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6,600 | Suppose that you have an abstract for a scientific paper: a combined effective model reproducing the equation of state of hadronic matter as obtained in recent lattice qcd simulations is presented .
the model reproduces basic physical characteristics encountered in dense hadronic matter in the quark - gluon plasma ( qgp ) phase and the lower temperature hadron resonance gas phase .
the hadronic phase is described by means of an extended mott - hagedorn resonance gas while the qgp phase is described by the extended pnjl model .
the dissociation of hadrons is obtained by including the state dependent hadron resonance width .
pacs numbers : 12.38.gc , 12.38.mh , 12.40.ee , 24.85.+p .
And you have already written the first three sentences of the full article: simulations of lattice qcd ( lqcd ) are in practice the only reliable approach to qcd thermodynamics which covers the broad region of strongly interacting matter properties from the hadron gas at low temperatures to a deconfined quark gluon plasma phase at high temperatures .
recently , finite temperature lqcd simulations have overcome the difficulties of reaching the low physical light quark masses and approaching the continuum limit which makes this theoretical laboratory now a benchmark for modeling qcd under extreme conditions .
we are going to present a combined effective model reproducing the equation of state of hadronic matter as obtained in recent lattice qcd simulations @xcite ..
Please generate the next two sentences of the article | the model should reproduce basic physical characteristics of processes encountered in dense hadronic matter , from the hot qcd phase through the critical temperature region till the lower temperature hadron resonance gas phase . in medium properties of hadrons are different from those in the vacuum .
the very notion of the mass shell should be modified , as was postulated quite long ago @xcite . |
6,601 | Suppose that you have an abstract for a scientific paper: in this paper , we demonstrate a source of photon pairs based on four - wave - mixing in photonic crystal fibres . careful engineering of the phase matching conditions in the fibres enables us to create photon pairs at 597 nm and 860 nm in an intrinsically factorable state showing no spectral correlations .
this allows for heralding one photon in a pure state and hence renders narrow band filtering obsolete .
the source is narrow band , bright and achieves an overall detection efficiency of up to 21% per photon .
for the first time , a hong - ou - mandel interference with unfiltered photons from separate fibre sources is presented .
10 url # 1`#1`urlprefix[2][]#2 e. knill , r. laflamme , and g. j. milburn , `` a scheme for efficient quantum computation with linear optics , '' nature * 409 * , 4652 ( 2001 ) .
http://dx.doi.org/10.1038/35051009 .
n. gisin and r. thew , `` quantum communication , '' nat photon * 1 * , 165171 ( 2007 ) . http://dx.doi.org/10.1038/nphoton.2007.22 .
t. nagata , r. okamoto , j. l. obrien , k. sasaki , and s. takeuchi , `` beating the standard quantum limit with four - entangled photons , '' science * 316 * , 726729 ( 2007 ) .
http://www.sciencemag.org/cgi/content/abstract/316/5825/726 .
a. b. uren , c. silberhorn , r. erdmann , k. banaszek , w. p. grice , i. a. walmsley , and m. g. l raymer , `` generation of pure - state single - photon wavepackets by conditional preparation based on spontaneous parametric downconversion , '' laser phys . * 15 * , 146161 ( 2005 ) .
a. soujaeff , s. takeuchi , k. sasaki , t. hasegawa , and m. matsui , `` heralded single photon source at 1550@xmath0 nm from pulsed parametric down conversion , '' j. mod . opt . * 54 * , 467471 ( 2007 ) .
http://www.informaworld.com/10.1080/09500340600742239 .
r. m. stevenson , r. j. young , p. atkinson , k. cooper , d. a. ritchie , and a. shields , `` a semiconductor source of triggered entangled photon pairs , '' nature * 439 * , 179182 (....
And you have already written the first three sentences of the full article: single photons are one of the basic building blocks of quantum information technologies .
numerous experimental implementations of quantum computation schemes @xcite , quantum communication protocols @xcite as well as quantum metrology @xcite are based on single photons as the physical realization of the qubit . in order to code the state of such flying qubits , quantum interferences
are commonly exploited , which requires the photons to be in a pure state @xcite ..
Please generate the next two sentences of the article | the creation of photon pairs is a crucial tool to many of the aforementioned applications , which are based on entangled 2-photon state ( e.g. entanglement swapping ) or require heralding the presence of a single photon by detecting its partner @xcite .
different approaches have been followed to produce photon pairs , e.g. quantum dot emission @xcite or atomic ensembles @xcite , but implementations are still quite cumbersome and in an early development stage . |
6,602 | Suppose that you have an abstract for a scientific paper: the constituents of cold dense matter are still far from being understood .
however , neutron star observations such as the recently observed pulsar psr j1614 - 2230 with a mass of @xmath0 m@xmath1 help to considerably constrain the hadronic equation of state ( eos ) .
we systematically investigate the influence of the hyperon potentials on the stiffness of the eos .
we find that they have but little influence on the maximum mass compared to the inclusion of an additional vector - meson mediating repulsive interaction amongst hyperons .
the new mass limit can only be reached with this additional meson regardless of the hyperon potentials .
further , we investigate the impact of the nuclear compression modulus and the effective mass of the nucleon at saturation density on the high density regime of the eos .
we show that the maximum mass of purely nucleonic stars is very sensitive to the effective nucleon mass but only very little to the compression modulus .
neutron stars , equation of state , hypernuclei , hadronic matter .
And you have already written the first three sentences of the full article: the equation of state ( eos ) in the vicinity of saturation density is pretty well understood .
but beyond saturation , the theories of dense matter present uncertainties .
neutron stars provide a fantastic astrophysical environment for testing theories of cold and dense matter . in the core of neutron stars.
Please generate the next two sentences of the article | , densities could reach values of several times @xmath2 g @xmath3 . at such high densities
, the fermi energies of the constituent particles could exceed the rest masses of heavier particles , and hence favour the appearance of such particles in the core . |
6,603 | Suppose that you have an abstract for a scientific paper: the extended euclidean algorithm ( eea ) for polynomial greatest common divisors is commonly used in solving the key equation in the decoding of reed - solomon ( rs ) codes , and more generally in bch decoding . for this particular application ,
the iterations in the eea are stopped when the degree of the remainder polynomial falls below a threshold .
while determining the degree of a polynomial is a simple task for human beings , hardware implementation of this stopping rule is more complicated .
this paper describes a modified version of the eea that is specifically adapted to the rs decoding problem .
this modified algorithm requires no degree computation or comparison to a threshold , and it uses a fixed number of iterations .
another advantage of this modified version is in its application to the errors - and - erasures decoding problem for rs codes where significant hardware savings can be achieved via seamless computation . .
And you have already written the first three sentences of the full article: reed - solomon ( rs ) codes are among the most widely used codes .
their applications range from consumer electronics such as compact disc ( cd ) and digital versatile disc ( dvd ) players to optical communication and data storage systems .
most high - throughput rs codec architectures are based on reformulated versions @xcite of either the berlekamp - massey algorithm @xcite or the extended euclidean algorithm ( eea ) @xcite ..
Please generate the next two sentences of the article | a variable number of iterations at most @xmath0 for correcting up to @xmath1 errors are used in most eea - based decoders .
one exception is the errors - only hypersystolic reed - solomon decoder proposed by berlekamp _ |
6,604 | Suppose that you have an abstract for a scientific paper: we conducted a very large array survey of eleven low luminosity active galactic nuclei for linear and circular polarization at 8.4 ghz .
we detected circular polarization in one source ( m81 * ) and linear polarization in 3 sources .
sensitivity limits were @xmath0 for both modes of polarization in 9 of 11 sources .
the detections confirm the importance of nonthermal emission in llagn . however , detection rates for circular and linear polarization are lower for these sources than for more powerful agn .
fractional linear polarization in detected sources is also lower than in more powerful agn .
the weak linear polarization in the survey sources indicates their overall similarity to sgr a*. confusion with thermal sources , depolarization and weaker , less extended jets may contribute to these differences .
we detect a rotation measure @xmath1 for ngc 4579 .
this may arise from magnetized plasma in the accretion , outflow or interstellar regions .
inverted spectra are present in both m81 * and sagittarius a * and absent from all sources in which circular polarization is not detected .
this suggests that optical depth effects are important in the creation of circular polarization . .
And you have already written the first three sentences of the full article: circular and linear polarization are important diagnostics of nonthermal radio emission and its environment in extragalactic radio sources and galactic micro - quasars . in active galactic nuclei ( agn ) , linear polarization ( lp ) has been used to demonstrate that the emission mechanism is synchrotron radiation , that magnetic fields are present and that shocks propagate in jets , compressing the magnetic fields ( e.g. , * ? ? ?
lp is typically greater than 1% and is present in a very high fraction of powerful extragalactic radio sources @xcite .
rotation measures are used to study the plasma density and magnetic field in accretion and outflow regions of agn @xcite ..
Please generate the next two sentences of the article | the significance of circular polarization ( cp ) is less clear .
a variety of mechanisms can produce the small levels of cp seen in these sources , including intrinsic and extrinsic origins . |
6,605 | Suppose that you have an abstract for a scientific paper: we briefly review the status of motivated beyond - the - mssm phenomenology in the light of the lhc searches to date .
in particular , we discuss the conceptual consequences of the exclusion bounds , of the hint for a higgs boson at about 125 gev , and of interpreting the excess of direct cp violation in the charm sector as a signal of new physics .
we try to go into the various topics in a compact way while providing a relatively rich list of references , with particular attention to the most recent developments .
given at http://indico.cern.ch/conferenceotherviews.py?view=standard&confid=153252[``xx international workshop on deep inelastic scattering and related subjects '' ] , 26 - 30 march 2012 , bonn , germany . ] @xmath0 1.0 cm * supersymmetry phenomenology beyond + the mssm after 5/fb of lhc data * 1.0 cm paolo lodone
+ institut de thorie des phnomnes physiques , epfl , lausanne , switzerland + 1.0 cm .
And you have already written the first three sentences of the full article: the theoretical difficulty in understanding the smallness of the fermi scale in the standard model ( sm ) with respect to any new physics at very high energies is the main motivation for expecting new phenomena to show up already in the energy range that is probed by the cern lhc .
one of the most appealing solutions to this ` hierarchy problem ' is supersymmetry ( susy ) , to the point that it is sometimes called ` the standard way beyond the sm ' .
since superpartners have not been found at colliders , supersymmetry is apparently pushed more and more to higher energies and this in principle weakens its power in solving the hierarchy problem , or equivalently some amount of finetuning is apparently reintroduced in the determination of the electroweak scale . while this is more and more unavoidably true at least for its minimal implementation , the minimal supersimmetric standard model ( mssm ) , it is also clear that non - minimal implementations or non - standard configurations can still have the chance to be natural , i.e. not finely - tuned ..
Please generate the next two sentences of the article | it is then crucial , from a conceptual point of view , to keep an eye on these natural configurations until they are excluded since , if it were not for the hierarchy problem , susy could manifest itself at much higher energies . ] .
the main recent experimental inputs that are relevent for our considerations are the following : * a sm - like higgs boson is now excluded from about 127 gev up to 600 gev @xcite@xcite . at the same time , there is a @xmath1 hint for a higgs - like scalar close to 125 gev . * direct searches of s - particles |
6,606 | Suppose that you have an abstract for a scientific paper: we report on the retrieval of directional sea surface roughness , in terms of its full directional mean square slope ( including direction and isotropy ) , from global navigation satellite system reflections ( gnss - r ) delay - doppler - map ( ddm ) data collected during an experimental flight at 1 km altitude .
this study emphasizes the utilization of the entire ddm to more precisely infer ocean roughness directional parameters .
in particular , we argue that the ddm exhibits the impact of both roughness and scatterer velocity .
obtained estimates are analyzed and compared to co - located jason-1 measurements , ecmwf numerical weather model outputs and optical data . .
And you have already written the first three sentences of the full article: [ b ! ] [ cols="^ " , ] several gnss constellations and augmentation systems are presently operational or under development , including the pioneering us global positioning system ( gps ) and the forthcoming european system , galileo .
these all - weather , long - term , stable and precise l - band signals can be used for bistatic remote sensing of the ocean surface and beyond , an emerging concept known as gnss - r . among several applications , two
have been emphasized by the community : sea - surface altimetry ( see and references therein ) and sea - surface `` speculometry '' ( a term discussed below ) , related to the statistical properties of sea surface gravity wave slopes ..
Please generate the next two sentences of the article | although this paper addresses the latter , we note the intrinsic capability of gnss - r for providing long term co - located measurements of both surface roughness and sea level with high spatial and temporal resolution . as recently demonstrated with scatterometer measurements ( ) , such a capability would help to better quantify the relationship of velocities in the upper ocean ( driven by wind stress forcing ) with surface height dynamics .
thanks to its passive multistatic character , gnss - r clearly holds the potential to provide an unprecedented spatio - temporal sampling of the ocean surface . |
6,607 | Suppose that you have an abstract for a scientific paper: the lagrangian fluid description is employed to solve the initial value problem for one - dimensional , compressible fluid flows represented by the euler - poisson system .
exact nonlinear and time - dependent solutions are obtained , which exhibit a variety of transient phenomena such as a density collapse in finite space - time or the appearance and , for the first time , a successive dissolution of wavelet structures during the same event .
the latter are superimposed on the gross density pattern in the course of the uni - directional expansion of an initially localized density hump .
whereas self - gravitating fluids will always experience collapse , neutral fluids and fluids with repulsive forces , such as a non - neutral , pure electron fluid , can exhibit an evolution of the second type , being determined by the initial conditions . for an electron fluid ,
being embedded in a neutralizing ion background , these nonlinearities are , however , strongly diminished due to the omnipresent plasma oscillations , which weaken and alternatively change the sign of the collective force . + .
And you have already written the first three sentences of the full article: there are a lot of many - body systems of different physical nature where the clustering of matter from smooth or almost smooth distributions of particles can occur ( see , for example , @xcite - @xcite ) .
such a process typically proceeds in particle ensembles with long - range forces , such as gravity or electric interactions , when the clustering leads to the formation of stable spatially inhomogeneous structures @xcite - @xcite .
these processes define the system s dynamics and existence . for example.
Please generate the next two sentences of the article | , the pancake and adhesion models predict the persistence of a density peak at the flow caustics which appears from the initial distributions having gaussian initial fluctuations and is due to the development of the gravitational instability @xcite . in this case
the singular behavior makes it impossible to reverse the process through the destruction of such structures . |
6,608 | Suppose that you have an abstract for a scientific paper: we perform a three - dimensional nested - grid radiation magneto - hydrodynamics ( rmhd ) simulation with self - gravity to study the early phase of the low - mass star formation process from a rotating molecular cloud core to a first adiabatic core just before the second collapse begins .
radiation transfer is handled with the flux - limited diffusion approximation , operator - splitting and implicit time - integrator . in the rmhd simulation ,
the outer region of the first core attains a higher entropy and the size of first core is larger than that in the magnetohydrodynamics simulations with the barotropic approximation .
bipolar molecular outflow consisting of two components is driven by magnetic lorentz force via different mechanisms , and shock heating by the outflow is observed . using the rmhd simulation we can predict and interpret the observed properties of star - forming clouds , first cores and outflows with millimeter / submillimeter radio interferometers , especially the atacama large millimeter / submillimeter array ( alma ) . .
And you have already written the first three sentences of the full article: radiation transfer plays a critical role in star formation and affects the structure of accretion flow and the resulting adiabatic cores even in a low - mass regime
. however multi - dimensional radiation hydrodynamics ( rhd ) simulations have been rarely performed due to their high computational cost .
therefore , the barotropic approximation , which omits radiation transfer and simplifies the thermal evolution of the gas , is widely used in multi - dimensional simulations ..
Please generate the next two sentences of the article | however , recent advancement in the computer technology and development of numerical techniques enable us to incorporate radiation transfer into a multi - dimensional magnetohydrodynamics ( mhd ) simulation within reasonable computational time , using a moment method with simplified closure relations .
we performed rmhd simulations of proto - stellar collapse with our newly developed numerical code and clarified the difference between rmhd and mhd with the barotropic approximation . |
6,609 | Suppose that you have an abstract for a scientific paper: some issues in inclusive and exclusive diffractive processes are discussed . .
And you have already written the first three sentences of the full article: there were 20 experimental presentations at this conference , all by expert people in the field .
all these talks were plenary , so there is no point of me summarizing again the contents of each talk .
instead , i would like to present a personal view and touch upon few selected issues which were presented here ..
Please generate the next two sentences of the article | in spite of the fact that diffractive processes have a long history , it is still not easy to give a precise and concise definition of what one calls a diffractive reaction . it is clearly a process where , in an exchange picture , no color is exchanged .
this however includes all the colorless particles . |
6,610 | Suppose that you have an abstract for a scientific paper: we find that _ kepler _ exoplanet candidate ( ec ) host stars are preferentially metal - rich , including the low - mass stellar hosts of small - radius ecs .
the last observation confirms a tentative hint that there is a correlation between the metallicity of low - mass stars and the presence of low - mass and small - radius exoplanets .
in particular , we compare the @xmath0@xmath1 color - color distribution of _ kepler _ ec host stars with a control sample of dwarf stars selected from the @xmath2 stars observed during q1 and q2 of the _ kepler _ mission but with no detected planets .
we find that at @xmath3 characteristic of solar - type stars , the average @xmath1 color of stars that host giant ecs is 4-@xmath4 redder than the average color of the stars in the control sample . at the same time , the average @xmath1 color of solar - type stars that host small - radius ecs is indistinguishable from the average color of the stars in the control sample .
in addition , we find that at @xmath5 indicative of late k dwarfs , the average @xmath1 color of stars that host small - radius ecs is 4-@xmath4 redder than the average color of the stars in the control sample .
these offsets are unlikely to be caused by differential reddening , age differences between the two populations , or the presence of giant stars in the control sample .
stellar models suggest that the first color offset is due to a 0.2 dex enhancement in [ fe / h ] of the giant ec host population at @xmath6 , while sloan photometry of m 67 and ngc 6791 suggests that the second color offset is due to a similar [ fe / h ] enhancement of the small - radius ec host population at @xmath7 .
these correlations are a natural consequence of the core - accretion model of planet formation . .
And you have already written the first three sentences of the full article: the groundbreaking early results of nasa s _ kepler _ mission @xcite have spectacularly added to our understanding of the frequency and properties of planets in the galaxy @xcite .
eight planetary systems discovered by _
kepler _ have already been confirmed by radial velocity or transit timing : four hot jupiters @xcite ; two saturn - mass planets and a super - earth in the kepler-9 system @xcite ; a neptune - mass planet kepler-4b @xcite ; kepler-10b , the smallest exoplanet yet known @xcite ; and the closely - aligned six transiting planet system kepler-11 @xcite ..
Please generate the next two sentences of the article | the properties of the exoplanet candidate ( ec ) population discovered by
_ kepler _ will provide strong constraints on models of planet formation , especially for low - mass stars and small planets . |
6,611 | Suppose that you have an abstract for a scientific paper: a self - interacting polymer with one end attached to a sticky surface has been studied by means of a flat - histogram stochastic growth algorithm known as flatperm .
we examined the four - dimensional parameter space of the number of monomers up to 91 , self - attraction , surface attraction and force applied to an end of the polymer . using this powerful algorithm the _ complete _ parameter space of interactions and
force has been considered .
recently it has been conjectured that a hierarchy of states appears at low temperature / poor solvent conditions where a polymer exists in a finite number of layers close to a surface .
we find re - entrant behaviour from a stretched phase into these layering phases when an appropriate force is applied to the polymer .
we also find that , contrary to what may be expected , the polymer desorbs from the surface when a sufficiently strong critical force is applied and does _ not _ transcend through either a series of de - layering transitions or monomer - by - monomer transitions .
new experimental methods in the physics of macromolecules @xcite have been used to study and manipulate single molecules and their interactions .
these methods make a contribution to our understanding of such phenomena as protein folding or dna un - zipping ; one can push or pull a single molecule and watch how it responds .
it is possible to apply ( and measure ) forces large enough to induce structural deformation of single molecules .
one can monitor the mechanism of some force - driven phase transition occurring at the level of a single molecule .
theoretical understanding of this behaviour has attracted much attention @xcite .
the response of a single polymer to an external force under good solvent conditions was considered some time ago@xcite .
the response under poor solvent conditions ( below the @xmath0-point ) , where the self - attraction and an external force compete with each other , was examined later @xcite .
another phenomenon commonly studied....
And you have already written the first three sentences of the full article: financial support from the dfg is gratefully acknowledged by jk and tp . financial support from the australian research council
is gratefully acknowledged by alo and ar .
alo also thanks the institut fr theoretische physik at the technische universitt clausthal ..
Please generate the next two sentences of the article | |
6,612 | Suppose that you have an abstract for a scientific paper: a canonical hyperkhler metric on the total space @xmath0 of a cotangent bundle to a complex manifold @xmath1 has been constructed recently by the author in @xcite .
this paper presents the results of @xcite in a streamlined and simplified form .
the only new result is an explicit formula obtained for the case when @xmath1 is an hermitian symmetric space . .
And you have already written the first three sentences of the full article: constructing a hyperkhler metric on the total space @xmath0 of the cotangent bundle to a khler manifold @xmath1 is an old problem , dating back to the very first examples of hyperkhler metrics given by e. calabi in @xcite .
since then , many people have obtained a lot of important results valid for manifolds @xmath1 in this or that particular class ( see , for example , the papers @xcite , @xcite , @xcite , @xcite , @xcite ) .
finally , the general problem has been more or less solved a couple of years ago , independently by b. feix @xcite and by the author @xcite ..
Please generate the next two sentences of the article | the metrics constructed in @xcite and @xcite are the same .
in fact , this metric satisfies an additional condition which makes it essentially unique which justifies the use of the term `` canonical metric '' . |
6,613 | Suppose that you have an abstract for a scientific paper: we report on a new survey for @xmath0 lyman-@xmath1 sources , the large area lyman alpha ( lala ) survey .
our survey achieves an unprecedented combination of volume and sensitivity by using narrow - band filters on the new @xmath2 pixel ccd mosaic camera at the 4 meter mayall telescope of kitt peak national observatory .
well - detected sources with flux and equivalent width matching known high redshift lyman-@xmath1 galaxies ( i.e. , observed equivalent width @xmath3 , @xmath4 , and @xmath5 ) have an observed surface density corresponding to @xmath6 per square degree per unit redshift at @xmath7 .
spatial variation in this surface density is apparent on comparison between counts in @xmath8 and @xmath9 filters .
early spectroscopic followup results from the keck telescope included three sources meeting our criteria for good lyman-@xmath1 candidates .
of these , one is confirmed as a @xmath10 source , while another remains consistent with either @xmath11 or @xmath12 .
we infer that @xmath13 to @xmath14 of our good candidates are _ bona fide _
lyman-@xmath1
emitters , implying a net density of @xmath15 lyman-@xmath1 emitters per square degree per unit redshift .
0@xmath16 16@xmath17 17f_17 2s @xmath18 .
And you have already written the first three sentences of the full article: more than three decades ago partridge and peebles ( 1967 ) predicted that galaxies in their first throes of star - formation should be strong emitters in the lyman-@xmath1 line .
their predictions were optimistic , based on converting roughly 2% of gas into stars in @xmath19 years in milky way sized galaxies , which translates into a luminosity of @xmath20 .
these objects are also expected to be common - if all the @xmath21 galaxies have undergone a phase of rapid star - formation one should see a surface density of about @xmath22 ( pritchet 1994 ) ..
Please generate the next two sentences of the article | searches based on these expectations did not detect lyman-@xmath1 emitters ( laes ) .
( see review by pritchet 1994 ; koo & kron 1980 ; pritchet & hartwick 1987 , 1990 ; cowie 1988 ; rhea et al 1989 ; smith et al 1989 ; lowenthal et al 1990 ; wolfe et al 1992 ; de propris et al 1993 ; macchetto et al 1993 ; mller & warren 1993 ; djorgovski & thompson 1992 ; djorgovski , thompson , & smith 1993 ; thompson , djorgovski , & trauger 1992 ; thompson et al 1993 ; thompson , djorgovski , & beckwith 1994 ; thommes et al 1998 . ) only recently have lyman-@xmath1 emitters been observed , albeit at luminosity levels roughly a hundred times lower than the original prediction . |
6,614 | Suppose that you have an abstract for a scientific paper: we present a natural generalization of holographic entanglement entropy proposals beyond the scope of ads / cft by anchoring extremal surfaces to holographic screens .
holographic screens are a natural extension of the ads boundary to arbitrary spacetimes and are preferred codimension 1 surfaces from the viewpoint of the covariant entropy bound .
a broad class of screens have a unique preferred foliation into codimension 2 surfaces called leaves .
our proposal is to find the areas of extremal surfaces achored to the boundaries of regions in leaves .
we show that the properties of holographic screens are sufficient to prove , under generic conditions , that extremal surfaces anchored in this way always lie within a causal region associated with a given leaf . within this causal region ,
a maximin construction similar to that of wall proves that our proposed quantity satisfies standard properties of entanglement entropy like strong subadditivity .
we conjecture that our prescription computes entanglement entropies in quantum states that holographically define arbitrary spacetimes , including those in a cosmological setting with no obvious boundary on which to anchor extremal surfaces . #
1#1 | # 1| # 1 # 1#2#1 | # 2 .
And you have already written the first three sentences of the full article: a theory of quantum gravity should not apply only to asymptotically locally anti - de sitter ( alads ) spacetimes . for this reason , the ads / cft correspondence @xcite , although immensely successful , has fallen short of a description of the quantum mechanics of spacetime .
the ads restriction is severe : maldacena s conjecture does not apply in an obvious way to even the cosmological spacetime we find ourselves in .
if a quantum theory applies to general spacetimes , it is desirable that it reduces to ads / cft in the appropriate cases ..
Please generate the next two sentences of the article | this suggests a strategy for guessing properties of a complete theory : consider specific aspects of ads / cft and devise generalizations that are applicable to other spacetimes .
if one knew only of special relativity , she could guess aspects of general relativity by thinking to `` promote '' the flat metric to a dynamical one . |
6,615 | Suppose that you have an abstract for a scientific paper: simple one zone homogeneous synchrotron self
compton models have severe difficulties is explaining the tev emission observed in the radiogalaxy m87 .
also the site the tev emission region is uncertain : it could be the unresolved jet close to the nucleus , analogously to what proposed for blazars , or an active knot , called hst1 , tens of parsec away .
we explore the possibility that the tev emission of m87 is produced in the misaligned subpc scale jet .
we base our modelling on a structured jet , with a fast spine surrounded by a slower layer . in this context
the main site responsible for the emission of the tev radiation is the layer , while the ( debeamed ) spine accounts for the emission from the radio to the gev band : therefore we expect a more complex correlation with the tev component than that expected in one zone scenarios , in which both components are produced by the same region .
observed from small angles , the spine would dominate the emission , with an overall spectral energy distribution close to those of bl lac objects with a synchrotron peak located at low energy ( lbls ) .
[ firstpage ] galaxies : active galaxies : jets galaxies : individual : m87radiation mechanisms : non thermal . .
And you have already written the first three sentences of the full article: an increasing number of extragalactic objects is detected at energies greater than 100 gev .
the list of published sources comprises 20 objectsrwagner / sources ] : as expected ( e.g. , costamante & ghisellini 2002 ) , the bulk of them ( 17 ) belongs to the class of highly peaked bl lac objects . in fact , the position of the synchrotron peak , usually located in ( or close to ) the x ray band assures the existence , in these sources , of electrons with extremely large lorentz factors ( @xmath0@xmath1 ) , a key ingredient for the emission in the tev band via inverse compton ( ic ) scattering .
the remaining three sources are bl lac itself , which belongs to the lbl class , ( albert et al ..
Please generate the next two sentences of the article | 2007 ) , 3c279 , a fsrqs , ( teshima et al . 2007 ) and the nearby ( 16 mpc , tonry 1991 ) radiogalaxy m87 ( aharonian et al .
2003 , 2006 ) . already suggested as a possible source of high - energy radiation ( e.g. bai & lee 2001 ) based on its similarity with bl lac objects ( tsvetanov et al . |
6,616 | Suppose that you have an abstract for a scientific paper: i review explanations for the three neutrino anomalies ( solar , atmospheric and lsnd ) which go beyond the `` conventional '' neutrino oscillations induced by mass - mixing .
several of these require non - zero neutrino masses as well . .
And you have already written the first three sentences of the full article: as is well - known , it is not possible to account for all three neutrino anomalies with just the three known neutrinos @xmath0 and @xmath1 .
if one or more of them can be explained in some other way , then no extra sterile neutrinos need be invoked .
this is one motivation for exotic scenarios . in any case.
Please generate the next two sentences of the article | it is important to rule out all explanations other than oscillations in order to establish neutrino mixing and oscillations as the unique explanation for the three observed neutrino anomalies .
i should mention that , in general , some ( but not all ) non - oscillatory explanations of the neutrino anomalies will involve non - zero neutrino masses and mixings . |
6,617 | Suppose that you have an abstract for a scientific paper: an analytical description of arbitrary strongly aberrated axially symmetric focusing is developed .
this is done by matching the solution of geometrical optics with a wave pattern which is universal for the underlying ray structure .
the corresponding canonical integral is the bessoid integral , which is a three - dimensional generalization of the pearcey integral that approximates the field near an arbitrary two - dimensional cusp .
we first develop the description for scalar fields and then generalize it to the vector case . as a practical example the formalism
is applied to the focusing of light by transparent dielectric spheres with a few wavelengths in diameter .
the results demonstrate good agreement with the mie theory down to mie parameters of about 30 .
compact analytical expressions are derived for the intensity on the axis and the position of the diffraction focus both for the general case and for the focusing by microspheres .
the high intensity region is narrower than for an ideal lens of the same aperture at the expense of longitudinal localization and has a polarization dependent fine structure , which can be explained quantitatively .
the results are relevant for aerosol and colloid science where natural light focusing occurs and can be used in laser micro- and nano - processing of materials . .
And you have already written the first three sentences of the full article: axially symmetric focusing of wave fields occurs in various areas of science , since physical systems often possess an intrinsic rotational symmetry .
in particular , the electromagnetic field enhancement by small spherical particles is important in many situations .
spheres have minimal surface energy for a given volume and thus are naturally formed as a result of phase separation , for example as aerosols or colloids ..
Please generate the next two sentences of the article | applications of colloidal microspheres in photonic crystals and photonic crystal slabs led to an explosion of the experimental and theoretical studies of their optical properties.@xcite the majority of these investigations concentrate on their collective properties in a periodic arrangement .
single microspheres are used as high quality optical resonators and as agents that allow controlled and highly localized wavelength - dependent field enhancement for non - linear optical studies and in resonance spectroscopy.@xcite here , the emphasis is placed on the eigenmode analysis and the distribution of the field within the sphere or in the immediate vicinity of its surface . lately |
6,618 | Suppose that you have an abstract for a scientific paper: we fully generalize a previously - developed computational geometry tool @xcite to perform large - scale simulations of arbitrary two - dimensional faceted surfaces @xmath0 .
our method uses a three - component facet / edge / junction storage model , which by naturally mirroring the intrinsic surface structure allows both rapid simulation and easy extraction of geometrical statistics .
the bulk of this paper is a comprehensive treatment of topological events , which are detected and performed explicitly .
in addition , we also give a careful analysis of the subtle pitfalls associated with time - stepping schemes for systems with topological changes .
the method is demonstrated using a simple facet dynamics on surfaces with three different symmetries .
appendices detail the reconnection of `` holes '' left by facet removal and a strategy for dealing with the inherent kinematic non - uniqueness displayed by several topological events . .
And you have already written the first three sentences of the full article: in many crystal - growing procedures of interest , a nano - scale faceted surface appears and proceeds to evolve , often exhibiting coarsening and even dynamic scaling , whereby characteristic statistics describing the surface remain constant even as the characteristic lengthscale increases through the vanishing of small facets . for many evolving faceted surfaces , a _ facet velocity law _
can be observed @xcite , assumed @xcite , or derived @xcite which specifies the normal velocity of each facet , often in configurational form which depends on the geometry of the facet . in this way , the dynamics of a continuous , two - dimensional surface can be concisely represented by a discrete collection of such velocities , and overall computational complexity reduced to that of a system of ode s ; the resulting system is known as a _ piecewise - affine dynamic surface _ , or pads . such theoretical simplification , in turn , enables the large - scale numerical simulations necessary for the statistical investigation of coarsening and dynamic scaling .
the numerics involved in the direct geometric simulation of an arbitrary pads is straightforward for one - dimensional surfaces , requiring nothing beyond traditional ode techniques except simple geometric translation between facet displacement and edge displacement , and a small surface correction associated with each coarsening event ..
Please generate the next two sentences of the article | consequently , such simulations accompany many of the above facet treatments of facet dynamics , and have also been independently repeated elsewhere @xcite .
however , in two dimensions , the corrections due to coarsening events are much more involved , and any code must be able to deal with a family of non - coarsening _ topological events _ that alter the neighbor relations between nearby facets . |
6,619 | Suppose that you have an abstract for a scientific paper: the correlation between radio and x - ray luminosity in the hard state of black hole x - ray binaries is important for unveiling the relation between the accretion flow and the jets . in this paper , we have modeled the quasi - simultaneous multi - band observations of a recently discovered transient x - ray source , igr j17177 - 3656 .
it is found that the source is probably an outlier following the steep radio / x - ray correlation rather than an outlier in the transition region as suggested by paizis et al .
( 2011 ) .
it is also found that the multi - band spectrum can be successfully modeled by the luminous hot accretion flow ( lhaf ) but less likely by the advection dominated accretion flow ( adaf ) .
our results support the point that lhaf can explain the steep radio / x - ray correlation .
[ firstpage ] x - rays : binaries - x - rays : individual : igr j17177 - 3656 - stars : winds , outflows - black hole physics - accretion , accretion disks .
And you have already written the first three sentences of the full article: the hard state of the black hole ( bh ) x - ray binaries is characterized by a power - law x - ray spectrum with photon index @xmath0 , and relatively strong radio emission ( e.g. * ? ? ?
* ; * ? ? ?
* ; * ? ? ?.
Please generate the next two sentences of the article | * ; * ? ? ?
during the hard states , there exists an interesting nonlinear correlation between the radio and x - ray luminosity , i.e. @xmath1 with @xmath2 ( e.g. * ? ? ? * ; * ? ? ? * ; * ? ? ? * ; * ? ? ? * ) . |
6,620 | Suppose that you have an abstract for a scientific paper: we analyze whether the prediction of the fractal markets hypothesis about a dominance of specific investment horizons during turbulent times holds .
to do so , we utilize the continuous wavelet transform analysis and obtained wavelet power spectra which give the crucial information about the variance distribution across scales and its evolution in time .
we show that the most turbulent times of the global financial crisis can be very well characterized by the dominance of short investment horizons which is in hand with the assertions of the fractal markets hypothesis .
critical events and turbulences on the financial markets have always attracted attention of financial researchers as these are the biggest challenges for prevailing theories and potentially good starting points for new paradigms .
the efficient markets hypothesis @xcite has been a cornerstone of mainstream financial economics for decades even though it provides no testable predictions about extreme events and even considers them highly improbable ( or even non - existent ) @xcite . in this paper
, we try to resurrect the practically forgotten fractal markets hypothesis @xcite and test whether its predictions about dominance of specific investment horizons during the turbulent times hold in practice . to do so , we assume that an increased volatility is a reflection of an increased trading activity @xcite and utilize the continuous wavelet transform analysis to get the wavelet power spectra , which can be interpreted as a scale- and time - characteristic variance .
wavelets have been widely used across various disciplines
cardiology @xcite , genetics @xcite , geophysics @xcite , neurology @xcite , traffic modeling @xcite , economics @xcite and others . using wavelets methodology ,
we are able to comment on evolution of trading activity in time but importantly also across scales and we show that predictions of the fractal markets hypothesis are indeed observed during the latest turbulences on the financial markets .
the....
And you have already written the first three sentences of the full article: to show whether the predictions of the fractal markets hypothesis hold , we analyze six developed ( liquid ) world indices .
the usa is represented by nasdaq composite index ( nasdaq ) .
the uk is covered by ftse 100 index ( ftse ) ..
Please generate the next two sentences of the article | continental europe is represented by stock indices of two most developed eurozone countries
german dax ( dax ) and french cac 40 ( cac ) . |
6,621 | Suppose that you have an abstract for a scientific paper: with the use of a background milky - way - like potential model , we performed stellar orbital and magnetohydrodynamic ( mhd ) simulations .
as a first experiment , we studied the gaseous response to a bisymmetric spiral arm potential : the widely employed cosine potential model and a self - gravitating tridimensional density distribution based model called perlas .
important differences are noticeable in these simulations , while the simplified cosine potential produces two spiral arms for all cases , the more realistic density based model produces a response of four spiral arms on the gaseous disk , except for weak arms -i.e .
close to the linear regime- where a two - armed structure is formed . in order to compare the stellar and gas response to the spiral arms ,
we have also included a detailed periodic orbit study and explored different structural parameters within observational uncertainties .
the four armed response has been explained as the result of ultra harmonic resonances , or as shocks with the massive bisymmetric spiral structure , among other . from the results of this work , and
comparing the stellar and gaseous responses , we tracked down an alternative explanation to the formation of branches , based only on the orbital response to a self - gravitating spiral arms model .
the presence of features such as branches , might be an indication of transiency of the arms .
[ firstpage ] mhd galaxy : disc galaxy : strcuture galaxy : kinematics and dynamics galaxies : spiral galaxies : structure .
And you have already written the first three sentences of the full article: spiral arms are one of the the most striking , beautiful and scientifically challenging structures of disc galaxies .
they have fascinated and intrigued astronomers for centuries . as a rough initial approximation to treat this complex problem , the spiral arms had to be assumed as almost massless and/or with extremely modest pitch angles , in order to obtain a solution as a linear perturbation to the axisymmetric background potential .
the proposed solution to the permanence of spiral arms in galaxies was based on the spiral density wave linear theory ( @xcite , inspired in the 60 s work of b. lindblad and p.o ..
Please generate the next two sentences of the article | lindblad ) .
the analytical solution at first order of the theory , known as the tight - winding approximation ( twa ) , that represents a weak potential model , extremely idealized as a smooth , even negligible perturbation to the background potential , was modeled as a simplified cosine function to represent the spiral arms gravitational potential . |
6,622 | Suppose that you have an abstract for a scientific paper: we study the concentration dependence of the superconducting critical temperature @xmath0 in a boron - doped diamond .
we evaluate the density of states at fermi level @xmath1 within the dynamical cluster approximation obtaining higher values than from the coherent potential approximation .
we discuss the @xmath0 as a function of @xmath1 within the bcs , the mcmillan , and the belitz theory .
the simplified belitz theory gives the best agreement with experimental data . since the density of states follows a simple power - law for accessible doping concetrations @xmath2 , the present theory offers an analytical formula for @xmath3 . .
And you have already written the first three sentences of the full article: a diamod doped with boron can become superconducting at temperatures of few kelvins @xcite .
such critical temperatures are surprisingly high for impurity band conductivity .
moreover , one can expect that @xmath4 will be soon further increased.
Please generate the next two sentences of the article | . it would be useful to predict an optimal sample composition from a microscopic theory .
to this end we evaluate the density of states at the fermi level within the dynamical cluster approximation and show that it can be approximated by a simple power - law . using this density of states |
6,623 | Suppose that you have an abstract for a scientific paper: we have imaged the halo populations of a sample of nearby spiral galaxies using the wide field planetary camera 2 on broad the hubble space telescope with the aim of studying the stellar population properties and relating them to those of the host galaxies . in four galaxies ,
the red - giant branch is sufficiently well populated to measure the magnitude of the tip of the red - giant branch ( trgb ) , a well - known distance indicator .
using both the sobel edge - detection technique and maximum - likelihood analysis to measure the @xmath0-band magnitude of the red giant branch tip , we determine distances to four nearby galaxies : ngc 253 , ngc 4244 , and ngc 4945 , ngc 4258 .
for the first three galaxies , the trgb distance determined here is more direct , and likely to be more accurate , than previous distance estimates . in the case of ngc 4258
, our trgb distance is in good agreement with the the geometrical maser distance , supporting the the large magellanic cloud distance modulus @xmath1 that is generally adopted in recent estimates of the hubble constant . .
And you have already written the first three sentences of the full article: the diffuse stellar halo component of galaxies represents a tiny fraction of the mass ( about 1% in the case of the milky way ; morrison 1993 ) and the low surface brightness of the population makes study in extragalactic settings difficult . however , galactic halos are unique laboratories for investigating fundamental galaxy properties
. age and/or metallicity distributions of halo stellar populations and their kinematics provide fossilized glimpses of the earliest conditions of galaxy formation .
halo populations may give us answers to key questions about the chronology of galaxy formation : how the halo formation was related to the assembly of galactic mass and the formation of galaxies ..
Please generate the next two sentences of the article | different views have been advanced toward understanding the formation of galactic stellar halos .
the first scenario was proposed by eggen , lynden - bell , & sandage ( 1962 ) , where the authors proposed that the metal - poor stars in the galactic halo were formed during a rapid collapse of a relatively uniform , isolated protogalactic cloud . |
6,624 | Suppose that you have an abstract for a scientific paper: the thermal pairing gap obtained by embedding the exact solutions of the pairing problem into the canonical ensemble is employed to calculate the width and strength function of the giant dipole resonance ( gdr ) within the phonon damping model .
the results of calculations describe reasonably well the data for the gdr width as well as the gdr linearized strength function , recently obtained for @xmath0tl in the temperature region between 0.8 and 1.2 mev , which other approaches that neglect the effect of non - vanishing thermal pairing fail to describe . .
And you have already written the first three sentences of the full article: since the discovery of the giant dipole resonance ( gdr ) as a collective thermal excitation in highly excited ( hot ) nuclei @xcite , many experiments were carried out in the last three decades to extract the gdr width and its shape ( linearized strength function ) as functions of nuclear temperature @xmath1 and angular momentum @xmath2 . a recent compilation of gdr built on excited states is given in ref .
@xcite . at present
, the well - established systematics accumulated by measuring the @xmath3 decays of various hot compound nuclei formed in heavy - ion fusion reactions and inelastic scattering of light particles on heavy targets has shown that the gdr width increases with temperature @xmath1 within the temperature region 1 mev @xmath4 3 4 mev ..
Please generate the next two sentences of the article | it has also shown that the gdr width s increase with angular momentum @xmath2 becomes noticeable only at @xmath5 27 30 @xmath6 in heavy nuclei , whereas its location ( peak energy ) remains mostly unchanged as @xmath1 and @xmath2 vary .
experimental studies often refer to the thermal shape fluctuation model ( tsfm ) @xcite as one of theoretical descriptions of the width s increase in this temperature region . |
6,625 | Suppose that you have an abstract for a scientific paper: optical experiments designed to explore quantum complementarity are reanalyzed .
it is argued that , for each , a classical explanation is not only possible , but more coherent and less contrived .
the final conclusion is that these experiments actually constitute support for criticism of the photon paradigm of electric charged particle interaction .
they offer little or nothing to say about quantum complementarity once the photon concept is not imposed by mandate . .
And you have already written the first three sentences of the full article: complementarity has become a catch - all concept to cover the weirdness of quantum mechanics ( qm ) .
mostly , this is because its originator , bohr , actually proposed this notion in order to capture exactly these weird features and legitimize them .
it is arguably the case , however , that having been unable to remove what were at first recognized as antinomies , they were just redubbed as deep , albeit preternatural , holistic insights into atomic scale ontology . following the popularization of the term in physics , bohr extended the concept to arenas outside the customary boundaries of science even , until it became for him a universal precept , the foundation of a total _ weltanschauung ..
Please generate the next two sentences of the article | _ history seems to show that he was only marginally successful at promulgating philosophy .
none of his students , nor readers of his papers , agree completely on just whatever it was he tried to convey under the term `` complementarity , '' even when restricted to within physics.@xcite nevertheless , through the decades , authors of textbooks and other secondary literature have focused the notion of complementarity on the issue of particle - wave identity . out of this literature over time a consensus has crystallized : complementarity refers to that feature of quantum theory to the effect that ensembles of all entities , depending on the scale of the interaction or measurement scheme , exhibit alternately either the properties of waves or particles . |
6,626 | Suppose that you have an abstract for a scientific paper: we give an elementary proof of the fact that any orientable 3-manifold admits a framing ( i.e. is parallelizable ) and any non - orientable 3-manifold admits a projective framing .
the proof uses only basic facts about immersions of surfaces in 3-space .
[ section ] [ thm]lemma [ thm]proposition [ thm]corollary [ thm]definition [ thm]remark .
And you have already written the first three sentences of the full article: a framing for a smooth @xmath0-manifold @xmath1 is a smooth choice of ordered basis @xmath2 for the tangent space at each point of @xmath1 .
a _ projective _ framing is a smooth choice of a _ pair _ of bases of the form @xmath3 .
it has long been established that any orientable 3-manifold admits a framing ( s ) and any non - orientable 3-manifold admits a projective framing ( hh ) ..
Please generate the next two sentences of the article | the original proofs rely on the notion of characteristic classes .
we present a proof for compact @xmath1 , which will only use basic facts about immersions of surfaces in 3-space . |
6,627 | Suppose that you have an abstract for a scientific paper: the electronic band structures , density of states plots and magnetic moments of fe@xmath0mnsi , fe@xmath0mnal , and co@xmath0mnge are studied by using the first principles calculations .
the fm solutions using lsda without _ u _ show the presence of half - metallic ferromagnetic ( hfm ) ground state in fe@xmath0mnsi , whereas the ground state of fe@xmath0mnal is found to be metallic . in both compounds
the maximum contribution to the total magnetic moment is from the mn atom , while the fe atom contributes very less .
the electronic structures and magnetic moments of fe - based compounds affected significantly by _ u _ , whereas its effect is very less on co@xmath1mnge .
the magnetic moment of fe atom in fe@xmath0mnsi ( fe@xmath0mnal ) , increased by @xmath2 70 % ( @xmath2 75 % ) and in mn atom it decreases by @xmath2 50 % ( @xmath2 70 % ) when the value of _ u _ is increased from 1 to 5 ev .
the hund s like exchange interactions are increasing in fe atom while decreasing in mn atom with increase in _
u_. the fe and mn moments are ferromagnetically coupled in fe@xmath0mnsi for all values of _ u _ , whereas in fe@xmath0mnal they coupled antiferromagnetically below _
u _ = 2 ev and ferromagnetically above it . above _ u _ = 2 ev the metallic ground state of fe@xmath0mnal changes to semiconducting ground state and the ferromagnetic coupling between fe and mn atoms appears to be responsible for this . .
And you have already written the first three sentences of the full article: after the discovery of half - metallic ferromagnetism in half - heusler alloy nimnsb by de groot et al.@xcite many of the compounds were found to be half - metallic in different experimental @xcite and theoretical studies@xcite .
the half - metallic ferromagnets ( hmfs ) have band gap at the fermi level ( _ e@xmath3 _ ) in one spin channel while the other spin channel is strongly metallic .
these materials show a complete spin polarization of the conduction electrons at the.
Please generate the next two sentences of the article | _ _ e@xmath3__. because of their exceptional band structures at the _ e@xmath3 _ , these materials are of great interest from theoretical and applications point of view .
co containing full - heusler alloys were firstly proposed by ishida et al.@xcite and were synthesised by webster@xcite . |
6,628 | Suppose that you have an abstract for a scientific paper: we present deep observations taken with the hst advanced camera for surveys of the central massive galaxy in a forming cluster at @xmath0 . the galaxy hosting the powerful radio source mrc 1138262
is associated with one of the most extensive merger systems known in the early universe .
our hst / acs image shows many star - forming galaxies merging within a @xmath1200 kpc region that emits both diffuse line emission and continuum in the rest - frame uv . because this galaxy lives in an overdense environment , it represents a rare view of a brightest cluster galaxy in formation at @xmath2 which may serve as a testbed for predictions of massive cluster galaxy formation . early universe , galaxies : clusters : general .
And you have already written the first three sentences of the full article: the formation and evolution of structure in the universe is a fundamental field of research in cosmology .
clusters of galaxies represent the most extreme deviation from initial conditions , and are therefore good evolutionary probes for studying the formation of the large - scale structure .
while clusters of galaxies have been studied extensively in the relatively nearby universe , their evolutionary history becomes obscure beyond roughly half the hubble time ( e.g. blakeslee et al ..
Please generate the next two sentences of the article | 2006 , mullis et al . 2005 , stanford et al .
their progenitors are difficult to identify when the density contrast between the forming cluster and the field becomes small , and mass condensations on the scales of clusters are extremely rare at any epoch ( kaiser 1984 ) . |
6,629 | Suppose that you have an abstract for a scientific paper: we consider a random walk @xmath0 with the constraint that each coordinate of the walk is at distance one from the following one . in this paper , we show that this random walk is slowed down by a variance factor @xmath1 with respect to the case of the classical simple random walk without constraint .
_ keywords _ : random walk , graph , central limit theorem _ ams classification ( 2000 ) _ : 05c81 , 60f05 . .
And you have already written the first three sentences of the full article: let @xmath0 denote the heights of @xmath2 simple random walks on @xmath3 , conditioned on satisfying @xmath4 , \left| z^{(i+1)}_n - z^{(i)}_n \right| = 1.\ ] ] more precisely , the random walk is a markov chain on the state space of @xmath5-step walks in @xmath6 @xmath7 , |z^{(i+1 ) } - z^{(i)}| = 1 \}\ ] ] where the next step from @xmath8 is selected uniformly among the neighbours of @xmath9 in the usual lattice @xmath10 that belong to @xmath11 .
in other words , we consider @xmath2 simple random walks on the lattice @xmath3 coupled under a shape condition . as in the case of a simple random walk ,
the rescaled trajectory of a walker , say @xmath12 , will converge in law to a brownian motion ..
Please generate the next two sentences of the article | however , it is interesting to note that the constraint between each coordinate only slow down the walk by decreasing its variance .
since it is classical to illustrate for our students the simple random walk as the motion of a drunk man , we can illustrate the previous mathematical fact by considering the random walk as the motion of a chain of prisoners . |
6,630 | Suppose that you have an abstract for a scientific paper: the string theory description of bps states in d - brane world - volume field theories may undergo transitions from open strings to string webs , as well as between different string webs , as one moves in the field theory moduli space .
these transitions are driven by the string creation phenomenon .
we demonstrate such transitions in the d3-brane realization of @xmath0 @xmath1 super - yang - mills theory . by -1.5 cm by -1.5
cm = 16.5 cm = 20.0 cm # 10= -.025em0 - 0 .05em0 - 0 -.025em.0433em0 h *s * *a * hep - th/9806011 + hutp-98/a027 0.5 cm 1.0 cm oren bergman and ansar fayyazuddin 0.5 cm _
lyman laboratory of physics + harvard university + cambridge , ma 02138 _ 1.5 cm june 1998 1.5 cm 1.5 cm pacs codes : 11.25.-w , 11.15.-q , 11.30.pb .
And you have already written the first three sentences of the full article: in type iib string theory there exists an @xmath2 multiplet of strings labeled by their nsns and rr charges @xmath3 @xcite .
these strings are allowed to connect at a point or a `` junction '' as long as charge is conserved at the junction @xcite . of particular interest are bps saturated junctions @xcite , which preserve a fraction ( 1/4 ) of the supersymmetry , and are therefore guaranteed to be stable .
recent interest in string webs has focused on their application to quantum field theory @xcite ..
Please generate the next two sentences of the article | one of the successes of string web technology was the first explicit construction of @xmath4 bps states in @xmath5 @xmath6 super - yang - mills ( sym ) theory @xcite .
in this example the dilaton and axion of type iib string theory are constant , and it is relatively straightforward to analyze the bps properties of string webs |
6,631 | Suppose that you have an abstract for a scientific paper: the vibrational modes of jahn - teller molecules are affected by a berry phase that is associated with a conical intersection of the adiabatic potentials .
we investigate theoretically the effect of this berry phase on the electronic transport properties of a single @xmath0 jahn - teller molecule when the tunneling electrons continually switch the molecule between a symmetric and a jahn - teller distorted charge state .
we find that the berry phase , in conjunction with a spectral trapping mechanism , leads to a current - blockade even in regions outside the coulomb blockade .
the blockade is strongly asymmetric in the gate voltage and induces pronounced negative differential conductance . .
And you have already written the first three sentences of the full article: the vision of molecular electronics has stimulated great interest in both the experimental @xcite and the theoretical @xcite understanding of electronic transport through single molecule devices .
the coupling of electronic degrees of freedom to few , well - defined molecular vibrations , a property that discriminates transport through single molecules from that through other nanostructures such as quantum dots , sets the stage for observing novel quantum - transport phenomena .
@xcite one of the simplest and most intensively studied models of such a device is a molecule with a single electronic level and a one - dimensional potential energy surface for the nuclear displacements ..
Please generate the next two sentences of the article | this model already gives rise to a large variety of interesting transport phenomena such as vibrational sidebands , @xcite electron shuttles , @xcite franck - condon blockade , @xcite avalanche - like transport , @xcite pair tunneling , @xcite and dynamical symmetry breaking .
@xcite generalizations of this model to two or more electronic levels have been suggested in order to account for non - degenerate but competing molecular states @xcite and for degenerate electronic states on a molecular dimer . |
6,632 | Suppose that you have an abstract for a scientific paper: while automata theory often concerns itself with regular predicates , relations corresponding to acceptance by a finite state automaton , in this article i study the regular functions , such relations which are also functions in the set - theoretic sense . here
i present a small ( but necessarily infinite ) collection of ( multi - ary ) functions which generate the regular functions under composition . to this end , this paper presents an interpretation of the powerset determinization construction in terms of compositions of input - to - run maps .
furthermore , known results using the krohn - rhodes theorem to further decompose my generating set are spelled out in detail , alongside some coding tricks for dealing with variable length words .
this will include two clear proofs of the krohn - rhodes theorem in modern notation . .
And you have already written the first three sentences of the full article: automata theory is particularly fruitful in terms of equivalence theorems : regular expressions , deterministic and nondeterministic automata , the myhill - nerode theorem , the regular word logic and the weak second order theory of one successor all are equally expressive in the languages they describe . in this paper ,
i concern myself not with regular predicates ( predicates which hold only for the words in a regular language ) but with regular functions , functions whose behavior can be recognized by an automaton .
this allows a translation of the krohn - rhodes theorem into yet another equivalent ..
Please generate the next two sentences of the article | the krohn - rhodes theorem concerns itself with _
finite state transducers _ , an abstraction of systems that : * accept inputs from a discrete set at discrete times , * retain some memory about previous inputs , which updates whenever an input is read , * for each input read , produce some output from a discrete set based on the input and memory . |
6,633 | Suppose that you have an abstract for a scientific paper: we analyze the backscattering current induced by a time dependent constriction as a tool to probe fractional topological insulators .
we demonstrate an enhancement of the total current for a fractional topological insulator induced by the dominant tunneling excitation , contrary to the decreasing present in the integer case for not too strong interactions .
this feature allows to unambiguously identify fractional quasiparticles .
furthermore , the dominant tunneling processes , which may involve one or two quasiparticles depending on the interactions , can be clearly determined . .
And you have already written the first three sentences of the full article: the close interplay between theory and experiments has always led to fundamental discoveries in condensed matter physics .
this is particularly evident in the search for topological states of matter , starting in the 80 s with the experimental observation of the integer quantum hall ( qh ) effect @xcite , characterized by chiral metallic edge states and insulating bulk states .
few years later , also fractional plateau of the conductance were discovered @xcite , theoretically explained by laughlin as a manifestation of the fractional qh effect @xcite ..
Please generate the next two sentences of the article | after the first theoretical proposal for realizing topological states of matter in the absence of magnetic fields @xcite , bernevig _ et al .
_ suggested that hgte / cdte quantum wells behave as a topological insulator ( ti ) @xcite . realizing the quantum spin hall ( qsh ) effect in the presence of time reversal ( tr ) symmetry @xcite . |
6,634 | Suppose that you have an abstract for a scientific paper: both in the faraday rotation measure and the intrinsic polarization angle , new features are revealed to indicate a helical magnetic field operating along the jet of the bright active galactic nuclei 3c 273 .
the helical field has been suggested to be related to the formation and collimation of jets by magnetohydrodynamic models .
the distribution of the rm shows a systematic gradient with respect to the jet axis , which is expected by a helical magnetic field .
in addition , the helical field can consistently explain two types in the direction of the projected magnetic field : parallel and perpendicular to the jet axis .
further , if the helical magnetic field is generated by winding up of an initial field by rotation of the accretion disk , we can uniquely determine the direction of the disk rotation , since the jet is approaching us . .
And you have already written the first three sentences of the full article: many jets emanating from active galactic nuclei ( agn ) show narrow and well - collimated structures from less than a parsec ( pc ) up to mpc scales ( e.g. , zensus 1997,references therein ) . from a theoretical point of view ,
several models were proposed concerning the formation and collimation process of a jet . for the formation of jets , radiative pressure models
( e.g. , icke 1980 , 1989 ; sikora et al ..
Please generate the next two sentences of the article | 1996 ) and magnetic field models ( e.g. , benford 1978 ; blandford , payne 1982 ; uchida , shibata 1985 , 1986 ; meier et al .
2001 ; koide et al . |
6,635 | Suppose that you have an abstract for a scientific paper: in this paper , we study massive gravity in the presence of born - infeld nonlinear electrodynamics .
first , we obtain metric function related to this gravity and investigate the geometry of the solutions and find that there is an essential singularity at the origin ( @xmath0 ) .
it will be shown that due to contribution of the massive part , the number , types and places of horizons may be changed .
next , we calculate the conserved and thermodynamic quantities and check the validation of the first law of thermodynamics .
we also investigate thermal stability of these black holes in context of canonical ensemble .
it will be shown that number , type and place of phase transition points are functions of different parameters which lead to dependency of stability conditions to these parameters .
also , it will be shown how the behavior of temperature is modified due to extension of massive gravity and strong nonlinearity parameter .
next , critical behavior of the system in extended phase space by considering cosmological constant as pressure is investigated .
a study regarding neutral einstein - massive gravity in context of extended phase space is done .
geometrical approach is employed to study the thermodynamical behavior of the system in context of heat capacity and extended phase space .
it will be shown that gts , heat capacity and extended phase space have consistent results .
finally , critical behavior of the system is investigated through use of another method .
it will be pointed out that the results of this method is in agreement with other methods and follow the concepts of ordinary thermodynamics . .
And you have already written the first three sentences of the full article: regarding experimental agreements of einstein gravity ( en ) in various area of astrophysics and cosmology , motivates one to consider it as an acceptable theory .
in addition , adding a constant term @xmath1 in the en - hilbert action may lead to agreement between the results of en-@xmath1 gravity with dark energy prediction .
on the other hand , general relativity is consistent with interaction of massless spin @xmath2 fields , in which related gravitons are massless particles with two degrees of freedom ..
Please generate the next two sentences of the article | since the quantum theory of massless gravitons is non - renormalizable @xcite , one may be motivated for modifying general relativity to massive gravity . in order to build up a massive theory with a massive spin @xmath2 particle propagation
, one can add a mass term to the en - hilbert action . |
6,636 | Suppose that you have an abstract for a scientific paper: in this document , we describe the fractal structure of the netsukuku topology .
moreover , we show how it is possible to use the qspn v2 on the high levels of the fractal .
this document is part of netsukuku .
+ copyright 2007 andrea lo pumo aka alpt @[email protected]@xmath1 .
all rights reserved .
this document is free ; you can redistribute it and/or modify it under the terms of the gnu general public license as published by the free software foundation ; either version 2 of the license , or ( at your option ) any later version .
this document is distributed in the hope that it will be useful , but without any warranty ; without even the implied warranty of merchantability or fitness for a particular purpose .
see the gnu general public license for more details .
you should have received a copy of the gnu general public license along with this document ; if not , write to the free software foundation , inc .
, 675 mass ave , cambridge , ma 02139 , usa . .
And you have already written the first three sentences of the full article: we re assuming that you already know the basics of the qspn .
if not , read the qspn document first : @xcite .
the aim of netsukuku is to be a ( physical ) scalable mesh network , completely distributed and decentralised , anonymous and autonomous ..
Please generate the next two sentences of the article | the software , which must be executed by every node of the net , has to be unobtrusive .
it has to use very few cpu and memory resources , in this way it will be possible to run it inside low - performance computers , like access points , embedded devices and old computers . |
6,637 | Suppose that you have an abstract for a scientific paper: we get the same degeneracy relation between @xmath0 and @xmath1 for the tachyon fields as for quintessence and phantom fields .
our results show that the dynamics of scalar fields with different origins becomes indistinguishable when the equation of state parameter @xmath2 does not deviate too far away from -1 , and the time variation @xmath3 satisfies the same bound for the same class of models . for the tachyon fields ,
a limit on @xmath3 exists due to the hubble damping and we derived the generic bounds on @xmath3 for different classes of models .
we may distinguish different models in the phase plane of @xmath4 .
the current constraints on @xmath2 and @xmath3 are consistent with all classes of models .
we need to improve the constraint on @xmath3 by 50% to distinguish different models . .
And you have already written the first three sentences of the full article: to explain the cosmic acceleration found by the observations of type ia supernovae ( sne ia ) in 1998 @xcite , we usually introduce dark energy with negative pressure which consists about 70% of the total energy density in the universe .
the cosmological constant with the constant equation of state @xmath5 is the simplest candidate of dark energy and it is consistent with current observational data , but its value is too small compared with that estimated from the vacuum energy of quantum field theory .
dynamical fields with scalar field such as quintessence @xcite , phantom @xcite , tachyon @xcite and k - essence @xcite were proposed for dark energy ..
Please generate the next two sentences of the article | the scalar field rolls down a very shallow potential , so its equation of state @xmath2 will approach @xmath6 and it dominates the universe only recently . according to its evolution , the scalar field was classified to several categories .
if the scalar field stuck in a local minimum and starts to roll down to the true minimum until recently , the dark energy models are called thawing models @xcite . for thawing models , @xmath2 starts with the value -1 at early times and then deviates from -1 at the present time . |
6,638 | Suppose that you have an abstract for a scientific paper: we present a comprehensive multiwavelength analysis of the bright , long duration gamma - ray burst grb 070125 , comprised of observations in @xmath0-ray , x - ray , optical , millimeter and centimeter wavebands .
simultaneous fits to the optical and x - ray light curves favor a break on day 3.78 , which we interpret as the jet break from a collimated outflow .
independent fits to optical and x - ray bands give similar results in the optical bands but shift the jet break to around day 10 in the x - ray light curve .
we show that for the physical parameters derived for grb 070125 , inverse compton scattering effects are important throughout the afterglow evolution .
while inverse compton scattering does not affect radio and optical bands , it may be a promising candidate to delay the jet break in the x - ray band .
radio light curves show rapid flux variations , which are interpreted as due to interstellar scintillation , and are used to derive an upper limit of @xmath1 cm on the radius of the fireball in the lateral expansion phase of the jet .
radio light curves and spectra suggest a high synchrotron self absorption frequency indicative of the afterglow shock wave moving in a dense medium .
our broadband modeling favors a constant density profile for the circumburst medium over a wind - like profile ( @xmath2 ) .
however , keeping in mind the uncertainty of the parameters , it is difficult to unambiguously distinguish between the two density profiles .
our broadband fits suggest that grb 070125 is a burst with high radiative efficiency ( @xmath3 ) . .
And you have already written the first three sentences of the full article: to understand the inner workings of gamma - ray burst ( grb ) central engines , it is necessary to constrain their true energy release . if a redshift is known , the isotropic energy release in gamma - rays , @xmath4 , is a readily measurable quantity .
the `` energy crisis '' brought on by implied energy releases of @xmath5 erg ( e.g. , * ? ? ?
* ; * ? ? ?.
Please generate the next two sentences of the article | * ) was resolved when it was realized that grb blast waves are collimated with opening angles @xmath6 of 2 - 30@xmath7 @xcite .
thus the beaming - corrected gamma - ray energy release , @xmath8 , is smaller than @xmath9 by a factor @xmath10 . |
6,639 | Suppose that you have an abstract for a scientific paper: we describe the program of research and development being undertaken by a consortium of illinois university groups to develop liquid - hydrogen energy absorbers for muon - beam cooling . .
And you have already written the first three sentences of the full article: ionization cooling of a muon beam can be accomplished by passing the beam through energy - absorbing material and accelerating structures , both embedded within a focusing magnetic lattice .
the rate of change of the normalized transverse emittance with path length is then approximately described by @xcite @xmath0 where @xmath1 is the path length , @xmath2 the muon energy , @xmath3 the radiation length of the absorber medium , @xmath4 , and @xmath5 is the betatron function of the beam ( where the size of the beam is given by @xmath6 ) . in eq .
[ eq : cool ] we see , in addition to the @xmath7 transverse cooling term , a transverse heating term due to multiple coulomb scattering of the muons in the absorbers . since cooling ceases once the heating and cooling terms are equal , eq . [ eq : cool ] implies an equilibrium emittance , which in principle ( neglecting other limiting effects ) would be reached asymptotically were the cooling channel continued indefinitely ..
Please generate the next two sentences of the article | since the heating term is proportional to @xmath5 and inversely proportional to the radiation length of the absorber medium , the goal of achieving as small an equilibrium emittance as possible requires us to locate the absorber only in low-@xmath5 regions and to use a medium with the longest possible radiation length , namely hydrogen . to achieve low @xmath5
, we want the strongest possible focusing elements . |
6,640 | Suppose that you have an abstract for a scientific paper: we report cousins @xmath0-band monitoring of the high - redshift ( @xmath1=4.40 ) radio quiet quasar q2203 + 292 from may 1999 to october 2007 .
the quasar shows maximum peak - to - peak light curve amplitude of @xmath20.3 mag during the time of our monitoring , and @xmath20.9 mag when combined with older literature data .
the rms of a fit to the light curve with a constant is 0.08 mag and 0.2 mag , respectively .
the detected changes are at @xmath23-sigma level .
the quasar was in a stable state during the recent years and it might have undergone a brightening event in the past .
the structure function analysis concluded that the object shows variability properties similar to those of the lower redshift quasars .
we set a lower limit to the q2203 + 292 broad line region mass of 0.3 - 0.4 m@xmath3 .
narrow - band imaging search for redshifted ly@xmath4 from other emission line objects at the same redshift shows no emission line objects in the quasar vicinity .
[ firstpage ] quasar : general - quasars : individual : q2203 + 292 .
And you have already written the first three sentences of the full article: many quasars show short - term or / and long - term variability ( ulrich , maraschi & urry 1997 ) .
these changes in the source flux help to constrain the physics and the size of the central engine .
astronomers came to an early understanding that the central engines of the agns and qsos can not be resolved easily , if at all , but that the variability timescales measure the size of the emitting regions ( i.e. blandford & mckee 1982 ) . later on , this became the basis of reverberation studies ( for a recent review see peterson et al ..
Please generate the next two sentences of the article | 2004 and the references therein ) that could map the innermost broad line regions ( hereafter blr ) .
nevertheless , the exact variability mechanisms remain unclear . typically , the variability is aperiodic , but it does show some dependencies on time lag , luminosity , wavelengths and redshift . |
6,641 | Suppose that you have an abstract for a scientific paper: the relative isoperimetric inequality inside an open , convex cone @xmath0 states that , at fixed volume , @xmath1 minimizes the perimeter inside @xmath0 . starting from the observation that this result can be recovered as a corollary of the anisotropic isoperimetric inequality ,
we exploit a variant of gromov s proof of the classical isoperimetric inequality to prove a sharp stability result for the relative isoperimetric inequality inside @xmath0 .
our proof follows the line of reasoning in @xcite , though several new ideas are needed in order to deal with the lack of translation invariance in our problem . * a sharp stability result for the relative isoperimetric inequality inside convex cones * a. figalli and e. indrei .
And you have already written the first three sentences of the full article: recently , there has been a lot of interest in quantitative estimates for isoperimetric @xcite , sobolev @xcite , gagliardo - nirenberg @xcite , and brunn - minkowski @xcite type inequalities .
the aim of all of these results is to show that if a set / function almost attains the equality in one of these inequalities , then it is close ( in a quantitative way ) to a minimizer .
these results have natural applications in the study of the asymptotic behavior of solutions to evolution equations @xcite , and to show stability for minimizers of perturbed variational problems , see for instance @xcite ..
Please generate the next two sentences of the article | our goal is to investigate stability for the relative isoperimetric inequality inside convex cones .
this inequality has been used , for instance , to characterize isoperimetric regions inside convex polytopes for small volumes ( * ? ? ? |
6,642 | Suppose that you have an abstract for a scientific paper: we calculate the torque on an ideal ( point ) dipole moving with constant velocity through uniform electric and magnetic fields . .
And you have already written the first three sentences of the full article: the torque on an electric dipole * p * , at rest in a uniform electric field * e * , is @xmath0 the torque on a magnetic dipole * m * , at rest in a uniform magnetic field * b * , is @xmath1 but what if the dipole is moving , at a constant velocity * v * ?
it is well known that a moving electric dipole acquires a _
dipole moment @xcite @xmath2.
Please generate the next two sentences of the article | so one might guess that the torque on a moving electric dipole in uniform electric and magnetic fields would be @xcite @xmath3 similarly , a moving magnetic dipole acquires an _ electric _ dipole moment @xcite @xmath4 and one might guess that the torque on a moving magnetic dipole would be @xmath5 but these formulas are incorrect ; in each case there is a third term:@xcite @xmath6 in general , then , @xmath7 our purpose in this note is to derive that result
. @xcite -.1in[.7 ] -.5 in |
6,643 | Suppose that you have an abstract for a scientific paper: the vista variables in the va lctea ( vvv ) eso public survey is an ongoing time - series , near - infrared ( ir ) survey of the galactic bulge and an adjacent portion of the inner disk , covering 562 square degrees of the sky , using eso s vista telescope .
the survey has provided superb multi - color photometry in 5 broadband filters ( @xmath0 , @xmath1 , @xmath2 , @xmath3 , and @xmath4 ) , leading to the best map of the inner milky way ever obtained , particularly in the near - ir .
the main variability part of the survey , which is focused on @xmath4-band observations , is currently underway , with bulge fields having been observed between 31 and 70 times , and disk fields between 17 and 36 times .
when the survey is complete , bulge ( disk ) fields will have been observed up to a total of 100 ( 60 ) times , providing unprecedented depth and time coverage .
here we provide a first overview of stellar variability in the vvv data , including examples of the light curves that have been collected thus far , scientific applications , and our efforts towards the automated classification of vvv light curves .
[ 1996/06/01 ] 2@xmath5 2c ii 4c iv 2fe ii 3fe iii 1 mg i 2 mg ii 2si ii 4si iv 2al ii 3al iii 1o
i 1n i 1h i = .
And you have already written the first three sentences of the full article: the vista variables in the va lctea ( vvv ) eso public survey @xcite is a time - series , near - infrared ( ir ) survey of the galactic bulge and an adjacent portion of the inner disk , covering 562 square degrees of the sky ( fig .
[ fig : area ] ) .
the survey has provided multi - color photometry in 5 broadband filters ( @xmath0 , @xmath1 , @xmath2 , @xmath3 , and @xmath4 ) , but its main goal is to provide , for the first time , a homogeneous database for a variability study of the observed regions in the @xmath4-band ..
Please generate the next two sentences of the article | vvv has much improved photometric precision compared with , and extends much deeper than , 2mass @xcite .
in addition , in contrast to single - epoch surveys , which only allow the construction of 2-dimensional ( 2d ) maps , with the addition of temporal information for well - established distance indicators such as rr lyrae stars ( e.g. , * ? ? ? * ; * ? ? ? * ; * ? ? ? * ; * ? ? ? |
6,644 | Suppose that you have an abstract for a scientific paper: metamaterials are patterned metallic structures which permit access to a novel electromagnetic response , negative index of refraction , impossible to achieve with naturally occurring materials . using the babinet principle , the complementary split ring resonator ( srr )
is etched in a metallic plate to provide negative @xmath0 , with perpendicular direction . here
we propose a new design , etched in a metallic plate to provide negative magnetic permeability , @xmath1 , with perpendicular direction .
the combined electromagnetic response of this planar metamaterial , where the negative @xmath1 comes from the aperture and the negative @xmath0 from the remainder of the continuous metallic plate , allows achievement of a double negative index metamaterial ( nim ) with only one metasurface and strong transmission .
these designs can be used to fabricate nims at microwave and optical wavelengths and three dimensional metamaterials . .
And you have already written the first three sentences of the full article: metamaterials are artificial materials that can be engineered to exhibit fascinating electromagnetic properties that do not occur in nature , such as negative refractive index , `` perfect '' imaging and electromagnetic cloaking @xcite , chiral metamaterials have shown giant optical activity @xcite , circular dichroism @xcite , negative refraction @xcite , and possible reversal of the casimir force @xcite .
most of the applications critically required an negative index of refraction in three dimensions ( 3d ) .
it is an open question , whether there is any 3d metamaterial design working for optical frequencies still feasible to fabricate . here.
Please generate the next two sentences of the article | , we theoretically proposed a new design that provides negative index of refraction with one surface and can be used to fabricate 3d metamaterials .
this is an important step towards the realization of bulk 3d at optical wavelengths . |
6,645 | Suppose that you have an abstract for a scientific paper: the results of the lowest frequency spectral survey carried out toward a molecular cloud and sensitive observations at selected frequencies are presented . the entire arecibo c - band ( 46 ghz )
was observed towards the cyanopolyyne peak of tmc-1 with an rms sensitivity of about 1718 mk ( about 22.5 mjy ) .
in addition , a number of selected frequency ranges within the c - band and x - band ( 810 ghz ) were observed with longer integration times and rms sensitivities 78 mk ( @xmath0 2 mjy ) or higher . in the spectral scan itself , already known h@xmath1co and hc@xmath2n lines were detected .
however , in more sensitive observations at selected frequencies , lines of c@xmath1s , c@xmath3s , c@xmath4h , c@xmath4h@xmath1 , hc@xmath3n and its @xmath5c substituted isotopic species , hc@xmath2n , hc@xmath6n , and hc@xmath7n were found , about half of them detected for the first time .
the rotational temperatures of the detected molecules fall in the range 49 k. cyanopolyyne column densities vary from @xmath8 @xmath9 for hc@xmath2n to @xmath10 @xmath9 for hc@xmath7n .
our results show that for molecular observations at low frequencies ( 410 ghz ) to be useful for studying dark clouds , the sensitivity must be of the order of 510 mk or better . to date , observations at around 10 ghz have been more productive than those at lower frequencies . .
And you have already written the first three sentences of the full article: most known interstellar molecules have been detected in the millimeter wavelength range .
this is clearly related to the fact that , in general , the simplest and hence the lightest molecules are the most abundant cosmic molecular species .
their strongest rotational lines at the temperatures characteristic of the molecular interstellar medium arise at mm and submm wavelengths ..
Please generate the next two sentences of the article | heavier molecules , often with large permanent dipole moments , have detectable rotational lines at lower frequencies in the microwave range .
transitions between low energy levels are more favorable in terms of line intensities , especially in regions of low or modest density and low temperature . |
6,646 | Suppose that you have an abstract for a scientific paper: technologically driven transport systems are characterized by a networked structure connecting operation centers and by a dynamics ruled by pre - established schedules .
schedules impose serious constraints on the timing of the operations , condition the allocation of resources and define a baseline to assess system performance . here
we study the performance of an air transportation system in terms of delays .
technical , operational or meteorological issues affecting some flights give rise to primary delays .
when operations continue , such delays can propagate , magnify and eventually involve a significant part of the network .
we define metrics able to quantify the level of network congestion and introduce a model that reproduces the delay propagation patterns observed in the u.s . performance data .
our results indicate that there is a non - negligible risk of systemic instability even under normal operating conditions .
we also identify passenger and crew connectivity as the most relevant internal factor contributing to delay spreading . .
And you have already written the first three sentences of the full article: air transportation systems have been traditionally described as graphs with vertices representing airports and edges direct flights during a fixed time period @xcite .
these graphs are called airport networks and have been studied at different geographical resolution scales , restricted , for instance , to a single country ( usually the u.s .
( usan ) @xcite but also china @xcite or europe @xcite ) , or for the whole world ( wan ) @xcite ..
Please generate the next two sentences of the article | these networks show high heterogeneity in the distribution of connections per airport and in the traffic sustained by each connection .
a non linear relation between the number of connections of the airports ( topology ) and the number of passengers ( traffic ) has been observed in ref . |
6,647 | Suppose that you have an abstract for a scientific paper: transport events in turbulent tokamak plasmas often exhibit non - local or non - diffusive action at a distance features that so far have eluded a conclusive theoretical description . in this paper a theory of non - local transport is investigated through a fokker - planck equation with fractional velocity derivatives . a dispersion relation for density gradient driven linear drift modes
is derived including the effects of the fractional velocity derivative in the fokker - planck equation .
it is found that a small deviation ( a few percent ) from the maxwellian distribution function alters the dispersion relation such that the growth rates are substantially increased and thereby may cause enhanced levels of transport . .
And you have already written the first three sentences of the full article: understanding anomalous transport in magnetically confined plasmas is an outstanding issue in controlled fusion research .
a satisfactorily understanding of the non - local features as well as the non - gaussian probability distribution functions ( pdfs ) found in experimental measurements of particle and heat fluxes is still lacking . in particular , experimental observations of the edge turbulence in the fusion devices @xcite show that in the scrape of layer ( sol ) the plasma fluctuations are characterized by non - gaussian pdfs .
it has been recognized that the nature of the cross - field transport through the sol is dominated by turbulence with a significant ballistic or non - local component where a diffusive description is improper @xcite ..
Please generate the next two sentences of the article | moreover , the scaling of the confinement time @xmath0 with @xmath1 @xcite is typical in low - confinement mode discharges , instead of the diffusion induced result @xmath2 , where @xmath3 is the system size .
there is a considerable amount of experimental evidence @xcite and recent numerical gyrokinetic @xcite and fluid @xcite simulations that plasma turbulence in tokamaks is highly non - local . |
6,648 | Suppose that you have an abstract for a scientific paper: we study how far the index theorem can be extrapolated from the continuum to finite lattices with finite topological charge densities . to examine how the wilson action approximates the index theorem , we specialize in the lattice version of the schwinger model .
we propose a new criterion for solutions of the ginsparg - wilson relation constructed with the wilson action .
we conclude that the neuberger action is the simplest one that maximally complies with the index theorem , and that its best parameter in @xmath0 is @xmath1 .
address = dep .
fsica and cfif , inst .
sup .
tc .
, 1049 - 001 lisboa , portugal .
And you have already written the first three sentences of the full article: one of the constraints that lead to the nielsen - ninomiya @xcite no - go theorem , is the chiral invariance of the dirac action @xmath2 for massless fermions on the lattice . under certain conditions @xcite , the spectrum of fermions @xmath3 would suffer from doubling , and
the axial anomaly would cancel .
this has been , from the onset , a recurrent problem of lattice qcd @xcite . in order to recover the axial anomaly , at least at the pertubative level , ginsparg and wilson @xcite derived a relation , the ginsparg - wilson relation ( gwr ) which explicitly breaks the standard chiral symmetry , @xmath4 where @xmath5 is a matrix proportional to the lattice spacing @xmath6 ( in most of this.
Please generate the next two sentences of the article | talk we will consider the case where @xmath5 is a simple number ) .
recently lsher @xcite proved that chiral invariance of an action @xmath2 which complies with the gwr can be recovered in an extended form , @xmath7 thus a conjecture appeared in the literature suggesting that it may be possible to overcome the nielsen - ninomiya no - go theorem on the lattice and to fully simulate , without doubling , the chiral symmetry of qcd ( see @xcite for a recent review ) . |
6,649 | Suppose that you have an abstract for a scientific paper: the concept of exchange in strongly - correlated fermions is reviewed with emphasis on the generalization of the heisenberg pair exchange to higher order @xmath0-particle permutations .
the `` frustration '' resulting from competing ferromagnetic three - spin exchange and antiferromagnetic two- and four - spin exchanges is illustrated on a two - dimensional model system : solid @xmath1he films .
recent experimental results proving the presence of significant four - spin exchange interactions in the cuo@xmath2 plaquettes of high @xmath3 cuprates are reported .
quantum spin systems , @xmath1he , cuprates . .
And you have already written the first three sentences of the full article: the concept of exchange interactions in almost - localized correlated fermions first appeared in the pioneering papers of heisenberg@xcite and was formulated in a more general mathematical way by dirac@xcite .
although the early papers by dirac already contain the general expression of the hamiltonian in terms of n - particle permutations , no attention was paid , up to the sixties , to higher orders than the `` pair - exchange '' heisenberg term .
thouless@xcite was the first to point out that higher order exchanges as three- and four - spin cyclic permutations might be important in quantum solids like @xmath1he ..
Please generate the next two sentences of the article | but only ten years later , striking experimental results on nuclear magnetism in the bcc phase of solid @xmath1he , in the millikelvin range@xcite , were interpreted by hetherington , delrieu and roger through a ring - exchange model with two- three- and four - particle interactions of comparable magnitude@xcite . from general considerations put forward by thouless , permutations of even parity ( like three - particle cycles ) induce ferromagnetism while odd permutations ( pair and four - particle exchanges ) favor antiferromagnetism , and the striking phase diagram of bcc solid @xmath1he corresponds to a highly frustrated quantum - spin system with competing three- and four - spin permutations . during the last two decades a lot of progress has been accomplished in the investigation of solid @xmath1he films adsorbed on graphite , a simple model system exhibiting even more frustration since the frustrated nature of ring - exchange interactions is enhanced by the frustrated geometry of the triangular lattice . the conceptual beauty of solid @xmath1he lies in the fact that the system is simple enough ( the pair interactions between @xmath1he atoms are mainly of hard core nature ) to allow the calculation of exchange frequencies from first principles@xcite and a quantitative comparison with experimental results . the relevance of the multi - spin exchange concept is not restricted to the physics of nuclear @xmath1he spins .
delrieu@xcite suggested that three - spin exchange might be dominant in the two - dimensional electron wigner solid near the quasi - classical limit , and this has been corroborated through wkb calculations@xcite . |
6,650 | Suppose that you have an abstract for a scientific paper: the diffuse galactic @xmath0-ray emission is produced by cosmic rays ( crs ) interacting with the interstellar gas and radiation field .
measurements by the energetic gamma - ray experiment telescope ( egret ) instrument on the _ compton gamma - ray observatory ( cgro ) _ indicated excess @xmath0-ray emission @xmath1 gev relative to diffuse galactic @xmath0-ray emission models consistent with directly measured cr spectra ( the so - called `` egret gev excess '' ) .
the excess emission was observed in all directions on the sky , and a variety of explanations have been proposed , including beyond - the - standard - model scenarios like annihilating or decaying dark matter .
the large area telescope ( lat ) instrument on the _ fermi _ gamma - ray space telescope has measured the diffuse @xmath0-ray emission with unprecedented sensitivity and resolution .
we report on lat measurements of the diffuse @xmath0-ray emission for energies 100 mev to 10 gev and galactic latitudes @xmath2 . the lat spectrum for this region of the sky is well reproduced by the diffuse galactic @xmath0-ray emission models mentioned above and inconsistent with the egret gev excess .
gamma rays , cosmic rays , fermi gamma - ray space telescope .
And you have already written the first three sentences of the full article: the diffuse @xmath0-ray emission , both galactic and extragalactic , is of significant interest for astrophysics , particle physics , and cosmology . the diffuse galactic emission ( dge ) is produced by interactions of crs , mainly protons and electrons , with the interstellar gas ( via @xmath3-production and bremsstrahlung ) and radiation field ( via inverse compton [ ic ] scattering ) .
it is a direct probe of cr fluxes in distant locations , and may contain signatures of physics beyond the standard model , such as dark matter annihilation or decay . the dge is a foreground for point - source detection and hence influences the determination of their positions and fluxes .
it is also a foreground for the much fainter extragalactic component , which is the sum of contributions from unresolved sources and truly diffuse emission , including any signatures of large scale structure formation , emission produced by ultra - high - energy crs interacting with relic photons , and many other processes ( e.g. , @xcite and references therein ) ..
Please generate the next two sentences of the article | therefore , understanding the dge is a necessary first step in all such studies .
the excess diffuse emission @xmath1 gev in the egret data @xcite relative to that expected from dge models consistent with the directly measured cr nucleon and electron spectra @xcite led to the proposal that this emission was the long - awaited signature of dark matter annihilation @xcite . |
6,651 | Suppose that you have an abstract for a scientific paper: the two - component fermi gas is the simplest fermion system displaying superfluidity , and as such is relevant to topics ranging from superconductivity to qcd .
ultracold atomic gases provide an exceptionally clean realisation of this system , where interatomic interactions and atom spin populations are both independently tuneable . here
we show that the finite temperature phase diagram contains a region of phase separation between the superfluid and normal states that touches the boundary of second - order superfluid transitions at a tricritical point , reminiscent of the phase diagram of @xmath0he-@xmath1he mixtures .
a variation of interaction strength then results in a line of tricritical points that terminates at zero temperature on the molecular bose - einstein condensate ( bec ) side . on this basis
, we argue that tricritical points are fundamental to understanding experiments on polarised atomic fermi gases
. over the past decade , experimental progress in the field of cold atomic gases has resulted in unprecedented control over pairing phenomena in two - component fermi gases . the ability to vary the effective interaction between atoms using magnetically tuned feshbach resonances
has already permitted the experimental investigation of the crossover from a bec of diatomic molecules to the bardeen - cooper - schrieffer ( bcs ) limit of weakly - bound cooper pairs of fermionic atoms @xcite .
a natural extension of these studies is an exploration of the fermi gas with imbalanced spin populations , especially since this system has a far richer phase diagram than the equal spin case . as well as exhibiting a quantum phase transition between the superfluid and normal states ,
the polarized fermi gas has been predicted to possess exotic superfluid phases such as the inhomogeneous fulde - ferrell - larkin - ovchinnikov ( fflo ) state @xcite , where the pairing of fermions occurs at finite centre - of - mass momentum , and the deformed fermi surface state @xcite .
the exact nature....
And you have already written the first three sentences of the full article: experiments to date exploit wide feshbach resonances and are thus well described by the simplest single - channel hamiltonian , where the two fermion species interact via an attractive contact potential @xmath2 here , @xmath3 ( we set @xmath4 and @xmath5 ) , @xmath6 is the volume , and we define the chemical potential @xmath7 and ` zeeman ' field @xmath8 such that @xmath9 and @xmath10 . at present , only pairing between different hyperfine species of the _ same _ atom has been explored experimentally , so we restrict ourselves to a single mass @xmath11 . the interaction strength @xmath12 is expressed in terms of the s - wave scattering length @xmath13 using the prescription : @xmath14 we also derive the fermi momentum using the average density @xmath15 , so that @xmath16 .
throughout our calculations , we will keep @xmath17 fixed .
the full phase diagram is parameterised by just a few observables : the temperature @xmath18 , the interaction strength @xmath19 , and the density difference or ` magnetisation ' @xmath20 . to determine the position of the phase boundaries.
Please generate the next two sentences of the article | , we must minimise the mean - field free energy density @xmath21,\end{gathered}\ ] ] with respect to the bcs order parameter @xmath22 , where @xmath23 and @xmath24 .
such a mean - field analysis provides a reasonable description of the zero temperature phase diagram , but at finite temperature , it neglects the contribution of non - condensed pairs to both the density @xmath25 and magnetisation @xmath26 . |
6,652 | Suppose that you have an abstract for a scientific paper: we consider the problem of estimating the mean @xmath0 of a gaussian vector @xmath1 with independent components of common unknown variance @xmath2 .
our estimation procedure is based on estimator selection . more precisely , we start with an arbitrary and possibly infinite collection @xmath3 of estimators of @xmath0 based on @xmath1 and , with the same data @xmath1 , aim at selecting an estimator among @xmath3 with the smallest euclidean risk .
no assumptions on the estimators are made and their dependencies with respect to @xmath1 may be unknown .
we establish a non - asymptotic risk bound for the selected estimator .
as particular cases , our approach allows to handle the problems of aggregation and model selection as well as those of choosing a window and a kernel for estimating a regression function , or tuning the parameter involved in a penalized criterion .
we also derive oracle - type inequalities when @xmath3 consists of linear estimators . for illustration
, we carry out two simulation studies .
one aims at comparing our procedure to cross - validation for choosing a tuning parameter .
the other shows how to implement our approach to solve the problem of variable selection in practice . , .
And you have already written the first three sentences of the full article: we consider the gaussian regression framework @xmath4 where @xmath5 is an unknown vector of @xmath6 and the @xmath7 are independent centered gaussian random variables with common variance @xmath2 . throughout the paper
, @xmath8 is assumed to be unknown which corresponds to the practical case .
our aim is to estimate @xmath0 from the observation of @xmath1 . for specific forms of @xmath0 , this setting allows to deal simultaneously with the following problems ..
Please generate the next two sentences of the article | [ ex - sd ] the vector @xmath0 is of the form @xmath9 where @xmath10 are distinct points of a set @xmath11 and @xmath12 is an unknown mapping from @xmath11 into @xmath13 .
[ ex - vs ] the vector @xmath0 is assumed to be of the form @xmath14 where @xmath15 is a @xmath16 matrix , @xmath17 is an unknown @xmath18-dimensional vector and @xmath18 some integer larger than 1 ( and possibly larger than @xmath19 ) . |
6,653 | Suppose that you have an abstract for a scientific paper: we present a survey of interstellar o vi absorption in the large magellanic cloud ( lmc ) towards 70 lines of sight based on _ far ultraviolet spectroscopic explorer ( fuse ) _ observations .
the survey covers o vi absorption in a large number of objects in different environmental conditions of the lmc .
overall , a high abundance of o vi is present in active and inactive regions of the lmc with mean log n(o vi ) = 14.23 atoms @xmath0 .
there is no correlation observed between o vi absorption and emissions from the hot gas ( x - ray surface brightness ) or the warm gas ( h@xmath1 surface brightness ) .
o vi absorption in the lmc is patchy and the properties are similar to that of the milky way ( mw ) . in comparison to the small magellanic cloud ( smc ) , o vi is lower in abundance even though smc has a lower metallicity compared to the lmc and the mw .
we present observations in 10 superbubbles of the lmc of which we detect o vi absorption in 5 superbubbles for the first time and the superbubbles show an excess o vi absorption of about 40% compared to non - superbubble lines of sight .
we have also studied the properties of o vi absorption in the 30 doradus region .
even though o vi does not show any correlation with x - ray emission for the lmc , a good correlation between log n(o vi ) and x - ray surface brightness for 30 doradus region is present .
we also find that o vi abundance decreases with increasing distance from the star cluster r136 .
[ firstpage ] galaxies : ism ism : structure ism : atoms galaxies : individual : large magellanic cloud ultraviolet : ism .
And you have already written the first three sentences of the full article: the interstellar medium ( ism ) of the milky way ( mw ) and other galaxies is a complex mix of gas and dust .
the processes involved in maintaining the mass , energy , and ionization balance of the ism are not properly understood .
high resolution ultraviolet ( _ uv _ ) spectra provides information about these processes as many absorption lines of atoms , ions and molecules are present in the _ uv _ band of the electromagnetic spectrum , one of the most important of which is o@xmath2 ( o vi ) , a diagnostic of temperatures of about @xmath3 k @xcite ..
Please generate the next two sentences of the article | such temperatures are found at the interface of hot ( t @xmath4 k ) and warm ( t @xmath5 k ) ionized gas in the ism .
thus , o vi absorption lines at 1031.9 and 1037.6 are crucial diagnostics of the energetic processes of interface environments in the ism of galaxies |
6,654 | Suppose that you have an abstract for a scientific paper: in this paper we analyze least recently used ( lru ) caches operating under the shot noise requests model ( snm ) .
the snm was recently proposed in @xcite to better capture the main characteristics of today video on demand ( vod ) traffic .
we investigate the validity of che s approximation @xcite through an asymptotic analysis of the cache eviction time .
in particular , we provide a large deviation principle , a law of large numbers and a central limit theorem for the cache eviction time , as the cache size grows large .
finally , we derive upper and lower bounds for the hit " probability in tandem networks of caches under che s approximation . caching systems , performance evaluation , asymptotic analysis .
primary : 68m20 ; secondary : 60f10 , 60f05 . .
And you have already written the first three sentences of the full article: the design and the analysis of caching systems , a very traditional and widely studied topic in computer science , has recently drawn again attention by the networking research community .
this interest revival is mainly due to the important role that caches play today in the distribution of contents over the internet .
massive content delivery networks , indeed , represent the standard solution adopted by content and network providers to reach large populations of geographically distributed users in an effective way ..
Please generate the next two sentences of the article | mcdn allow providers to cache contents close to the users , achieving the twofold goal of reducing network traffic while minimizing the latency suffered by users .
unfortunately , the performance evaluation of caching systems is very hard , as the computational cost to analyze the behavior of a cache is exponential in both the cache size and the number of contents @xcite . |
6,655 | Suppose that you have an abstract for a scientific paper: in this work we consider @xmath0form fields in a @xmath1brane embedded in a @xmath2 space - time .
the membrane is generated by a domain wall in a randall - sundrum - like scenario .
we study conditions for localization of zero modes of these fields .
the expression agrees and generalizes the one found for the zero , one , two and three - forms in a @xmath3brane . by a generalization
we mean that our expression is valid for any form in an arbitrary dimension with codimension one .
we also point out that , even without the dilaton coupling , some form fields are localized in the membrane .
the massive modes are considered and the resonances are calculated using a numerical method .
we find that different spaces have identical resonance structures , which we call dual spaces of resonances(dsr ) . .
And you have already written the first three sentences of the full article: duality is a sort of symmetry that exists between two or more very special theories .
the remarkable fact about these kinds of symmetries is that when we make the duality transformations over the important fields , we change the regime of couplings in the theories involved . in other words ,
if we have a theory whose coupling constant is @xmath4 , it is possible to build another theory with coupling constant @xmath5 , i.e. , we can do strong coupling calculations in one model in perturbation approach if we change it by its dual ..
Please generate the next two sentences of the article | the most basic example is the duality between the sine - gordon model and the thirring model . in this case , the solitons of the first model are exchanged by the particles of the former @xcite .
another examples are the network of dualities relating the five superstring theories and eleven - dimensional m - theory @xcite . |
6,656 | Suppose that you have an abstract for a scientific paper: the gravitational radiation backreaction effects are considered in the lense - thirring approximation .
new methods for parameterizing the orbit and for averaging the instantaneous radiative losses are developed . to first order in the spin @xmath0 of the black hole , both in the absence and in the presence of gravitational radiation , a complete description of the test - particle orbit
is given .
this is achieved by two improvements over the existing descriptions .
first , by introducing new angle variables with a straightforward geometrical meaning .
second , by finding a new parametrization of a generic orbit , which assures that the integration over a radial period can be done in an especially simple way , by applying the residue theorem .
the instantaneous gravitational radiation losses of the system are computed using the formulation of _ blanchet , damour and iyer(1989)_. all losses are given both in terms of the dynamical constants of motion and the properly defined orbital elements @xmath1 and @xmath2 .
the radiative losses of the constants characterizing the lense - thirring motion , when suitably converted , are in agreement with earlier results of _ kidder , will and wiseman(1993 ) , ryan(1996 ) and shibata(1994)_. in addition , the radiative losses of two slowly changing orbital elements @xmath3 are given in order to complete the characterization of the orbit .
# 1@xmath4#1 .
And you have already written the first three sentences of the full article: the determination of the signal template of the radiating companion of a black hole is of great importance for the forthcoming interferometric gravitational observatories . an inspiralling neutron star or a several solar - mass black hole orbiting a massive black hole , as well as a particle constituent contributing to the radiation of the debris trapped by the black hole are notable examples of these companions . either is the case , one wants to describe the evolution of the orbit of a test particle in the neighborhood of a black hole under the influence of gravitational radiation backreaction . in a highly idealized picture ,
the orbit of the particle is a carter geodesic@xcite characterized by four constants of the motion , the energy , the total angular momentum , the rest - mass of the particle and the separation constant . in the spirit of perturbation theory , the radiation backreaction effects may be taken into account by evolving these constants of the motion , thus picturing the trajectory of the particle by a sequence of geodesic orbits .
the history of the orbit may be divided in separate epoches ..
Please generate the next two sentences of the article | for example , the first thing that happens to a particle trapped by a nonrotating _ schwarzschild _ black hole on an arbitrary but distant orbit is that it loses eccentricity due to radiation losses , and the radius shrinks until the close region of the last stable circular orbit is approached .
there one has to replace the adiabatic picture with one valid in the strong field regime . the description of a generic orbit in the strong field region of a spinning _ kerr _ |
6,657 | Suppose that you have an abstract for a scientific paper: we present a simple method for determining the exact noise power spectra in linear chemical reaction networks .
we apply the method to networks which are representative of biochemical processes such as gene expression and signal detection .
our results clarify how noise is transmitted by signal detection motifs , and indicate how to coarse - grain networks by the elimination of fast reactions . .
And you have already written the first three sentences of the full article: it is now clear that chemical noise can sometimes play a significant role in the functioning of biochemical reaction networks @xcite .
such noise is implicated in the spontaneous flipping of genetic switches @xcite , and has been shown to have an adverse effect on the functioning of a synthetic chemical oscillator @xcite . in some circumstances
it has also been argued that noise can have a beneficial effect , for example in stochastic focusing @xcite ..
Please generate the next two sentences of the article | chemical noise in reaction networks can be characterised by the root mean square ( rms ) deviation of number of molecules from the mean .
noise is important if the rms deviation is a significant fraction of the mean . |
6,658 | Suppose that you have an abstract for a scientific paper: we derive a family of post - newtonian ( pn ) dedekind ellipsoids to first order .
they describe non - axially symmetric , homogeneous , and rotating figures of equilibrium .
the sequence of the newtonian dedekind ellipsoids allows for an axially symmetric limit in which a uniformly rotating maclaurin spheroid is recovered . however , the approach taken by @xcite to find the pn dedekind ellipsoids excludes such a limit . in @xcite
, we considered an extension to their work that permits a limit of 1 pn maclaurin ellipsoids . here
we further detail the sequence and demonstrate that a choice of parameters exists with which the singularity formerly found in @xcite along the sequence of pn dedekind ellipsoids is removed . .
And you have already written the first three sentences of the full article: the modeling of equilibrium figures is one major goal in astrophysics . in the case of compact objects ,
relativistic effects become relevant and it is necessary to treat them using general relativity . exact solutions in this field
are rare , and one is generally required to resort to approximation or numerical methods . a detailed treatment of these issues can be found in meinel et al ..
Please generate the next two sentences of the article | ( 2008 ) , friedman & stergioulas ( 2013 ) , where the latter includes important discussions of stability .
although it is the numerical approach , with its many possibilities for taking into account the properties of matter , that provides the most accurate means of modeling real astrophysical objects , it is essential that one pursues analytic methods in order to gain deeper insight into the nature of the theory of relativity and how it differs from newtonian theory . |
6,659 | Suppose that you have an abstract for a scientific paper: sphere decoding ( sd ) of polar codes is an efficient method to achieve the error performance of maximum likelihood ( ml ) decoding .
but the complexity of the conventional sphere decoder is still high , where the candidates in a target sphere are enumerated and the radius is decreased gradually until no available candidate is in the sphere . in order to reduce the complexity of sd , a stack sd ( ssd ) algorithm with an efficient enumeration is proposed in this paper .
based on a novel path metric , ssd can effectively narrow the search range when enumerating the candidates within a sphere .
the proposed metric follows an exact ml rule and takes the full usage of the whole received sequence .
furthermore , another very simple metric is provided as an approximation of the ml metric in the high signal - to - noise ratio regime . for short polar codes ,
simulation results over the additive white gaussian noise channels show that the complexity of ssd based on the proposed metrics is up to @xmath0 times lower than that of the conventional sd .
polar codes , successive cancellation decoding , sphere decoding , maximum likelihood rule . .
And you have already written the first three sentences of the full article: s a major breakthrough in coding theory , polar codes , introduced by arikan in @xcite , can asymptotically achieve the channel capacity of binary symmetric channels using a successive cancellation ( sc ) decoder with a complexity of @xmath1 , where @xmath2 , is the code block length .
later , some improved algorithms of sc are described in @xcite @xcite @xcite . yet still
the performance of these decoders is inferior to that of the maximum likelihood ( ml ) decoder , or at least can not be proven to achieve the ml performance ..
Please generate the next two sentences of the article | an ml decoder of polar codes is implemented by viterbi algorithm in @xcite ; but the decoding complexity grows exponentially with the code length . inspired by the sphere decoding ( sd ) for space - time block codes @xcite @xcite , an sd algorithm of polar codes is proposed in @xcite to perform ml decoding with a cubic complexity .
the sphere decoder configures an initial target radius , and the candidates in the sphere are enumerated . |
6,660 | Suppose that you have an abstract for a scientific paper: we present a novel _ ab initio _
approach for computing intramolecular charge and energy transfer rates based upon a projection operator scheme that parses out specific internal nuclear motions that accompany the electronic transition .
our approach concentrates the coupling between the electronic and nuclear degrees of freedom into a small number of reduced harmonic modes that can be written as linear combinations of the vibrational normal modes of the molecular system about a given electronic minima . using a time - convolutionless master - equation approach , parameterized by accurate quantum - chemical methods , we benchmark the approach against experimental results and predictions from marcus theory for triplet energy transfer for a series of donor - bridge - acceptor systems .
we find that using only a single reduced mode termed the `` primary '' mode , one obtains an accurate evaluation of the golden - rule rate constant and insight into the nuclear motions responsible for coupling the initial and final electronic states .
we demonstrate the utility of the approach by computing the inelastic electronic transition rates in a model donor - bridge - acceptor complex that has been experimentally shown that its exciton transfer pathway can be radically modified by mode - specific infrared excitation of its vibrational mode . .
And you have already written the first three sentences of the full article: energy and electronic transport plays a central role in a wide range of chemical and biological systems .
it is the fundamental mechanism for transporting the energy of an absorbed photon to a reaction center in light harvesting systems and for initiating a wide range of photo - induced chemical processes , including vision , dna mutation , and pigmentation .
the seminal model for calculating electron transfer rates was developed by marcus in the 1950s@xcite ..
Please generate the next two sentences of the article | @xmath0 where @xmath1 is energy required to reorganize the environment following the transfer of an electron from donor to acceptor .
and @xmath2 is the driving force for the reaction , as illustrated in fig . |
6,661 | Suppose that you have an abstract for a scientific paper: we study the deterministic effects of raman - induced crosstalk in amplified wavelength division multiplexing ( wdm ) optical fiber transmission lines .
we show that the dynamics of pulse amplitudes in an @xmath0-channel transmission system is described by an @xmath0-dimensional predator - prey model .
we find the equilibrium states with non - zero amplitudes and prove their stability by obtaining the lyapunov function .
the stability is independent of the exact details of the approximation for the raman gain curve .
furthermore , we investigate the impact of cross phase modulation and raman self and cross frequency shifts on the dynamics and establish the stability of the equilibrium state with respect to these perturbations .
our results provide a quantitative explanation for the robustness of differential - phase - shift - keyed wdm transmission against raman crosstalk effects . .
And you have already written the first three sentences of the full article: one of the important nonlinear processes affecting pulse propagation in massive wavelength division multiplexing ( wdm ) optical fiber communication systems is due to inter - pulse raman - induced crosstalk @xcite . in this process , which takes place during collisions between pulses from different frequency channels ( interchannel collisions ) , energy is transferred from high - frequency pulses to low - frequency pulses .
it is known that the magnitude of the raman - induced energy exchange in a single interchannel collision is independent of the frequency difference between the channels .
consequently , the magnitude of the cumulative energy shifts for a given pulse grows with the square of the number of channels , a result that is valid for linear transmission @xcite , conventional soliton transmission @xcite , and strongly dispersion - managed ( dm ) soliton transmission @xcite ..
Please generate the next two sentences of the article | therefore , in a 100-channel system , for example , the raman crosstalk effects can be larger by a factor of @xmath1 compared with a two - channel system operating at the same bit rate per channel .
early studies of raman crosstalk in wdm transmission focused on the dependence of the energy shifts on the total number of channels @xcite , as well as on the impact of energy depletion @xcite and group velocity dispersion @xcite on the dynamics . later on attention turned to the combined effects of raman crosstalk and bit - pattern randomness in the on - off - keying ( ook ) transmission scheme , and it was found that the probability density function ( pdf ) of the pulse amplitudes is lognormal @xcite . |
6,662 | Suppose that you have an abstract for a scientific paper: a new iterative method for non - lte multilevel polarized radiative transfer in hydrogen lines is presented .
iterative methods ( such as the jacobi method ) tend to damp out high - frequency components of the error fast , but converges poorly due to slow reduction of low - frequency components .
the idea is to use a set of differently coarsed grids to reduce both the short- and long - period errors .
this leads to the so - called multigrid ( mg ) methods . for the grid of @xmath0 spatial points , the number of iterations required to solve a non - lte transfer problem is of the order of @xmath1
this fact could be of great importance for problems with fine structure and for multi - dimensional models .
the efficiency of the so - called standard mg iteration in comparison to jacobi iteration is shown .
the formalism of density matrix is applied to the demonstrative example of 1d , semi - infinite , non - magnetic , 3-principal level hydrogen atmospheric model .
the effect of depolarizing collisions with thermal electrons is taken into account as well as general treatment of overlapping profiles . .
And you have already written the first three sentences of the full article: in this paper we briefly discuss the usage of multigrid ( mg ) iteration schemes to solve the non - lte problem of the 2nd kind as defined by @xcite .
the era of extensive development of mg methods started in 1970 s by the work of @xcite .
several steps in using mg methods applied to radiative transfer were made by @xcite , @xcite , and @xcite ..
Please generate the next two sentences of the article | these authors showed that this technique leads to a great improvement of the convergence rate .
this paper demonstrates how to apply these methods to a more general solution of polarized radiative transfer with realistic multilevel atomic models and complicated structure of overlapping lines . |
6,663 | Suppose that you have an abstract for a scientific paper: we study the effect of nuclear reaction on a thin , axisymmetric , differentially rotating , inviscid , steady accretion flow around a black hole from an analytical point of view .
we find that for most of the reasonable disk parameters , when @xmath0-reaction , dissociation of deuterium and helium are taken into account , the _ transonic _ region of the disk continues to have the inner sonic point and if the temperature of the flow at the injection point could be raised ( by say , some heating processes ) the flow would to pass through this inner sonic point .
otherwise , the flow may be unstable .
we use the sonic point analysis to study the solution . in the rest of the disk parameters
the inner sonic point is absent altogether and the flow will definitely be unstable . psfig.tex .
And you have already written the first three sentences of the full article: black hole accretion flow can reach a temperature of about @xmath1k if no cooling processes are included . here
, @xmath2 is the gravitational radius of a black hole , @xmath3 is the boltzmann constant , @xmath4 is the gravitational constant , @xmath5 is the mass of the black hole , @xmath6 is the mass of the proton and @xmath7 is the velocity of light . in a realistic flow ,
the temperature is smaller ..
Please generate the next two sentences of the article | for instance , in a shakura - sunyaev ( 1973 ) keplerian disk , the temperature becomes close to a few times @xmath8k . in a two - temperature transonic flow
, the ions may remain hot ( @xmath9k ) while the electrons may be cooler ( ( @xmath10k ) depending on accretion rate of the keplerian and sub - keplerian components ( colpi , maraschi & treves , 1984 ; chakrabarti & titarchuk , 1995 ) . |
6,664 | Suppose that you have an abstract for a scientific paper: we demonstrate that resonant shattering flares can occur during close passages of neutron stars in eccentric or hyperbolic encounters .
we provide updated estimates for the rate of close encounters of compact objects in dense stellar environments , which we find are substantially lower than given in previous works .
while such occurrences are rare , we show that shattering flares can provide a strong electromagnetic counterpart to the gravitational wave bursts expected from such encounters , allowing triggered searches for these events to occur . .
And you have already written the first three sentences of the full article: the major expected source of gravitational waves for the advanced ligo @xcite class of gravitational wave detectors are compact binary systems .
the long inspiral signals from such binaries will be detected by matched filtering with theoretical templates , which allows signal - to - noise to be built up over many orbits @xcite .
gravitational waves ( gws ) are also emitted as broad band bursts when compact objects undergo close passages , either during single parabolic or hyperbolic encounters , or during repeated eccentric encounters @xcite ..
Please generate the next two sentences of the article | such events occur rarely , but are more likely in dense stellar environments , such as globular clusters or galactic nuclear clusters .
the brief duration of such bursts do not allow a large integrated buildup of signal to noise , and they may be difficult to detect without some electromagnetic trigger . |
6,665 | Suppose that you have an abstract for a scientific paper: we present a preliminary analysis of the photon beam asymmetry observable ( @xmath0 ) from the photoproduction reaction channel @xmath1 .
this new data was obtained using the near-@xmath2 cebaf large acceptance spectrometer ( clas ) at jefferson laboratory , usa , employing a linearly polarised photon beam with an energy range 1.1 - 2.3 gev .
the measurement will provide new data to address the poorly established neutron excitation spectrum and will greatly expand the sparse world data - set both in energy and angle . .
And you have already written the first three sentences of the full article: despite decades of study our knowledge of the fundamental resonance spectrum of the nucleon is still incomplete . many resonance properties are uncertain and some resonances predicted to exist are yet to be observed .
most predictions of the resonance spectrum are based on phenomenological models , such as the constituent quark model or the di - quark model , but lattice predictions directly from quantum chromodynamics ( qcd ) are fast developing . experimental differentiation between these theoretical approaches based on the presently established resonance spectrum
is , however , inconclusive due to the many `` missing '' and poorly established resonances . insufficient accuracy and quantity of observables.
Please generate the next two sentences of the article | obtained results in too many ambiguities and the famous case of the missing resonances in baryon spectroscopy @xcite .
have they not yet been observed or are they simply not there ? a promising tool to learn about the resonance spectrum is the photoproduction of pions from nucleon targets , as many resonances are expected to couple to the pion decay channel and polarised real photons , with a well - understood electromagnetic interaction , provide a powerful probe . in such pseudo - scalar meson production reactions |
6,666 | Suppose that you have an abstract for a scientific paper: we present a normal form for travelling waves in one - dimensional excitable media in form of a differential delay equation . the normal form is built around the well - known saddle - node bifurcation generically present in excitable media .
finite wavelength effects are captured by a delay .
the normal form describes the behaviour of single pulses in a periodic domain and also the richer behaviour of wave trains .
the normal form exhibits a symmetry preserving hopf bifurcation which may coalesce with the saddle - node in a bogdanov - takens point , and a symmetry breaking spatially inhomogeneous pitchfork bifurcation .
we verify the existence of these bifurcations in numerical simulations .
the parameters of the normal form are determined and its predictions are tested against numerical simulations of partial differential equation models of excitable media with good agreement .
* excitable media are often found in biological and chemical systems .
examples of excitable media include electrical waves in cardiac and nerval tissue @xcite , camp waves in slime mold aggregation @xcite and intracellular calcium waves @xcite .
excitable media support localized pulses and periodic wave trains . in 2 dimensions rotating vortices ( or spirals ) and in 3 dimensions scroll waves @xcite
are possible .
the critical behaviour of pulses , wave trains and spirals , i.e. propagation failure , is often associated with clinical situations .
the study of spiral waves is particularly important as they are believed to be responsible for pathological cardiac arrhythmias @xcite .
spiral waves may be created in the heart through inhomogeneities in the cardiac tissue .
some aspects of spiral wave break up can be studied by looking at a one - dimensional slice of a spiral i.e. at a one - dimensional wave train @xcite .
+ we investigate critical behaviour relating to one - dimensional wave propagation .
we develop a normal form which allows us to study the bifurcation behaviour of critical waves . in....
And you have already written the first three sentences of the full article: many chemical and biological systems exhibit excitability . in small ( zero - dimensional ) geometry
they show threshold behaviour , i.e. small perturbations immediately decay , whereas sufficiently large perturbations decay only after a large excursion .
this behaviour is crucial for the electrical activation of cardiac tissue or the propagation of nerve pulses where activation should only be possible after a sufficiently large stimulus ..
Please generate the next two sentences of the article | moreover , the decay to the rest state allows for the medium to be repeatedly activated - also crucial for the physiological functioning of the heart and the nervous system .
one - dimensional excitable media support travelling pulses , or rather , periodic wave trains ranging in wavelength @xmath0 from the localized limit @xmath1 to a minimal value @xmath2 below which propagation fails . |
6,667 | Suppose that you have an abstract for a scientific paper: we propose a simple spectral model for the seyfert 1 galaxy mcg-6 - 30 - 15 that can explain most of the 1 40 kev spectral variation by change of the partial covering fraction , similar to the one proposed by miller et al .
( 2008 ) .
our spectral model is composed of three continuum components ; ( 1 ) a direct power - law component , ( 2 ) a heavily absorbed power - law component by mildly ionized intervening matter , and ( 3 ) a cold disk reflection component far from the black hole with moderate solid - angle ( @xmath0 ) accompanying a narrow fluorescent iron line .
the first two components are affected by the surrounding highly ionized thin absorber with @xmath1@xmath2 and @xmath3 .
the heavy absorber in the second component is fragmented into many clouds , each of which is composed of radial zones with different ionization states and column densities , the main body ( @xmath4@xmath2 , @xmath5 ) , the envelope ( @xmath6@xmath2 , @xmath7 ) and presumably a completely opaque core .
these parameters of the ionized absorbers , as well as the intrinsic spectral shape of the x - ray source , are unchanged at all .
the central x - ray source is moderately extended , and its luminosity is not significantly variable .
the observed flux and spectral variations are mostly explained by variation of the geometrical partial covering fraction of the central source from 0 ( uncovered ) to @xmath80.63 by the intervening ionized clouds in the line of sight .
the ionized iron k - edge of the heavily absorbed component explains most of the seemingly broad line - like feature , a well - known spectral characteristic of mcg-6 - 30 - 15 .
the direct component and the absorbed component anti - correlate , cancelling their variations each other , so that the fractional spectral variation becomes the minimum at the iron energy band ; another observational characteristic of mcg-6 - 30 - 15 is thus explained . .
And you have already written the first three sentences of the full article: the seyfert 1 galaxy mcg-6 - 30 - 15 is the primary `` disk - line '' target , in which a relativistically broadened iron k - emission line is suggested to originate in the innermost region of the accretion disk around the black hole ( e.g. , tanaka et al .
mcg-6 - 30 - 15 is also known to exhibit characteristic x - ray spectral variations ; inoue & matsumoto ( 2001 , 2003 ) , fabian et al .
( 2002 ) and matsumoto et al ..
Please generate the next two sentences of the article | ( 2003 ) reported significantly small variability in the iron line energy band of mcg 6 - 30 - 15 .
it is found that the energy - dependent root mean square ( rms ) variability is suppressed around the iron line energy , particularly in longer timescales . |
6,668 | Suppose that you have an abstract for a scientific paper: we describe an efficient dqc1-algorithm to quantify the amount of geometric quantum discord present in the output state of a dqc1 computation .
dqc1 is a model of computation that utilizes separable states to solve a problem with no known efficient classical algorithm and is known to contain quantum correlations as measured by the discord . for the general case of a @xmath0-qubit dqc1-state we provide an analytical expression for the geometric quantum discord and find that its typical ( and maximum ) value decreases exponentially with @xmath1 .
this is in contrast to the standard quantum discord whose value for typical dqc1-states is known to be independent of @xmath1 .
we experimentally demonstrate the proposed algorithm on a four - qubit liquid - state nuclear magnetic resonance quantum information processor . in the special case of a two - qubit dqc1 model
, we also provide an expression for the quantum discord that only requires the outcome of the dqc1 algorithm . since its inception in 2001 , quantum discord ( qd ) @xcite and related measures
have been used to quantify the amount of non - classical correlations in a physical system .
in addition to quantifying the most well known quantum correlations of entanglement , they also capture the quantum correlations that exist in separable states .
discord measures are based on the premise that if a measurement on one part of a bipartite state disturbs the total state , there must be correlations stronger than what is found in the classical world .
quantum discord has been studied extensively over the past few years , from operational definitions @xcite , to witnesses @xcite and analytical expressions for specific sets of states @xcite .
however , it is generally difficult to calculate as it requires both full state knowledge and an optimization over all projective measurements of a subsystem . even in the simple case of two qubits ,
a general closed form expression does not exist .
the measure of geometric quantum discord (....
And you have already written the first three sentences of the full article: quantum discord is the most well - known measure of non - classical correlations and is thought to differentiate quantum and classical systems @xcite .
it is defined as the minimum difference between two classically equivalent formulations of the mutual information between subsystems @xmath2 and @xmath3 , @xmath4 and @xmath5 , where @xmath6 is the shannon entropy when @xmath7 is described by a classical probability distribution , and is the von neumann entropy when @xmath7 describes a quantum system . in the quantum case
the conditional entropy depends on the measurement basis , @xmath8 , where @xmath9 is a complete set of orthonormal projectors on @xmath10 such that @xmath11 , @xmath12 is the probability of observing outcome @xmath13 on system @xmath2 , and @xmath14/p_k$ ] is the state of system @xmath3 conditional on the measurement of system @xmath2 returning measurement outcome @xmath13 ..
Please generate the next two sentences of the article | the quantum discord , @xmath15 , thus reduces to @xmath16 where @xmath17 is the reduced density matrix of system @xmath2 . in order to calculate this quantity ,
full state knowledge is required in addition to a minimization over all possible projective measurements on subsystem @xmath2 . while there is no analytical expression for the quantum discord of a general state , the discord for various sets of two - qubit states |
6,669 | Suppose that you have an abstract for a scientific paper: we report that two rotated layers of blue phosphorene behave as a direct band gap semiconductor .
the optical spectrum shows absorption peaks in the visible region of the spectrum and in addition the energy of these peaks can be tuned with the rotational angle .
these findings makes twisted bilayer blue phosphorene a strong candidate as a solar cell or photodetection device .
our results are based on ab initio calculations of several rotated blue phosphorene layers .
blue phosphorene , bilayer , rotated , ab initio .
And you have already written the first three sentences of the full article: starting with the synthesis of graphene@xcite a new era of two dimensional ( 2d ) materials have emerged . among them
we find hexagonal boron nitride , molybdenum disulphide , dichalcogenides , layered oxides@xcite , silicene and more recently one layer of black phosphorous ( phosphorene)@xcite . these materials , in general , have diverse properties , but some of them are semiconductors , a dream of stacking them in a certain order has become a reality resulting in structures with desired properties@xcite .
it has been possible not only to stack them in certain order but also rotate layers as well to exploit certain properties that twisted structures posses@xcite ..
Please generate the next two sentences of the article | for instance in twisted bilayer graphene a plethora of interesting angle dependent properties have been found @xcite .
single layer phosphorene is a direct band gap semiconductor ( 2 @xmath0 ) . |
6,670 | Suppose that you have an abstract for a scientific paper: the description logic @xmath0 has recently drawn considerable attention since , on the one hand , important inference problems such as the subsumption problem are polynomial . on the other hand , @xmath0 is used to define large biomedical ontologies .
unification in description logics has been proposed as a novel inference service that can , for example , be used to detect redundancies in ontologies .
the main result of this paper is that unification in @xmath0 is decidable .
more precisely , @xmath0-unification is np - complete , and thus has the same complexity as @xmath0-matching .
we also show that , w.r.t .
the unification type , @xmath0 is less well - behaved : it is of type zero , which in particular implies that there are unification problems that have no finite complete set of unifiers . .
And you have already written the first three sentences of the full article: description logics ( dls ) @xcite are a family of logic - based knowledge representation formalisms , which can be used to represent the conceptual knowledge of an application domain in a structured and formally well - understood way .
they are employed in various application domains , such as natural language processing , configuration of technical systems , databases , and biomedical ontologies , but their most notable success so far is the adoption of the dl - based language owl @xcite as standard ontology language for the semantic web . in dls
, concepts are formally described by _.
Please generate the next two sentences of the article | concept terms _ , i.e. , expressions that are built from concept names ( unary predicates ) and role names ( binary predicates ) using concept constructors .
the expressivity of a particular dl is determined by which concept constructors are available in it . from a semantic point of view |
6,671 | Suppose that you have an abstract for a scientific paper: spectral properties of the two - dimensional bose - hubbard model , which emulates ultracold gases of atoms confined in optical lattices , are investigated by means of the variational cluster approach .
the phase boundary of the quantum phase transition from mott phase to superfluid phase is calculated and compared to recent work . moreover the single - particle spectral functions in both the first and the second mott lobe are presented and the corresponding densities of states and momentum distributions are evaluated . a qualitatively similar intensity distribution of the spectral weight can be observed for spectral functions in the first and the second mott lobe . .
And you have already written the first three sentences of the full article: pioneering experiments on ultracold gases of atoms trapped in optical lattices allowed for a direct observation of quantum many - body phenomena , such as the quantum phase transition from mott phase to superfluid phase.@xcite optical lattices are realized by counterpropagating laser beams , which form a periodic potential.@xcite the bosonic particles located on the optical lattice gain kinetic energy when tunneling through the potential wells of neighboring sites of the periodic potential and they exhibit a repulsive interaction when a lattice site is occupied by more than one atom .
a condensate of ultracold atoms can be driven from superfluid phase to mott phase by gradually increasing the intensity of the laser beams .
the potential wells of the optical lattice are shallow for low laser - beam intensity ..
Please generate the next two sentences of the article | thus the bosonic particles can overcome the barrier easily and are delocalized on the whole lattice .
however , for large intensity of the laser beams the potential wells are deep and there is little probability for the atoms to tunnel from one lattice site to another . |
6,672 | Suppose that you have an abstract for a scientific paper: star - forming disc galaxies such as the milky way need to accrete @xmath0 1 @xmath1 of gas each year to sustain their star formation .
this gas accretion is likely to come from the cooling of the hot corona , however it is still not clear how this process can take place .
we present simulations supporting the idea that this cooling and the subsequent accretion are caused by the passage of cold galactic - fountain clouds through the hot corona .
the kelvin - helmholtz instability strips gas from these clouds and the stripped gas causes coronal gas to condense in the cloud s wake . for likely parameters of the galactic corona and of typical fountain clouds we obtain a global accretion rate of the order of that required to feed the star formation . address = dipartimento di astronomia , universit di bologna , via ranzani 1 , 40127 bologna , italy .
address = rudolf peierls centre for theoretical physics , oxford university , keble road , oxford ox1 3np , uk .
address = dipartimento di astronomia , universit di bologna , via ranzani 1 , 40127 bologna , italy .
address = dipartimento di astronomia , universit di bologna , via ranzani 1 , 40127 bologna , italy .
address = dipartimento di astronomia , universit di bologna , via ranzani 1 , 40127 bologna , italy .
address = inaf - osservatorio astronomico di bologna , via ranzani 1 , 40127 , bologna , italy . .
And you have already written the first three sentences of the full article: star - forming disc galaxies like the milky way must accrete @xmath0 1 @xmath2 of fresh gas each year ( see * ? ? ? * and references therein ) and have built their discs gradually over the last 10 gyr ( e.g. * ? ? ?
a central question is the origin of the accreted gas and how this gas reaches the thin disc whitin which the process of star formation takes place .
the virial - temperature corona , in which disc galaxies are embedded , is the only reservoir of baryons capable of sustaining an accretion rate of @xmath3 for a hubble time ..
Please generate the next two sentences of the article | we present the results of a set of grid - based hydrodynamical simulations supporting the idea that the gas needed by the disc to form stars is drawn from this corona .
coronae of disc galaxies are similar in many respects to the hot atmospheres of giant elliptical galaxies and galaxy clusters , but with lower gas temperature and density ( e.g. * ? ? ? |
6,673 | Suppose that you have an abstract for a scientific paper: we develop a holomorphic functional calculus for ( multivalued linear ) operators on locally convex vector spaces .
this includes the case of fractional powers along lipschitz curves . .
And you have already written the first three sentences of the full article: if @xmath0 is a not everywhere defined operator on a locally convex vector space @xmath1 and @xmath2 is a lipschitz curve system on the riemann sphere then @xmath3 if @xmath4 and the resolvent operators of @xmath0 with poles from @xmath2 applied @xmath5 times to @xmath6 give a continuous function on @xmath7 . the slowly growing holomorphic functions on the complement of the lipschitz curve system @xmath2 form the algebra @xmath8 .
this algebra has a natural filtration : @xmath9 if @xmath10 is a superposition of rational functions with a pole in @xmath2 with multiplicity at most @xmath5 . in case
@xmath11 it means that @xmath12 where @xmath13 are finite borel measures on @xmath2 ..
Please generate the next two sentences of the article | having such representations we may define the operator @xmath14 on @xmath15 if @xmath9 .
we do that by substituting @xmath0 into @xmath16 formally . in the special case above @xmath17 the objective of this paper |
6,674 | Suppose that you have an abstract for a scientific paper: the effects of spatial confinements and smooth cutoffs of the waiting time distribution in continuous - time random walks ( ctrws ) are studied analytically .
we also investigate dependences of ergodic properties on initial ensembles ( i.e. , distributions of the first waiting time ) . here
, we consider two ensembles : the equilibrium and a typical non - equilibrium ensembles . for both ensembles
, it is shown that the time - averaged mean square displacement ( tamsd ) exhibits a crossover from normal to anomalous diffusion due to the spacial confinement and this crossover does not vanish even in the long measurement time limit . moreover , for the non - equilibrium ensemble , we show that the probability density function of the diffusion constant of tamsd follows the transient mittag - leffler distribution , and that scatter in the tamsd shows a clear transition from weak ergodicity breaking ( an irreproducible regime ) to ordinary ergodic behavior ( a reproducible regime ) as the measurement time increases .
this convergence to ordinary ergodicity requires a long measurement time compared to common distributions such as the exponential distribution ; in other words , the weak ergodicity breaking persists for a long time . in addition , it is shown that , besides the tamsd , a class of observables also exhibits this slow convergence to ergodicity .
we also point out that , even though the system with the equilibrium initial ensemble shows no aging , its behavior is quite similar to that for the non - equilibrium ensemble . .
And you have already written the first three sentences of the full article: recently , slow anomalous diffusion , which is defined by the sublinear dependence of the mean square displacement ( msd ) on time , has been found in various phenomena including lipid granules diffusing in living fission yeast cells @xcite , colloidal particles diffusing on sticky surfaces @xcite and in networks of entangled actin filaments @xcite , mrna molecules diffusing in _ e. coli _
@xcite , chromosomal loci diffusing in bacteria @xcite , telomeres diffusing in nuclei of eukaryote cells @xcite , and proteins diffusing in dextran solutions @xcite . to understand these phenomena , two types of slow diffusion models have been extensively studied so far : ( 1 ) continuous - time random walks ( ctrws ) @xcite and ( 2 ) the generalized langevin equation ( gle ) and fractional brownian motions ( fbms ) @xcite . for the ctrw model ,
if the probability density function ( pdf ) of the waiting times between jumps of the particle is a power law @xmath0 with @xmath1 , the ensemble - averaged msd ( eamsd ) shows slow diffusion @xcite : @xmath2 '' to stand for an asymptotic relation , i.e. , @xmath3 means @xmath4 for some asymptotic limit such as @xmath5 ..
Please generate the next two sentences of the article | on the other hand , we use `` @xmath6 '' to stand for a stricter asymptotic relation : @xmath7 means @xmath8 for some asymptotic limit .
furthermore , we use `` @xmath9 '' when @xmath10 is an approximation of @xmath11 , and `` @xmath12 '' when @xmath10 is proportional to @xmath11 , that is , they are not necessarily asymptotic relations . ] . typical origins of such power - law waiting times are complex energy landscapes @xcite and diffusion in inner degrees of freedom @xcite . similarly , eamsd of gle shows slow diffusion if the memory kernel @xmath13 decays algebraically @xmath14 with @xmath1 @xcite . |
6,675 | Suppose that you have an abstract for a scientific paper: background : : in the absence of accurate data on the free two - body hyperon - nucleon interaction , the spectra of hypernuclei can provide information on the details of the effective hyperon - nucleon interaction .
purpose : : to obtain a high - resolution spectrum for the @xmath0be@xmath1 reaction .
method : : electroproduction of the hypernucleus has been studied for the first time with sub - mev energy resolution in hall a at jefferson lab on a @xmath0be target . in order to increase the counting rate and to provide unambiguous kaon identification , two superconducting septum magnets and a ring imaging cherenkov detector ( rich )
were added to the hall a standard equipment .
results : : the cross section to low - lying states of is concentrated within 3 mev of the ground state and can be fitted with four peaks .
the positions of the doublets agree with theory while a disagreement could exist with respect to the relative strengths of the peaks in the doublets . a @xmath2 separation energy , @xmath3 , of 8.36 @xmath4 0.08 ( stat . ) @xmath4 0.08 ( syst . ) mev was measured , in agreement with an earlier experiment . , , .
And you have already written the first three sentences of the full article: hypernuclei provide a unique laboratory for the investigation of hadronic many - body systems with strangeness -1 and for the study of new aspects of the strong and weak interactions in nuclei . because direct measurements of hyperon - nucleon ( @xmath5 ) scattering at low energies are prohibited by the short hyperon lifetime ,
hypernuclear spectra are the only way to study this interaction .
thus , a unique opportunity to obtain this information is provided by observing the fine structure of hypernuclei caused by the specific spin - dependence of the hyperon - nucleon interaction ..
Please generate the next two sentences of the article | such characteristics are realized in practice only in @xmath2 hypernuclei and are hardly seen in other hypernuclei .
thus the spectroscopy of @xmath2 hypernuclei has a unique value in strangeness nuclear physics . in the past , |
6,676 | Suppose that you have an abstract for a scientific paper: we establish a maximin characterisation of the linear escape rate of the orbits of a non - expansive mapping on a complete ( hemi-)metric space , under a mild form of busemann s non - positive curvature condition ( we require a distinguished family of geodesics with a common origin to satisfy a convexity inequality ) .
this characterisation , which involves horofunctions , generalises the collatz - wielandt characterisation of the spectral radius of a non - negative matrix .
it yields as corollaries a theorem of kohlberg and neyman ( 1981 ) , concerning non - expansive maps in banach spaces , a variant of a denjoy - wolff type theorem of karlsson ( 2001 ) , together with a refinement of a theorem of gunawardena and walsh ( 2003 ) , concerning order - preserving positively homogeneous self - maps of symmetric cones .
an application to zero - sum stochastic games is also given . .
And you have already written the first three sentences of the full article: a self - map @xmath0 of a metric space @xmath1 is _ non - expansive _ if @xmath2 .
a general problem consists in studying the asymptotic behaviour of the orbits of @xmath0 .
this is motivated in particular by the celebrated theorem of denjoy and wolff @xcite on the iteration of holomorphic self - maps of the unit disk ( these maps are non - expansive in poincare s metric ) ..
Please generate the next two sentences of the article | other motivations arise from the cases of non - expansive self - maps of banach spaces and of self - maps of cones that are non - expansive in hilbert s , thompson s or riemannian metric , which have received a considerable attention , due in particular to applications in game theory @xcite , discrete event systems @xcite , quadratic optimal control or filtering @xcite , and non - linear perron - frobenius theory @xcite .
several denjoy - wolff type results , either in the setting of metric spaces , or concerning the special case of cones have appeared , see in particular @xcite . |
6,677 | Suppose that you have an abstract for a scientific paper: we present results from a lattice study of the semileptonic decay @xmath0 .
we use @xmath1 improved quenched lattices of the milc collaboration , with lattice spacing @xmath2 fm . for the valence quarks ,
the tadpole - improved clover action is used , with the fermilab method employed for the heavy quarks .
form factors are extracted from the vector as well as the axial - vector part of the current . .
And you have already written the first three sentences of the full article: current knowledge of the ckm matrix element @xmath3 is derived from the mesonic decays @xmath4 or @xmath5 .
experimental knowledge of the @xmath6 semileptonic decay can lead to an independent estimate of @xmath3 if the effect of the strong interaction in the decay are understood , _
e.g. _ , via lattice qcd ..
Please generate the next two sentences of the article | a first lattice study of the baryonic semileptonic decay was performed by the ukqcd collaboration @xcite .
we report our initial results for the dominant form factors of this decay . |
6,678 | Suppose that you have an abstract for a scientific paper: in paper iii of our series @xmath0a uniform analysis of the ly-@xmath1 forest at @xmath2 " , we presented a set of 270 quasar spectra from the archives of the faint object spectrograph ( fos ) on the hubble space telescope ( hst ) .
a total of 151 of these spectra , yielding 906 lines , are suitable for using the proximity effect signature to measure @xmath3 , the mean intensity of the hydrogen - ionizing background radiation field , at low redshift . using a maximum likelihood technique and the best estimates possible for each qso s lyman limit flux and systemic redshift
, we find @xmath4 ergs s@xmath5 @xmath6 hz@xmath5 sr@xmath5 at @xmath7 .
this is in good agreement with the mean intensity expected from models of the background which incorporate only the known quasar population .
when the sample is divided into two subsamples , consisting of lines with @xmath8 and @xmath9 , the values of @xmath3 found are 6.5@xmath10 ergs s@xmath5 @xmath6 hz@xmath5 sr@xmath5 , and 1.0@xmath11 ergs s@xmath5 @xmath6 hz@xmath5 sr@xmath5 , respectively , indicating that the mean intensity of the background is evolving over the redshift range of this data set . relaxing the assumption that the spectral shapes of the sample spectra and the background are identical , the best fit hi photoionization rates are found to be @xmath12 s@xmath5 for all redshifts , and @xmath13 s@xmath5 and @xmath14 s@xmath5 for @xmath8 and @xmath9 , respectively . the inclusion of blazars , associated absorbers , or damped ly-@xmath1 absorbers , or the consideration of a @xmath15 cdm cosmology rather than one in which @xmath16 has no significant effect on the results .
the result obtained using radio loud objects is not significantly different from that found using radio quiet objects .
allowing for a variable equivalent width threshold gives a consistently larger value of @xmath3 than the constant threshold treatment , though this is found to be sensitive to the inclusion of a small number of weak lines near the qso emission redshifts .
....
And you have already written the first three sentences of the full article: the spectra of quasars show a @xmath0forest `` of absorption lines blueward of the ly-@xmath1 emission line ( lynds 1971 , sargent et al . 1980 , weymann , carswell , & smith 1981 ) .
observational and theoretical work in recent years has shown that most of this absorption can be attributed to neutral hydrogen in galaxies and large - scale structure along the line of sight ( cen et al .
1994 , lanzetta et al ..
Please generate the next two sentences of the article | 1995,1996 , zhang et al .
1995 , hernquist et al . |
6,679 | Suppose that you have an abstract for a scientific paper: in this work , inspired by the observation of charmoniumlike @xmath0 , we study the photoproduction of charged charmoniumlike @xmath0 with an effective lagrangian approach and the regge trajectories model .
the numerical results indicate that the reggeized treatment can lead to a lower total cross section of the @xmath0 photoproduction and the peak position of cross section was moved to the higher energy point when the reggeized treatment was added .
moreover , using the data from the compass experiment and presented theoretical predictions , an upper limit of the decay width of @xmath1 is estimated .
the relevant results not only shed light on the further experiment of searching for the charmoniumlike @xmath2 state via meson photoproduction , but also provide valuable informations for having a better comprehension of the nature of charmoniumlike @xmath2 state . .
And you have already written the first three sentences of the full article: as of now , most of hadrons can be well described by the classical constituent quark model in the picture of @xmath3 for mesons and @xmath4 for baryons . however , according to the quantum chromodynamics , the exotic states ( such as the multiquark states , molecule states etc . )
are also allowed to exist in our universe .
therefore , searching and explaining these exotic states arouse great interest among researchers ..
Please generate the next two sentences of the article | in the experiments , a series of charmoniumlike and bottomoniumlike states referred to @xmath5 have been observed belle03,lhc13,ba05,belle07,bes13,belle110,bes14,bes111,belle08,belleprd , belle100,lhc14,belle14,ab12,ia12,iab . especially , those charged @xmath6 states are even more exotic since they have a minimal quark content of @xmath7 ( @xmath8 ) or @xmath9 ( @xmath10 ) @xcite .
later , some neutral @xmath6 states ( including @xmath11 , @xmath12 and @xmath13 ) were reported by experiments @xcite , which provide important informations of confirming and understanding the exotic @xmath6 states . on theoretical aspects , |
6,680 | Suppose that you have an abstract for a scientific paper: we demonstrate an experiment which utilizes a sagnac interferometer to measure a change in optical frequency of 129 @xmath0 7 @xmath1 with only 2 mw of continuous wave , single mode input power .
we describe the measurement of a weak value and show how even higher frequency sensitivities may be obtained over a bandwidth of several nanometers .
this technique has many possible applications , such as precision relative frequency measurements and laser locking without the use of atomic lines . .
And you have already written the first three sentences of the full article: precision frequency measurements @xcite of a stabilized laser source are of great importance in the field of metrology @xcite as well as atomic , molecular @xcite and optical physics @xcite . here
we show that weak values @xcite in an optical deflection measurement experiment @xcite can produce frequency shift resolutions down to 129 @xmath0 7 @xmath1 with only 2 mw of continuous wave optical power . by performing a weak measurement of the deflection of an infrared laser source that has passed through a weakly dispersive prism , we are able to measure a change in optical frequency comparable to precision fabry - perot interferometers @xcite .
this technique is relatively simple , requiring only a few common optical components and operating at atmospheric pressure ..
Please generate the next two sentences of the article | additionally , we show that this technique has low noise over a large range of response frequencies , making it desirable for many applications such as doppler anemometry @xcite , tests of the isotropy of light propagation @xcite or laser locking without the use of high finesse fabry - perot interferometers @xcite or atomic lines .
first developed as a way to understand preselected and postselected quantum measurements and how they relate to time - reversal symmetry in quantum mechanics , the _ weak value _ |
6,681 | Suppose that you have an abstract for a scientific paper: laser induced thermal desorption of xe atoms into vacuum from a metal surface following the nano - second pulsed laser heating was investigated by the time - of - flight ( tof ) measurement .
the desorption flow was studied at a wide range of desorption flux by varying the initially prepared xe coverage @xmath0 ( 1 ml @xmath1 atoms / m@xmath2 ) . at @xmath3 ml , the tof of xe was well represented by a maxwell - boltzmann velocity distribution , which is in good agreement with thermal desorption followed by collision - free flow . at @xmath4 ml , the peak positions of the tof spectra were shifted towards the smaller values and became constant at large @xmath0 , which were well fitted with a shifted maxwell - boltzmann velocity distribution with a temperature @xmath5 and a stream velocity @xmath6 . with @xmath5 fixed at 165 k , @xmath6 was found to increase from 80 to 125 m/ s with increasing @xmath0 from 1.2 to 4 ml . at @xmath7
ml , the value of @xmath6 become constant at 125 m/ s. the converging feature of @xmath6 was found to be consistent with analytical predictions and simulated results based on the knudsen layer formation theory .
we found that the knudsen layer formation in laser desorption is completed at knudsen number kn @xmath8 . .
And you have already written the first three sentences of the full article: laser induced desorption of atoms and molecules from solid surfaces is a vital phenomenon to investigate fundamentals such as surface electronic structures and dynamics.@xcite besides , laser desorption is an essential technique for pulsed laser deposition used in thin film growth @xcite and mass spectrometry of protein employing matrix - assisted laser desorption ionization.@xcite when desorption flux is small , the velocity distribution of desorbed atoms is directly governed by the desorption mechanism .
when the desorption flux is large enough , on the other hand , the post - desorption collision between desorbed particles may become significant and modify the velocity distribution in the vicinity of the surface after the desorption .
manifestations of the collision effect in laser induced desorption have been reported both by experiments and simulations as the modifications of the angular and velocity distribution of desorbing atoms and molecules.@xcite cowin _.
Please generate the next two sentences of the article | _ investigated the angular dependence of the translational temperature of d@xmath9 desorbed from tungsten surfaces under a pulsed laser irradiation.@xcite the translational temperature of d@xmath9 desorbed in the surface normal direction was higher than those in oblique directions .
they attributed the variation of the translational temperature to the collision effect . |
6,682 | Suppose that you have an abstract for a scientific paper: tropical geometry is used to develop a new approach to the theory of discriminants and resultants in the sense of gelfand , kapranov and zelevinsky .
the tropical @xmath0-discriminant is the tropicalization of the dual variety of the projective toric variety given by an integer matrix @xmath0 .
this tropical algebraic variety is shown to coincide with the minkowski sum of the row space of @xmath0 and the tropicalization of the kernel of @xmath0 .
this leads to an explicit positive formula for all the extreme monomials of any @xmath0-discriminant . .
And you have already written the first three sentences of the full article: let @xmath0 be an integer @xmath1-matrix such that @xmath2 is in the row span of @xmath0 .
this defines a _ projective toric variety _
@xmath3 in @xmath4 ..
Please generate the next two sentences of the article | its _ dual variety _
@xmath5 is the closure in the projective space dual to @xmath4 of the set of hyperplanes that are tangent to @xmath3 at a regular point . the toric variety @xmath3 is called _ non - defective _ if its dual variety @xmath5 has codimension one . in this case , the _ |
6,683 | Suppose that you have an abstract for a scientific paper: the critical current density @xmath0 of k@xmath1fe@xmath2se@xmath3 single crystals can be enhanced by more than one order of magnitude , up to @xmath4 2.1@xmath510@xmath6 a/@xmath7 by post annealing and quenching technique .
a scaling analysis reveals the universal behavior of the normalized pinning force as a function of the reduced - field for all temperatures , indicating the presence of a single vortex pinning mechanism .
the main pinning sources are three dimensional ( 3d ) point - like normal cores .
the dominant vortex interaction with pinning centers is via spatial variations in critical temperature @xmath8 ( `` @xmath9 pinning '' ) . .
And you have already written the first three sentences of the full article: recently discovered iron - based superconductors@xcite induce great interest in scientific community because of rather high @xmath8 , proximity to the spin - density wave state and multiband nature of electronic transport.@xcite@xmath10@xcite however , these materials also encourage potential technical applications due to high upper critical fields @xmath11 and critical current densities @xmath12.@xcite@xmath10yang h in the family of iron - based superconductors , fech ( ch = s , se , and te , fech-11 type ) materials have the simplest crystal structure , nearly isotropic high @xmath13 and rather high @xmath12,@xcite@xmath14@xcite but their relatively low @xmath8 impedes prospects for applications .
superconducting @xmath8 was raised up to about 32 k in a@xmath1fe@xmath2se@xmath3 ( a = k , rb , cs , and tl , fech-122 type ) iron selenide superconductors with rather high @xmath13 ( @xmath4 56 t for @xmath15 at 1.6 k).@xcite@xmath14@xcite preliminary results indicate that the @xmath12 of k@xmath1fe@xmath2se@xmath3 is much lower when compared to iron arsenides or binary fech-11 type iron selenides.karpinski@xmath14@xcite@xmath14@xcite@xmath14@xcite@xmath10@xcite post annealing and quenching treatment can induce metallic and superconducting state in as - grown and insulating k@xmath1fe@xmath2se@xmath3 crystals,@xcite yet current carrying characteristics of such materials are not known . in this work , we report on the significant enhancement of critical current density in k@xmath1fe@xmath2se@xmath3 single crystals obtained via post - annealing and quenching process .
we also give detailed insight into the vortex pinning mechanism ..
Please generate the next two sentences of the article | main pinning sources are the 3d normal cores whereas dominant vortex interaction with pinning centers is via spatial variations in @xmath8 .
details of crystal growth and structure characterization were reported elsewhere.@xcite the as - grown crystals were sealed into pyrex tube under vacuum ( @xmath4 10@xmath16 pa ) . |
6,684 | Suppose that you have an abstract for a scientific paper: the anti - correlations between the equivalent widths of emission lines and the continuum luminosity in agns , known as the baldwin effect are well established for broad lines , but are less well studied for narrow lines . in this paper
we explore the baldwin effect of narrow emission lines over a wide range of ionization levels and critical densities using a large sample of broad - line , radio - quiet agns taken from sloan digital sky survey ( sdss ) data release 4 .
these type1 agns span three orders of magnitude in continuum luminosity .
we show that most narrow lines show a similar baldwin effect slope of about -0.2 while the significant deviations of the slopes for [ nii ] @xmath06583 , [ oii ] @xmath03727 , [ nev ] @xmath03425 , and the narrow component of h@xmath1 can be explained by the influence of metallicity , star - formation contamination and possibly by difference in the shape of the uv - optical continuum .
the slopes do not show any correlation with either the ionization potential or the critical density .
we show that a combination of 50% variations in continuum near 5100 and a log - normal distribution of observed luminosity can naturally reproduce a constant baldwin effect slope of -0.2 for all narrow lines .
the variations of the continuum could be due to variability , intrinsic anisotropic emission , or an inclination effect . .
And you have already written the first three sentences of the full article: the anti - correlation between the equivalent widths of broad emission lines and agn luminosity ( the `` baldwin effect '' ; hereinafter be ) was first discovered by baldwin ( 1977 ) for the civ @xmath01549 broad emission line in high redshift agns .
it was initially hoped to be able to use the effect to calibrate the agn luminosity to be able to use agns as cosmological standard candles ( baldwin et al .
1978 ) , but the large dispersion of this relationship rendered this impossible ( baldwin et al ..
Please generate the next two sentences of the article | 1989 ; zamorani et al . 1992 ) .
the be is now well established for nearly all broad emission lines and the slope of the be steepens with increasing ionization potential ( zheng & malkan 1993 ; dietrich et al . |
6,685 | Suppose that you have an abstract for a scientific paper: three bright molecular line sources in g333 have recently been shown to exhibit signatures of infall .
we describe a molecular line radiative transfer modelling process which is required to extract the infall signature from mopra and nanten2 data .
the observed line profiles differ greatly between individual sources but are reproduced well by variations upon a common unified model where the outflow viewing angle is the most significant difference between the sources .
the models and data together suggest that the observed properties of the high - mass star - forming regions such as infall , turbulence , and mass are consistent with scaled - up versions of the low - mass case with turbulent velocities that are supersonic and an order of magnitude larger than those found in low - mass star - forming regions . using detailed radiative transfer modeling ,
we show that the g333 cores are essentially undergoing a scaled - up version of low mass star formation .
this is an extension of earlier work in that the degree of infall and the chemical abundances are constrained by the rt modeling in a way that is not practical with a standard analysis of observational data .
we also find high velocity infall and high infall mass rates , possibly suggesting accelerated collapse due to external pressure
. molecular depletion due to freeze - out onto dust grains in central regions of the cores is suggested by low molecular abundances of several species .
strong evidence for a local enhancement of -bearing species towards the outflow cloud cores is discussed , consistent with the presence of shocks caused by the supersonic motions within them .
[ firstpage ] stars : formation ism : clouds ism : molecules ism : structure radio lines : ism . .
And you have already written the first three sentences of the full article: massive star formation must eventually differ substantially from low mass star formation because the outcomes are so different .
massive stars form in groups inside dense clusters of lower mass stars and whereas in low mass star formation , more isolated single stars or binary stars are formed .
both modes of star formation are initiated in cold molecular clouds so a key question is at what point of evolution do the two types of star formation diverge . for several decades ,.
Please generate the next two sentences of the article | high quality data have been available for nearby low mass star formation .
spatially resolved molecular line observations in many species and transitions can be readily obtained . by combining this data with radiative transfer codes , |
6,686 | Suppose that you have an abstract for a scientific paper: the large hadron collider is shown to have great scope for a light charged higgs discovery , in the context of the @xmath0-violating type - i two higgs doublet model .
this scenario with similar masses of @xmath1 and @xmath2 was suggested by the puzzling departure from charged current lepton universality found in the lep data . with the lightest neutral higgs mass set to @xmath3
, the charged - neutral higgs associated production mechanism can cause a significant excess in the @xmath4 events over a vast range of @xmath5 as long as the higgs mixing pattern avoids a few limiting cases .
thanks to the low @xmath1 mass , the charged higgs loop can play a striking role in neutral higgs decays into @xmath6 , thereby compensating for a suppressed gluon - gluon fusion rate .
the effect of scalar pseudo - scalar mixing on loop - induced higgs signals is also discussed . .
And you have already written the first three sentences of the full article: there are many motivations to introduce an extended higgs sector .
examples are , including obsolete ones , fine - tuning in the weak - scale higgs mass @xcite suggesting supersymmetry @xcite , @xmath0-violation @xcite , grand unification @xcite , extended gauge symmetry @xcite , strong @xmath0 problem @xcite , string theory @xcite , vacuum stability @xcite , light fermion mass / weak - scale hierarchy @xcite , fermion flavour structure @xcite , neutrino mass @xcite , dark matter ( see e.g. @xcite ) , cosmic rays @xcite , baryogenesis @xcite , inflation @xcite , novel collider phenomenology @xcite , as well as anomalies seen in precision ( see e.g. @xcite ) and accelerator ( see e.g. @xcite ) experiments . in this article , we entertain the possibility that an intriguing outcome from the lep experiment is in fact pointing to an extended higgs sector , which may be directly inspected at the large hadron collider ( lhc ) . specifically , we take as our framework the two higgs doublet model ( 2hdm ) of type - i with @xmath7 in the vicinity of the @xmath2-boson mass .
the two main points of this paper are the following ..
Please generate the next two sentences of the article | ( 1 ) the charged higgs produced in association with the lightest neutral higgs can be discovered as an excess in the @xmath8 process at the lhc .
moreover , this could happen even at the early stage with @xmath9 in a substantial portion of the parameter space . |
6,687 | Suppose that you have an abstract for a scientific paper: hindered magnetic dipole transitions @xmath0 are studied in the covariant light - front approach . compared with the allowed magnetic dipole transitions , we find that results for hindered magnetic dipole transitions are sensitive to heavy quark mass and shape parameters of the light - front wave functions .
it is possible to tune the parameters so that the predictions of branching fractions of @xmath1 are consistent with the recent experimental data , but the relevant decay constant of @xmath2 is much smaller than that of @xmath3 .
we also generalize the investigation to the charmonium sector and find the the same conclusion .
since the photon energy in allowed magnetic dipole ( m1 ) transitions is limited , hindered m1 transitions with changes of principal quantum numbers are believed to offer better chances to discover the pseudoscalar quarkoniums such as @xmath2 .
several years ago , the cleo collaboration set the upper bounds for this kind of decays @xcite @xmath4 in 2008 the babar collaboration observed a peak in the photon energy spectrum at @xmath5 mev in radiative @xmath6 decay @xcite .
this is viewed as the first observation of the @xmath2 meson which is the lowest bottomonium ground state .
the branching ratio of this radiative decay is @xmath7 the measured mass @xmath8 gives the mass split @xmath9 subsequently the @xmath2 meson has also been observed in the radiative @xmath10 decay @xcite @xmath11 the ratio of the two branching fractions is measured as @xmath12 the recently updated results by the cleo collaboration @xcite are consistent with measurements by the babar collaboration taking into account the uncertainties @xmath13 decay widths of m1 transitions can be expressed in a well - known formula @xmath14 @xmath15 is the fine - structure constant , @xmath16 denotes the charge in unit of @xmath17 of the transition quark , and @xmath18 denotes the quark mass .
@xmath19 is the energy of the photon in the vector meson rest frame . for allowed transitions @xmath20 ,
the....
And you have already written the first three sentences of the full article: i would like to acknowledge y. jia and c.d .
l for fruitful discussions and kind encouragement , h.y .
cheng , c.k ..
Please generate the next two sentences of the article | chua and x.h .
liu for useful discussions on the harmonic oscillator wave functions , y.m . |
6,688 | Suppose that you have an abstract for a scientific paper: the quantization scheme by noncommutative geometry developed in string theory is applied to establish the conservation law of twisted spin and spin current densities in the spin - orbit coupled systems . starting from the pedagogical introduction to hopf algebra and deformation quantization ,
the detailed derivation of the conservation law is given . .
And you have already written the first three sentences of the full article: electrons are described by the dirac equation where the u(1 ) maxwell electromagnetic field ( emf ) @xmath0 is coupled to the charge current @xmath1 as described by the lagrangian ( in the natural unit where @xmath2 ; @xmath3 ) @xcite @xmath4 \psi.\ ] ] where @xmath5 is the covariant derivative , @xmath6 is the electron mass .
note that the spin is encoded by 4 component nature of the spinors @xmath7 and @xmath8 and the @xmath9 gamma matrices @xmath10 , but the charge and charge current alone determine the electromagnetic properties of the electrons , which are given by @xmath11 in condensed matter physics , on the other hand , the low energy phenomena compared with the mass gap @xmath12 are considered , and only the positive energy states described by the two - component spinor are relevant .
then , the relativistic spin - orbit interaction originates when the negative energy states ( positron stats ) are projected out to derive the effective hamiltonian or lagrangian ..
Please generate the next two sentences of the article | the projection to a subspace of the hilbert space leads to the nontrivial geometrical structure which is often described by the gauge theory .
this is also the case for the dirac equation , and the resultant gauge field is su(2 ) non - abelian gauge field corresponding to the zeeman effect ( time - component ) and the spin - orbit interaction ( spatial components ) as described below . |
6,689 | Suppose that you have an abstract for a scientific paper: the more precise extraction for the ckm matrix element @xmath0 in the heavy quark effective field theory ( hqeft ) of qcd is studied from both exclusive and inclusive semileptonic @xmath1 decays .
the values of relevant nonperturbative parameters up to order @xmath2 are estimated consistently in hqeft of qcd .
using the most recent experimental data for @xmath1 decay rates , @xmath3 is updated to be @xmath4 from @xmath5 decay and @xmath6 from @xmath7 decay as well as @xmath8 from inclusive @xmath9 decay . #
1@xmath10#1 : 12.15.hh , 12.39.hg , 13.20.he @xmath0 , heavy quark effective field theory .
And you have already written the first three sentences of the full article: the cabibbo - kobayashi - maskawa ( ckm ) matrix element @xmath11 describes the rich phenomena of flavor - changing transitions between the two heavy quarks @xmath12 and @xmath13 .
its precise extraction has become a very important issue in heavy flavor physics .
generally @xmath0 is extracted by studying either exclusive or inclusive semileptonic @xmath1 decays . since long distance contributions are involved in these decays , theoretical estimates of the nonperturbative parameters are of crucial importance for a precise extraction of @xmath0 ..
Please generate the next two sentences of the article | heavy quark symmetry ( hqs ) @xcite and effective field theories of heavy quarks play a special role in such estimates . in this short note
, we are going to provide a more precise extraction for @xmath0 from both exclusive and inclusive semileptonic @xmath1 decays within the framework of hqeft of qcd . |
6,690 | Suppose that you have an abstract for a scientific paper: the question of existence of general , asymptotically flat radiative spacetimes and examples of explicit classes of radiative solutions of einstein s field equations are discussed in the light of some new developments .
the examples are cylindrical waves , robinson - trautman and type n spacetimes and especially boost - rotation symmetric spacetimes representing uniformly accelerated particles or black holes . .
And you have already written the first three sentences of the full article: in physical theories on a fixed background spacetime , as in newtonian theory or special relativity , it is not difficult to formulate asymptotic fall - off conditions on fields of spatially bounded systems .
for example , the gravitational potential due to a newtonian star is usually required to decay to zero at infinity of euclidean space , with the decay rate being compatible with laplace s equation . in general relativity
no a priori given background space exists ..
Please generate the next two sentences of the article | the metric itself is both a dynamical field and a quantity which determines distances .
one expects that in a suitable coordinate system far away from a system of bodies the metric should have a form @xmath0 small quantities , where @xmath1 is minkowski metric . |
6,691 | Suppose that you have an abstract for a scientific paper: we study three - flavor collective neutrino transformations in the dense - neutrino region above the neutrino sphere of a supernova core .
we find that two - flavor conversions driven by the atmospheric mass difference and the 13-mixing angle capture the full effect if one neglects the second - order difference between the @xmath0 and @xmath1 refractive index .
including this `` mu tau matter term '' provides a resonance at a density of @xmath2 that typically causes significant modifications of the overall @xmath3 and @xmath4 survival probabilities .
this effect is surprisingly sensitive to deviations from maximal 23-mixing , being different for each octant . .
And you have already written the first three sentences of the full article: neutrinos of different flavor suffer different refraction in matter @xcite .
the energy shift between @xmath3 and @xmath0 or @xmath1 is @xmath5 with @xmath6 the fermi constant , @xmath7 the baryon density , and @xmath8 the electron fraction .
@xmath9 is caused by the charged - current @xmath3-electron interaction that is absent for @xmath0 and @xmath1 . for a matter density @xmath10.
Please generate the next two sentences of the article | g @xmath11 we have @xmath12 ev , yet this small energy shift is large enough to be of almost universal importance for neutrino oscillation physics . in normal matter , @xmath13 and @xmath14 leptons appear only as virtual states in radiative corrections to neutral - current @xmath0 and @xmath1 scattering , causing a shift @xmath15 between @xmath0 and @xmath1 .
it has the same effect on neutrino dispersion as real @xmath14 leptons with an abundance @xcite @xmath16 = 2.7\times10^{-5}\ , , \label{eq : ytau}\ ] ] where @xmath17 was assumed . for the neutron abundance we have used @xmath18 , |
6,692 | Suppose that you have an abstract for a scientific paper: let @xmath0 be a based map of simply connected spaces .
the corresponding evaluation map @xmath1 induces a homomorphism of homotopy groups whose image in @xmath2 is called the @xmath3th evaluation subgroup of @xmath4 .
the @xmath3th gottlieb group of @xmath5 occurs as the special case in which @xmath6 and @xmath7 .
we identify the homomorphism induced on rational homotopy groups by this evaluation map , in terms of a map of complexes of derivations constructed using sullivan minimal models .
our identification allows for the characterization of the rationalization of the @xmath3th evaluation subgroup of @xmath4 .
it also allows for the identification of several long exact sequences of rational homotopy groups , including the long exact sequence induced on rational homotopy groups by the evaluation fibration . as a consequence ,
we obtain an identification of the rationalization of the so - called @xmath8-sequence of the map @xmath4 .
this is a sequence in general not exact of groups and homomorphisms that includes the gottlieb groups of @xmath5 and the evaluation subgroups of @xmath4 .
we use these results to study the @xmath8-sequence in the context of rational homotopy theory .
we give new examples of non - exact @xmath8-sequences and uncover a relationship between the homology of the rational @xmath8-sequence and negative derivations of rational cohomology .
we also relate the splitting of the rational @xmath8-sequence of a fibre inclusion to a well - known conjecture in rational homotopy theory . .
And you have already written the first three sentences of the full article: suppose given a based map @xmath9 of simply connected cw complexes .
denote by @xmath10 the path component of the space of ( unbased ) maps @xmath11 consisting of those maps that are homotopic to @xmath4 .
then evaluation at the basepoint of @xmath5 gives a based map @xmath12 ..
Please generate the next two sentences of the article | we refer to this map as the _ evaluation map_. we define the _ @xmath3th evaluation subgroup of @xmath4 _ to be the subgroup @xmath13 of @xmath2 .
the famous gottlieb groups @xmath14 occur as the special case in which @xmath15 and @xmath16 @xcite . |
6,693 | Suppose that you have an abstract for a scientific paper: the occurrence of swarms of small bubbles in a variety of industrial systems enhances their performance .
however , the effects that size polydispersity may produce on the stability of kinematic waves , the gain factor , mean bubble velocity , kinematic and dynamic wave velocities is , to our knowledge , not yet well established .
we found that size polydispersity enhances the stability of a bubble column by a factor of about @xmath0 as a function of frequency and for a particular type of bubble column . in this way our modelpredicts effects that might be verified experimentally but this , however , remain to be assessed .
our results reinforce the point of view advocated in this work in the sense that a description of a bubble column based on the concept of randomness of a bubble cloud and average properties of the fluid motion , may be a useful approach that has not been exploited in engineering systems . .
And you have already written the first three sentences of the full article: the theoretical description of multiphase flows is essentially based on analyzing the reponse of a cloud of dispersed particles of different size ranges in a fluid .
these particles constitute dynamic phases and hence a multiphase flow .
a widely used multiphase system is a bubble column which is a reactor where a discontinuous gas phase in the form of bubbles , moves relative to a continuous phase ..
Please generate the next two sentences of the article | bubble columns have a wide range of applications in chemical industries , biotechnology or in nuclear reactors @xcite , @xcite , @xcite , @xcite , nucreac .
the transient behavior is important at the start - up of these systems and its analysis is essential in order to characterize the dynamic performance of the columns . among the phenomena that occur in these systems |
6,694 | Suppose that you have an abstract for a scientific paper: we present generalized supernova ( sn ) light curve ( lc ) models for a variety of power inputs including the previously proposed ideas of radioactive decay of @xmath0ni and @xmath0co and magnetar spin - down .
we extend those solutions to include finite progenitor radius and stationary photospheres as might be the case for sn that are powered by interaction of the ejecta with circumstellar matter ( csm ) .
we provide an expression for the power input that is produced by self - similar forward and reverse shocks that efficiently convert their kinetic energy into radiation .
we find that this ejecta - csm interaction luminosity that we derive is in agreement with results from multi - dimensional radiation hydrodynamics simulations in the case of an optically - thin csm .
we develop a semi - analytical model for the case of an optically - thick csm by invoking an approximation for the effects of radiative diffusion similar to that adopted by arnett ( 1982 ) for sn ii and compare this model to the results of numerical radiation hydrodynamics models .
this model can give complex light curves , but for monotonically declining shock input , the lcs have a smooth rise , peak and decline . in the context of this model , we provide predictions of the shock breakout of the forward shock from the optically - thick part of the csm envelope .
we also introduce a hybrid lc model that incorporates ejecta - csm interaction plus @xmath0ni and @xmath0co radioactive decay input .
we fit this hybrid model to the lc of the super - luminous supernova ( slsn ) 2006gy .
we find that shock heating produced by ejecta - csm interaction plus some contribution from radioactive decay provides a better fit to the lc of this event than previously presented models .
we also address the relation between sn iil and sn iin with ejecta - csm interaction models . the faster decline of sn iil can be reproduced by the diffusion of previously deposited shock power if the shock power input to the diffusive component vanishes when....
And you have already written the first three sentences of the full article: the current sn classification scheme is based on both the properties of the spectrum and of the light curve .
the basic properties of stripped envelope sne ( ia , b , c ) light curves ( lcs ) are well reproduced by considering the diffusion of the radioactive decay energy of @xmath0ni and @xmath0co into homologously expanding sn ejecta ( arnett 1979 , 1980 , 1982 , 1996 - hereafter a79 , a80 , a82 , a96 ) .
core - collapse sne are divided into the type ib / c and type ii subclasses ..
Please generate the next two sentences of the article | sn ib / ic are considered explosions of compact progenitors that have lost their outer hydrogen ( for sn ib ) and helium ( for sn ic ) envelopes .
a79 addressed what we would now call sn ib ; a80 and a82 pertained more directly to sn ia , but the principles are the same . for type ii sn , |
6,695 | Suppose that you have an abstract for a scientific paper: we analyze transport of local magnetization and develop schemes to control transport behavior in finite spin-1/2 heisenberg chains and spin-1/2 heisenberg two - leg ladders at zero temperature . by adjusting parameters in the hamiltonians
, these quantum systems may show both integrable and chaotic limits .
we provide examples of chaotic systems leading to diffusive and to ballistic transport .
in addition , methods of coherent quantum control to induce a transition from diffusive to ballistic transport are proposed . .
And you have already written the first three sentences of the full article: a complete understanding of transport behavior in many - body systems is one of the utmost challenges in fundamental studies of non - equilibrium statistical mechanics . in the classical domain
, it is widely believed that chaotic systems should show diffusive ( normal ) transport , whereas integrability should be associated with ballistic ( abnormal ) transport @xcite , although normal transport has also been verified for a non - chaotic system @xcite . in the quantum domain , the conditions that determine specific transport behaviors are still under debate , but here also , the main conjecture is of the correspondence integrable - ballistic and chaotic - diffusive @xcite .
several theoretical approaches have been undertaken to address this issue , including : attempts to derive the fourier law from a microscopic foundation by applying the hilbert space average method @xcite and by numerically studying transport of heat in finite chaotic and non - chaotic systems coupled to heat reservoirs @xcite ; analysis of the transport behavior of local magnetization in isolated finite systems at zero temperature @xcite ; new advances toward the problem of quantum thermalization @xcite ; comparisons of the results for conductivity in integrable and chaotic systems at finite temperature and in the thermodynamic limit @xcite , a subject of intense discussion here being the possibility of ballistic transport in non - integrable quasi - one - dimensional systems @xcite ; numerical studies of spin diffusion at long times at infinity temperature @xcite ; as well as studies of transport properties near the metal - insulator transition @xcite ..
Please generate the next two sentences of the article | investigations of transport behavior in the particular case of quasi - one - dimensional spin-1/2 systems have been highly motivated by experiments in low - dimensional magnetic compounds , such as copper oxide ( cuprate ) systems , where ballistic behavior has been observed for heat conduction @xcite , and also for magnetization , as revealed by nuclear magnetic resonance ( nmr ) experiments @xcite .
these compounds are described by models of interacting spins-1/2 arranged in structures such as chains , two - leg ladders , and square lattices @xcite . |
6,696 | Suppose that you have an abstract for a scientific paper: we consider the isoperimetric problem for the sum of two gaussian densities in the line and the plane .
we prove that the double gaussian isoperimetric regions in the line are rays and that if the double gaussian isoperimetric regions in the plane are half - spaces , then they must be bounded by vertical lines . .
And you have already written the first three sentences of the full article: sudakov - tsirelson and borell proved independently ( see @xcite ) that for @xmath0 endowed with a gaussian measure , half - spaces bounded by hyperplanes are isoperimetric , i.e. , minimize weighted perimeter for given weighted volume .
caete et al .
* question 6 ) , in response to a question of brancolini , conjectured that for @xmath0 endowed with a finite sum of gaussian measures centered on the @xmath1-axis , half - spaces bounded by vertical hyperplanes are isoperimetric ..
Please generate the next two sentences of the article | we consider the case of two such gaussians in @xmath2 or @xmath3 .
our theorem [ 2.18 ] proves that on the double gaussian line , rays are isoperimetric . |
6,697 | Suppose that you have an abstract for a scientific paper: by using overlap majorana fermions , the @xmath0 chiral multiple can be formulated so that the supersymmetry is manifest and the vacuum energy is cancelled in the free limit , thanks to the bilinear nature of the free action .
it is pointed out , however , that in this formulation the reflection positivity seems to be violated in the bosonic part of the action , although it is satisfied in the fermionic part
. it is found that the positivity of the spectral density of the bosonic two - point correlation function is ensured only for the spacial momenta @xmath1 @xmath2 .
it is then argued that in formulating @xmath0 wess - zumino model with the overlap majorana fermion , one may adopt a simpler nearest - neighbor bosonic action , discarding the free limit manifest supersymmetry .
the model still preserves the would - be u(1)@xmath3 symmetry and satisfies the reflection positivity . .
And you have already written the first three sentences of the full article: the chiral multiplet of @xmath0 supersymmetry@xcite can be formulated on the lattice so that the supersymmetry is preserved and the vacuum energy is cancelled in the free limit , thanks to the bilinear nature of the free action . by using overlap ( majorana ) fermion @xcite for the fermionic component
, species doublers@xcite are successfully removed and u(1)@xmath3 symmetry can be maintained at the same time@xcite . with this chiral multiplet
, one may formulate lattice @xmath0 wess - zumino model with exact u(1)@xmath3 symmetry@xcite ..
Please generate the next two sentences of the article | a numerical study of this lattice @xmath0 wess - zumino model has recently been reported in @xcite .
the purpose of this short article is , however , to show that in this formulation of the chiral multiplet , the reflection positivity@xcite seems to be violated in the bosonic part of the action , although it is satisfied in the fermionic part , as shown recently in @xcite . |
6,698 | Suppose that you have an abstract for a scientific paper: * low - loss transmission and sensitive recovery of weak radio - frequency ( rf ) and microwave signals is an ubiquitous technological challenge , crucial in fields as diverse as radio astronomy , medical imaging , navigation and communication , including those of quantum states .
efficient upconversion of rf - signals to an optical carrier would allow transmitting them via optical fibers instead of copper wires dramatically reducing losses , and give access to the mature toolbox of quantum optical techniques , routinely enabling quantum - limited signal detection .
research in the field of cavity optomechanics @xcite has shown that nanomechanical oscillators can couple very strongly to either microwave @xcite or optical fields @xcite .
an oscillator accommodating both these functionalities would bear great promise as the intermediate platform in a radio - to - optical transduction cascade . here
, we demonstrate such an opto - electro - mechanical transducer following a recent proposal @xcite utilizing a high - q nanomembrane .
a moderate voltage bias ( @xmath0 ) is sufficient to induce strong coupling @xcite between the voltage fluctuations in a radio - frequency resonance circuit and the membrane s displacement , which is _ simultaneously _ coupled to light reflected off its metallized surface .
the circuit acts as an antenna ; the voltage signals it induces are detected as an optical phase shift with quantum - limited sensitivity .
the corresponding half - wave voltage is in the microvolt range , orders of magnitude below that of standard optical modulators .
the noise added by the mechanical interface is suppressed by the electro - mechanical cooperativity @xmath1 and has a temperature of @xmath2 , where @xmath3 is the room temperature at which the entire device is operated .
this corresponds to a sensitivity limit as low as @xmath4 , or @xmath5 in a narrow frequency band around @xmath6 .
our work introduces an entirely new approach to all - optical , ultralow - noise detection of....
And you have already written the first three sentences of the full article: the detailed circuit diagram we use for our experiments is sketched in fig.s1 .
all the electronic components for controlling the coupling are placed on a pcb ( printed circuit board ) that is shielded with a metal box .
the output of the pcb goes to the electrical feedthroughs of the vacuum chamber in which the membrane - capacitor system is placed ..
Please generate the next two sentences of the article | the decay rate of the lc circuit is a crucial parameter for reaching the strong coupling regime since the coupling rate should exceed this rate . in our setup
, we use a high - q ferrite inductor which is made of ferrite 61 material ( including a mixture of zinc and nickel ) that is known for minimized core and eddy current losses . |
6,699 | Suppose that you have an abstract for a scientific paper: quasiclassical boundary conditions for electrochemical potentials at the interface between diffusive ferromagnetic and non - magnetic metals are derived for the first time .
an expression for the boundary resistance accurately accounts for the momentum conservation law as well as essential gradients of the chemical potentials .
conditions are established at which spin - asymmetry of the boundary resistance has positive or negative sign .
dependence of the spin asymmetry and the absolute value of the boundary resistance on the exchange splitting of the conduction band opens up new possibility to estimate spin polarization of the conduction band of ferromagnetic metals .
consistency of the theory is checked on existing experimental data . .
And you have already written the first three sentences of the full article: discovery of giant magnetoresistance ( mr ) in magnetic multilayers @xcite , which consist of alternating ferromagnetic metal ( f ) and normal metal ( n ) layers , stimulated intensive studies of spin - polarized transport through layered magnetic structures @xcite . in a paper
@xcite the semiclassical theory of mr in magnetic multilayers has been developed for geometry , in which the electric current is perpendicular to the layers ( cpp geometry ) .
it has been shown that when thickness of the metals in a stack is small compared with the spin diffusion length , the magnetoresistance of multilayers can be calculated within the two - current series - resistor model @xcite . in this case.
Please generate the next two sentences of the article | mr is expressed via the resistance of the f / n interface ( boundary resistance ) , @xmath0r_{f / n}^{\ast } $ ] , and the bulk specific resistance of the ferromagnetic layer , @xmath1\rho _ { f}^{\ast } $ ] @xcite . in these expressions @xmath2 and @xmath3 are parameters of spin asymmetry of the boundary and bulk scattering resistances .
it follows from works @xcite that their linear combination , @xmath4 , determines sign of mr in layered @xmath5\times n$ ] structures ( @xmath6 is the thickness of the ferromagnetic layers ) . in works @xcite positive ( inverse ) mr due to negative value of @xmath2 in @xmath7 multilayers has been observed for the first time . |
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