath16 and @xmath17 , assuming a m31 distance modulus of ( @xmath18)@xmath19 = 24.4 corresponding to a distance of 760 kpc ..
Please generate the next two sentences of the article | the remnant of sn 1885 remained undetected for over a century despite numerous searches in the optical and radio @xcite .
the remnant was finally detected in 1989 , not through its emission , but as a small dark spot of absorption in the m31 bulge on an image taken using a near - uv filter ( 3900 @xmath20 100 ) sensitive to h & k resonance line absorption @xcite . |
3,416 | Suppose that you have an abstract for a scientific paper: we investigate the nontrivial interplay between geometry and temperature in the casimir effect for the sphere - plate and cylinder - plate configurations . at low temperature ,
the thermal contribution to the casimir force is dominated by this interplay , implying that standard approximation techniques such as the pfa are inapplicable even in the limit of small surface separation .
thermal fluctuations on scales of the thermal wavelength lead to a delocalization of the thermal force density at low temperatures . as a consequence ,
the temperature dependence strongly differs from naive expectations .
most prominently , thermal forces can develop non - monotonic behavior below a critical temperature .
we perform a comprehensive study of such geothermal phenomena in these casimir geometries , using analytical and numerical worldline techniques for dirichlet scalar fluctuations . .
And you have already written the first three sentences of the full article: the casimir effect @xcite , inspiring many branches of physics @xcite , features a decisive geometry dependence : the fluctuation - induced interaction between test bodies or surfaces depends on their shape and orientation .
this is because the casimir effect arises from the fluctuation spectrum in presence of the surfaces relative to the vacuum fluctuations .
the spectral properties in turn are a direct consequence of the geometry ..
Please generate the next two sentences of the article | this geometry dependence becomes even more pronounced at finite temperature @xmath0 : thermal fluctuations can predominantly be associated with a characteristic length scale , the thermal wavelength @xmath1 .
thermal fluctuations contribute to the casimir force , whenever the scale set by the thermal wavelength is commensurate with a mode of the fluctuation spectrum as defined by the geometry . |
3,417 | Suppose that you have an abstract for a scientific paper: we use the mean - field dynamo equations to show that an incoherent alpha effect in mirror - symmetric turbulence in a shearing flow can generate a large scale , coherent magnetic field .
we illustrate this effect with simulations of a few simple systems . in accretion disks ,
this process can lead to axisymmetric magnetic domains whose radial and vertical dimensions will be comparable to the disk height
. this process may be responsible for observations of dynamo activity seen in simulations of dynamo - generated turbulence involving , for example , the balbus - hawley instability . in this case
the magnetic field strength will saturate at @xmath0 times the ambient pressure in real accretion disks .
the resultant dimensionless viscosity will be of the same order .
in numerical simulations the azimuthal extent of the simulated annulus should be substituted for @xmath1 .
we compare the predictions of this model to numerical simulations previously reported by brandenburg et al .
( 1995 ) . in a radiation pressure
dominated environment this estimate for viscosity should be reduced by a factor of @xmath2 due to magnetic buoyancy . .
And you have already written the first three sentences of the full article: understanding the transport of angular momentum in accretion disks is one of the basic challenges in modern astrophysics .
the traditional approach ( @xcite ) is to assume that accretion disks are characterized by an effective viscosity , arising from an unspecified collective process , given by @xmath3 , where @xmath4 is the local sound speed , @xmath5 is the disk half - thickness , and @xmath6 is a constant of order unity .
more recently , there has been the realization ( @xcite ) that a previously discovered magnetic field instability in a shearing flow ( @xcite , @xcite ) will act to produce a positive angular momentum flux in an accretion disk ..
Please generate the next two sentences of the article | this has given rise to two separate , but related claims .
the first is the proposal that this is the dominant mechanism of angular momentum transport in ionized accretion disks . |
3,418 | Suppose that you have an abstract for a scientific paper: interacting quintessence models have been proposed to explain or , at least , alleviate the coincidence problem of late cosmic acceleration . in this paper
we are concerned with two aspects of these kind of models : ( i ) the dynamical evolution of the model of chimento _ et al . _
[ l.p .
chimento , a.s .
jakubi , d. pavn , and w. zimdahl , phys .
rev .
d * 67 * , 083513 ( 2003 ) .
] , i.e. , whether its cosmological evolution gives rise to a right sequence of radiation , dark matter and dark energy dominated eras , and ( ii ) whether the dark matter dark energy ratio asymptotically evolves towards a non - zero constant . after showing that the model correctly reproduces these eras
, we correlate three data sets that constrain the interaction at three redshift epochs : @xmath0 , @xmath1 , and @xmath2 .
we discuss the model selection and argue that even if the model under consideration fulfills both requirements , it is heavily constrained by observation .
the prospects that the coincidence problem can be explained by the coupling of dark matter to dark energy are not clearly favored by the data . .
And you have already written the first three sentences of the full article: recent measurements of luminosity distances using supernovae type ia ( snia ) @xcite , of the cosmic microwave background ( cmb ) temperature anisotropies with the wilkinson microwave anisotropy ( wmap ) satellite @xcite , large scale structure @xcite , the integrated sachs
wolfe effect @xcite , and weak lensing @xcite , strongly suggest that the universe is currently undergoing a phase of accelerated expansion -see
@xcite for recent reviews . within general relativity.
Please generate the next two sentences of the article | the obvious candidate to explain the present acceleration is the cosmological constant ( or vacuum energy ) , and in fact the nave model built on it , @xmath3cdm , seems to pass reasonably well all cosmological tests .
however , it suffers from two serious drawbacks from the theoretical side : the unnatural low value of the corresponding energy density , 123 magnitude orders larger than observed , and the so - called coincidence problem " , namely , why are the densities of matter and vacuum of the same order precisely today ? " , that requires the vacuum energy density to be 96 orders of magnitude smaller than the matter density at the planck scale . |
3,419 | Suppose that you have an abstract for a scientific paper: we discuss a preliminary study of the impact of duality violations on extractions from @xmath0 decay data of the @xmath1 vevs which determine chiral limit standard model @xmath2 matrix elements of the electroweak penguin operators . .
And you have already written the first three sentences of the full article: in the standard model ( sm ) , @xmath3 is dominated by contributions from the gluonic and electroweak penguin ( ewp ) operators , @xmath4 and @xmath5 . in the @xmath6
chiral limit , the @xmath2 matrix elements of the ewp operators @xmath7 , are determined by two 4-quark vevs , @xmath8 and @xmath9 , which also determine the dimension @xmath1 part of the ope of the flavor @xmath10 v - a correlator difference @xmath11 @xcite , where the superscript @xmath12 denotes the sum of spin @xmath13 and @xmath14 components and , with @xmath15 the standard v or a @xmath10 current , the scalar correlators @xmath16 are defined via @xmath17 since @xmath18^{ope}_{d=6}$ ] is strongly dominated by the contribution involving @xmath9 , which vev also dominates the chiral limit @xmath5 matrix element , the extraction of @xmath18_{d=6}^{ope}$ ] is of considerable phenomenological interest , and a number of dispersive and finite energy sum rule ( fesr ) analyses have attempted it @xcite .
@xmath0 decay data plays a key role in these analyses since the spectral function of @xmath19 , @xmath20 , is directly measurable for @xmath21 in non - strange hadronic @xmath0 decays ..
Please generate the next two sentences of the article | explicitly , in the sm , with @xmath22 a short - distance ew correction , @xmath23 , @xmath24 and @xmath25/ \gamma [ \tau^- \rightarrow \nu_\tau e^- { \bar \nu}_e ] $ ] , one has , for the continuum ( non-@xmath26-pole ) part of @xmath27 @xcite @xmath28 dispersive analyses employ the unsubtracted dispersion relation for @xmath19 and require either assumptions about the saturation of the dispersion integral within the range kinematically accessible in @xmath0 decays , or supplementary constraints on @xmath29 for @xmath30 , such as those provided by the weinberg sum rules @xcite and the dgmly @xmath26 electromagnetic ( em ) self - energy sum rule @xcite ( see , e.g. , ref .
@xcite for details ) . |
3,420 | Suppose that you have an abstract for a scientific paper: we study the @xmath0-@xmath1 characteristics of s@xmath2/n / n contacts , where s@xmath2 is a bcs superconductor s with a built - in exchange field @xmath3 , n represents a normal metal wire , and n a normal metal reservoir .
the superconductor s@xmath2 is separated from the n - wire by a spin filter which allows the passage of electrons with a certain spin direction so that only fully polarized triplet cooper pairs penetrate into the n - wire .
we show that both the subgap conductance @xmath4 and the excess current @xmath5 , which occur in conventional s / n / n contacts due to andreev reflection ( ar ) , exist also in the considered system . in our case , they are caused by unconventional ar that is not accompanied by spin flip .
the excess current @xmath5 exists only if @xmath3 exceeds a certain magnitude @xmath6 . at @xmath7
the excess current is converted into a deficit current @xmath8 .
the dependencies of the differential conductance and the current @xmath5 are presented as a function of voltage and @xmath3 . .
And you have already written the first three sentences of the full article: as is well known , a so - called excess current @xmath5 appears at large voltages @xmath1 in josephson junctions ( jj ) with a direct conductance,@xcite that is , the current @xmath5 arises in jjs of the s / n / s or s / c / s types , where n denotes a normal metal ( a wire or a film ) and c a constriction .
this means that the current - voltage ( @xmath0-@xmath1 ) characteristics at large @xmath1 ( @xmath9 , where @xmath10 is the energy gap in the superconductors s ) has the form @xmath11 where @xmath12 is the resistance of the jj in the normal state and the constant @xmath5 is the excess current which can be written in the form @xmath13 here , @xmath14 is a numerical factor equal to @xmath15 in the diffusive limit,@xcite and @xmath16 in ballistic jjs with ideal ( fully transparent ) interfaces.@xcite eq .
( [ 1 ] ) also describes the asymptotic behavior ( @xmath17 ) of the @xmath0-@xmath1 characteristics of s / n / n contacts,@xcite where n is a normal metal reservoir . in the latter case ,.
Please generate the next two sentences of the article | the excess current is twice smaller than in the s / n / s jjs .
the excess current @xmath5 is an essential characteristics of s / |
3,421 | Suppose that you have an abstract for a scientific paper: we consider an alternative approach to double special - relativistic theories .
the point of departure is not @xmath0-deformed algebra ( or even group - theoretical considerations ) but rather 3 physical postulates defining particle s velocity , mass , and the upper bound on its energy in terms of the respective classical quantities . for a specific definition of particle s velocity
we obtain magueijo - smolin ( ms ) version of the double special - relativistic theory .
it is shown that this version follows from the @xmath0-poincare algebra by the appropriate choice of on the shell mass , such that it is always less or equal planck s mass .
the @xmath0-deformed hamiltonian is found which invalidates the recent arguments about unphysical predictions of the ms transformation . a recent research ( e.g.@xcite,@xcite,@xcite,@xcite,@xcite,@xcite,@xcite ) on the so - called double special relativity not only reexamined its relation to @xmath0-deformed kinematics , but in one specific example @xcite also subjected to criticism physical predictions of one of these theoretical constructs @xcite .
+ it should be mentioned that as early as in @xmath1 , j.lukierski with collaborators @xcite demonstrated that there exist an infinite set of transformations reducing the @xmath0-deformed casimir in majid - ruegg basis @xcite ( used in all the double - special relativistic theories , e.g.@xcite ) to the diagonal form .
in fact , it is possible to show that any of these transformations correspond to a different choice of what one can consider as a definition of the deformed mass .
this makes it difficult , without any additional assumptions , to choose a unique physical theory corresponding to the respective transformation .
this difficulty is emphasized @xcite by what looks like apparent non - physical predictions of one of these constructions @xcite .
+ here we revisit the latter work @xcite , more specifically its treatment of the energy - momentum domain , this time departing not from the group -....
And you have already written the first three sentences of the full article: after this paper has been written , paper @xcite appeared , where ( among some other topics ) the addition law for energy - momentum was modified as compared to the one used in @xcite .
this was done to comply with the physical requirement that a set of particles with even sub - planckian energies can have an energy much exceeding the planck energy .
the modification was achieved by simply replacing the planck energy @xmath123 in our units ) for a system of @xmath115 particles with @xmath124 ..
Please generate the next two sentences of the article | + here we demonstrate that the modified addition law follows from our scheme , by simply adjusting one of our postulates ( postulate iii , ) .
the modification is as follows : we require that for a set of @xmath115 particles the upper bound on both energy and momentum ( normalized by planck energy @xmath0 ) is to be not @xmath125 , but @xmath115 . |
3,422 | Suppose that you have an abstract for a scientific paper: the acceleration of charged particles , producing collimated mono - energetic beams , over short distances holds the promise to offer new tools in medicine and diagnostics . here , we consider a possible mechanism for accelerating protons to high energies by using a phase - modulated circularly polarized electromagnetic wave propagating along a constant magnetic field .
it is observed that a plane wave with dimensionless amplitude of 0.1 is capable to accelerate a 1 kev proton to 386 mev under optimum conditions .
finally we discuss possible limitations of the acceleration scheme . .
And you have already written the first three sentences of the full article: laser induced particle acceleration has drawn considerable interest among researchers all over the world since the pioneering work by tajima and dawson @xcite .
the acceleration gradient of conventional linear accelerators is of the order of @xmath0 v / cm , however today s state of the art lasers are capable to produce the acceleration gradient many orders of what can be achieved using conventional linacs . in general laser based accelerators can be divided based on the medium in which the acceleration takes place , which can be either vacuum or a plasma .
the vacuum as a medium for particle acceleration has some inherent advantages over plasma medium ..
Please generate the next two sentences of the article | the problems like instabilities are absent in vacuum , it is easier to inject the pre - accelerated particle beam in vacuum as compared to the plasma , collisions of particles with media causing energy loss and beam spreading is ruled out , etc .
thus we will focus on particle acceleration in vacuum in this article . |
3,423 | Suppose that you have an abstract for a scientific paper: * purpose : * the inverse of a deformation vector field ( dvf ) is often needed in deformable registration , 4d image reconstruction , and adaptive radiation therapy .
this study aims at improving both the accuracy with respect to inverse consistency and efficiency of the numerical dvf inversion by developing a fixed - point iteration method with feedback control . + * method : * we introduce an iterative method with active feedback control for dvf inversion .
the method is built upon a previous fixed - point iteration method , which is represented as a particular passive instance in the new method . at each iteration step , we measure the inconsistency , namely the residual , between the iterative inverse estimate and the input dvf . the residual is modulated by a feedback control mechanism before being incorporated into the next iterate .
the feedback control design is based on analysis of error propagation in the iteration process .
the control design goal is to suppress estimation error progressively to make the convergence region as large as possible , and to make estimate errors vanish faster whenever possible .
we demonstrated the feedback control with a single - parameter control mechanism .
the optimal parameter value is determined either analytically by a closed - form expression for analytical test data , or numerically for experimental data . the feedback control design is demonstrated and assessed with two data sets : an analytic dvf pair , and a dvf generated between two phases of the 4d extended cardiac - torso ( xcat ) digital anthropomorphic phantom .
* results : * the single - parameter feedback control improved both the convergence region and convergence rate of the iterative algorithm , for both datasets . with the analytic data ,
the iteration becomes convergent over the entire image domain , and the convergence is sped up substantially compared to the precursor method , which suffers from slow convergence or even divergence , as the deformation becomes larger . with the....
And you have already written the first three sentences of the full article: we consider numerical inversion of a forward deformation vector field ( dvf ) from one image to another . very often the inverse dvf is needed along with the forward dvf to map medical images , structures , or doses back and forth throughout the process of 4d image reconstruction and adaptive radiotherapy @xcite .
the inverse dvf may be obtained in different ways , such as through deformable registration with swapped inputs , simultaneous registration in both directions , or inverting the forward dvf from the reference image to the deformed target image . the latter option ( inverting the forward dvf ) is often preferred in clinical applications , due to several reasons :
inversion is typically faster , empirically ; image quality can be quite different for the reference and target image sets , which may make the other approaches more error - prone @xcite ; and inversion can ensure consistency between forward and inverse dvfs @xcite ..
Please generate the next two sentences of the article | previously , chen _ et al . _
@xcite developed a fixed - point iteration method for dvf inversion . in this study |
3,424 | Suppose that you have an abstract for a scientific paper: we consider scattering state contributions to the partition function of a two - dimensional ( 2d ) plasma in addition to the bound - state sum .
a partition function continuity requirement is used to provide a statistical mechanical heuristic proof of levinson s theorem in two dimensions .
we show that a proper account of scattering eliminates singularities in thermodynamic properties of the nonideal 2d gas caused by the emergence of additional bound states as the strength of an attractive potential is increased .
the bound - state contribution to the partition function of the 2d gas , with a weak short - range attraction between its particles , is found to vanish logarithmically as the binding energy decreases .
a consistent treatment of bound and scattering states in a screened coulomb potential allowed us to calculate the quantum - mechanical second virial coefficient of the dilute 2d electron - hole plasma and to establish the difference between the nearly ideal electron - hole gas in gaas and the strongly correlated exciton / free - carrier plasma in wide - gap semiconductors such as znse or gan . .
And you have already written the first three sentences of the full article: two - dimensional ( 2d ) systems play a central role in contemporary condensed matter physics .
novel phenomena such as the quantum hall effect @xcite observed when a 2d electron gas at low temperature is subjected to a strong magnetic field , as well as practical developments based on quasi-2d systems , e.g. , high - mobility field - effect transistors @xcite or semiconductor quantum - well lasers @xcite have brought significant technological advances .
such devices are based on the quasiequilibrium response of the internal electron or electron - hole plasmas to an external stimulation ..
Please generate the next two sentences of the article | hence it is essential to understand the fundamental quantum - statistical properties of such two - dimensional interacting plasmas at finite temperatures .
one of the well - known differences between 2d and 3d nonrelativistic quantum mechanics is the presence of at least one bound state for any symmetric attractive potential in two dimensions . |
3,425 | Suppose that you have an abstract for a scientific paper: since its launch in october 2002 , esa s integral observatory has enabled significant advances to be made in the study of galactic nucleosynthesis . in particular , the imaging ge spectrometer spi combines for the first time the diagnostic powers of high resolution gamma - ray line spectroscopy and moderate spatial resolution .
this review summarizes the major nucleosynthesis results obtained with integral so far .
positron annihilation in our galaxy is being studied in unprecented detail .
spi observations yield the first sky maps in both the 511 kev annihilation line and the positronium continuum emission , and the most accurate spectrum at 511 kev to date , thereby imposing new constraints on the source(s ) of galactic positrons which still remain(s ) unidentified .
for the first time , the imprint of galactic rotation on the centroid and shape of the 1809 kev gamma - ray line due to the decay of @xmath0al has been seen , confirming the galactic origin of this emission .
spi also provided the most accurate determination of the gamma - ray line flux due to the decay of @xmath1fe .
the combined results for @xmath0al and @xmath1fe have important implications for nucleosynthesis in massive stars , in particular wolf - rayet stars .
both ibis and spi are searching the galactic plane for young supernova remnants emitting the gamma - ray lines associated with radioactive @xmath2ti .
none have been found so far , which raises important questions concerning the production of @xmath2ti in supernovae , the galactic supernova rate , and the galaxy s chemical evolution . .
And you have already written the first three sentences of the full article: gamma - ray line astronomy has opened a new and unique window for studying nucleosynthesis in our galaxy .
the singular advantage of gamma - ray spectroscopy over other observations is that it offers the opportunity to detect directly and identify uniquely individual isotopes at their birthplaces .
the rate at which radioactive decays proceed is in general unaffected by the physical conditions in their environment , such as temperature or density ..
Please generate the next two sentences of the article | the interstellar medium is not dense enough to attenuate gamma rays , so that radioactive decays can be observed throughout our galaxy .
recent reviews on implications of gamma - ray observations for nucleosynthesis in our galaxy can be found in @xcite and @xcite . |
3,426 | Suppose that you have an abstract for a scientific paper: let @xmath0 be a rationally parametrized planar homogeneous potential of homogeneity degree @xmath1 .
we design an algorithm that computes polynomial _ necessary _ conditions on the parameters @xmath2 such that the dynamical system associated to the potential @xmath3 is integrable .
these conditions originate from those of the morales - ramis - sim integrability criterion near all darboux points .
the implementation of the algorithm allows to treat applications that were out of reach before , for instance concerning the non - integrability of polynomial potentials up to degree @xmath4 .
another striking application is the first complete proof of the non - integrability of the _ collinear three body problem_. * categories and subject descriptors : * + i.1.2 [ * computing methodologies * ] : symbolic and algebraic manipulations _ algebraic algorithms _ + * general terms : * algorithms , theory . + * keywords : * integrability , potentials , algorithms . .
And you have already written the first three sentences of the full article: let us consider the hamiltonian system @xmath5 with @xmath6 , called the _
potential_. system describes the motion of a particle in the plane submitted to the force field @xmath7 .
it always admits the so - called _ hamiltonian _ @xmath8 as a rational first integral ..
Please generate the next two sentences of the article | the potential @xmath3 is called _ ( rationally ) integrable _ if system admits another rational first integral @xmath9 , functionally independent on @xmath10 . intuitively , the integrability of @xmath3 is equivalent to the fact that can be solved in explicit terms .
integrability is a rare phenomenon and it is in general a difficult task to determine whether a given potential is integrable or not . for _ homogeneous potentials _ in @xmath11 , _ necessary _ conditions for integrability |
3,427 | Suppose that you have an abstract for a scientific paper: in july 2012 , as the four ground - based gamma - ray telescopes of the h.e.s.s .
( _ high energy stereoscopic system _ ) array reached their tenth year of operation in khomas highlands , namibia , a fifth telescope took its first data as part of the system .
this new cherenkov detector , comprising a @xmath0 reflector with a highly pixelized camera in its focal plane , improves the sensitivity of the current array by a factor two and extends its energy domain down to a few tens of gev .
the present part i of the paper gives a detailed description of the fifth h.e.s.s .
telescope s camera , presenting the details of both the hardware and the software , emphasizing the main improvements as compared to previous h.e.s.s . camera technology
. high energy stereoscopic system , h.e.s.s . , camera , electronics , hardware , software , calibration .
And you have already written the first three sentences of the full article: in 2005 , three years after the first h.e.s.s . 12 m telescope was commissioned and one year after the fourth was installed , the decision was taken by french and german agencies to build a fifth instrument .
this new imaging atmospheric cherenkov telescope was mainly designed to obtain an energy threshold of @xmath1 , increasing the sensitivity of the array towards low energies @xcite . in order to achieve this goal , a new fast
, high sensitivity and low dead - time 2048 pixel camera was designed to equip the focal plane of a parabolic tessellated mirror of @xmath0 . with this new telescope , the h.e.s.s ..
Please generate the next two sentences of the article | project was entering its second phase .
the goal of the h.e.s.s . |
3,428 | Suppose that you have an abstract for a scientific paper: we present an unsupervised , local activation - dependent learning rule for intrinsic plasticity ( ip ) which affects the composition of ion channel conductances for single neurons in a use - dependent way .
we use a single - compartment conductance - based model for medium spiny striatal neurons in order to show the effects of parametrization of individual ion channels on the neuronal activation function .
we show that parameter changes within the physiological ranges are sufficient to create an ensemble of neurons with significantly different activation functions .
we emphasize that the effects of intrinsic neuronal variability on spiking behavior require a distributed mode of synaptic input and can be eliminated by strongly correlated input .
we show how variability and adaptivity in ion channel conductances can be utilized to store patterns without an additional contribution by synaptic plasticity ( sp ) .
the adaptation of the spike response may result in either `` positive '' or `` negative '' pattern learning . however , read - out of stored information depends on a distributed pattern of synaptic activity to let intrinsic variability determine spike response .
we briefly discuss the implications of this conditional memory on learning and addiction . * _ keywords : _ * single neuron model , striatal medium spiny neuron , ion channels , activation function , unsupervised learning , intrinsic plasticity , pattern learning , neuronal variability .
And you have already written the first three sentences of the full article: a role for modification of activation functions , or intrinsic plasticity ( ip ) , for behavioral learning has been demonstrated for a number of systems @xcite .
for instance , in rabbit eyeblink conditioning , when ion channels related to afterhyperpolarization are being suppressed by a learning event , they can become permanently suppressed .
this has been shown for pyramidal cells of hippocampal areas ca1 and ca3 , and for cerebellar purkinje cells @xcite . in some cases , these changes are permanent and still present after 30 days @xcite , in other cases , intrinsic changes disappear after 3 - 7 days , while the behavioral memory remains intact , raising questions about the long - term component of intrinsic plasticity in these systems ..
Please generate the next two sentences of the article | there are at the present time conflicting ideas on the significance of ip compared to synaptic plasticity @xcite , and the range of functions that ip may have in adaptivity @xcite .
few computational models have been proposed that show how modification in activation functions can be achieved with ion channel based models of realistic single neurons . |
3,429 | Suppose that you have an abstract for a scientific paper: we combine data from our recent _ fuse _ survey of interstellar molecular hydrogen absorption toward 50 high - latitude agn with cobe - corrected _ iras _ 100 @xmath0 m emission maps to study the correlation of infrared cirrus with h@xmath1 .
a plot of the h@xmath1 column density vs. ir cirrus intensity shows the same transition in molecular fraction , @xmath2 , as seen with total hydrogen column density , n@xmath3 .
this transition is usually attributed to h@xmath1 self - shielding " , and it suggests that many diffuse cirrus clouds contain h@xmath1 in significant fractions , @xmath4 130% .
these clouds cover @xmath5% of the northern sky at @xmath6 , at temperature - corrected 100 @xmath0 m intensities @xmath7 mjy sr@xmath8 .
the sheetlike cirrus clouds , with hydrogen densities @xmath9 @xmath10 , may be compressed by dynamical processes at the disk - halo interface , and they are conducive to h@xmath1 formation on grain surfaces . exploiting the correlation between n@xmath11 and 100 @xmath0 m intensity , we estimate that cirrus clouds at @xmath6 contain @xmath12 in h@xmath1 . extrapolated over the inner milky way , the cirrus may contain @xmath13 of h@xmath1 and @xmath14 in total gas mass . if elevated to 100 pc , their gravitational potential energy is @xmath15 erg . .
And you have already written the first three sentences of the full article: in an attempt to understand the molecular content and physical characteristics of interstellar gas in the low galactic halo , we exploit infrared and ultraviolet data from two nasa satellites : the _ infrared astronomical satellite _ ( _ iras _ ) mission of 1983 and the _ far ultraviolet spectroscopic explorer _ ( _ fuse _ ) satellite of 19992005 . the combination of infrared emission and ultraviolet absorption along sight lines to 45 active galactic nuclei ( agn ) allows us to correlate the infrared cirrus emission intensity with the molecular hydrogen ( h@xmath1 ) absorption column density at select locations at high galactic latitude . _
iras _ mapped the sky in four infrared bands centered on 12 , 25 , 60 , and 100 @xmath0 m .
low et al . ( 1984 ) introduced one of the most surprising results from the _ iras _.
Please generate the next two sentences of the article | maps : diffuse filamentary dust clouds that pervade our galaxy at high latitudes , even in the direction of the galactic poles .
these infrared cirrus " clouds are most prominent at long wavelengths , 100 @xmath0 m , but some can be seen in the 60 @xmath0 m , 25 @xmath0 m , and 12 @xmath0 m bands . |
3,430 | Suppose that you have an abstract for a scientific paper: link prediction is one of the fundamental problems in network analysis . in many applications , notably in genetics
, a partially observed network may not contain any negative examples of absent edges , which creates a difficulty for many existing supervised learning approaches .
we develop a new method which treats the observed network as a sample of the true network with different sampling rates for positive and negative examples .
we obtain a relative ranking of potential links by their probabilities , utilizing information on node covariates as well as on network topology .
empirically , the method performs well under many settings , including when the observed network is sparse .
we apply the method to a protein - protein interaction network and a school friendship network . .
And you have already written the first three sentences of the full article: a variety of data in many different fields can be described by networks .
examples include friendship and social networks , food webs , protein - protein interaction and gene regulatory networks , the world wide web , and many others .
one of the fundamental problems in network science is link prediction , where the goal is to predict the existence of a link between two nodes based on observed links between other nodes as well as additional information about the nodes ( node covariates ) when available ( see , @xcite and @xcite for recent reviews ) ..
Please generate the next two sentences of the article | link prediction has wide applications .
for example , recommendation of new friends or connections for members is an important service in online social networks such as facebook . in biological networks , such as protein - protein interaction and gene regulatory networks , |
3,431 | Suppose that you have an abstract for a scientific paper: the small dispersion limit of solutions to the camassa - holm ( ch ) equation is characterized by the appearance of a zone of rapid modulated oscillations . an asymptotic description of these oscillations is given , for short times , by the one - phase solution to the ch equation , where the branch points of the corresponding elliptic curve depend on the physical coordinates via the whitham equations .
we present a conjecture for the phase of the asymptotic solution .
a numerical study of this limit for smooth hump - like initial data provides strong evidence for the validity of this conjecture .
we present a quantitative numerical comparison between the ch and the asymptotic solution .
the dependence on the small dispersion parameter @xmath0 is studied in the interior and at the boundaries of the whitham zone . in the interior of the zone ,
the difference between ch and asymptotic solution is of the order @xmath0 , at the trailing edge of the order @xmath1 and at the leading edge of the order @xmath2 . for the latter we present a multiscale expansion which describes the amplitude of the oscillations in terms of the hastings - mcleod solution of the painlev ii equation .
we show numerically that this multiscale solution provides an enhanced asymptotic description near the leading edge .
small dispersion limit , whitham equations , painlev transcendents , multiple scale analysis primary , 65m70 ; secondary , 65l05 , 65m20 .
And you have already written the first three sentences of the full article: the camassa - holm ( ch ) equation @xmath3 was discovered by camassa and holm @xcite as a model for unidirectional propagation of waves in shallow water , @xmath4 representing the height of the free surface about a flat bottom , @xmath5 being a constant related to the critical shallow water speed and @xmath6 a constant proportional to the mean water depth @xcite . equation ( [ ch ] ) had been previously found by fokas and fuchssteiner @xcite using the method of recursion operators and shown to be a bi - hamiltonian equation with an infinite number of conserved functionals .
it was also rediscovered by dai @xcite as a model for nonlinear waves in cylindrical hyperelastic rods , with @xmath4 representing the radial stretch relative to a pre - stressed state .
equation ( [ ch ] ) finally also arises in the study of the motion of a non - newtonian fluid of second grade in the limit when the viscosity tends to zero @xcite . a class of two .
Please generate the next two sentences of the article | component generalizations of the ch equation has been recently obtained in @xcite . the initial value problem for ( [ ch ] ) @xmath7 presents interesting features : first for @xmath8 there may exist peakons , i.e. , non smooth solutions , second even for a smooth initial datum @xmath9 the wave - breaking phenomenon may occur ,
that is the solution @xmath4 remains bounded while its slope becomes unbounded in finite time . |
3,432 | Suppose that you have an abstract for a scientific paper: necessary and sufficient conditions are given for a satellite knot to be fibered .
any knot @xmath0 embeds in an unknotted solid torus @xmath1 with arbitrary winding number in such a way that no satellite knot with pattern @xmath2 is fibered .
in particular , there exist nonfibered satellite knots with fibered pattern and companion knots and nonzero winding number . .
And you have already written the first three sentences of the full article: proposition 4.15 of the monograph _ knots _ @xcite erroneously asserts and proves that a satellite knot is fibered if and only if it has nonzero winding number and both its companion and pattern knots are fibered . in 1990 , the third author of the present paper contacted the authors of _ knots _ , informed them of the mistake , and provided a counterexample .
the recent second edition of the now - classic textbook acknowledged the error and reproduced the example .
however , the necessary and sufficient conditions that it provided are not the most convenient in practice ..
Please generate the next two sentences of the article | the present paper is an expanded version of an unpublished note that the third author wrote in 1991 .
its algebraic necessary and sufficient conditions for a satellite knot to fiber , do not appear to be well known . |
3,433 | Suppose that you have an abstract for a scientific paper: we build a gauge model based on the @xmath0 symmetry where the scalar spectrum needed to generate gauge boson and fermion masses has a smaller scalar content than usually assumed in literature .
we compute the running of its abelian gauge coupling and show that a landau pole shows up at the tev scale , a fact that we use to consistently implement those fermion masses that are not generated by yukawa interactions , including neutrino masses .
this is appropriately achieved by non renormalizable effective operators , suppressed by the landau pole scale .
also , @xmath1 models embedded in this gauge structure are bound to be strongly coupled at this same energy scale , contrary to what is generally believed , and neutrino mass generation is rather explained through the same effective operators used in the larger gauge group . besides , their nice features , as the existence of cold dark matter candidates and the ability to reproduce the observed standard model higgs - like phenomenology , are automatically inherited by our model .
finally , our results imply that this model is constrained to be observed or discarded soon , since it must be realized at the currently probed energy scale in lhc .
electroweak gauge model , effective theory , fermion mass 12.60.cn , 12.60.fr , 14.60.pq , 14.60.st .
And you have already written the first three sentences of the full article: the recent discovery at the large hadron collider ( lhc ) of a spin zero resonance @xcite , most certainly the standard model ( sm ) higgs boson , have already given some clues of what kind of new physics we need to proceed beyond . besides , we know that the sm is not the last answer to the questions brought by the huge endeavor carried over the last three decades of researching in particle physics . some of the new challenges involve neutrino s mass and mixing , the dark matter problem , the matter - antimatter asymmetry , among others .
this motivates us to search for new broader models and theories for attacking these puzzles in the most simple and easiest way .
one such possibility is the enlargement of the gauge group symmetry , implying in new interactions and particle spectrum ..
Please generate the next two sentences of the article | here we focus on one of these gauge extensions of the sm , which can be realized at some tev scale , the @xmath2 @xcite gauge group , which we call 341 for short .
the 341 model is built as a simple extension of the electroweak symmetry gauge group @xmath3 of sm . |
3,434 | Suppose that you have an abstract for a scientific paper: we study the influence of multiple bands on the properties of josephson junctions .
in particular we focus on the two gap superconductor magnesium diboride .
we present a formalism to describe tunneling at a point contact between two mgb@xmath0 electrodes generalizing the transfer - matrix approach to multiple bands .
a simple model is presented to determine the effective hopping amplitudes between the different energy bands as a function of the misorientation angle of the electrodes .
we calculate the critical current and the current - voltage characteristics for n - i - s and s - i - s contacts with different orientation for junctions with both high and low transparency .
we find that interband tunneling processes become increasingly important with increasing misorientation angle .
this is reflected in certain features in the differential tunneling conductance in both the tunneling limit as well as for multiple andreev reflections . .
And you have already written the first three sentences of the full article: the two gap superconductor mgb@xmath0 is considered to be a good candidate for superconducting devices due to its comparatively high critical temperature , its easy handling and cheap preparation .
presently , its use in josephson junctions is being investigated @xcite .
one of its peculiar properties is the presence of two distinct superconducting gaps existing on different bands at the fermi surface ..
Please generate the next two sentences of the article | these bands are @xmath1 and @xmath2 bands arising from the boron @xmath3 and @xmath4/@xmath5 orbitals , respectively @xcite .
these two types of bands possess different parity with respect to reflection at the boron plane . |
3,435 | Suppose that you have an abstract for a scientific paper: ls i + 61@xmath0303 is one of the few high - mass x - ray binaries that have been recently observed at tev and gev energies .
here we investigate the hard x - ray spectral and timing properties of this source using the ibis / isgri instrument on - board the _ integral _ satellite .
we carry out a systematic analysis based on all available _ integral _ data since december 28 , 2002 up to april 30 , 2008 . the total exposure time analyzed amounts to 2.1 ms , hence more than doubling the previous reported sample .
the source is best detected in the 18 - 60 kev band , with a significance level of 12.0@xmath1 .
the hard x - ray data are best fit with a simple power law with a photon index of @xmath2 [email protected] .
we detect a periodical signal at 27 @xmath3 4 days , matching the orbital period of 26.496 days previously reported at other wavelengths . the hard x - rays orbital lightcurve is obtained and compared with those derived at other frequencies .
[ firstpage ] x - rays : individuals : ls i + 61@xmath0303 .
And you have already written the first three sentences of the full article: ls i + 61@xmath0303 is among the few binaries observed to date to emit high energy @xmath4-rays .
it hosts a bo ve main - sequence star ( hutchings & crampton 1981 ; casares et al . 2005 ) , orbited by a compact object of yet unknown nature , with a period of [email protected] days ( gregory 2002 ) .
the system is located at a distance of about 2 kpc ..
Please generate the next two sentences of the article | the orbital zero phase is taken at jd 2443366.775 ( gregory & taylor 1978 ) , and the phase values of [email protected] ( casares et al . 2005 ) , @xmath20.275 ( aragona et al . 2009 ) , and [email protected] ( grundstrom et al
. 2007 ) represent the periastron passage uncertainty . |
3,436 | Suppose that you have an abstract for a scientific paper: we present a comprehensive analysis of the landau - zener tunnelling of a nonlinear three - level system in a linearly sweeping external field .
we find the presence of nonzero tunnelling probability in the adiabatic limit ( i.e. , very slowly sweeping field ) even for the situation that the nonlinear term is very small and the energy levels keep the same topological structure as that of linear case .
in particular , the tunnelling is irregular with showing an unresolved sensitivity on the sweeping rate . for the case of fast - sweeping fields
, we derive an analytic expression for the tunnelling probability with stationary phase approximation and show that the nonlinearity can dramatically influence the tunnelling probability when the nonlinear `` internal field '' resonate with the external field .
we also discuss the asymmetry of the tunnelling probability induced by the nonlinearity .
physics behind the above phenomena is revealed and possible application of our model to triple - well trapped bose - einstein condensate is discussed . .
And you have already written the first three sentences of the full article: avoided crossing of energy levels is a universal phenomenon for the quantum non - integrable systems where the symmetry break leads to the splitting of degenerate energy levels forming a tiny energy gap . around the avoided crossing point of the two levels the landau - zener tunnelling ( lzt ) model
provides an effective description for the tunnelling dynamics under assumption that the energy bias of two levels undergoes a linear change with time@xcite .
it is a basic model in quantum mechanics and has versatile applications in quantum chemistry @xcite , collision theory @xcite , and more recently in the spin tunnelling of nanomagnets wensdorf1,wensdorf2 , bose - einstein condensates ( bec ) @xcite and quantum computing @xcite , to name only a few ..
Please generate the next two sentences of the article | lzt model has been extended to many versions taking diverse physical conditions into account : lzt problem with a time - varied sweeping rate@xcite , lzt model with a fast noise from the outer environment @xcite , lzt model with periodic modulation @xcite , and so on . among them , lzt in a nonlinear two - level system is one of most interesting models and attracts much attention recentlyraghavan , bwu , zobay , jliu1 . in this model ,
the level energies depend on the occupation of the levels , may arise in a meanfield treatment of a many - body system where the particles predominantly occupy two energy levels . the nonlinear lzt model |
3,437 | Suppose that you have an abstract for a scientific paper: the numerical algorithm of the inverse quantum scattering is developed .
this algorithm is based on the marchenko theory , and includes three steps .
the first one is the algebraic pad approximation of the unitary s - matrix , what is realized by solving a system of linear equations .
second step is the exact solution of the marchenko equation .
the used approximant reduces it to another system of linear equations . at this step
we get the real - valued potential .
it is shown numerically that the developed algorithm is able not only to generate the given @xmath0-matrix dependence , but converges to the initial potential . at third step
we construct the optical complex - valued potential which gives the needed s - matrix .
it is shown that the modern phase shift analysis data allow to construct the nucleon - nucleon optical potentials of two kinds .
these potentials describe the deuteron properties and the phase shift analysis data up to 3 gev and they have different behavior at short distances .
one is a repulsive core potential and another is a moscow attractive potential with forbidden states .
* reconstruction of the optical potential in the inverse quantum scattering .
application to the relativistic inelastic nn scattering * n.a .
khokhlov@xmath1 , v.a .
knyr@xmath2 + @xmath3 _ e - mail : [email protected]_ ; @xmath4 _ e - mail : [email protected]_ .
And you have already written the first three sentences of the full article: quantum inversion has many applications in nuclear physics .
most of the potential descriptions of the few - body nuclear scattering base on the inversion of the scattering data .
though nucleon - nucleon interaction is used as input for all nuclear calculations , here we always have some fitted parameters and this fitting is , of course inversion ..
Please generate the next two sentences of the article | moreover all modern high - precision nucleon - nucleon potentials are fitted to scattering data and are now perceived as phenomenology .
the problem here is `` that quantitative models for the nuclear force have only a poor theoretical background , while theory based models yield only poor results '' @xcite . at the same time the nucleon - nucleon phase shift analysis data are smooth in all investigated energy region up to 3 gev @xcite |
3,438 | Suppose that you have an abstract for a scientific paper: we have identified 335 galaxy cluster and group candidates , 106 of which are at @xmath0 , using a @xmath1 m selected sample of objects from a 7.25 deg@xmath2 region in the _ spitzer _ infrared array camera ( irac ) shallow survey .
clusters were identified as 3-dimensional overdensities using a wavelet algorithm , based on photometric redshift probability distributions derived from irac and noao deep wide - field survey data .
we estimate only @xmath3 of the detections are spurious . to date 12 of the @xmath0 candidates
have been confirmed spectroscopically , at redshifts from 1.06 to 1.41 .
velocity dispersions of @xmath4 km s@xmath5 for two of these argue for total cluster masses well above @xmath6 , as does the mass estimated from the rest frame near infrared stellar luminosity .
although not selected to contain a red sequence , some evidence for red sequences is present in the spectroscopically confirmed clusters , and brighter galaxies are systematically redder than the mean galaxy color in clusters at all redshifts .
the mean @xmath7 $ ] color for cluster galaxies up to @xmath8 is well matched by a passively evolving model in which stars are formed in a 0.1 gyr burst starting at redshift @xmath9 . at @xmath0 , a wider range of formation histories is needed , but higher formation redshifts ( i.e. @xmath10 ) are favored for most clusters . .
And you have already written the first three sentences of the full article: as the most massive gravitationally bound systems in the universe , the rate of emergence of galaxy clusters since the big bang might be expected to be among the most straightforward predictions of cosmological models . yet despite the advent of the era of precision cosmology ushered in by observations of sne and the cosmic microwave background ( cmb ) , significant uncertainty remains in the expected numbers of galaxy clusters at @xmath0 .
the cmb temperature anisotropies on scales corresponding to clusters are not accurately known , leading to a range of values for @xmath11 , the rms matter fluctuation in a sphere of radius @xmath12 mpc at @xmath13 .
estimates of @xmath11 vary significantly , including e.g. @xmath14 @xcite , @xmath15 @xcite , @xmath16 @xcite , @xmath17 @xcite , @xmath18 @xcite , @xmath19 @xcite , and @xmath20 @xcite ..
Please generate the next two sentences of the article | the range @xmath21 to 1 corresponds to a variation of a factor of nearly 20 in the predicted numbers of @xmath0 clusters with @xmath22 ( e.g. * ? ? ?
removing this uncertainty is a major goal of upcoming sunyaev - zeldovich cluster surveys such as the sza ( sunyaev - zeldovich array ; * ? ? ? |
3,439 | Suppose that you have an abstract for a scientific paper: this paper demonstrates that complex @xmath0-symmetric periodic potentials possess real band spectra
. however , there are significant qualitative differences in the band structure for these potentials when compared with conventional real periodic potentials . for example , while the potentials @xmath1 @xmath2 have infinitely many gaps , at the band edges there are periodic wave functions but no antiperiodic wave functions . numerical analysis and higher - order wkb techniques
are used to establish these results .
.5 cm for a quantum mechanical model having a periodic potential the schrdinger equation is @xmath3 where the potential @xmath4 is periodic with period @xmath5 : @xmath6 in conventional treatments of eq .
( [ e1 ] ) @xcite the periodic potential @xmath4 is assumed to be real . imposing the condition that the wave function @xmath7 be bounded leads to a real spectrum consisting of continuous bands separated by gaps .
there is an infinite number of bands and gaps , except for the special family of so - called _ finite - gap _ potentials such as the lam potentials @xcite . in this note
we extend the conventional analysis to include the case of complex periodic potentials .
we find that complex periodic potentials having @xmath0 symmetry exhibit _ real _ band spectra , despite the non - hermitian character of the schrdinger equation ( [ e1 ] ) .
( here , @xmath8 represents parity reflection and @xmath9 represents time reversal . ) potentials having this symmetry satisfy @xmath10^*=v(x ) .
\label{e3}\end{aligned}\ ] ] examples of such potentials are @xmath11 , @xmath12 , and @xmath13 .
in addition to the property that these potentials have real spectra , the band structure displays several novel features that are strikingly different from the case of real periodic potentials .
the work reported here was motivated by recent investigations of non - hermitian @xmath0-symmetric hamiltonian models having real discrete spectra .
one such class of models is defined by the....
And you have already written the first three sentences of the full article: we are grateful to the u.s .
department of energy for financial support ..
Please generate the next two sentences of the article | |
3,440 | Suppose that you have an abstract for a scientific paper: when a massive star ends its life , its core collapses , forming a neutron star or black hole and producing some of the most energetic explosions in the universe .
core - collapse supernovae and long - duration gamma - ray bursts are the violent signatures of compact remnant formation . as such , both fields are intertwined and , coupled with theory , observations of transients can help us better understand compact remnants just as neutron star and black hole observations can constrain the supernova and gamma - ray burst engine .
we review these ties in this paper . .
And you have already written the first three sentences of the full article: in molecular clouds , clumps of gas can become gravitationally bound and contract . ultimately , the compressing gas heats up sufficiently to drive the fusion of hydrogen into helium and the birth of a star . for most of its life , hydrogen fusion powers the star ( the so - called main sequence evolution ) .
ultimately , the hydrogen is depleted in the core and the star expands into a giant phase as its core contracts . for massive stars , this phase represents just the first in a series of burning phases where the ashes of the first phase ignite as the core contracts : core contraction continues until helium fusion occurs , a second core contraction until the products of helium fusion ( carbon , oxygen ) ignite , and so on until an iron core is built in the center of the star .
silicon shell burning above the iron core continues to increase its mass until the thermal and electron degeneracy pressure in the core is no longer able to support its mass and the core collapses ..
Please generate the next two sentences of the article | the collapse of these cores produce most of the stellar - massed neutron stars ( nss ) and black holes ( bhs ) in the universe .
the energy released in these core collapses produce supernovae ( type ib / c and ii ) and long - duration gamma - ray bursts ( grbs ) . |
3,441 | Suppose that you have an abstract for a scientific paper: prospects are examined for the detection of a slow decay of the lightest neutralino ( or any other longlived particles ) at the cern lhc and at very large hadron collider ( vlhc ) .
we first point out that such hadron colliders will become the `` neutralino factory '' producing @xmath0@xmath1 neutralinos / yr , if gluinos and/or squarks actually exist below @xmath2 tev .
the lightest neutralino ( @xmath3 ) , usually assumed to be stable , will be unstable if lighter superparticles such as the gravitino ( @xmath4 ) or axino ( @xmath5 ) exist , or @xmath6-parity is not conserved .
the decay signal would , however , be missed in usual collider experiments , particularly when the decay mostly occurs outside the detector . in order to search for such a slow decay of @xmath3 ,
we propose a dedicated experiment where the collision products are dumped by a thick shield , which is followed by a long decay tunnel .
the decay product of @xmath3 can be detected by a detector located at the end of the tunnel .
the slow arrival time and the large off angle ( to the direction of the interaction point ) of the decay product will provide a clear signature of slowly decaying @xmath3 s .
one can explore the decay length ( @xmath7 ) in a wide range , _
i.e. _ , 0.2 m to @xmath8 km for @xmath9 gev and 1 m to 2 km for @xmath10 gev at the lhc .
this corresponds to the range of the susy breaking scale @xmath11 to @xmath12 gev in case of the @xmath13 decay predicted in gauge - mediated susy breaking models . at vlhc
, one can extend the explorable range of @xmath14 up to @xmath15 gev , and that of @xmath16 up to @xmath17 gev . in case of the @xmath18 decay
, the peccei - quinn symmetry breaking scale @xmath19 can be explored up to @xmath20 gev .
the mass of the decaying particle can be determined by using the correlation between the energy and the arrival time of the decay product . with the setup we propose
, one can also search for ( i ) other decay modes of @xmath3 such as @xmath6-parity violating one ,....
And you have already written the first three sentences of the full article: the search for supersymmetric particles is now an integral part of all current , as well as future , experimental programs at high - energy colliders . aside from many attractive features of supersymmetry ( susy )
@xcite , the driving force for these searches comes from the recognition that weak - scale susy , which is introduced to solve the gauge hierarchy problem , requires that the susy partners of the standard model ( sm ) particles must be accessible to experiments that probe the tev energy scale .
if this is the case , a large number of gluinos and squarks will be produced at future hadron colliders such as the cern lhc ( operated at @xmath21 tev with luminosity @xmath22 @xmath23s@xmath24 ) and very large hadron collider ( vlhc ; operated at @xmath25200 tev with @xmath22@xmath26 @xmath23s@xmath24 ) ..
Please generate the next two sentences of the article | once produced , gluinos and squarks will subsequently decay to the lightest neutralino ( @xmath3 ) .
this means that such hadron colliders will become the `` neutralino factory '' , which is capable of producing up to @xmath1 @xmath3 s per year . |
3,442 | Suppose that you have an abstract for a scientific paper: we study a model of growing population that competes for resources . at each time step , all existing particles reproduce and the offspring randomly move to neighboring sites . then at any site with more than one offspring the particles are annihilated .
this is a non - monotone model , which makes the analysis more difficult .
we consider the _ extinction window _ of this model in the finite mean - field case , where there are @xmath0 sites but movement is allowed to any site ( the complete graph ) .
we show that although the system survives for exponential time , the extinction window is logarithmic . .
And you have already written the first three sentences of the full article: perhaps the most classical population model is the _ galton - watson branching process_. originally devised to model the survival of aristocratic patrilineal surnames , the galton - watson process may be described as follows : start with one existing particle . at every time step ,
all existing particles reproduce an independent number of offspring and die out .
the main question is then , what is the probability that the system survives forever ?.
Please generate the next two sentences of the article | by use of generating functions it is fairly simple to analyze this model , and in fact it is well known that in a galton - watson process with offspring distribution @xmath1 , the probability of extinction is given by the unique minimal solution of the equation @xmath2 $ ] in the interval @xmath3 $ ] .
moreover , the solution @xmath4 satisfies @xmath5 if and only if @xmath6 \leq 1 $ ] . |
3,443 | Suppose that you have an abstract for a scientific paper: a compact general integral formula is derived from which the fermionic contribution to the one - loop coefficient in the perturbative expansion of the @xmath0 coupling in powers of the bare lattice coupling can be extracted .
it is seen to reproduce the known results for unimproved naive , staggered and wilson fermions , and has advantageous features which facilitate the evaluation in the case of improved lattice fermion formulations .
this is illustrated in the case of wilson clover fermions , and an expression in terms of known lattice integrals is obtained in this case which gives the coefficient to much greater numerical accuracy than in the previous literature . .
And you have already written the first three sentences of the full article: when transforming results from lattice simulations into a continuum scheme such as @xmath0 it is often desirable to know the perturbative expansion of the renormalized coupling in powers of the bare lattice coupling .
this is useful as an intermediate step for relating the @xmath0 coupling to the coupling defined in nonperturbative lattice schemes such as the ones based on the static quark potential @xcite and schrdinger functional @xcite , and is also needed to translate bare lattice quark masses into the @xmath0 scheme ( see , e.g. , @xcite ) .
the one loop coefficient in the expansion is of further interest because it determines the ratio of the lattice and @xmath0 @xmath1-parameters @xcite ..
Please generate the next two sentences of the article | moreover , the one loop coefficient is also needed for determining the two loop relation between the couplings , from which the third term in the lattice beta - function ( governing the approach to the continuum limit ) can be determined @xcite . in this paper
we derive , for general lattice fermion formulation , a compact general integral formula from which the fermionic contribution to the one - loop coefficient in the perturbative expansion of the @xmath0 coupling in powers of the bare lattice coupling can be extracted . |
3,444 | Suppose that you have an abstract for a scientific paper: in this paper , we establish a new inequality tying together the effective length and the maximum correlation between the outputs of an arbitrary pair of boolean functions which operate on two sequences of correlated random variables .
we derive a new upper - bound on the correlation between the outputs of these functions .
the upper - bound is useful in various disciplines which deal with common - information .
we build upon witsenhausen s @xcite bound on maximum - correlation .
the previous upper - bound did not take the effective length of the boolean functions into account .
one possible application of the new bound is to characterize the communication - cooperation tradeoff in multi - terminal communications . in this problem , there are lower - bounds on the effective length of the boolean functions due to the rate - distortion constraints in the problem , as well as lower bounds on the output correlation at different nodes due to the multi - terminal nature of the problem . .
And you have already written the first three sentences of the full article: a fundamental problem of broad theoretical and practical interest is to characterize the maximum correlation between the outputs of a pair of functions of random sequences .
consider the two distributed agents shown in figure [ fig : agents ] .
a pair of correlated discrete memoryless sources ( dms ) are fed to the two agents ..
Please generate the next two sentences of the article | these agents are to each make a binary decision .
the goal of the problem is to maximize the correlation between the outputs of these agents subject to specific constraints on the decision functions . |
3,445 | Suppose that you have an abstract for a scientific paper: an extension of the standard model by at least one extra u(1 ) gauge symmetry has been investigated by many authors . in this paper
we explore the possibility that this extra u(1 ) is anomalous .
one of the possible signatures of this model could be given by the photons produced in the decays of the nlsp into the lsp . beyond the sm
; lhc ; anomalous u(1 ) models ; nlsp radiative decay .
And you have already written the first three sentences of the full article: the start of the lhc has greatly motivated detailed phenomenological studies of scenarios which involve physics beyond the standard model ( sm ) . among them
d - brane constructions in string theory are one of the most promising framework in which the sm can be embedded and extended . such brane constructions naturally lead to extra anomalous @xmath0 s in the four dimensional low energy theory and , in turn , to the presence of possible heavy @xmath1 particles in the spectrum
. these particles should be among the early findings of lhc and besides for the above cited models they are also a prediction of many other theoretical models of the unification of forces ( see @xcite for a recent review ) . in.
Please generate the next two sentences of the article | @xcite we have considered a minimal extension of the minimal supersymmetric standard model ( mssm ) with a single extra @xmath2 gauge symmetry in a string - inspired setup .
we believe that our model encodes the key features of the low - energy sector of some of those brane construction . in this framework we studied in @xcite the radiative decay of the next to lightest supersymmetric particle ( nlsp ) into the lightest supersymmetric particle ( lsp ) . |
3,446 | Suppose that you have an abstract for a scientific paper: in this paper , an uplink scheduling policy problem to minimize the network latency , defined as the air - time to serve all of users with a quality - of - service ( qos ) , under an energy constraint is considered in a training - based large - scale antenna systems ( lsas ) employing a simple linear receiver .
an optimal algorithm providing the exact latency - optimal uplink scheduling policy is proposed with a polynomial - time complexity . via numerical simulations
, it is shown that the proposed scheduling policy can provide several times lower network latency over the conventional ones in realistic environments .
in addition , the proposed scheduling policy and its network latency are analyzed asymptotically to provide better insights on the system behavior .
four operating regimes are classified according to the average received signal quality , @xmath0 , and the number of bs antennas , @xmath1 .
it turns out that orthogonal pilots are optimal only in the regime @xmath2 and @xmath3 . in other regimes ( @xmath4 or @xmath5 ) , it turns out that non - orthogonal pilots become optimal .
more rigorously , the use of non - orthogonal pilots can reduce the network latency by a factor of @xmath6 when @xmath4 or by a factor of @xmath7 when @xmath8 and @xmath9 , which would be a critical guideline for designing 5 g future cellular systems . large - scale antenna system , training - based transmission , network latency minimization , uplink scheduling policy , non - orthogonal pilots .
And you have already written the first three sentences of the full article: to continuous introduction of mobile devices and services , future cellular systems are facing a significantly increased number of mobile devices requesting large data volume . to accommodate such a large growth of mobile devices , there are active researches on the 5th generation ( 5 g ) cellular system .
new targets for the 5 g cellular system are to support latency - sensitive applications such as tactile internet @xcite and low energy consumption for machine - type communication ( mtc ) @xcite or the internet of things ( iot ) @xcite .
unfortunately , a cellular system can not achieve the two targets simultaneously , but a non - trivial tradeoff can exist ..
Please generate the next two sentences of the article | although this tradeoff is very important to 5 g cellular system designers , related researches are rare .
this is because it is often hard to deal with the latency and the energy consumption analytically so that intensive simulation - based network plannings are widely spread @xcite , @xcite . |
3,447 | Suppose that you have an abstract for a scientific paper: we present new h@xmath0 and h@xmath1 images of the hh 1/2 system , and we find that the h@xmath0/h@xmath1 ratio has high values in ridges along the leading edges of the hh 1 bow shock and of the brighter condensations of hh 2 .
these ridges have h@xmath0/h@xmath2 , which is consistent with collisional excitation from the @xmath3 to the @xmath4 and 4 levels of hydrogen in a gas of temperatures @xmath5 k. this is therefore the first direct proof that the collisional excitation / ionization region of hydrogen right behind herbig - haro shock fronts is detected . .
And you have already written the first three sentences of the full article: hh 1 and 2 were the first herbig - haro ( hh ) objects to be discovered ( herbig 1951 ; haro 1952 ) , and have played an important role in the field of hh objects ( see the historical review of raga et al .
for example , hst images ( schwartz et al . 1993 ; hester et al . 1998 ) , proper motions ( ground based : herbig & jones 1981 ; hst : bally et al .
2002 ; ir : noriega - crespo et al ..
Please generate the next two sentences of the article | 1997 ; radio : rodrguez et al .
2000 ) , and detections in radio continuum ( pravdo et al . |
3,448 | Suppose that you have an abstract for a scientific paper: we study particle current in a recently proposed model for coherent quantum transport . in this model a system connected to mesoscopic fermi reservoirs ( meso - reservoir ) is driven out of equilibrium by the action of super reservoirs thermalized to prescribed temperatures and chemical potentials by a simple dissipative mechanism described by the lindblad equation .
we compare exact ( numerical ) results with theoretical expectations based on the landauer formula . .
And you have already written the first three sentences of the full article: particle current trough a coherent mesoscopic conductor connected at its left and right hand side to reservoirs is usually described in the non - interacting case by a formula , due to landauer , based on the following physical picture : electrons in the left ( right ) reservoir which are fermi distributed with chemical potential @xmath0 ( @xmath1 ) and inverse temperature @xmath2 ( @xmath3 ) can come close to the conductor and feed a scattering state that can transmit it to the right ( left ) reservoir . all possible dissipative processes such as thermalization occur in the reservoirs while the system formed by the conductor and the leads is assumed to be coherent .
the probability of being transmitted is a property of the conductor connected to the leads which is treated as a scattering system . in this picture , the probability that an outgoing electron comes back to the conductor before being thermalized is neglected , the contact is said to be reflectionless .
this description of the non - equilibrium steady state ( ness ) current through a finite system has been rigorously proved in some particular limiting situations @xcite , such as infinite reservoirs , but several difficulties prevail the understanding of non - equilibrium states in general and the description of current in more general situations , for instance in the case of interacting particles ..
Please generate the next two sentences of the article | two frameworks are usually considered to study these open quantum systems : one deals with the properties of the state of the total ( infinite ) system @xcite where reservoirs are explicitly considered as part of the system .
the other is based on the master equation of the reduced density operator , obtained by tracing out the reservoirs degrees of freedom and is better suited to be applied to different systems and to compute explicitly some averaged ness properties , at the price of several approximations such as _ e.g. _ , born - markov ( see e.g. @xcite ) . in this paper |
3,449 | Suppose that you have an abstract for a scientific paper: many deep wide - band wide - field radio interferometric surveys are being designed to accurately measure intensities , spectral indices and polarization properties of faint source populations . in this paper
we compare various wideband imaging methods to evaluate the accuracy to which intensities and spectral indices of sources close to the confusion limit can be reconstructed .
we simulated a wideband single - pointing ( c - array , l - band ( 1 - 2ghz ) ) and 46-pointing mosaic ( d - array , c - band ( 4 - 8ghz ) ) jvla observation using realistic brightness distribution ranging from @xmath0jy to @xmath1jy and time- , frequency- , polarization- and direction - dependent instrumental effects .
the main results from these comparisons are ( a ) errors in the reconstructed intensities and spectral indices are larger for weaker sources even in the absence of simulated noise , ( b ) errors are systematically lower for joint reconstruction methods ( such as mt - mfs ) along with a - projection for accurate primary beam correction , and ( c ) use of mt - mfs for image reconstruction eliminates clean - bias ( which is present otherwise ) .
auxiliary tests include solutions for deficiencies of data partitioning methods ( e.g. the use of masks to remove clean bias and hybrid methods to remove sidelobes from sources left undeconvolved ) , the effect of sources not at pixel centers and the consequences of various other numerical approximations within software implementations .
this paper also demonstrates the level of detail at which such simulations must be done in order to reflect reality , enable one to systematically identify specific reasons for every trend that is observed and to estimate scientifically defensible imaging performance metrics and the associated computational complexity of the algorithms / analysis procedures . .
And you have already written the first three sentences of the full article: the recent upgrade of the very large array ( vla ) has resulted in a greatly increased imaging sensitivity due to the availability of large instantaneous bandwidths at the receivers and correlator .
at least two new dish array telescopes ( in particular , askap and meerkat ) are currently under construction to improve upon the vla s specifications in terms of instantaneous sky coverage and total collecting area .
a considerable amount of observing time has been allotted on all three instruments for large survey projects that need deep and sometimes high dynamic range imaging over fields of view that span one or more primary beams ..
Please generate the next two sentences of the article | desired data products include images and high precision catalogs of source intensity , spectral index , polarized intensity and rotation measure , produced by largely automated imaging pipelines .
for these experiments , data sizes range from a few hundred gigabytes up to a few terabytes and contain a large number of frequency channels for one or more pointings . in this imaging regime , |
3,450 | Suppose that you have an abstract for a scientific paper: perturbing a cft by a relevant operator on a half space and letting the perturbation flow to the far infrared we obtain an rg interface between the uv and ir cfts .
if the ir cft is trivial we obtain an rg boundary condition .
the space of massive perturbations thus breaks up into regions labelled by conformal boundary conditions of the uv fixed point . for the 2d critical ising model perturbed by a generic relevant operator
we find the assignment of rg boundary conditions to all flows .
we use some analytic results but mostly rely on tcsa and tffsa numerical techniques .
we investigate real as well as imaginary values of the magnetic field and , in particular , the rg trajectory that ends at the yang - lee cft .
we argue that the rg interface in the latter case does not approach a single conformal interface but rather exhibits oscillatory non - convergent behaviour .
.5 in * rg boundaries and interfaces in ising field theory * + .250 in .5 in anatoly konechny 0.5 cm _ department of mathematics , heriot - watt university + edinburgh eh14 4as , united kingdom + and + maxwell institute for mathematical sciences + edinburgh , united kingdom + _ e - mail : [email protected] .5 in .
And you have already written the first three sentences of the full article: we are interested in rg flows in two - dimensional euclidean quantum field theories .
we will look at flows that originate in a uv fixed point described by a 2d @xmath0 and arrive at an ir fixed point described by a @xmath1 which may be trivial if a mass gap develops along the flow .
the flows are triggered by perturbations of @xmath0 by relevant operators @xmath2 ..
Please generate the next two sentences of the article | in general it is a hard non - perturbative problem to determine the infrared properties of the perturbed theory , in particular to identify @xmath1 when it is non - trivial .
a technique that allows one to investigate the perturbed theories numerically in the infrared including the flows to non - trivial fixed points is the truncated conformal space approach ( tcsa ) invented in @xcite . |
3,451 | Suppose that you have an abstract for a scientific paper: directional detection of dark matter allows for unambiguous direct detection of wimps as well as discrimination between various dark matter models in our galaxy .
the dmtpc detector is a low - pressure tpc with optical readout designed for directional direct detection of wimps . by using @xmath0 gas as the active material
, the detector also has excellent sensitivity to spin - dependent interactions of dark matter on protons . .
And you have already written the first three sentences of the full article: directional detection allows for unambiguous observation of dark matter ( dm ) even in presence of insidious backgrounds . when a weakly interacting massive particle ( wimp ) collides with a nucleus in the active mass of the detector , the direction of the nuclear recoil encodes the direction of the incident particle . for detectors consisting of a low - pressure gas ( about 50 torr ) ,
the typical length of such a recoil is 1 - 2 mm , which is sufficiently long to be reconstructed .
the simplest models of the distribution of wimps in our galaxy suggest that the orbital motion of the sun about the galactic center will cause an earth - bound observer to experience a wimp wind with speed 220 km / s ( the galacto - centric velocity of the sun ) , originating from the direction of the sun s motion . because the direction of this wind is inclined by 42@xmath1 with respect to the rotational axis of the earth , the average dm direction changes by almost 90@xmath1 every 12 hours @xcite . an ability to measure such a direction would allow for a powerful suppression of insidious backgrounds ( e.g. neutrons ) as well as a unique instrument to test local dm halo models ..
Please generate the next two sentences of the article | our detector consists of a low - pressure tpc with optical readout .
the target gas is @xmath0 , whose spin 1/2 fluorine nuclei provide the ideal target material to detect spin - dependent interactions @xcite . in addition |
3,452 | Suppose that you have an abstract for a scientific paper: we study the combined effects of relaxation , tidal heating and binary heating on globular cluster evolution , exploring the physical consequences of external effects and examining evolutionary trends in the milky way population .
our analysis demonstrates that heating on circular and low - eccentricity orbits can dominate cluster evolution .
the results also predict rapid evolution on eccentric orbits either due to strong relaxation caused by the high densities needed for tidal limitation or due to efficient bulge shocking of low density clusters .
the combination of effects leads to strong evolution of the population as a whole .
for example , within the solar circle , tidally - limited @xmath0 clusters lose at least 40% of their mass in 10 gyr . at high eccentricity
most of these clusters evaporate completely .
bulge shocking disrupts clusters within 40 kpc which have less than 80% of their mass within their pericentric inner lagrange point .
our results are consistent with suggestions that the shape of the cluster luminosity function results from evaporation and disruption of low mass clusters ; they further predict that the net velocity dispersion of the cluster system in the inner galaxy has decreased with time .
preliminary constraints on formation models are also discussed .
we conclude that the observed cluster system has largely been shaped by dynamical selection .
= -0.7 in # 1#2#1 # 2 # 1#2d # 1d # 2 2#1#2d^2 # 1d#2 ^ 2 # 1to 0pt#1 globular clusters : general the galaxy galaxies : star clusters
stellar dynamics .
And you have already written the first three sentences of the full article: many studies of globular cluster evolution have focused on internal mechanisms which drive evolution .
this work has produced a clear picture in which initial stellar evolution causes significant mass loss from a nascent cluster ( e.g. chernoff & weinberg 1990 ) ; two - body relaxation leads to mass segregation ( e.g. inagaki & saslaw 1985 ) and core collapse in surviving clusters ( e.g. cohn 1980 ) ; binary heating halts collapse ( e.g. lee et al . 1991 ) ; and the cluster continuously loses mass due to the escape of stars , eventually undergoing complete evaporation ( e.g. lee & goodman 1995 ) .
it is also recognized that the galaxy influences cluster evolution ..
Please generate the next two sentences of the article | the time - dependent tidal field heats clusters and tidal limitation aids in the removal of escaping stars .
previous investigations have considered disk shocking , bulge shocking and tidal limitation , concluding that each will play a role , particularly in the inner galaxy ( e.g. spitzer & chevalier 1973 ; chernoff & shapiro 1987 ; aguilar , hut & ostriker 1988 ; weinberg 1994 ) . |
3,453 | Suppose that you have an abstract for a scientific paper: we compute the minimal and the maximal bound on the number of generators of a minimal smooth monomial togliatti system of forms of degree @xmath0 in @xmath1 variables , for any @xmath2 and @xmath3 .
we classify the togliatti systems with number of generators reaching the lower bound or close to the lower bound .
we then prove that if @xmath4 ( resp @xmath5 ) all range between the lower and upper bound is covered , while if @xmath6 ( resp .
@xmath7 ) there are gaps if we only consider smooth minimal togliatti systems ( resp .
if we avoid the smoothness hypothesis ) .
we finally analyze for @xmath4 the mumford - takemoto stability of the syzygy bundle associated to smooth monomial togliatti systems . .
And you have already written the first three sentences of the full article: the classification of the smooth projective varieties satisfying at least one laplace equation is a classical problem , still very far from being solved .
we recall that a projective variety @xmath8 is said to satisfy a laplace equation of order @xmath0 , for an integer @xmath9 , if its @xmath0-osculating space at a general point has dimension strictly less than expected .
the most famous example is the togliatti surface , a rational surface in @xmath10 parametrized by cubics , obtained from the @xmath11rd veronese embedding @xmath12 of @xmath13 by a suitable projection from four points : the del pezzo surface obtained projecting @xmath12 from three general points on it admits a point which belongs to all its osculating spaces , so projecting further from this special point one obtains a surface having all osculating spaces of dimension @xmath14 instead of the expected @xmath15 ..
Please generate the next two sentences of the article | this surface is named from eugenio togliatti who gave a classification of rational surfaces parametrized by cubics and satisfying at least one laplace equation of order @xmath16 . for more details
see the original articles of togliatti @xcite , @xcite , or @xcite , @xcite , @xcite for discussions of this example . in @xcite |
3,454 | Suppose that you have an abstract for a scientific paper: the pauli exclusion principle ( pep ) is one of the basic principles of modern physics and , even if there are no compelling reasons to doubt its validity , it is still debated today because an intuitive , elementary explanation is still missing , and because of its unique stand among the basic symmetries of physics .
the present paper reports a new limit on the probability that pep is violated by electrons , in a search for a shifted k@xmath0 line in copper : the presence of this line in the soft x - ray copper fluorescence would signal a transition to a ground state already occupied by 2 electrons .
the obtained value , @xmath1 , improves the existing limit by almost two orders of magnitude . , , , , , , , , , , , , , , , , , , ,
, symmetrization principle , identical particles , tests of quantum field theories , anomalous atomic transitions , x rays , ccd 11.30.-j ; 03.65.-w ; 29.30.kv ; 32.30.rj .
And you have already written the first three sentences of the full article: the pauli exclusion principle ( pep ) is a consequence of the spin - statistics connection @xcite and plays a fundamental role in our understanding of many physical and chemical phenomena , from the periodic table of elements , to the electric conductivity in metals , to the degeneracy pressure , which makes white dwarfs and neutron stars stable , just to cite few ones .
although the principle has been spectacularly confirmed by the number and accuracy of its predictions , its foundation lies deep in the structure of quantum field theory and has defied all attempts to produce a simple proof , as nicely stressed by r. feynman @xcite .
given its basic standing in quantum theory , it seems appropriate to carry out precise tests of the pep validity and , indeed , in the last fifty years , several experiments have been performed to search for possible small violations @xcite ..
Please generate the next two sentences of the article | often , these experiments were born as by - products of experiments with a different objective ( e.g. dark matter searches , proton decay , etc .. ) , and most of the recent limits on the validity of pep have been obtained for nuclei or nucleons .
concerning the violation of pep for electrons , greenberg and mohapatra @xcite examined all experimental data which could be related , directly or indirectly , to pep , up to 1987 . in their analysis |
3,455 | Suppose that you have an abstract for a scientific paper: there is an open set of right triangles such that for each irrational triangle in this set ( i ) periodic billiards orbits are dense in the phase space , ( ii ) there is a unique nonsingular perpendicular billiard orbit which is not periodic , and ( iii ) the perpendicular periodic orbits fill the corresponding invariant surface .
[ 1]*proof of # 1 .
* + .
And you have already written the first three sentences of the full article: a billiard ball , i.e. a point mass , moves inside a polygon @xmath0 with unit speed along a straight line until it reaches the boundary @xmath1 , then instantaneously changes direction according to the mirror law : `` the angle of incidence is equal to the angle of reflection , '' and continues along the new line .
if the trajectory hits a corner of the polygon , in general it does not have a unique continuation and thus by definition it stops there .
billiards in polygons are easy to describe , but it is difficult to prove deep theorems about them because of a lack of machinery ..
Please generate the next two sentences of the article | for example , it is unknown if every polygon contains a periodic billiard orbit . on the other hand , for so called rational polygons
, one can apply teichmller theory to obtain many deep theorems . |
3,456 | Suppose that you have an abstract for a scientific paper: this paper presents a mechanism that may modify the extinction law for snia observed at higher redshift .
starting from the observations that ( 1 ) snia occur predominantly in spiral galaxies , ( 2 ) star - formation ejects ism out of the plane of spirals , ( 3 ) star - formation alters the extinction properties of the dust in the ism , and ( 4 ) there is substantially more star - formation at higher redshift , i propose that spiral galaxies have a dustier halo in the past than they do now . the ejected material s
lower value of @xmath0 will lead to a lower average value ( @xmath1 ) for snia observed at higher redshift .
two relations in snia observations indicate evolution of the average @xmath0 : the relation of observed @xmath0 with inclination of the host galaxy at low redshift and the matching of the distribution of extinction values ( @xmath2 ) for snia in different redshift intervals .
the inclination effect does point to a halo with lower @xmath0 values .
in contrast , the distributions of @xmath2 values match best for a @xmath3 evolution that mimics the relation of snia dimming with redshift attributed to the cosmological constant .
however , even in the worse case scenario , the evolution @xmath1 can not fully explain the dimming of snia : host galaxy extinction law evolution is not a viable alternative to account for the dimming of snia .
future observations of snia multi - color lightcurves and spectra will solve separately for values of @xmath2 and @xmath0 for each snia .
solving for evolution of @xmath1 ( and @xmath2 ) with redshift will be important for the coming generation of cosmological snia measurements and has the bonus science of insight into the distribution of dust - rich ism in the host galaxies in the distant past .
[ firstpage ] ( cosmology : ) distance scale cosmology : observations galaxies : high - redshift galaxies : ism ( ism : ) dust , extinction ( stars : ) supernovae : general .
And you have already written the first three sentences of the full article: supernova type 1a ( snia ) distance modulus measurements have grown into a powerful measurement of the equation of state of our universe .
accurate cosmological distances combined with redshift measurements allow for a precise characterisation of the hubble flow as well as the additional acceleration attributed to the cosmological constant @xcite .
the increasing statistics of snia measurements together with more information for each separate supernova event have progressively lowered the observational uncertainties : dust extinction , photometric error and lightcurve characterisation ( see e.g. , * ? ? ?.
Please generate the next two sentences of the article | * ; * ? ? ?
* ; * ? ? ? |
3,457 | Suppose that you have an abstract for a scientific paper: we show that the np - hard quadratic unconstrained binary optimization ( qubo ) problem on a graph @xmath0 can be solved using an adiabatic quantum computer that implements an ising spin-1/2 hamiltonian , by reduction through _ minor - embedding _ of @xmath0 in the quantum hardware graph @xmath1 .
there are two components to this reduction : _ embedding _ and _ parameter setting_. the embedding problem is to find a minor - embedding @xmath2 of a graph @xmath0 in @xmath1 , which is a subgraph of @xmath1 such that @xmath0 can be obtained from @xmath2 by contracting edges .
the parameter setting problem is to determine the corresponding parameters , qubit biases and coupler strengths , of the embedded ising hamiltonian . in this paper
, we focus on the parameter setting problem . as an example , we demonstrate the embedded ising hamiltonian for solving the maximum independent set ( mis ) problem via adiabatic quantum computation ( aqc ) using an ising spin-1/2 system .
we close by discussing several related algorithmic problems that need to be investigated in order to facilitate the design of adiabatic algorithms and aqc architectures . .
And you have already written the first three sentences of the full article: adiabatic quantum computation ( aqc ) was proposed by farhi et al.@xcite in 2000 .
the aqc model is based on the _ adiabatic theorem _ ( see , e.g. @xcite ) .
informally , the theorem says that if we take a quantum system whose hamiltonian `` slowly '' changes from @xmath3 ( initial hamiltonian ) to @xmath4 ( final hamiltonian ) , then if we start with the system in the _ groundstate _.
Please generate the next two sentences of the article | ( eigenvector corresponding to the lowest eigenvalue ) of @xmath3 , then at the end of the evolution the system will be `` predominantly '' in the ground state of @xmath4 . the theorem is used to construct _
adiabatic algorithms _ for optimization problems in the following way : the initial hamiltonian @xmath3 is designed such that the system can be readily initialized into its known groundstate , while the groundstate of the final hamiltonian @xmath4 encodes the answer to the desired optimization problem . |
3,458 | Suppose that you have an abstract for a scientific paper: we have carried out extensive radio and optical follow - up of 176 sources from the 15ghz 9th cambridge survey .
optical identifications have been found for 155 of the radio sources ; optical images are given with radio maps overlaid .
the continuum radio spectrum of each source spanning the frequency range 1.4 - 43ghz is also given .
two flux - limited samples are defined , one containing 124 sources complete to 25mjy and one of 70 sources complete to 60mjy .
between one fifth and one quarter of sources from these flux - limited samples display convex radio spectra , rising between 1.4 and 4.8ghz .
these rising - spectrum sources make up a much larger fraction of the radio source population at this high selection frequency than in lower frequency surveys .
we find that by using non - simultaneous survey flux density measurements at 1.4 and 15ghz to remove steep spectrum objects , the efficiency of selecting objects with spectra rising between 1.4 and 4.8ghz ( as seen in simultaneous measurements ) can be raised to 49percent without compromising the completeness of the rising spectrum sample .
[ firstpage ] galaxies : active radio continuum : general surveys .
And you have already written the first three sentences of the full article: in this paper we present the results of our follow - up work on the 9th cambridge survey ( 9c hereafter ) .
the 9c survey was carried out at 15ghz with the ryle telescope ( rt see * ? ? ?
* ) , primarily motivated by the need to identify foreground sources in the fields surveyed by the cambridge / jodrell / tenerife cosmic microwave background experiment , the very small array ( vsa , e.g. * ? ? ?.
Please generate the next two sentences of the article | a rastering technique was used to scan the fields with each possible detection being followed up with pointed observations to confirm its existence and measure its flux density or to rule it out : see @xcite for a full description of 9c .
the survey fields were chosen to contain few very bright radio sources , but otherwise should be representative of the radio sky in general . |
3,459 | Suppose that you have an abstract for a scientific paper: we present the first measurement of the spatial clustering of mid - infrared selected obscured and unobscured quasars , using a sample in the redshift range @xmath0 selected from the 9 deg@xmath1 botes multiwavelength survey . recently
the _ spitzer space telescope _ and x - ray observations have revealed large populations of obscured quasars that have been inferred from models of the x - ray background and supermassive black hole evolution . to date , little is known about obscured quasar clustering , which allows us to measure the masses of their host dark matter halos and explore their role in the cosmic evolution of black holes and galaxies . in this study
we use a sample of 806 mid - infrared selected quasars and @xmath2250,000 galaxies to calculate the projected quasar - galaxy cross - correlation function @xmath3 .
the observed clustering yields characteristic dark matter halo masses of @xmath4 ) = 12.7^{+0.4}_{-0.6}$ ] and @xmath5 for unobscured quasars ( qso-1s ) and obscured quasars ( obs - qsos ) , respectively .
the results for qso-1s are in excellent agreement with previous measurements for optically - selected quasars , while we conclude that the obs - qsos are _ at least _ as strongly clustered as the qso-1s .
we test for the effects of photometric redshift errors on the optically - faint obs - qsos , and find that our method yields a robust lower limit on the clustering ; photo-@xmath6 errors may cause us to underestimate the clustering amplitude of the obs - qsos by at most @xmath720% .
we compare our results to previous studies , and speculate on physical implications of stronger clustering for obscured quasars . .
And you have already written the first three sentences of the full article: supermassive black holes with masses @xmath8 are ubiquitous in the nuclei of local galaxies of moderate to high mass ( e.g. , * ? ? ?
it is now well established that most of the total mass in black holes in the nearby universe was accreted in luminous episodes with high eddington rates ( e.g. , * ? ? ?
* ; * ? ? ?.
Please generate the next two sentences of the article | * ) , with the growth for massive ( @xmath9 ) black holes occurring predominantly at @xmath10 ( e.g. , * ? ? ?
* ; * ? ? ? |
3,460 | Suppose that you have an abstract for a scientific paper: a model was developed for the excitation of the uibs by h atom impacts in the interstellar medium .
it builds upon the fact that , in the presence of far uv radiation and hydrocarbon grains , the hydrogen gas will be partially dissociated and the grain surface will be partially hydrogenated and partially covered with free carbon bonds . under such a statistical equilibrium , h atoms from the gas will recombine with c atoms at the grain surface at some rate . at each recombination , the h atom deposits an energy of about 5 ev in the grain .
half of this is directly converted into vibrational excitation , always distributed in the same way among the most tightly coupled vibration modes of the grain .
absent frequent grain - grain collisions , the only outlet for this energy is ir reemission , part of it in the uibs , provided the chemical structure of the grains is adequate , and the other part in the continuum .
the partition only depends upon the grain size , all grains being assumed to have the same constitution . only a fraction , about 0.25 , of the grains ( among the smallest ones ) will contribute significantly to the uibs .
it is shown quantitatively that h impacts are generally more efficient excitation agents than uv absorption because of the overwhelming abundance of hydrogen relative to uv photons .
only very close to young bright stars is this no longer true because photon flux then largely exceeds h atom flux .
thus h impacts and fuv absorption are both necessary to understand the variety of observed uib spectra .
the model translates into a small number of equations enabling a quantitative comparison of its predictions with available astronomical observations , which have become exquisitely rich and accurate in the last two decades .
[ firstpage ] .
And you have already written the first three sentences of the full article: infrared radiation from molecules and grains in space is usually or mostly attributed to heating by visible and uv light absorption .
while this may be justified by the ubiquity of light radiation , it must be remembered that the ism ( interstellar medium ) is also permeated with atomic hydrogen .
h atoms are also found in abundance in the limbs of molecular clouds illuminated by bright young stars ( pdrs or photodissociated regions ) ..
Please generate the next two sentences of the article | this paper accordingly explores the relative importance of deposition of energy by atomic hydrogen impacts on the same targets .
as is well known , the formation of molecular hydrogen by two isolated h atoms is forbidden by energy and momentum conservation ; it is therefore associated instead with recombination in presence of a third body * ( see spitzer 1977 ) . |
3,461 | Suppose that you have an abstract for a scientific paper: self - organization of active matter as well as driven granular matter in non - equilibrium dynamical states has attracted considerable attention not only from the fundamental and application viewpoints but also as a model to understand the occurrence of such phenomena in nature .
these systems share common features originating from their intrinsically out - of - equilibrium nature .
it remains elusive how energy dissipation affects the state selection in such non - equilibrium states . as a simple model system , we consider a non - equilibrium stationary state maintained by continuous energy input , relevant to industrial processing of granular materials by vibration and/or flow .
more specifically , we experimentally study roles of dissipation in self - organization of a driven granular particle monolayer .
we find that the introduction of strong inelasticity entirely changes the nature of the liquid - solid transition from two - step ( nearly ) continuous transitions ( liquid - hexatic - solid ) to a strongly discontinuous first - order - like one ( liquid - solid ) , where the two phases with different effective temperatures can coexist , unlike thermal systems , under a balance between energy input and dissipation .
our finding indicates a pivotal role of energy dissipation and suggests a novel principle in the self - organization of systems far from equilibrium .
a similar principle may apply to active matter , which is another important class of out - of - equilibrium systems . on noting that interaction forces in active matter , and particularly in living systems , are often non - conservative and dissipative , our finding may also shed new light on the state selection in these systems . .
And you have already written the first three sentences of the full article: despite the fact that self - organization of a system in an out - of - equilibrium state plays a crucial role in dynamical structural formation in nature , physical principles behind such phenomena have remained elusive .
active matter @xcite and driven granular matter @xcite are two important classes of out - of - equilibrium systems .
they share an intrinsic out - of - equilibrium nature , and the only basic difference is that the energy is injected locally for the active systems whereas globally for the granular systems @xcite ..
Please generate the next two sentences of the article | this global nature of energy input makes granular matter physically simpler than active matter .
thus , granular matter is not only important for its own sake , but also regarded as a model for understanding the physics of active matter . |
3,462 | Suppose that you have an abstract for a scientific paper: motivated by the discovery of gravitational waves ( gws ) and no evidence of new physics at current lhc , we discuss that many extended new physics models with hidden gauge group could undergo one or several times first - order phase transitions associated with the gauge group symmetry breaking in the evolution history of universe , which might produce detectable phase transition gws signals at future gws experiments , such as elisa . .
And you have already written the first three sentences of the full article: the observation of gravitational waves ( gws ) by advanced laser interferometer gravitational wave observatory ( aligo ) @xcite has initiated a new era of exploring the cosmology , the nature of gravity as well as the fundamental particle physics by the gws detectors @xcite . especially , due the the limitation of the colliders energy , gws detectors can be used as new techniques to probe the symmetry breaking patterns or phase transition history for a large class of new physics models with hidden gauge group extensions of the standard model ( sm ) , which are motivated by the experimental results in our understanding of particle cosmology and fundamental physics ( such as the dark matter mystery or the puzzling observed baryon asymmetry of the universe ) , and no evidence for new physics discovered at current collider experiments .
the increasingly attractive new physics models with hidden non - abelian gauge group extensions of the sm have many new particles without leaving any observable imprints at current particle colliders .
however , the gws experiments may provide a possible approach to test their existence ..
Please generate the next two sentences of the article | for example , to explain the baryon asymmetry of the universe via electroweak baryogenesis by the hidden sectors , a strong first - order phase transition is usually needed to realize the departure from thermal equilibrium @xcite . and
during the first - order phase transition , the gws will be produced through three mechanisms : collisions of expanding bubbles , sounds waves , and magnetohydrodynamic turbulence of bubbles in the hot plasma @xcite . |
3,463 | Suppose that you have an abstract for a scientific paper: we show that forward proton tagging may significantly enlarge the potential of studying the higgs sector at the lhc .
we concentrate on higgs production via central exclusive diffractive processes ( cedp ) .
particular attention is paid to regions in the mssm parameter space where the partial width of the higgs boson decay into two gluons much exceeds the sm case ; here the cedp are found to have special advantages .
ippp/03/51 + dcpt/03/102 + 4 december 2003 + * extending the study of the higgs sector at the lhc by proton tagging * a.b .
kaidalov@xmath0 , v.a .
khoze@xmath1 , a.d . martin@xmath2 and m.g .
ryskin@xmath1 + @xmath3 department of physics and institute for particle physics phenomenology , + university of durham , dh1 3le , uk + @xmath4 institute of theoretical and experimental physics , moscow , 117259 , russia + @xmath5 petersburg nuclear physics institute , gatchina , st . petersburg , 188300 , russia + @xmath6 department of physics , university of canterbury , christchurch , new zealand + .
And you have already written the first three sentences of the full article: the higgs sector is ( so far ) an elusive basic ingredient of the fundamental theory of particle interactions .
searches for higgs bosons , and the study of their properties , are one of the primary goals of the large hadron collider ( lhc ) at cern , which is scheduled to commence taking data in the year 2007 .
the conventional folklore is that ( under reasonable model assumptions ) at least one higgs boson should be discovered at the lhc . in particular ,.
Please generate the next two sentences of the article | if the light higgs predicted by the standard model ( sm ) exists , it will almost certainly be found at the lhc in the first years of running or even maybe before , at the tevatron .
moreover the lhc should provide a complete coverage of the sm higgs mass range . |
3,464 | Suppose that you have an abstract for a scientific paper: in this paper we solve the hydrodynamical equations of optically thin , steady state accretion disks around kerr black holes . here , fully general relativistic equations are used .
we use a new method to calculate the shear tensor in the lnrf ( locally non - rotating frame ) , blf ( boyer - lindquist frame ) and frf ( fluid rest frame ) .
we show that two components of shear tensor in the frf are nonzero ( in previous works only one nonzero component was assumed ) .
we can use these tensors in usual transonic solutions and usual causal viscosity , but we derive solutions analytically by some simplifications .
then we can calculate the four velocity and density in all frames such as the lnrf , blf and frf .
keywords : black hole accretion disks , relativistic disks , accretion disks , shear tensor , hydrodynamic . .
And you have already written the first three sentences of the full article: accretion disks are important in several astrophysical systems . they can be found around young stellar objects(yso ) , around compact stellar objects in our galaxy and around several super - massive black holes in active galactic nuclei(agn ) . in super massive accretion disks
the mass of black hole is @xmath0 . to study such disks we use the general relativity with relativistic hydrodynamics in kerr metric background geometry . in relativistic navier - stokes fluid
we have stress - energy tensor which is related to viscosity and is the cause of redistribution of energy and momentum in fluid ..
Please generate the next two sentences of the article | this tensor is defined by the four velocity and metric . in the previous studies ,
the relativistic and stationary solutions of standard black hole disks were solved . |
3,465 | Suppose that you have an abstract for a scientific paper: we discuss fermion pair productions in strong electric and magnetic fields .
we point out that , in the case of massless fermions , the vacuum persistency probability per unit time and volume is zero in the strong electric and magnetic fields , while it is finite when the magnetic field is absent .
the contribution from the lowest landau level ( lll ) dominates this phenomenon .
we also discuss dynamics of the vacuum decay , using an effective theory of the lll projection , taking into account the back reaction . .
And you have already written the first three sentences of the full article: dynamics in strong fields has been an interesting subject in theoretical physics .
recently , this subject is being paid attention also in the experimental physics of creation of the quark gluon plasma . in high - energy heavy - ion collision experiments , at the so - called glasma stage @xcite just after the collision , longitudinal color electric and magnetic fields are expected to be produced in the context of the color glass condensate of order @xmath0@xmath1 gev in rhic and @xmath2 gev in lhc . in the peripheral collision , a strong magnetic field of order @xmath3 mev
would be induced ..
Please generate the next two sentences of the article | the question is how the strong fields decay and the system is thermalized . in this work ,
we concentrate on how the strong fields decay into particles . for this purpose |
3,466 | Suppose that you have an abstract for a scientific paper: the generalized thomas - kuhn sum rules are used to eliminate the explicit dependence on dipolar terms in the traditional sum - over - states ( sos ) expression for the second hyperpolarizability to derive a new , yet equivalent , sos expression .
this new dipole - free expression may be better suited to study the second hyperpolarizability of non - dipolar systems such as quadrupolar , octupolar , and dodecapolar structures .
the two expressions lead to the same fundamental limits of the off - resonance second hyperpolarizability ; and when applied to a particle in a box and a clipped harmonic oscillator , have the same frequency - dependence .
we propose that the new dipole - free equation , when used in conjunction with the standard sos expression , can be used to develop a three - state model of the dispersion of the third - order susceptibility that can be applied to molecules in cases where normally many more states would have been required .
furthermore , a comparison between the two expressions can be used as a convergence test of molecular orbital calculations when applied to the second hyperpolarizability . .
And you have already written the first three sentences of the full article: the sum - over - states ( sos ) expressions have been used for more than three decades in the study of nonlinear optical phenomena , and are perhaps the most universally used equations in molecular nonlinear optics .
the sum - over - states expression is obtained from quantum perturbation theory and is usually expressed in terms of the matrix elements of the dipole operator , @xmath0 , and the zero - field energy eigenvalues , @xmath1.@xcite + the sos expressions for the first and second hyperpolarizability derived by orr and ward using the method of averages@xcite are often used because they explicitly eliminate the unphysical secular terms that are present in other derivations.@xcite these secular - free expressions contain summations over _ all _ excited states .
+ finite - state approximations are used to apply the theory to experimental results ..
Please generate the next two sentences of the article | oudar and chemla studied the first hyperpolarizability of nitroanilines by considering only two states , the ground and the dominant excited state.@xcite although the general validity of this `` two - level '' model has been questioned , especially in its use for extrapolating measurement results to zero frequency , the approximation is still widely used in experimental studies of the nonlinear properties of organic molecules .
+ several approaches have been used to develop approximate expressions for the second - hyperpolarizability in the off - resonance regime.@xcite while such approximations are helpful , they systematically ignore some of the contributions to the sos expression . as our goal is to derive a general expression that is equivalent to the traditional sos one |
3,467 | Suppose that you have an abstract for a scientific paper: fifty - one object in the @xmath0 methanol line at 84.5 ghz was detected during a survey of class i maser sources .
narrow maser features were found in 17 of these .
broad quasi - thermal lines were detected towards other sources .
one of the objects with narrow features , the young bipolar outflow l 1157 was also observed in the @xmath1 line at 95.2 ghz ; a narrow line was detected at this frequency .
analysis showed that the broad lines are usually inverted .
the quasi - thermal profiles imply that the line opacities are not larger than several units .
these results confirm the plausibility of models in which compact class i masers appear in extended sources as a result of an appropriate velocity field .
measurements of linear polarization at 84.5 ghz in 13 sources were made .
no polarization was found except a tentative detection of a weak polarization in m 8e .
# 1_#1 _ # 1_#1 _ = # 1 1.25 in .125 in .25 in .
And you have already written the first three sentences of the full article: methanol masers in the @xmath0 line at 84521.21 mhz were found by batrla and menten ( 1988 ) and menten ( 1991 ) towards ngc 2264 , omc-2 , and dr 21 , but no extended survey in this line had been done .
the @xmath0 transition belongs to the class i ( menten , 1991 ) .
its excitation is similar to that of the @xmath2 and @xmath3 transitions ..
Please generate the next two sentences of the article | since methanol masers emit in several lines of the same class , we expect the detection of a fairly large number of maser sources at 84.5 ghz .
their parameters should be taken into account when modeling maser sources . |
3,468 | Suppose that you have an abstract for a scientific paper: in magnets with non - collinear spin configuration the expectation value of the conventionally defined spin current operator contains a contribution which renormalizes an external magnetic field and hence affects only the precessional motion of the spin polarization .
this term , which has been named angular spin current by sun and xie [ phys .
rev b * 72 * , 245305 ( 2005 ) ] , does not describe the translational motion of magnetic moments .
we give a prescription how to separate these two types of spin transport and show that the translational movement of the spin is always polarized along the direction of the local magnetization .
we also show that at vanishing temperature the classical magnetic order parameter in magnetic insulators can not carry a translational spin current , and elucidate how this affects the interpretation of spin supercurrents .
= 10000 .
And you have already written the first three sentences of the full article: the notion of spin currents describing the motion of magnetic moments associated with the spins of the electrons in solids is of central importance in the field of spintronics where one tries to use the spin degree of freedom to store and process information .
unfortunately , in systems lacking spin - rotational invariance ( which can be broken by an external magnetic field or by relativistic effects such as spin - orbit coupling or dipole - dipole interactions ) the proper definition of the quantum mechanical operator representing the spin current is ambiguous , because the magnetization does not satisfy a local conservation law . in the past decade
several authors have proposed resolutions of this ambiguity @xcite , but a generally accepted agreement on the correct definition of the spin current operator in systems without spin conservation has not been found . the purpose of this work is show that the distinction between translational and angular spin currents proposed by sun and xie @xcite leads to a simple and unique definition of the concept of spin transport in condensed matter systems ..
Please generate the next two sentences of the article | sun and xie @xcite pointed out that spin currents describe moving magnetic dipoles , and that generally the transport of any vector can be decomposed into a translational part characterized by some velocity @xmath0 and an angular part described by some angular velocity @xmath1 , see fig .
[ fig : transport ] . in the context of spin transport sun and |
3,469 | Suppose that you have an abstract for a scientific paper: the study of the universe at energies above 100 gev is a relatively new and exciting field .
the current generation of pointed instruments have detected tev gamma rays from at least 10 sources and the next generation of detectors promises a large increase in sensitivity .
we have also seen the development of a new type of all - sky monitor in this energy regime based on water cherenkov technology ( milagro ) . to fully understand the universe at these extreme energies requires a highly sensitive detector capable of continuously monitoring the entire overhead sky .
such an instrument could observe prompt emission from gamma - ray bursts and probe the limits of lorentz invariance at high energies .
with sufficient sensitivity it could detect short transients ( @xmath015 minutes ) from active galaxies and study the time structure of flares at energies unattainable to space - based instruments . unlike pointed instruments a wide - field instrument can make an unbiased study of all active galaxies and enable many multi - wavelength campaigns to study these objects .
this paper describes the design and performance of a next generation water cherenkov detector . to attain a low energy threshold and have high sensitivity
the detector should be located at high altitude ( @xmath1 4 km ) and have a large area ( @xmath040,000 m@xmath2 ) .
such an instrument could detect gamma ray bursts out to a redshift of 1 , observe flares from active galaxies as short as 15 minutes in duration , and survey the overhead sky at a level of 50 mcrab in one year . .
And you have already written the first three sentences of the full article: the past 15 years have seen large advances in the capabilities of ground - based gamma ray detection , from the pioneering observation of the crab nebula by the whipple observatory in 1989@xcite to the new generation of air cherenkov telescope arrays such as hess@xcite , veritas@xcite , and cangaroo@xcite and large area air cherenkov telescopes such as stacee @xcite , celeste@xcite , and magic@xcite .
there are now at least 10 known sources of very - high - energy ( vhe ) gamma rays@xcite .
the physics of these objects is astounding : from spinning neutron stars to super - massive black holes , these objects manage to accelerate particles to energies well in excess of 10 tev ..
Please generate the next two sentences of the article | how this acceleration occurs is not well understood and there is not universal agreement on what particles are being accelerated in some of these sources . at lower energies egret
has detected over 270 sources of high - energy gamma rays@xcite and glast is expected to detect several thousand sources . |
3,470 | Suppose that you have an abstract for a scientific paper: in this work we study the equatorial causal geodesics of the taub - nut ( tn ) space - time in comparison with _ mass - less _ tn space - time .
we emphasized both on the null circular geodesics and time - like circular geodesics . from the effective potential diagram of
null and time - like geodesics , we differentiate the geodesics structure between tn spacetime and mass - less tn space - time .
it has been shown that there is a key role of the nut parameter to changes the shape of pattern of the potential well in the nut spacetime in comparison with _ mass - less _ nut space - time .
we compared the isco ( innermost stable circular orbit ) , mbco ( marginally bound circular orbit ) and cpo ( circular photon orbit ) of the said space - time with graphically in comparison with mass - less cases .
moreover , we compute the radius of isco , mbco and cpo for _ extreme _ tn black hole ( bh ) .
interestingly , we show that these _ three radii _ coincides with the killing horizon i.e. the null geodesic generators of the horizon . finally in appendix - a , we compute the center - of - mass ( cm ) energy for tn bh and mass - less tn bh .
we show that in both cases the cm energy is finite . for _ extreme _ nut bh
, we have found that the diverging nature of cm energy . _ first _ , we have observed that a non - asymptotic flat , spherically symmetric and stationary extreme bh is showing such feature . .
And you have already written the first three sentences of the full article: the taub - nut ( newman , unti and tamburino ) space - time @xcite is a stationary , spherically symmetric and non - asymptotically flat solution of the vacuum einstein equation in general theory of relativity .
the space - time has topology @xmath0 with lorentzian signature @xcite .
the nut space - time is described by two parameters : one is the mass parameter @xmath1 and another one is the nut parameter @xmath2 ..
Please generate the next two sentences of the article | there is no modification required in the einstein - hilbert action to accommodate the nut charge @xcite or `` dual mass '' @xcite or `` gravito - magnetic mass '' or `` gravito - magnetic monopole '' @xcite .
this dual mass is an intrinsic feature of general theory of relativity . |
3,471 | Suppose that you have an abstract for a scientific paper: speech is a distinctive complex feature of human capabilities . in order to understand the physics underlying speech production , in this work we empirically analyse the statistics of large human speech datasets ranging several languages .
we first show that during speech the energy is unevenly released and power - law distributed , reporting a universal robust gutenberg - richter - like law in speech .
we further show that such earthquakes in speech show temporal correlations , as the interevent statistics are again power - law distributed .
since this feature takes place in the intraphoneme range , we conjecture that the responsible for this complex phenomenon is not cognitive , but it resides on the physiological speech production mechanism .
moreover , we show that these waiting time distributions are scale invariant under a renormalisation group transformation , suggesting that the process of speech generation is indeed operating close to a critical point .
these results are put in contrast with current paradigms in speech processing , which point towards low dimensional deterministic chaos as the origin of nonlinear traits in speech fluctuations .
as these latter fluctuations are indeed the aspects that humanize synthetic speech , these findings may have an impact in future speech synthesis technologies .
results are robust and independent of the communication language or the number of speakers , pointing towards an universal pattern and yet another hint of complexity in human speech . the description , understanding and modelling of speech is an interdisciplinary topic of current interest for physics @xcite , social and cognitive sciences @xcite , data mining as well as engineering @xcite .
classical speech synthesis technologies and algorithms were firstly based on linear stochastic models and linear prediction @xcite , and their underlying theory , so called source - filter theory of speech production , was initially relying on several key assumptions including uncoupled vocal....
And you have already written the first three sentences of the full article: a tv broadcast speech database named kalaka-2 @xcite is employed for analysing language - dependent speech .
it was originally designed for language recognition evaluation purposes and consists of wide - band tv broadcast speech recordings ( roughly 4 hours per language ) featuring 6 different languages : basque , catalan , galician , spanish , portuguese and english .
tv broadcast shows were recorded and sampled using @xmath7 bytes at @xmath8 samples / second rate , taking care of including as much diversity as possible regarding speakers and speech modalities ..
Please generate the next two sentences of the article | it includes both planned and spontaneous speech throughout diverse environment conditions , such as studio or outside journalist reports but excluding telephonic channel .
therefore audio excerpts may contain voices from several speakers but only a single language . |
3,472 | Suppose that you have an abstract for a scientific paper: one of the points at issue with closed - loop - type interferometers is beating in the aharonov - bohm ( ab ) oscillations .
recent observations suggest the possibility that the beating results from the berry - phase pickup by the conducting electrons in materials with the strong spin - orbit interaction ( soi ) . in this study , we also observed beats in the ab oscillations in a gate - defined closed - loop interferometer fabricated on a gaas / al@xmath0ga@xmath1as two - dimensional electron - gas heterostructure .
since this heterostructure has very small soi the picture of the berry - phase pickup is ruled out .
the observation of beats in this study , with the controllability of forming a single transverse sub - band mode in both arms of our gate - defined interferometer , also rules out the often - claimed multiple transverse sub - band effect .
it is observed that nodes of the beats with an @xmath2 period exhibit a parabolic distribution for varying the side gate .
these results are shown to be well interpreted , without resorting to the soi effect , by the existence of two - dimensional multiple longitudinal modes in a single transverse sub - band .
the fourier spectrum of measured conductance , despite showing multiple @xmath3 peaks with the magnetic - field dependence that are very similar to that from strong - soi materials , can also be interpreted as the two - dimensional multiple - longitudinal - modes effect . .
And you have already written the first three sentences of the full article: an electron traversing a path enclosing magnetic flux acquires an additional phase by the magnetic vector potential .
this additional phase causes the aharonov - bohm ( ab ) oscillation of the electronic magnetoconductance@xcite with the period of @xmath3 .
the ab oscillation in solid state devices was first observed by webb _ et al._@xcite and timp _ et al._@xcite in metal and semiconductor ab rings , respectively ..
Please generate the next two sentences of the article | especially , ab rings fabricated on the two - dimensional electron gas ( 2deg ) layer formed in a semiconductor heterojunction structure like gaas / algaas have been studied intensively , because the electron phase coherence in this system extends much longer than the size of an ab ring .
for instance , a structure of a quantum dot embedded in one arm of an ab ring was employed recently for accurate measurements of the phase change of traversing electrons through a quantum dot . |
3,473 | Suppose that you have an abstract for a scientific paper: we have evaluated a 20-in .
photoelectric lens image intensifier tube ( pli ) to be mounted on the spherical focal surface of the ashra light collectors , where ashra stands for all - sky survey high resolution air - shower detector , an unconventional optical collector complex that images air showers produced by very high energy cosmic - ray particles in a 42@xmath0-diameter field of view with a resolution of a few arcminutes .
the pli , the worlds largest image intensifier , has a very large effective photocathode area of 20-in .
diameter and reduces an image size to less than 1-inch diameter using the electric lens effect .
this enables us to use a solid - state imager to take focal surface images in the ashra light collector .
thus , pli is a key technology for the ashra experiment to realize a much lower pixel cost in comparison with other experiments using photomultiplier arrays at the focal surface . in this paper
we present the design and performance of the 20-in .
pli .
first generation image intensifier tube ; large sensitive area ; photodetector ; high energy astrophysics ; ashra experiment .
And you have already written the first three sentences of the full article: the all - sky survey high resolution air - shower detector ( ashra ) @xcite is an experiment for obtaining fine images of air - showers produced by very high energy ( vhe ) cosmic - ray particles as well as directly observing starlight to monitor optical transients .
ashra has an potential to provide a systematic exploration of extragalactic vhe particle radiators in the universe .
the ashra observational station consists of 12 light collectors covering 77% of the entire sky with a total of 50 mega pixels in cmos sensor arrays ..
Please generate the next two sentences of the article | each light collector has a 42@xmath0 field of view ( fov ) and a spot size resolution of a few arcmin .
the focal surface of the ashra optical system consists of a photoelectric lens image intensifier tube ( pli ) sensitive to uv and visible rays . |
3,474 | Suppose that you have an abstract for a scientific paper: ultraviolet observations from low earth orbit ( leo ) have to deal with a foreground comprised of airglow and zodiacal light which depend on the look direction and on the date and time of the observation .
we have used all - sky observations from the galex spacecraft to find that the airglow may be divided into a baseline dependent on the sun angle and a component dependent only on the time from local midnight .
the zodiacal light is observable only in the near ultraviolet band ( 2321 ) of galex and is proportional to the zodiacal light in the visible but with a color of 0.65 indicating that the dust grains are less reflective in the uv . .
And you have already written the first three sentences of the full article: measurements of the diffuse ultraviolet ( uv ) radiation field have to contend with a number of contaminating sources including atmospheric emission lines and the zodiacal light @xcite .
these foreground sources are particularly important at high galactic latitudes where the galactic contribution to the radiation field is relatively small and at longer wavelengths where the zodiacal light , which follows the solar spectrum , becomes increasingly important .
it has been difficult to disentangle these components , largely because of a lack of relevant observations . ideally , these would be spectroscopic observations with moderate resolutions over a large part of the sky with different sun angles ..
Please generate the next two sentences of the article | however , what we have is thousands of observations from the galaxy evolution explorer ( _ galex _ ) in two bands ( fuv : 1531 and nuv : 2321 ) with observations far from the sun to minimize foreground emission . despite these drawbacks
, we have used the _ galex _ |
3,475 | Suppose that you have an abstract for a scientific paper: it has previously been discovered that there is a universal power law behavior exhibited by the late x - ray emission ( lxre ) of a `` golden sample '' ( gs ) of six long energetic grbs , when observed in the rest - frame of the source .
this remarkable feature , independent of the different isotropic energy ( @xmath0 ) of each grb , has been used to estimate the cosmological redshift of some long grbs .
this analysis is extended here to a new class of 161 long grbs , all with @xmath1 erg .
these grbs are indicated as binary - driven hypernovae ( bdhne ) in view of their progenitors : a tight binary system composed of a carbon - oxygen core ( co@xmath2 ) and a neutron star undergoing an induced gravitational collapse ( igc ) to a black hole triggered by the co@xmath2 explosion as a supernova ( sn ) .
we confirm the universal behavior of the lxre for the `` enlarged sample '' ( es ) of 161 bdhne observed up to the end of 2015 , assuming a double - cone emitting region .
we obtain a distribution of half - opening angles peaking at @xmath3 , with a mean value of @xmath4 , and a standard deviation of @xmath5 .
this , in turn , leads to the possible establishment of a new cosmological candle . within the igc model ,
such universal lxre behavior is only indirectly related to the grb and originates from the sn ejecta , of a standard constant mass , being shocked by the grb emission .
the fulfillment of the universal relation in the lxre and its independence of the prompt emission , further confirmed in this article , establishes a crucial test for any viable grb model . .
And you have already written the first three sentences of the full article: the initial observations by the batse instrument on board the compton @xmath6-ray observatory satellite have evidenced what has later become known as the prompt radiation of grbs . on the basis of their hardness as well as their duration , grbs were initially classified into short and long at a time when their cosmological nature was still being disputed .
the advent of the _ bepposax _ satellite @xcite introduced a novel approach to grbs by introducing joint observations in the x - rays and @xmath6-rays thanks to its instruments : the gamma - ray burst monitor ( @xmath7@xmath8 kev ) , the wide field cameras ( @xmath9@xmath10 kev ) , and the narrow field instruments ( @xmath9-@xmath11 kev ) .
the unexpected and welcome discovery of the existence of a well separate component in the grb soon appeared : the afterglow radiation lasting up to @xmath12@xmath13 s after the emission of the prompt radiation ..
Please generate the next two sentences of the article | beppo - sax clearly indicated the existence of a power law behavior in the late x - ray emission ( lxre ; see fig .
[ bepposax ] ) . |
3,476 | Suppose that you have an abstract for a scientific paper: an edge in a @xmath0-connected graph @xmath1 is called _ @xmath0-contractible _ if the graph @xmath2 obtained from @xmath1 by contracting @xmath3 is @xmath0-connected .
generalizing earlier results on @xmath4-contractible edges in spanning trees of @xmath4-connected graphs , we prove that ( except for the graphs @xmath5 if @xmath6 ) ( a ) every spanning tree of a @xmath0-connected triangle free graph has two @xmath0-contractible edges , ( b ) every spanning tree of a @xmath0-connected graph of minimum degree at least @xmath7 has two @xmath0-contractible edges , ( c ) for @xmath8 , every dfs tree of a @xmath0-connected graph of minimum degree at least @xmath9 has two @xmath0-contractible edges , ( d ) every spanning tree of a cubic @xmath4-connected graph nonisomorphic to @xmath10 has at least @xmath11 many @xmath4-contractible edges , and ( e ) every dfs tree of a @xmath4-connected graph nonisomorphic to @xmath10 , the prism , or the prism plus a single edge has two 3-contractible edges .
we also discuss in which sense these theorems are best possible . *
ams classification : * 05c40 , 05c05 .
* keywords : * contractible edge , spanning tree , dfs tree , fox . .
And you have already written the first three sentences of the full article: all graphs throughout are assumed to be finite , simple , and undirected . for terminology
not defined here we refer to @xcite or @xcite .
a graph is called _ @xmath0-connected _ ( @xmath12 ) if @xmath13 and @xmath14 is connected for all @xmath15 with @xmath16 ..
Please generate the next two sentences of the article | let @xmath17 denote the _ connectivity _ of @xmath1 , that is , the largest @xmath0 such that @xmath1 is @xmath0-connected . a set @xmath15 is called a _
smallest separating set _ if @xmath18 and @xmath14 is disconnected . by @xmath19 |
3,477 | Suppose that you have an abstract for a scientific paper: we study cosmic - ray acceleration in a supernova remnant ( snr ) and the escape from it .
we model nonthermal particle and photon spectra for the hidden snr in the open cluster westerlund 2 , and the old - age mixed - morphology snr w 28 .
we assume that the snr shock propagates in a low - density cavity , which is created and heated through the activities of the progenitor stars and/or previous supernova explosions .
we indicate that the diffusion coefficient for cosmic - rays around the snrs is less than @xmath0% of that away from them .
we compare our predictions with the gamma - ray spectra of molecular clouds illuminated by the cosmic - rays ( fermi and h.e.s.s . ) .
we found that the spectral indices of the particles are @xmath1 .
this may be because the particles were accelerated at the end of the sedov phase , and because energy dependent escape and propagation of particles did not much affect the spectrum . .
And you have already written the first three sentences of the full article: supernova remnants ( snrs ) are canonically considered the main sources of cosmic - rays in the galaxy .
the detection of non - thermal x - ray emission from snrs clearly indicates that electrons are actually accelerated around the snr shocks @xcite , and the observations can constrain the electron spectra . on the other hand , observational confirmation of accelerated protons is not as easy as that of electrons .
one way to study the acceleration and spectrum of protons is to study gamma - ray emission through @xmath2-interactions and the decay of neutral pions ( e.g. * ? ? ?.
Please generate the next two sentences of the article | * ; * ? ? ?
* ; * ? ? ? |
3,478 | Suppose that you have an abstract for a scientific paper: we show that prony s method provides the full solution to the nonlinear equations of the connected moments expansion ( cmx ) .
knowledge of all the parameters in the cmx ansatz is useful for the analysis of the convergence properties of the approach .
prony s method is also suitable for the calculation of the correlation function for simple quantum mechanical models . .
And you have already written the first three sentences of the full article: horn and weinstein@xcite and horn et al@xcite proposed the @xmath0expansion for the calculation of the ground
state energy of quantum mechanical models .
it is the taylor expansion about @xmath1 of a monotonically decreasing function @xmath2 that leads to the ground .
Please generate the next two sentences of the article | state energy when @xmath3 provided that the chosen reference function exhibits a nonzero overlap with the ground state .
the coefficients of such maclaurin series are known as connected moments or cummulants . |
3,479 | Suppose that you have an abstract for a scientific paper: the force field by lenosky and coworkers is the latest force field for silicon which is one of the most studied materials .
it has turned out to be highly accurate in a large range of test cases .
the optimization and parallelization of this force field using openmp and fortan90 is described here .
the optimized program allows us to handle a very large number of silicon atoms in large scale simulations .
since all the parallelization is hidden in a single subroutine that returns the total energies and forces , this subroutine can be called from within a serial program in an user friendly way .
-0.75 in .
And you have already written the first three sentences of the full article: title of program : siliconiap computer hardware and operating system : any shared memory computer running under unix or linux programming language : fortran90 with openmp compiler directives memory requirements : roughly 150 words per atom no . of bits in a word : 64 no . of processors
used : tested on up to 4 processors has the code been vectorized or parallelized : parallelized withe openmp no .
of bytes in distributed program , including test data , etc : 50 000 distribution format : compressed tar file keywords : silicon , interatomic potential , force field , molecular dynamics nature of physical problem : condensed matter physics method of solution : interatomic potential restrictions on the complexity of the problem : none typical running time : 30 @xmath0sec per step and per atom on a compaq dec alpha unusual features of the program : none.
Please generate the next two sentences of the article | due to its technological importance , silicon is one of the most studied materials . for small
system sizes ab - initio density functional calculations @xcite are the preferred approach . |
3,480 | Suppose that you have an abstract for a scientific paper: preliminary measurements are reported on the azimuthal single - spin asymmetry of exclusive @xmath0 mesons for a transversely polarized hydrogen target at hermes using the @xmath1 gev hera positron beam . within the generalized parton distribution ( gpd )
formalism , this asymmetry is sensitive to the total angular momentum of quarks and gluons in the nucleon . since the gpd formalism is only valid for mesons produced by longitudinal photons , the transverse target - spin asymmetry of longitudinal @xmath0 mesons
is extracted assuming @xmath2-channel helicity conservation and compared to theoretical calculations . .
And you have already written the first three sentences of the full article: hard exclusive meson production in deep inelastic lepton scattering provides access to the unknown generalized parton distributions ( gpds ) of the nucleon @xcite . for such reactions
, it has been shown that for longitudinal virtual photons , the @xmath3 amplitude can be factorized into a hard lepton - scattering part and two soft parts which parameterize the structure of the nucleon by gpds and the structure of the produced meson by distribution amplitude @xcite .
gpds reflect the 3-dimensional structure of the nucleon and contain information about the total angular momentum carried by partons in the nucleon ..
Please generate the next two sentences of the article | hard exclusive production of @xmath0 mesons is sensitive to the gpds @xmath4 and @xmath5 which are the ones related to the total angular momenta @xmath6 and @xmath7 of quarks and gluons in the nucleon @xcite .
the gpd @xmath4 is already somewhat constrained , while the gpd @xmath5 is still unknown . in the case of a transversely polarized target , |
3,481 | Suppose that you have an abstract for a scientific paper: we present quantum mechanical and quasiclassical trajectory calculations of cross sections for rovibrational transitions in ortho- and para - h@xmath0 induced by collisions with he atoms .
cross sections were obtained for kinetic energies between 10@xmath1 and 3 ev , and the corresponding rate coefficients were calculated for the temperature range 100@xmath24000 k. comparisons are made with previous calculations . .
And you have already written the first three sentences of the full article: rovibrationally excited h@xmath0 molecules have been observed in many astrophysical objects ( for recent studies , see weintraub et al .
1998 ; van dishoeck et al . 1998 ; shupe et al .
1998 ; bujarrabal et al . 1998 ; stanke et al . 1998 ) ..
Please generate the next two sentences of the article | the rovibrational levels of the molecule may be populated by ultraviolet pumping , by x - ray pumping , by the formation mechanism , and by collisional excitation in shock - heated gas ( dalgarno 1995 ) .
the excited level populations are then modified by collisions followed by quadrupole emissions . |
3,482 | Suppose that you have an abstract for a scientific paper: we explicitly construct a quantum circuit which exactly generates random three - qubit states .
the optimal circuit consists of three cnot gates and fifteen single qubit elementary rotations , parametrized by fourteen independent angles .
the explicit distribution of these angles is derived , showing that the joint distribution is a product of independent distributions of individual angles apart from four angles . .
And you have already written the first three sentences of the full article: quantum information science ( see e.g. @xcite and references therein ) has received an increased attention in recent years due to the understanding that it enables to perform procedures not possible by purely classical resources .
experimental techniques to manipulate increasingly complex quantum systems are also rapidly progressing .
one of the central issues is on the one hand to control and manipulate delicate complex quantum states in an efficient manner , but on the other hand at the same time to prevent all uncontrollable influences from the environment . in order to tackle such problems ,.
Please generate the next two sentences of the article | one has to understand the structure and properties of quantum states .
this can be done either through studies of particular states in a particular setting , or through focusing on the properties of the most generic states . |
3,483 | Suppose that you have an abstract for a scientific paper: a brief review of the recent experimental verifications of the casimir force between extended bodies is presented . with modern techniques
, it now appears feasible to test the force law with precision better than 1% ; i will address the issues relating to the theoretical interpretation of experiments at this level of accuracy .
keywords : casimir force , quantum electrodynamics , fluctuations pacs numbers : 12.20.fv,07.07mp ( submitted for the casimir 90th birthday issue of comments on atomic and molecular physics ) .
And you have already written the first three sentences of the full article: the force between uncharged conducting surfaces , the so - called `` casimir force , '' has been described as one of the least intuitive consequences of quantum electrodynamics . for conducting parallel flat plates separated by distance @xmath0 ,
this force per unit area @xmath1 has the magnitude @xcite : @xmath2 this relationship can be derived by considering the electromagnetic mode structure between the two plates , as compared to free space , and by assigning a zero - point energy of @xmath3 to each electromagnetic mode ( photon ) .
the change in total energy density between the plates , as compared to free space , as a function of separation @xmath4 , leads to the force of attraction ..
Please generate the next two sentences of the article | the only fundamental constants that enter eq .
( 1 ) are @xmath5 and @xmath6 ; the electron charge @xmath7 is absent , implying that the electromagnetic field is not coupling to matter . |
3,484 | Suppose that you have an abstract for a scientific paper: ultraviolet , optical , and near - infrared photometry and optical spectroscopy of the broad - lined type ic supernova ( sn ) 2009bb are presented , following the flux evolution from @xmath010 to @xmath1285 days past @xmath2-band maximum .
thanks to the very early discovery , it is possible to place tight constraints on the sn explosion epoch .
the expansion velocities measured from near maximum spectra are found to be only slightly smaller than those measured from spectra of the prototype broad - lined sn 1998bw associated with grb 980425 .
fitting an analytical model to the pseudo - bolometric light curve of sn 2009bb suggests that [email protected] m@xmath4 of material was ejected with 0.22 @xmath30.06 m@xmath4 of it being @xmath5ni .
the resulting kinetic energy is [email protected]@xmath6 erg .
this , together with an absolute peak magnitude of m@xmath7 @xmath8 @[email protected] , places sn 2009bb on the energetic and luminous end of the broad - lined type ic ( sn ic ) sequence .
detection of helium in the early time optical spectra accompanied with strong radio emission , and high metallicity of its environment makes sn 2009bb a peculiar object .
similar to the case for grbs , we find that the bulk explosion parameters of sn 2009bb can not account for the copious energy coupled to relativistic ejecta , and conclude that another energy reservoir ( a central engine ) is required to power the radio emission . nevertheless , the analysis of the sn 2009bb nebular spectrum suggests that the failed grb detection is not imputable to a large angle between the line - of - sight and the grb beamed radiation .
therefore , if a grb was produced during the sn 2009bb explosion , it was below the threshold of the current generation of @xmath9-ray instruments . .
And you have already written the first three sentences of the full article: a decade has passed since the discovery of the association between the long - duration gamma ray burst ( grb ) 980425 and the broad - lined type ic sn 1998bw @xcite .
this realization led to a renewed interest in the study of stripped - envelope core - collapse supernovae ( sne ) . in the case of sn 1998bw , the high kinetic energy inferred from the expansion velocity coupled with an exceedingly high luminosity and strong radio emission set it apart from all other previously - observed core - collapse sne .
since then these attributes have been shown also by other grb - related sne like sn 2003lw @xcite and sn 2003dh @xcite ..
Please generate the next two sentences of the article | the x - ray flash sn 2006aj @xcite , was not as extreme as the previous sne , nevertheless it shows expansion velocity much higher then normal type ic sne .
in addition to these grb related , broad - lined sne ic , there have also been a number of other discovered broad - lined events that are apparently not associated with a grb , e.g. sn 1997ef , @xcite , sn 2002ap @xcite , sn 2003jd @xcite and sn 2007ru @xcite . |
3,485 | Suppose that you have an abstract for a scientific paper: we fabricate gravitino vertex interactions using as only input on - shell yang - mills amplitudes and the kawai - lewellen - tye gauge theory / gravity relations .
a useful result of this analysis is simpler tree - level feynman rules for gravitino scattering than in traditional gauges .
all results are explicitly verified until five point scattering .
+ + .
And you have already written the first three sentences of the full article: a remarkable and intimate connection between gravity and yang - mills amplitudes exist through the kawai - lewellen - tye ( klt ) relations @xcite . in the field theory limit ( @xmath0 ) these relations
take the form @xmath1 here @xmath2 , @xmath3 , @xmath4 are gravity and yang - mills amplitudes and @xmath5 is a specific function of kinematic invariants depending on the input yang - mills amplitudes .
the klt relations are a widely used tool for computing gravity amplitudes via a recycling of results for yang - mills amplitudes . for tree and loop amplitudes klt.
Please generate the next two sentences of the article | can be combined with string theory inspired diagram rules as well as unitarity cut techniques @xcite .
recently , inspired by witten s work @xcite , we have seen remarkable progress in yang - mills amplitude computations ( for recent reviews see @xcite ) . via klt , this progress has fed into gravity yielding a much better understanding of amplitudes @xcite . |
3,486 | Suppose that you have an abstract for a scientific paper: in this paper , we investigate the @xmath0 photoproduction of jet plus missing energy signal to set limits on the couplings of the fermionic dark matter to the quarks at the lhc via the main reaction @xmath1 .
we assume a typical lhc multipurpose forward detectors and work in a model independent effective field theory framework .
typically , when we do the background analysis , we also include their corresponding single diffractive ( sd ) productions .
our result shows that by requiring a @xmath2 ( @xmath3 ) signal deviation , with an integrated luminosity of @xmath4 , the lower bounds of wimp masses scale can be detected up to @xmath5 equal 665.5 , 808.9 and 564.0 gev for the forward detector acceptances @xmath6 , @xmath7 , and @xmath8 , respectively , where @xmath9 , @xmath10 and @xmath11 .
* keywords * : dark matter , forward detector , large hadron collider + * pacs numbers * : 12.60.-i , 14.70.bh , 95.35.+d .
And you have already written the first three sentences of the full article: cosmological observations imply the existence of dark matter ( dm ) to be the dominant component of cosmical matter@xcite .
its relic density has been determined precisely by the wmap experiment to be @xmath12@xcite and it is believed to be non - baryonic , cold , dissipationless and stable on time scales .
in addition to these , their physical properties , like making ups or deep natures , are still unknown . revealing the distribution and.
Please generate the next two sentences of the article | the nature of dark matter is one of the most interesting challenges in the fields of both cosmology and particle physics .
many dark matter candidates have been proposed . weakly interacting massive particles ( wimps ) |
3,487 | Suppose that you have an abstract for a scientific paper: we address the issue of the cosmological bias between matter and galaxy distributions , looking at dark - matter haloes as a first step to characterize galaxy clustering . starting from the linear density field at high redshift , we follow the centre of mass trajectory of the material that will form each halo at late times ( proto - halo ) .
we adopt a fluid - like description for the evolution of perturbations in the proto - halo distribution , which is coupled to the matter density field via gravity .
we present analytical solutions for the density and velocity fields , in the context of renormalized perturbation theory .
we start from the linear solution , then compute one - loop corrections for the propagator and the power spectrum .
finally we analytically resum the propagator and we use a suitable extension of the time - renormalization - group method @xcite to resum the power spectrum . for halo masses
@xmath0 our results at @xmath1 are in good agreement with n - body simulations .
our model is able to predict the halo - matter cross spectrum with an accuracy of @xmath2 per cent up to @xmath3 mpc@xmath4 approaching the requirements of future galaxy redshift surveys .
[ firstpage ] cosmology : theory , large - scale structure of universe galaxies : haloes methods : analytical , n - body simulations . .
And you have already written the first three sentences of the full article: redshift surveys have shown that the clustering properties of galaxies strongly depend on their luminosity , color and morphological ( or spectral ) type ( e.g. @xcite ; @xcite ) .
this indicates that galaxies do not perfectly trace the distribution of the underlying dark matter , a phenomenon commonly referred to as ` galaxy biasing ' .
its origin lies in the details of the galaxy formation process which is shaped by the interplay between complex hydrodynamical and radiative processes together with the dark - matter driven formation of the large - scale structure ..
Please generate the next two sentences of the article | attempts to infer cosmological parameters from galaxy clustering studies are severely hampered by galaxy biasing .
a number of theoretical arguments and the outcome of numerical simulations both suggest that , on sufficiently large scales , the power spectra of galaxies and matter should be proportional to each other : @xmath5 where the linear bias factor @xmath6 depends on galaxy type but is generally scale independent ( e.g. @xcite ; @xcite ) . |
3,488 | Suppose that you have an abstract for a scientific paper: we suggest an interferometric scheme assisted by squeezing and linear feedback to realize the whole class of field - quadrature quantum nondemolition measurements , from von neumann projective measurement to fully non - destructive non - informative one . in our setup , the signal under investigation is mixed with a squeezed probe in an interferometer and , at the output , one of the two modes is revealed through homodyne detection .
the second beam is then amplitude - modulated according to the outcome of the measurement , and finally squeezed according to the transmittivity of the interferometer . using strongly squeezed or anti - squeezed probes respectively , one achieves either a projective measurement , _
i.e. _ homodyne statistics arbitrarily close to the intrinsic quadrature distribution of the signal , and conditional outputs approaching the corresponding eigenstates , or fully non - destructive one , characterized by an almost uniform homodyne statistics , and by an output state arbitrarily close to the input signal . by varying the squeezing between these two extremes , or simply by tuning the internal phase - shift of the interferometer , the whole set of intermediate cases can also be obtained . in particular , an optimal quantum nondemolition measurement of quadrature
can be achieved , which minimizes the information gain versus state disturbance trade - off . .
And you have already written the first three sentences of the full article: in order to be manipulated and transmitted information should be encoded into some degree of freedom of a physical system . ultimately , this means that the input alphabet should correspond to the spectrum of some observable , _ i.e. _ that information is transmitted using _
quantum signals_. at the end of the channel , to retrieve this kind of quantum information , one should measure the corresponding observable . as a matter of fact
, the measurement process unavoidably introduces some disturbance , and may even destroys the signal , as it happens in many quantum optical detectors , which are mostly based on the irreversible absorption of the measured radiation ..
Please generate the next two sentences of the article | actually , even in a measurement scheme that somehow preserves the signal for further uses , one is faced by the information gain versus state disturbance trade - off , _
i.e. _ by the fact that the more information is obtained , the more the signal under investigation is being modified . |
3,489 | Suppose that you have an abstract for a scientific paper: we compute the dc and the optical conductivity of graphene for finite values of the chemical potential by taking into account the effect of disorder , due to mid - gap states ( unitary scatterers ) and charged impurities , and the effect of both optical and acoustic phonons .
the disorder due to mid - gap states is treated in the coherent potential approximation ( cpa , a self - consistent approach based on the dyson equation ) , whereas that due to charged impurities is also treated via the dyson equation , with the self - energy computed using second order perturbation theory .
the effect of the phonons is also included via the dyson equation , with the self energy computed using first order perturbation theory . the self - energy due to phonons is computed both using the bare electronic green s function and the full electronic green s function , although we show that the effect of disorder on the phonon - propagator is negligible .
our results are in qualitative agreement with recent experiments .
quantitative agreement could be obtained if one assumes water molelcules under the graphene substrate .
we also comment on the electron - hole asymmetry observed in the dc conductivity of suspended graphene . .
And you have already written the first three sentences of the full article: the isolation of a single carbon layer via micromechanical cleavage has triggered immense research activity.@xcite apart from the anomalous quantum hall effect due to chiral dirac - like quasi - particles,@xcite the finite `` universal '' dc conductivity at the neutrality point attracted major attention.@xcite for recent reviews see refs . .
the electronic properties of graphene are characterized by two nonequivalent fermi - surfaces around the @xmath0 and @xmath1-points , respectively , which shrink to two points at the neutrality point @xmath2 ( @xmath3 is chemical potential ) .
the spectrum around these two points is given by an ( almost ) isotropic energy dispersion @xmath4 with the fermi velocity @xmath5 m / s.@xcite graphene can thus be described by an effective ( 2 + 1)-dimensional relativistic field theory with the velocity of light @xmath6 replaced by the fermi velocity @xmath7.@xcite relativistic field theories in ( 2 + 1 ) dimensions were investigated long before the actual discovery of graphene@xcite and also the two values of the universal conductivities of a clean system at the neutrality point depending on whether one includes a broadening @xmath8 or not were reported then.@xcite in the first case , one obtains @xmath9,@xcite the second case yields @xmath10.@xcite interestingly , the first value is also obtained without the limit @xmath8 within the self - consistent coherent potential approximation ( cpa).@xcite we also note that the constant conductivity holds for zero temperature , only ; for finite temperature the dc conductivity is zero.@xcite if leads are attached to the graphene sample , an external broadening is introduced and the conductivity is given by @xmath11 @xcite which has been experimentally verified for samples with large aspect ratio.@xcite this is in contrast to measurements of the optical conductivity , where leads are absent and a finite energy scale given by the frequency @xmath12 of the incoming beam renders the intrinsic disorder negligible , @xmath13 ..
Please generate the next two sentences of the article | one thus expects the universal conductivity to be given by @xmath10 , which was measured in various experiments in graphene on a sio@xmath14,@xcite sic - substrate@xcite and free hanging.@xcite also in graphene bilayer and multilayers,@xcite as well as in graphite@xcite the conductivity per plane is of the order of @xmath15 .
the above results were obtained from the kubo or laundauer formula and assumed coherent transport . also diffusive models based on the semi - classical boltzmann approach |
3,490 | Suppose that you have an abstract for a scientific paper: we investigate the mixing properties of scalars stirred by spatially smooth , divergence - free flows and maintained by a steady source - sink distribution .
we focus on the spatial variation of the scalar field , described by the _ dissipation wavenumber _ , @xmath0 , that we define as a function of the mean variance of the scalar and its gradient .
we derive a set of upper bounds that for large pclet number ( @xmath1 ) yield four distinct regimes for the scaling behaviour of @xmath0 , one of which corresponds to the batchelor regime .
the transition between these regimes is controlled by the value of @xmath2 and the ratio @xmath3 , where @xmath4 and @xmath5 are respectively , the characteristic lengthscales of the velocity and source fields .
a fifth regime is revealed by homogenization theory .
these regimes reflect the balance between different processes : scalar injection , molecular diffusion , stirring and bulk transport from the sources to the sinks .
we verify the relevance of these bounds by numerical simulations for a two - dimensional , chaotically mixing example flow and discuss their relation to previous bounds .
finally , we note some implications for three dimensional turbulent flows . .
And you have already written the first three sentences of the full article: mixing of scalar fields is a problem that is crucial to several environmental issues as well as engineering applications . in many situations
the underlying flow is spatially smooth and divergence - free while molecular diffusion is usually much weaker than the stirring strength of the flow ( see e.g. @xcite ) .
notwithstanding the apparent simplicity of the flow , its effect on the scalar field can be rather complex : a simple time - dependence is often sufficient for the flow to be chaotically mixing in which case the gradients of the scalar fields are greatly amplified ( @xcite ) ..
Please generate the next two sentences of the article | @xcite recognized that this amplification is responsible for the rapid dissipation of any initial scalar inhomogeneity and thus the efficiency at which a scalar is mixed . in the continual presence of sources and sinks ,
a statistical equilibrium is attained in which the rate of injection of scalar variance balances the rate of its dissipation . in this case , the most basic way to measure the flow s mixing efficiency is to consider the equilibrium variance of the scalar : the lower its value , the better mixed is the scalar field . @xcite |
3,491 | Suppose that you have an abstract for a scientific paper: spiral waves in two - dimensional excitable media have been observed experimentally and studied extensively .
it is now well - known that the symmetry properties of the medium of propagation drives many of the dynamics and bifurcations which are experimentally observed for these waves . also , symmetry - breaking induced by boundaries , inhomogeneities and anisotropy have all been shown to lead to different dynamical regimes as to that which is predicted for mathematical models which assume infinite homogeneous and isotropic planar geometry .
recent mathematical analyses incorporating the concept of forced symmetry - breaking from the euclidean group of all planar translations and rotations have given model - independent descriptions of the effects of media imperfections on spiral wave dynamics .
in this paper , we continue this program by considering rotating waves in dynamical systems which are small perturbations of a euclidean - equivariant dynamical system , but for which the perturbation preserves only the symmetry of a regular square lattice . .
And you have already written the first three sentences of the full article: two dimensional spiral waves are observed in many different situations @xcite . in excitable biological tissue such as the cerebral cortex ,
the myocardium or the retina , spirals are usually precursors to serious pathological conditions @xcite .
thus there is great interest in understanding the dynamics of spiral waves , and how these are affected by model parameters and interactions with medium imperfections ..
Please generate the next two sentences of the article | one of the most important theoretical breakthroughs in the study of spiral waves has been the adoption of techniques from group - equivariant dynamical systems @xcite .
typically the physical systems in which spirals are observed are modeled using systems of reaction - diffusion partial differential equations @xmath0 where @xmath1 is a function @xmath2 which can represent a vector of concentrations , electrical potentials , _ et cetera _ depending on the system being modeled . |
3,492 | Suppose that you have an abstract for a scientific paper: this paper discusses the monte carlo and molecular dynamics methods .
both methods are , in principle , simple .
however , simple does not mean risk - free .
in the literature , many of the pitfalls in the field are mentioned , but usually as a footnote and these footnotes are scattered over many papers .
the present paper focuses on the ` dark side ' of simulation : it is one big footnote .
i should stress that ` dark ' , in this context , has no negative moral implication .
it just means : under - exposed . .
And you have already written the first three sentences of the full article: at the 2012 varenna summer school on _ physics of complex colloids _ , i gave a series of lectures on computer simulations in the context of complex liquids .
the lectures were introductory , although occasionally , i would mix in a more general cautionary remark
. it seemed to me that there was little point in writing a chapter in the proceedings on ` introduction to computer simulations ' ..
Please generate the next two sentences of the article | books on the topic exist .
however , i did not quite know what to write instead . |
3,493 | Suppose that you have an abstract for a scientific paper: we present a global study of the simplest scalar phantom dark matter model .
the best fit parameters of the model are determined by simultaneously imposing ( i ) relic density constraint from wmap , ( ii ) 225 live days data from direct experiment xenon100 , ( iii ) upper limit of gamma - ray flux from fermi - lat indirect detection based on dwarf spheroidal satellite galaxies , and ( iv ) the higgs boson candidate with a mass about 125 gev and its invisible branching ratio no larger than 40% if the decay of the higgs boson into a pair of dark matter is kinematically allowed .
the allowed parameter space is then used to predict annihilation cross sections for gamma - ray lines , event rates for three processes mono-@xmath0 jet , single charged lepton and two charged leptons plus missing energies at the large hadron collider , as well as to evaluate the muon anomalous magnetic dipole moment for the model . .
And you have already written the first three sentences of the full article: evidences for the existence of dark matter are mainly coming from cosmological observations related to the physics of gravity .
these include the relic density of dark matter , anisotropies in the cosmic microwave background ( cmb ) , large scale structure of the universe , as well as the bullet clusters and the associated gravitational lensing effects .
while we still do not know what the nature of dark matter is , it is clear that there is no room to accommodate dark matter in the standard model ( sm ) of particle physics based on gauge invariance of @xmath1 and einstein - hilbert gravity theory based on general coordinate invariance . while it is plausible that the nature of dark matter may have a purely gravitational origin , theories that have been put forward thus far are not as convincing as those from the particle physics point of view ..
Please generate the next two sentences of the article | in particular the relic density strongly suggests that dark matter may be a weakly interacting massive particle ( wimp ) .
if dark matter can indeed be related to weak scale physics , there may be hope for us to detect them in various underground experiments of direct detection as well as in space experiments using balloons , satellites , or space station of indirect detection . |
3,494 | Suppose that you have an abstract for a scientific paper: we report the discovery of two new accreting pulsating white dwarf stars amongst the cataclysmic variables of the sloan digital sky survey : sdssj074531.91 + 453829.5 and sdssj091945.10 + 085710.0 .
we observe high amplitude non - sinusoidal variations of 4.57% at a period close to 1230s in the optical light curves of sdssj074531.91 + 453829.5 and a low amplitude variation of 0.71.6% near 260s in the light curves of sdssj091945.10 + 085710.0 .
we infer that these optical variations are a consequence of nonradial g - mode pulsations in the accreting primary white dwarfs of these cataclysmic variables .
however we can not rule out the remote possibility that the 260s period could be the spin period of the accreting white dwarf sdssj091945.10 + 085710.0 .
we also uncovered a non - variable sdssj171145.08 + 301320.0 during our search ; our two observing runs exclude any pulsation related periodicities in the range of 851400s with an amplitude @xmath00.5% .
this discovery paper brings the total number of known accreting white dwarf pulsators to eleven . .
And you have already written the first three sentences of the full article: cataclysmic variables ( cvs ) are close binary systems in which a late - type star ( secondary ) fills its roche lobe and transfers mass through the inner lagrangian point to a white dwarf ( primary ) .
gw librae was the first cv discovered with an accreting white dwarf showing photometric variations consistent with nonradial g - mode pulsations observed in non - interacting white dwarf stars @xcite . this discovery has opened a new venue of opportunity for us to learn about the stellar parameters of accreting variable white dwarfs using asteroseismic techniques .
we can probe the insides of a white dwarf using asteroseismology just like seismologists on earth can learn about the interior of our planet using earthquakes ..
Please generate the next two sentences of the article | a unique model fit to the observed periods of the variable white dwarf can reveal information about the stellar mass , core composition , age , rotation rate , magnetic field strength , and distance ( see the review paper * ? ? ?
this information could prove vital in determining the system dimensions and parameters , and may be the only way to derive conclusive results for non - eclipsing cvs . |
3,495 | Suppose that you have an abstract for a scientific paper: this review discusses detector physics and monte carlo techniques for cryogenic , radiation detectors that utilize combined phonon and ionization readout .
a general review of cryogenic phonon and charge transport is provided along with specific details of the cryogenic dark matter search detector instrumentation . in particular
this review covers quasidiffusive phonon transport , which includes phonon focusing , anharmonic decay and isotope scattering .
the interaction of phonons in the detector surface is discussed along with the downconversion of phonons in superconducting films .
the charge transport physics include a mass tensor which results from the crystal band structure and is modeled with a herring vogt transformation .
charge scattering processes involve the creation of neganov - luke phonons .
transition - edge - sensor ( tes ) simulations include a full electric circuit description and all thermal processes including joule heating , cooling to the substrate and thermal diffusion within the tes , the latter of which is necessary to model normal - superconducting phase separation .
relevant numerical constants are provided for these physical processes in germanium , silicon , aluminum and tungsten .
random number sampling methods including inverse cumulative distribution function ( cdf ) and rejection techniques are reviewed . to improve the efficiency of charge transport modeling , an additional second order inverse cdf method is developed here along with an efficient barycentric
coordinate sampling method of electric fields .
results are provided in a manner that is convenient for use in monte carlo and references are provided for validation of these models .
= 1 .
And you have already written the first three sentences of the full article: cryogenic radiation - detectors that utilize ionization , phonon and / or scintillation measurements are being used in a number of experiments .
both the cryogenic dark matter search ( cdms ) @xcite and edelweiss @xcite dark matter search utilize silicon and / or germanium targets to detect recoils of radiation in the target masses .
a combination of ionization and phonon readout is used to provide discrimination of gamma- and neutron - recoil types ..
Please generate the next two sentences of the article | the cresst dark matter search utilizes cawo@xmath0 targets and readout scintillation and phonon signal to discriminate between recoil types .
the advantage of reading out both phonon and ionization ( or scintillation ) signals comes about from the differing ratios of ionization and phonon energy or scintillation and phonon energy created in electron- and nuclear - recoils in the detectors . |
3,496 | Suppose that you have an abstract for a scientific paper: screening of topological charges ( singularities ) is discussed for paraxial optical fields with short and with long range correlations . for short range screening the charge variance @xmath0 in a circular region @xmath1 with
radius @xmath2 grows linearly with @xmath2 , instead of with @xmath3 as expected in the absence of screening ; for long range screening @xmath4 grows faster than @xmath2 : for a field whose autocorrelation function is the zero order bessel function @xmath5 , @xmath6 .
a @xmath5 correlation function is not attainable in practice , but we show how to generate an optical field whose correlation function closely approximates this form ; screening in such a field is well described by our theoretical results for @xmath7 .
@xmath0 can be measured by counting positive and negative singularities inside @xmath1 , or more easily by counting signed zero crossings on the perimeter @xmath8 of @xmath1 .
for the first method @xmath4 is calculated by integration over the charge correlation function @xmath9 , for the second by integration over the zero crossing correlation function @xmath10 . using the explicit forms of @xmath9 and of @xmath11 we show that both methods of calculation yield the same result .
we show that for short range screening the zero crossings can be counted along a straight line whose length equals @xmath8 , but that for long range screening this simplification no longer holds .
we also show that for realizable optical fields , for sufficiently small @xmath2 , @xmath12 , whereas for sufficiently large @xmath2 , @xmath13 these universal laws are applicable to both short and pseudo - long range correlation functions . .
And you have already written the first three sentences of the full article: random ( and other ) paraxial optical fields generically contain numerous point topological singularities ( defects ) in a plane ( the @xmath14-plane ) oriented perpendicular to the propagation direction ( @xmath15-axis ) .
these singularities , which include phase singularities ( optical vortices ) @xcite polarization singularities ( c points ) @xcite , gradient singularities ( maxima , minima , and saddle points ) @xcite , and curvature singularities ( umbilic points ) @xcite , are the defining features of the optical field , and are characterized by signed winding numbers ( topological charges ) @xmath16 .
generically , vortices and gradient singularities have charge @xmath17 , whereas the charge of c points and umbilic points is @xmath18 . like electrostatic charges , topological charges screen one another :.
Please generate the next two sentences of the article | positive charges tend to be surrounded by a net excess of negative charge , and vice versa hal81,liumaz92,robbod96,frewil98,berden00,den02,fresos02,fol03,den03,wil04,folgnu04,freego07,egosos07 .
a formal measure of screening is the charge correlation function @xmath19 @xcite , which by convention is constructed to measure the net excess of negative charge surrounding a positive charge at the origin . |
3,497 | Suppose that you have an abstract for a scientific paper: in ruderman & sutherland ( rs75 ) model , the normal neutron stars as pulsars bear a severe problem , namely the binding energy problem that both ions ( e.g. , @xmath0fe ) and electrons on normal neutron star surface can be pulled out freely by the unipolar generator induced electric field so that sparking on polar cap can hardly occur . this problem could be solved within the partially screened gap ( psg ) model in the regime of neutron stars . however , in this paper we extensively study this problem in a bare strange quark star ( bss ) model .
we find that the huge potential barrier built by the electric field in the vacuum gap above polar cap could usually prevent electrons from streaming into the magnetosphere unless the electric potential of a pulsar is sufficiently lower than that at infinite interstellar medium .
other processes , such as the diffusion and thermionic emission of electrons have also been included here .
our conclusions are as follows : both positive and negative particles on a bss s surface would be bound strongly enough to form a vacuum gap above its polar cap as long as the bss is not charged ( or not highly negative charged ) , and multi - accelerators could occur in a bss s magnetosphere .
our results would be helpful to distinguish normal neutron stars and bare quark stars through pulsar s magnetospheric activities .
[ firstpage ] magnetospheric activities pulsars : general .
And you have already written the first three sentences of the full article: although pulsar - like stars have many different manifestations , they are populated mainly by rotation - powered radio pulsars .
a lot of information about pulsar radiative process is inferred from the integrated and individual pulses , the sub - pulses , and even the micro - structures of radio pulses . among the magnetospheric emission models , the user - friendly nature of ruderman & sutherland ( 1975 ; hereafter rs75 ) model is a virtue not shared by others @xcite . in rs75 and its modified versions ( e.g. , * ? ? ?
* ) , a vacuum gap exists above polar cap of a pulsar , in which charged particles ( electrons and positrons ) are accelerated because of @xmath1 ..
Please generate the next two sentences of the article | these accelerated charged particles , moving along the curved magnetic field lines , radiate curvature or inverse - compton - scattering - induced high energy photons which are converted to @xmath2 while propagating in strong magnetic field .
a follow - up breakdown of the vacuum gap produces secondary electron - positron pairs plasma that radiate coherent radio emission . |
3,498 | Suppose that you have an abstract for a scientific paper: i present a review of using rare @xmath0 decays to search for physics beyond the standard model .
@xmath0 decays that proceed either through annihilation or loop topologies at leading order in the standard model provide unique probes in the search for new physics .
the latest experimental results from the @xmath0 factories ( babar and belle ) and the tevatron experiments ( cdf and d0 ) on rare decays and their impact on various scenarios for new physics will be presented . .
And you have already written the first three sentences of the full article: in the past decade , we have seen enormous progress in understanding flavor physics and @xmath1 violation . after turning on in 1999 , the new asymmetric - energy @xmath0 factories , pep - ii @xcite and kekb @xcite , quickly achieved luminosities that exceeded their design targets and the expectations of many .
this allowed the corresponding experiments , babar @xcite and belle @xcite , to quickly provide the first precision test of the ckm @xcite mechanism for @xmath1 violation .
the measurements of the proper - time - dependent @xmath1 asymmetry in charmonium-@xmath2 decays of neutral @xmath0 mesons ( @xmath3)@xcite are in very good agreement with the ckm prediction of @xmath3 from independent constraints ..
Please generate the next two sentences of the article | it is convenient , both for visualization and quantitative analysis , to interpret experimental results within the ckm framework as constraints on the geometry of the so - called `` unitarity triangle '' @xcite , which is from the first and third columns of the ckm quark mixing matrix @xmath4 @xmath5 if one renormalizes the triangle by rescaling the sides by @xmath6 and adopts the wolfenstein phase convention @xcite , experimental results are interpreted as constraints on the apex of the triangle ( @xmath7 ) .
two independent groups ( ckmfitter@xcite and utfit@xcite ) provide the results of this analysis . |
3,499 | Suppose that you have an abstract for a scientific paper: we study numerically scattering and transport statistical properties of tight - binding random networks characterized by the number of nodes @xmath0 and the average connectivity @xmath1 .
we use a scattering approach to electronic transport and concentrate on the case of a small number of single - channel attached leads .
we observe a smooth crossover from insulating to metallic behavior in the average scattering matrix elements @xmath2 , the conductance probability distribution @xmath3 , the average conductance @xmath4 , the shot noise power @xmath5 , and the elastic enhancement factor @xmath6 by varying @xmath1 from small ( @xmath7 ) to large ( @xmath8 ) values .
we also show that all these quantities are invariant for fixed @xmath9 .
moreover , we proposes a heuristic and universal relation between @xmath2 , @xmath4 , and @xmath5 and the disorder parameter @xmath10 . .
And you have already written the first three sentences of the full article: during the last three decades there has been an increasing number of papers devoted to the study of random graphs and complex networks , in view of the fact that they describe systems in many knowledge areas : from maths and physics to finance and social sciences , passing through biology and chemistry @xcite . in particular , some of those works report studies of spectral and eigenfunction properties of complex networks ; see for example refs .
that is , since complex networks composed by nodes and the bonds joining them can be represented by sparse matrices , it is quite natural to ask about the spectral and eigenfunction properties of such _ adjacency _ matrices . then , in fact , studies originally motivated on physical systems represented by hamiltonian sparse random matrices @xcite can be directly applied to complex networks .
in contrast to the numerous works devoted to study spectral and eigenfunction properties of complex netwoks , to our knowledge , just a few focus on some of their scattering and transport properties @xcite ..
Please generate the next two sentences of the article | so , in the present work we study numerically several statistical properties of the scattering matrix and the electronic transport across disordered tight - binding networks described by sparse real symmetric matrices . we stress that we use a scattering approach to electronic transport ; see for example @xcite .
in addition , we concentrate on the case of a small number of attached leads ( or terminals ) , each of them supporting one open channel . |
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