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5,700 | Suppose that you have an abstract for a scientific paper: atoms in high - finesse optical resonators interact via the photons they multiply scatter into the cavity modes .
the dynamics is characterized by dispersive and dissipative optomechanical long - range forces , which are mediated by the cavity photons , and exhibits a steady state for certain parameter regimes . in standing - wave cavities
the atoms can form stable spatial gratings . moreover ,
their asymptotic distribution is a maxwell - boltzmann whose effective temperature is controlled by the laser parameters . in this work we show that in a two - mode standing - wave cavity the stationary state possesses the same properties and phases of the generalized hamiltonian mean field model in the canonical ensemble .
this model has three equilibrium phases : a paramagnetic , a nematic , and a ferromagnetic one , which here correspond to different spatial orders of the atomic gas and can be detected by means of the light emitted by the cavities .
we further discuss perspectives for investigating in this setup the ensemble inequivalence predicted for the generalized hamiltonian mean field model . .
And you have already written the first three sentences of the full article: atomic ensembles in optical resonators offer a promising platform for studying the physics of long - range interacting systems @xcite .
the long - range interaction here originates from multiple scattering of cavity photons , which carry the information about the positions of the scattering atoms and thus mediate an optomechanical interparticle potential @xcite . in a single - mode cavity
the photons are coherent over the cavity mode volume , which makes the interaction range as large as the system size ..
Please generate the next two sentences of the article | therefore , the energy is non - additive like in gravitational and coulomb systems in two or more dimensions @xcite . in equilibrium
statistical mechanics , consequences of non - additivity are for instance the super - linear scaling of thermodynamic quantities with the system size and the inequivalence of the statistical ensembles @xcite , one manifestation of which are negative specific heats in the microcanonical ensemble @xcite . |
5,701 | Suppose that you have an abstract for a scientific paper: motivated by the asset - liability management of a nuclear power plant operator , we consider the problem of finding the least expensive portfolio , which outperforms a given set of stochastic benchmarks . for
a specified loss function , the expected shortfall with respect to each of the benchmarks weighted by this loss function must remain bounded by a given threshold .
we consider different alternative formulations of this problem in a complete market setting , establish the relationship between these formulations , present a general resolution methodology via dynamic programming in a non - markovian context and give explicit solutions in special cases . _
key words : _ multiple risk constraints , expected loss , asset liability management , snell envelope , dynamic programming . .
And you have already written the first three sentences of the full article: in various economic contexts , institutions hold assets to cover future random liabilities .
banks and insurance companies are required by the authorities to hold regulatory capital to cover the risks they take .
pension funds face random future liabilities due to longevity risk and the structure of the pension plans which may involve variable annuity - type features ..
Please generate the next two sentences of the article | the problem of managing a portfolio of assets under the condition of covering future liabilities or benchmarks , in particular in the context of pension plans , is commonly known as asset - liability management ( alm ) @xcite . the present study is mainly motivated by the alm problem of a nuclear power plant operator . in several countries ,
energy companies operating nuclear power plants are required by law to hold decomissioning funds , to cover the future costs of decontaminating and dismantling the plants , as well as the treatment and long - term storage of the radioactive waste . in france , this obligation was introduced by the law n@xmath0 2006 - 739 of june 28 , 2006 relative to sustainable management of radioactive substances and waste . according to this law , the three major players of the civil nuclear industry in france ( edf , areva and cea ) must hold portfolios of assets dedicated to future nuclear decomissioning charges @xcite |
5,702 | Suppose that you have an abstract for a scientific paper: the disordered quasi-1d magnet bacu@xmath0sigeo@xmath1 is considered as one of the best physical realizations of the random heisenberg chain model , which features an irregular distribution of the exchange parameters and whose ground state is predicted to be the scarcely investigated _ random - singlet _ state ( rss ) . based on extensive @xmath2si nmr and magnetization studies of bacu@xmath0sigeo@xmath1 , combined with numerical quantum monte carlo simulations , we obtain remarkable quantitative agreement with theoretical predictions of the random heisenberg chain model and strong indications for the formation of a random - singlet state at low temperatures in this compound . as a local probe , nmr is a well - adapted technique for studying the magnetism of disordered systems . in this case
it also reveals an additional local transverse staggered field ( ltsf ) , which affects the low - temperature properties of the rss .
the proposed model hamiltonian satisfactorily accounts for the temperature dependence of the nmr line shapes . .
And you have already written the first three sentences of the full article: spin- heisenberg chains adopt a non - magnetic ground state , which qualitatively can be seen as a linear superposition of states representing all the possible ways of forming singlets in the system.@xcite with quantum fluctuations suppressing any long - range order , the translational symmetry is preserved . at large length scales ( low energies ) _ any _ amount of disorder in the exchange parameters is predicted to dominate over the quantum or thermal fluctuations@xcite and the resulting system is known as `` random heisenberg chain '' ( rhc ) . in practice , the disorder leads to an inhomogeneous ground state by associating to every random configuration of exchange paths a unique way of forming singlets , regardless of the distance between the involved spins and of their interactions .
this new type of ground state , specific to random heisenberg chains , is called _ random - singlet state _ ( rss).@xcite it is widely accepted@xcite that the interest in rhcs originally arose from a novel approach to deal with random exchanges in the isotropic spin- heisenberg model , introduced in 1979 by dasgupta and ma.@xcite their new physical insight into the effects of disorder was later developed into a formal theory by fisher@xcite and , subsequently , applied to a large variety of problems involving magnets with quenched disorder.@xcite however , it is only the recent combined availability of materials representing physical realizations of disordered quasi-1d quantum magnets@xcite and of novel stochastic numerical methods@xcite that made possible the first quantitative studies concerning the impact of disorder on materials whose magnetic properties are well described by an antiferromagnetic heisenberg - chain hamiltonian [ see eq . ] .
the aim of the present work was to identify a model material featuring the properties of an rhc and , through experimental and numerical methods , to demonstrate that the chosen rhc hamiltonian describes its physical behavior . here.
Please generate the next two sentences of the article | we present a set of field- and temperature - dependent magnetization and @xmath3si nuclear magnetic resonance ( nmr ) data of the electronic insulator bacu@xmath0sigeo@xmath1.@xcite its relevant structural unit is shown in fig .
[ fig : struct_basge ] and its physical properties can be discussed in terms of the one - dimensional hamiltonian : @xmath4 \nonumber \\ & - g \mu_{\mathrm{b } } \sum_{i}h s^z_i + \mu_{\mathrm{b } } h_{\perp } \sum_{i } ( -1)^i s^x_i . \label{rhc1}\end{aligned}\ ] ] here @xmath5 represent the random exchange couplings along the spin - chain sites @xmath6 , @xmath7 is the bohr magneton , @xmath8 the uniform applied magnetic field , @xmath9 a locally induced transverse staggered field,@xcite and the spin operators refer to a spin @xmath10 . |
5,703 | Suppose that you have an abstract for a scientific paper: core collapse supernovae ( sn ) are the final stages of stellar evolution in massive stars during which the central region collapses , forms a neutron star ( ns ) , and the outer layers are ejected .
recent explosion scenarios assumed that the ejection is due to energy deposition by neutrinos into the envelope but detailed models do not produce powerful explosions .
there is mounting evidence for an asphericity in the sn which is difficult to explain within this picture .
this evidence includes the observed high polarization , pulsar kicks , high velocity iron - group and intermediate - mass elements material observed in remnants , etc .
the discovery of highly magnetars revived the idea that the basic mechanism for the ejection of the envelope is related to a highly focused mhd - jet formed at the ns .
our 3-d hydro simulations of the jet propagation through the star confirmed that the mechanism can explain the asphericities . in this paper ,
detailed 3-d models for jet induced explosions of `` classical '' core collapse supernovae are presented .
we demonstrate the influence of the jet properties and of the underlaying progenitor structure on the final density and chemical structure .
finally , we discuss the observational consequences , predictions and tests of this scenario . .
And you have already written the first three sentences of the full article: supernovae ( sn ) are among the most spectacular events because they reach the same brightness as an entire galaxy .
this makes them good candidates to determine extragalactic distances and to measure the basic cosmological parameters .
moreover , they are thought to be the major contributors to the chemical enrichment of the interstellar matter with heavy elements ..
Please generate the next two sentences of the article | energy injection by sn into the interstellar medium , triggers star formation and feedback in galaxy formation , and is regarded as a key for our understanding of the formation and evolution of galaxies .
core collapse supernovae are thought to be the final stages of the evolution of massive stars which live only @xmath0 to @xmath1 years . |
5,704 | Suppose that you have an abstract for a scientific paper: a phenomenological theory is proposed to analyze the asymptotic dynamics of perturbed inviscid kolmogorov shear flows in two dimensions .
the phase diagram provided by the theory is in qualitative agreement with numerical observations , which include three phases depending on the aspect ratio of the domain and the size of the perturbation : a steady shear flow , a stationary dipole , and four traveling vortices .
the theory is based on a precise study of the inviscid damping of the linearized equation and on an analysis of nonlinear effects . in particular , we show that the dominant landau pole controlling the inviscid damping undergoes a bifurcation , which has important consequences on the asymptotic fate of the perturbation . .
And you have already written the first three sentences of the full article: patterns in effective two - dimensional ( 2d ) fluids flows are found in nature in various contexts @xcite : atmospheric @xcite and oceanic flows @xcite are examples . to understand such large scale patterns
theoretically , the 2d euler equation describing perfect fluids flows is a simplified starting point . in this context
, the study of nonlinear structures , such as kelvin s cat s eyes , over a shear flow has a long history @xcite , which includes more recent mathematical developments @xcite ..
Please generate the next two sentences of the article | statistical physics has often been invoked to explain the formation of large vortices since onsager @xcite .
the miller - robert - sommeria ( mrs ) theory @xcite , which constructs the microcanonical measure for 2d euler flows by taking all the invariants into account , is a particularly successful achievement . |
5,705 | Suppose that you have an abstract for a scientific paper: we describe an analysis of the time - resolved measurements of the surface magnetic field in the roap star @xmath0 equ .
we have obtained a high - resolution and high s / n spectroscopic time - series , and the magnetic field was determined using zeeman resolved profiles of the feii 6149.25 and fei 6173.34 lines .
contrary to recent reports we do not find any evidence of magnetic variability with pulsation phase , and derive an upper limit of 510 g for pulsational modulation of the surface magnetic field in @xmath0 equ .
stars : chemically peculiar stars : oscillations stars : magnetic field stars : individual : @xmath0 equ [ cols="^,^,^,^,^,^,^,^,^ " , ] .
And you have already written the first three sentences of the full article: after discovery of the conspicuous radial velocity ( rv ) pulsational variations in a sample of rapidly oscillating magnetic peculiar ( roap ) stars ( kanaan & hatzes , savanov , malanushenko & ryabchikova , kochukhov & ryabchikova for @xmath0 equ ; baldry et al . , baldry & bedding , kochukhov & ryabchikova for @xmath1 cirand hd 83368 ) , attempts to search for magnetic field variations over the pulsational period have been made .
first , hubrig et al .
@xcite tried to measure pulsational variability of the longitudinal magnetic field @xmath2 in six roap stars ..
Please generate the next two sentences of the article | their sample included @xmath0 equ probably one of the most favourable stars for this kind of investigation .
equ is a bright northern roap star with a strong magnetic field , and with one of the largest pulsational rv amplitudes which exceeds 1000 ms@xmath3 in individual spectral lines . |
5,706 | Suppose that you have an abstract for a scientific paper: the riemannian @xmath0 symbols are spin networks that assign an amplitude to each 4-simplex in the barrett - crane model of riemannian quantum gravity .
this amplitude is a function of the areas of the 10 faces of the 4-simplex , and barrett and williams have shown that one contribution to its asymptotics comes from the regge action for all non - degenerate 4-simplices with the specified face areas .
however , we show numerically that the dominant contribution comes from degenerate 4-simplices . as a consequence
, one can compute the asymptotics of the riemannian @xmath0 symbols by evaluating a ` degenerate spin network ' , where the rotation group @xmath1 is replaced by the euclidean group of isometries of @xmath2 .
we conjecture formulas for the asymptotics of a large class of riemannian and lorentzian spin networks in terms of these degenerate spin networks , and check these formulas in some special cases . among other things
, this conjecture implies that the lorentzian @xmath0 symbols are asymptotic to @xmath3 times the riemannian ones . .
And you have already written the first three sentences of the full article: in the ponzano regge model of 3-dimensional riemannian quantum gravity @xcite , an amplitude is associated with each tetrahedron in a triangulation of spacetime .
the amplitude depends on the tetrahedron s six edge lengths , which are assumed to be quantized , taking values proportional to @xmath4 where @xmath5 is a half - integer spin .
one can compute this amplitude either by evaluating an @xmath6 spin network shaped like a tetrahedron , or by doing an integral . approximating this integral by the stationary phase method , ponzano and.
Please generate the next two sentences of the article | regge argued that when all six spins are rescaled by the same factor @xmath7 , the @xmath8 asymptotics of the amplitude are given by a simple function of the volume of the tetrahedron and the regge calculus version of its einstein action .
nobody has yet succeeded in making their argument rigorous , but roberts @xcite recently proved their asymptotic formula by a different method . this result lays the foundation for a careful study of the relation between the ponzano regge model and classical general relativity in 3 dimensions . |
5,707 | Suppose that you have an abstract for a scientific paper: the development of cosmic ray air showers can be influenced by atmospheric electric fields . under fair weather conditions these fields are small , but
the strong fields inside thunderstorms can have a significant effect on the electromagnetic component of a shower .
understanding this effect is particularly important for radio detection of air showers , since the radio emission is produced by the shower electrons and positrons .
we perform monte carlo simulations to calculate the effects of different electric field configurations on the shower development .
we find that the electric field becomes important for values of the order of 1 kv / cm .
not only can the energy distribution of electrons and positrons change significantly for such field strengths , it is also possible that runaway electron breakdown occurs at high altitudes , which is an important effect in lightning initiation . , , , , cosmic rays , extensive air showers , atmospheric electricity , radiation by moving charges , computer modeling and simulation 96.50.s- , 96.50.sd , 92.60.pw , 41.60.-m , 07.05.tp .
And you have already written the first three sentences of the full article: the effect of atmospheric electric fields on the development of extensive air showers from high energy cosmic rays has not received much attention in the past . because of the large energies of shower particles , the electric fields present in the atmosphere are generally much too small to alter the particle energies significantly .
the largest fields are of the order of 1 kv / cm and only occur in thunderstorms @xcite .
in such fields the hadronic and muonic part of the shower are hardly affected , although a muon deficit due to increased decay rate has been reported by alexeenko et al ..
Please generate the next two sentences of the article | the effects on the electromagnetic shower are much larger , but they are , as we will show in this work , local in the sense that the amount and energy distribution of electromagnetic particles quickly adapts to the local background field . below thunderstorms the electric field decreases , so particle detector arrays will in general not be strongly sensitive to the influence of electric fields .
mountain top experiments , however , can be very close to , or even inside thunderstorms . |
5,708 | Suppose that you have an abstract for a scientific paper: the right handed neutrino mass matrix that is central to the understanding of small neutrino masses via the seesaw mechanism can arise either ( i ) from renormalizable operators or ( ii ) from nonrenormalizable or super - renormalizable operators , depending on the symmetries and the higgs content of the theory beyond the standard model . in this paper , we study lepton flavor violating ( lfv ) effects in the first class of seesaw models wherein the @xmath0 majorana masses arise from renormalizable yukawa couplings involving a @xmath1 higgs field .
we present detailed predictions for @xmath2 and @xmath3 branching ratios in these models taking the current neutrino oscillation data into account . focusing on minimal supergravity models , we find that for a large range of mssm parameters suggested by the relic abundance of neutralino dark matter and that is consistent with higgs boson mass and other constraints , these radiative decays are in the range accessible to planned experiments .
we compare these predictions with lepton flavor violation in the second class of models arising entirely from the dirac yukawa couplings .
we study the dependence of the ratio @xmath4 on the mssm parameters and show that measurement of @xmath5 can provide crucial insight into the origin of the seesaw mechanism .
epsf.tex ( # 1 width # 2)=#2 1.0 in .
And you have already written the first three sentences of the full article: with the evidence for neutrino masses and mixings from solar and atmospheric neutrino data getting more and more firm , the nature of new physics that could explain the observations is under a great deal of scrutiny @xcite .
there are several issues that need to be understood , notably ( a ) the smallness of neutrino masses , and ( b ) the origin of the large atmospheric neutrino as well as the solar neutrino mixing angles , the latter being favored@xcite by the combined solar neutrino results@xcite including the recent sno neutral current data @xcite .
seesaw mechanism@xcite provides one of the simplest ways to understand the small neutrino masses ..
Please generate the next two sentences of the article | it assumes the existence of a set of three right handed neutrinos ( @xmath0 ) that have masses at the scale @xmath6 corresponding to a new ( local ) @xmath7 symmetry of weak interactions .
atmospheric neutrino observations suggest that the scale @xmath6 is much lower than the planck scale , leading to a new threshold inferred solely from experiments . at low energies , these heavy right handed neutrinos induce operators of the form @xmath8 , where @xmath9 is the dirac yukawa coupling matrix connecting the @xmath0 with the left - handed neutrinos ( @xmath10 ) and the standard model ( sm ) higgs doublet @xmath11 . |
5,709 | Suppose that you have an abstract for a scientific paper: a search for tribaryon states was performed at kek - ps .
we adopted the @xmath0he(@xmath1 reaction to populate the states with strangeness @xmath21 , charge 0 and isospin 1 .
no significant narrow structure was observed in the mass region from 3000 to 3200 mev/@xmath3 in an inclusive missing mass spectrum . the upper limit of the formation branching ratio was determined to be ( @xmath4 , ( @xmath5 and ( @xmath6/(@xmath7 ) with 95 % confidence level for narrow states with an assumed width of 0 , 20 and 40 mev/@xmath3 , respectively .
, , , , , , , , , , , , , , , , , , , , , , , , , 13.75.jz , 25.80.nv .
And you have already written the first three sentences of the full article: a possible existence of a tribaryon state with strangeness @xmath8 and isospin 0 has been predicted theoretically by akaishi and yamazaki as a deeply - bound @xmath9 nuclear state in @xmath10he nuclei @xcite .
recently , the kek - ps e471 group reported a distinct peak in a missing mass spectrum of the @xmath0he(@xmath11 reaction @xcite , which was interpreted to be a signal of a tribaryon state with strangeness @xmath21 and isospin 1 , called s@xmath12 ( m = 3117.0@xmath13 mev/@xmath3 and @xmath14 21 mev/@xmath3 ) .
the same group obtained another candidate of the tribaryon state , s@xmath15(3140 ) , in the @xmath0he(@xmath16 missing mass spectrum , but its statistical significance was not sufficient to claim a definitive evidence for its existence @xcite ..
Please generate the next two sentences of the article | these results have triggered many theoretical interpretations @xcite . meanwhile the finuda group observed a peak in the proton momentum spectrum of @xmath17li(@xmath18 ) @xcite .
they attributed the peak to the proton emission from the @xmath19 capture on a `` quasi '' deuteron in @xmath17li as , @xmath20 ( @xmath21 mev/@xmath22 ) , which was introduced as an interpretation of s@xmath23(3115 ) by ref . |
5,710 | Suppose that you have an abstract for a scientific paper: we apply a recently developed technique of calculating the minimum jet kinetic power to the major mass ejections of the black - hole binary grs 1915 + 105 observed in radio wavelengths in 1994 and 1997 .
we derive for them the distance - dependent minimum power , and the corresponding mass flow rate and the total energy and mass content .
we find that a fast increase of the jet power with the increasing distance combined with the jet power estimates based on the bolometric luminosity imply the source distance is @xmath0 kpc .
if the jet in grs 1915 contains ions , their bulk motion dominates the jet power , which was either neglected or not properly taken into account earlier .
we also reconsider the parameters of the binary , and derive the current best estimates of the distance - dependent black - hole mass and the inclination based on existing measurements combined with the kinematic constraints from the mass ejections .
we also find the measurement of the donor radius of steeghs et al
. implies the distance to the system of @xmath0 kpc , in agreement with the estimate from the jet power .
[ firstpage ] acceleration of particles ism : jets and outflows radiation mechanisms : non - thermal radio continuum : stars stars : individual : grs 1915 + 105 . .
And you have already written the first three sentences of the full article: grs 1915 + 105 is a galactic black - hole binary with a number of highly interesting and unique properties .
it is a long - lived transient , which outburst began in 1992 @xcite and is still lasting .
it was the first galactic source discovered to show superluminal motion ( @xcite , hereafter mr94 ) ..
Please generate the next two sentences of the article | it is unusually highly variable in x - rays ( e.g. , @xcite ) , and it is one of the intrinsically brightest galactic x - ray binaries , occasionally radiating above the eddington limit @xcite . the minimum jet power in the superluminal ejection in 1994 was claimed to be highly super - eddington @xcite . here , we reconsider the minimum kinetic jet power , the mass flow rate , and the total energy and mass of the major mass ejections of grs 1915 + 105 observed in 1994 ( mr94 ) and in 1997 ( @xcite , hereafter f99 ) .
we use the method developed in @xcite ( hereafter z14 ) . |
5,711 | Suppose that you have an abstract for a scientific paper: machine learning methods for solving the equations of dynamical mean - field theory are developed .
the method is demonstrated on the three dimensional hubbard model .
the key technical issues are defining a mapping of an input function to an output function , and distinguishing metallic from insulating solutions .
both metallic and mott insulator solutions can be predicted .
the validity of the machine learning scheme is assessed by comparing predictions of full correlation functions , of quasi - particle weight and particle density to values directly computed .
the results indicate that with modest further development , machine learning approach may be an attractive computational efficient option for real materials predictions for strongly correlated systems .
the quantum many - body problem of predicting properties of systems containing electrons or other fermionic entities has challenged physicists and chemists for decades .
this is so because the minus sign associated with fermionic exchange creates a host of difficulties including long - ranged entanglement and a monte - carlo sign problem .
the net effect is to place the generic fermion many - body problem in the class of problems whose full solution is exponentially hard .
although new developments such as matrix product and tensor network methods may provide solutions to ground - state properties with only power - law cost , search for efficient approximate methods to handle a wide range of phenomena at a wide range of temperatures remains a key goal of condensed matter physics and quantum chemistry . in this work ,
we investigate the use of machine learning ( ml ) @xcite to leverage existing results and provide an efficient approximate solution to a generic class of problems in quantum many - body physics .
ml is in essence a way to use a database of known solutions to infer information about a new problem . in the condensed matter physics context
it has been used as an intermediate step in molecular dynamics....
And you have already written the first three sentences of the full article: the dispersion relation for the the single band tight - binding simple cubic lattice with nearest and next - nearest hopping is given by @xmath70 , \end{split}\ ] ] where @xmath71 @xmath72 labels the three cartesian directions of the nearest neighbor bonds of the cubic lattice .
the bandwith @xmath73 \text { or } [ 0,\pi,\pi]}-\varepsilon_{[0,0,0]}$ ] is given by @xmath74 as mentioned in the main text , we define the energy unit by fixing @xmath75 .
this fixes the value of @xmath76 for the different @xmath56 ..
Please generate the next two sentences of the article | our database contains data for @xmath21 $ ] .
we also tested our predictive power by using a lattice with @xmath77 . |
5,712 | Suppose that you have an abstract for a scientific paper: traditionally , the distance to ngc 4038/39 has been derived from the systemic recession velocity , yielding about 20 mpc for @xmath0 km s@xmath1 mpc@xmath1 . recently
, this widely adopted distance has been challenged based on photometry of the presumed tip of the red giant branch ( trgb ) , which seems to yield a shorter distance of @xmath2 mpc and , with it , nearly 1 mag lower luminosities and smaller radii for objects in this prototypical merger . here
we present a new distance estimate based on observations of the type ia supernova ( sn ) 2007sr in the southern tail , made at las campanas observatory as part of the carnegie supernova project .
the resulting distance of @xmath3 mpc [ @xmath4 mag ] is in good agreement with a refined distance estimate based on the recession velocity and the large - scale flow model developed by tonry and collaborators , @xmath5 mpc .
we point out three serious problems that a short distance of 13.3 mpc would entail , and trace the claimed short distance to a likely misidentification of the trgb . reanalyzing
_ hubble space telescope _
( _ hst _ ) data in the archive with an improved method , we find a trgb fainter by 0.9 mag and derive from it a preliminary new trgb distance of @xmath6 mpc .
finally , assessing our three distance estimates we recommend using a conservative , rounded value of @xmath7 mpc as the best currently available distance to the antennae . .
And you have already written the first three sentences of the full article: the antennae ( ngc 4038/39 ) are the nearest example of a major merger involving two gas - rich disk galaxies of comparable mass .
they allow us to study processes of dissipational galaxy assembly from close up , thus providing a valuable glimpse of what must have been more frequent events in the early universe .
the antennae have been observed extensively at all wavelengths ( e.g. , x - rays : @xcite ; uv : @xcite ; optical : @xcite ; ir : @xcite ; and 21-cm line : @xcite ) and have also been repeatedly modeled via n - body and hydrodynamical simulations ( e.g. , * ? ? ?.
Please generate the next two sentences of the article | * ; * ? ? ?
* ; * ? ? ? |
5,713 | Suppose that you have an abstract for a scientific paper: we introduce an efficient mcmc sampling scheme to perform bayesian inference in the m / g/1 queueing model given only observations of interdeparture times .
our mcmc scheme uses a combination of gibbs sampling and simple metropolis updates together with three novel `` shift '' and `` scale '' updates . we show that our novel updates improve the speed of sampling considerably , by factors of about @xmath0 to about @xmath1 on a variety of simulated data sets .
this paper proposes a new approach to computation for bayesian inference for the m / g/1 queue ( markovian arrival process / general service time distribution/1 server ) .
inference for this model using abc ( approximate bayesian computation ) was previously considered by bonassi ( 2013 ) , fearnhead and prangle ( 2012 ) , and blum and francois ( 2010 ) .
abc , in general , does not yield samples from the exact posterior distribution .
we use the strategy of considering certain unobserved quantities as latent variables , allowing us to use markov chain monte carlo ( mcmc ) , which converges to the exact posterior distribution . .
And you have already written the first three sentences of the full article: in the m / g/1 queueing model , customers arrive at a single server with independent interarrival times , @xmath2 , distributed according to the @xmath3 distribution . here , @xmath4 is the arrival rate , hence @xmath2 has density function @xmath5 for @xmath6 and @xmath7 otherwise .
they are served with independent service times @xmath8 , which have a @xmath9 distribution .
( our mcmc approach can be generalized to other service time distributions . ).
Please generate the next two sentences of the article | we do not observe the interarrival times , only the interdeparture times , @xmath10 .
the goal is to infer the unknown parameters of the queueing model , @xmath11 , using observed interdeparture times , @xmath12 . |
5,714 | Suppose that you have an abstract for a scientific paper: we study experimentally and theoretically the polarization alternation during the switch - on transient of a quasi - isotropic co@xmath0 laser emitting on the fundamental mode .
the observed transient dynamics is well reproduced by means of a model which provides a quantitative discrimination between the intrinsic asymmetry due to the kinetic coupling of molecules with different angular momenta , and the extrinsic anisotropies , due to a tilted intracavity window .
furthermore , the experiment provides a numerical assignment for the decay rate of the coherence term for a co@xmath0 laser . .
And you have already written the first three sentences of the full article: laser dynamics is commonly studied considering the electric field as a scalar variable , since in most systems the polarization state is imposed by anisotropies of the cavity .
for instance , brewster windows or gratings , generally used in gas lasers to close the laser tube or to select a vibro - rotational transition , impose a linearly polarized state of the laser emission .
however , in perfectly cylindrical laser cavities without any elements to select a preferred polarization , the study of the dynamics includes the necessity of considering the vector nature of the electric field ..
Please generate the next two sentences of the article | several theoretical works have been devoted to the study of the polarization dynamics of the quasi - isotropic laser , showing the important role played by the material variables .
in particular , the degeneracy of the angular momentum states of the laser transition sublevels has been considered as the coupling source between different polarization states . |
5,715 | Suppose that you have an abstract for a scientific paper: two - particle two - hole contributions to electromagnetic response functions are computed in a fully relativistic fermi gas model .
all one - pion exchange diagrams that contribute to the scattering amplitude in perturbation theory are considered , including terms for pionic correlations and meson - exchange currents ( mec ) .
the pionic correlation terms diverge in an infinite system and thus are regularized by modification of the nucleon propagator in the medium to take into account the finite size of the nucleus .
the pionic correlation contributions are found to be of the same order of magnitude as the mec . .
And you have already written the first three sentences of the full article: the goal of this paper is to present a fully relativistic calculation of the two - particle two - hole ( 2p-2h ) contributions to the inclusive @xmath0 response functions of nuclei for intermediate to high momentum transfers in a fermi gas model .
consistency with perturbation theory is maintained and all diagrams with one - pion exchange in the nuclear current are considered , constructed by attaching a photon to all possible lines in the basic one - pion exchange feynman diagram . in this way not only meson - exchange currents ( mec ) arise ( for example , where the photon is attached to the pion ) , but also pionic correlation diagrams , where the virtual photon is absorbed by one of the two interacting nucleons .
both kinds of diagrams are considered in our model , together with the usual virtual @xmath1-isobar electroexcitation and decay ..
Please generate the next two sentences of the article | we are motivated by previous work presented in @xcite , where only the mec were included in the 2p-2h transverse ( @xmath2 ) response , together with earlier work both in non - relativistic @xcite and relativistic @xcite regimes .
the contribution found from the 2p-2h excitations is small at the quasielastic ( qe ) peak , and increases with energy transfer , being more important in the dip region , where it is dominated by the @xmath1 current . at the non - relativistic level attempts |
5,716 | Suppose that you have an abstract for a scientific paper: we consider the canonical problem of an array of rods , which act as resonators , placed on an elastic substrate ; the substrate being either a thin elastic plate or an elastic half - space . in both cases the flexural plate , or rayleigh surface , waves in the substrate interact with the resonators to create interesting effects such as effective band - gaps for surface waves or filters that transform surface waves into bulk waves ; these effects have parallels in the field of optics where such sub - wavelength resonators create metamaterials , and metasurfaces , in the bulk and at the surface respectively . here
we carefully analyse this canonical problem by extracting the dispersion relations analytically thereby examining the influence of both the flexural and compressional resonances on the propagating wave . for an array of resonators atop an elastic half - space
we augment the analysis with numerical simulations . amongst other effects
, we demonstrate the striking effect of a dispersion curve that transitions from rayleigh wave - like to shear wave - like behaviour and the resultant change in displacement from surface to bulk waves .
= 1 [ firstpage ] .
And you have already written the first three sentences of the full article: metamaterials , as synthetic composite materials with a structure such that they exhibit properties not usually found in natural materials , now form a major emerging research area that barely existed before 2000 ; in fact , the term `` metamaterial '' itself was first used in 1999 . since then
, the area has grown extensively and shows little sign of slowing down .
the key point is that materials can be designed to have , say , a negative refractive index as predicted by @xcite and later by@xcite ; and subsequently fabricated by @xcite , which is impossible in naturally occurring materials ..
Please generate the next two sentences of the article | the first metamaterials were developed in optics and electromagnetism and relied upon having simultaneously negative permittivity and permeability , this was made physically possible using a microstructured periodic medium consisting of sub - wavelength resonators such as split - ring resonators @xcite .
it has subsequently been realised that these ideas can also be profitably utilised to create acoustic or elastic ( negative density and negative shear or bulk modulus ) metamaterials @xcite . similarly , although metamaterials were initially developed for bulk media , one can also create microstructured surfaces that act as metasurfaces @xcite with , again , most of the activity centered around electromagnetic waves and surface plasmons . |
5,717 | Suppose that you have an abstract for a scientific paper: image decomposition of galaxies is now routinely used to estimate the structural parameters of galactic components . in this work ,
i address questions on the reliability of this technique .
in particular , do bars and agn need to be taken into account to obtain the structural parameters of bulges and discs ? and to what extent can we trust image decomposition when the physical spatial resolution is relatively poor ? with this aim , i performed multi - component ( bar / bulge / disc / agn ) image decomposition of a sample of very nearby galaxies and their artificially redshifted images , and verified the effects of removing the bar and agn components from the models .
neglecting bars can result in a overestimation of the bulge - to - total luminosity ratio of a factor of two , even if the resolution is low .
similar effects result when bright agn are not considered in the models , but only when the resolution is high .
i also show that the structural parameters of more distant galaxies can in general be reliably retrieved , at least up to the point where the physical spatial resolution is @xmath0 1.5 kpc , but bulge parameters are prone to errors if its effective radius is small compared to the seeing radius , and might suffer from systematic effects .
i briefly discuss the consequences of these results to our knowledge of the stellar mass budget in the local universe , and finish by showing preliminary results from a large sdss sample on the dichotomy between classical and pseudo - bulges . .
And you have already written the first three sentences of the full article: parametric decomposition of galaxy images has become a popular tool to estimate the structural parameters of different galactic components , particularly bulges and discs . through this sort of analysis , one is also able to determine the relative importance of the bulge component , with parameters such as the bulge - to - total luminosity ratio b / t , one of the major features that define the @xcite sequence .
it thus provides indispensable means to investigate the formation and evolution of galaxies , and the origin of the hubble sequence , some of the key subjects in current astrophysical research .
recently , the focus of studies using image decomposition shifted from relatively small samples of very nearby galaxies , where the fits can be done on a more careful , individual basis ( e.g. , ( * ? ? ?.
Please generate the next two sentences of the article | * de jong 1995 ) ) , to include large samples of more distant galaxies , using automated procedures , that allow solid statistical analyses ( e.g. , ( * ? ? ?
* allen 2006 ) ) . |
5,718 | Suppose that you have an abstract for a scientific paper: cosmic string networks generate cosmological perturbations actively throughout the history of the universe .
thus , the string sourced anisotropy of the cosmic microwave background is not affected by silk damping as much as the anisotropy seeded by inflation .
the spectrum of perturbations generated by strings does not match the observed cmb spectrum on large angular scales ( @xmath0 ) and is bounded to contribute no more than @xmath1 of the total power on those scales .
however , when this bound is marginally saturated , the anisotropy created by cosmic strings on small angular scales @xmath2 will dominate over that created by the primary inflationary perturbations .
this range of angular scales in the cmb is presently being measured by a number of experiments ; their results will test this prediction of cosmic string networks soon . .
And you have already written the first three sentences of the full article: in the past decade , a series of experiments , in particular the wilkinson microwave anisotropy probe ( wmap ) @xcite , have measured the anisotropy in the cosmic microwave background ( cmb ) radiation with extraordinary precision .
the data from these experiments have helped to usher in the era of precision cosmology .
most of the cosmological results that have been obtained from these experiments have been derived from the microwave anisotropy at relatively large angular scales ..
Please generate the next two sentences of the article | the remarkable agreement between the angular power spectrum of these data and the predictions of the adiabatic inflationary scenario have established the empirical success of inflationary cosmology .
cosmic strings , though ruled out as the origin of cosmological structure , have recently enjoyed a renaissance . |
5,719 | Suppose that you have an abstract for a scientific paper: the two - dimensional kinetic ising model , when exposed to an oscillating applied magnetic field , has been shown to exhibit a nonequilibrium , second - order dynamic phase transition ( dpt ) , whose order parameter @xmath0 is the period - averaged magnetization .
it has been established that this dpt falls in the same universality class as the equilibrium phase transition in the two - dimensional ising model in zero applied field . here
we study for the first time the scaling of the dynamic order parameter with respect to a nonzero , period - averaged , magnetic ` bias ' field , @xmath1 , for a dpt produced by a square - wave applied field .
we find evidence that the scaling exponent , @xmath2 , of @xmath1 at the critical period of the dpt is equal to the exponent for the critical isotherm , @xmath3 , in the equilibrium ising model .
this implies that @xmath1 is a significant component of the field conjugate to @xmath0 .
a finite - size scaling analysis of the dynamic order parameter above the critical period provides further support for this result .
we also demonstrate numerically that , for a range of periods and values of @xmath1 in the critical region , a fluctuation - dissipation relation ( fdr ) , with an effective temperature @xmath4 depending on the period , and possibly the temperature and field amplitude , holds for the variables @xmath0 and @xmath1 .
this fdr justifies the use of the scaled variance of @xmath0 as a proxy for the nonequilibrium susceptibility , @xmath5 , in the critical region . .
And you have already written the first three sentences of the full article: the dynamic phase transition ( dpt ) in a ferromagnetic system below its critical temperature was first observed in numerical solutions of a mean - field model exposed to an oscillating magnetic field @xcite .
it was then studied further , both in mean - field models @xcite and in kinetic monte carlo ( kmc ) simulations @xcite . a review of this early work can be found in ref .
more recently , the study of the dpt has expanded to include varying ( and often more physical ) model geometries ..
Please generate the next two sentences of the article | these include mean - field studies of domain - wall motion in an anisotropic xy model in one dimension @xcite , kmc simulations of a three - dimensional ising system @xcite , and kmc simulations of a uniaxially anisotropic heisenberg system in an off - axial field @xcite , an elliptically polarized applied field @xcite , and with the effect of a thin - film surface energy @xcite .
the phenomenon has also been observed in simulations of co oxidation under oscillating co pressure @xcite . |
5,720 | Suppose that you have an abstract for a scientific paper: we show that smooth isoperimetric profiles are exceptional for real analytic riemannian manifolds .
for instance , under some extra assumption , this can happen only on topological spheres .
_ to cite this article : renata grimaldi , stefano nardulli , pierre pansu , c. r. acad .
sci .
paris , ser .
i * * * ( 200 + ) . _ 0.5 * rsum * 0.5 * differentiabilit du profil isoprimtrique et topologie des varits riemanniennes analytiques relles * on montre que la differentiabilit du profil isoprimtrique est une condition trs contraignante pour les varits riemannniennes analytiques relles .
par exemple , sous une hypothse supplmentaire , ce nest possible que si la varit est homomorphe une sphre .
_ pour citer cet article : renata grimaldi , stefano nardulli , pierre pansu , c. r. acad .
sci .
paris , ser .
i * * * ( 200 + ) .
_ differential geometry , , received * * * * * ; accepted after revision + + + + + + presented by - .
And you have already written the first three sentences of the full article: le _ profil isoprimtrique _ dune varit riemannienne @xmath0 est la fonction @xmath1 qui , en @xmath2 , vaut la borne infrieure @xmath3 des volumes des bords des domaines de volume gal @xmath4 .
il y a peu de varits riemanniennes do nt on connaisse exactement le profil ( voir @xcite pour un tat de lart ) .
parmi tous les exemples connus , seule la sphre ronde a un profil lisse ..
Please generate the next two sentences of the article | toute varit possde - t - elle une mtrique riemanienne de profil lisse ?
dans @xcite , on construit sur toute varit de dimension 2 ayant suffisamment de bout des mtriques lisses de profil lisse . |
5,721 | Suppose that you have an abstract for a scientific paper: the recent discoveries of massive neutron stars , such as psr j@xmath0 and psr j@xmath1 , have raised questions about the existence of exotic matter such as hyperons in the neutron star core . the validity of many established equations of states ( eos s ) like the gm1 and fsugold are also questioned .
we investigate the existence of hyperonic matter in the central regions of massive neutron stars using relativistic mean field ( rmf ) theory with the recently proposed iufsu model .
the iufsu model is extended by including hyperons to study the neutron star in @xmath2 equilibrium . the effect of different hyperonic potentials , namely @xmath3 and @xmath4 potentials , on the eos and hence the maximum mass of neutron stars has been studied .
we have also considered the effect of stellar rotation since the observed massive stars are pulsars .
it has been found that a maximum mass of @xmath5 , which is within the 3@xmath6 limit of the observed mass of psr j@xmath0 , can be obtained for rotating stars , with certain choices of the hyperonic potentials .
the said star contains a fair amount of hyperons near the core .
0.2 cm .
And you have already written the first three sentences of the full article: the recent discoveries of the massive neutron stars psr j@xmath0 @xcite and psr j@xmath1 @xcite have brought new challenges for theories of dense matter beyond the nuclear saturation density .
recently the radio timing measurements of the pulsar psr j@xmath0 and its white dwarf companion have confirmed the mass of the pulsar to be in the range of @xmath7 m@xmath8 at @xmath9 or @xmath10 m@xmath8 at @xmath11 confidence @xcite .
this is only the second neutron star(ns ) with a precisely determined mass around 2m@xmath8 , after psr j@xmath1 and has a 3@xmath6 lower mass limit @xmath12 m@xmath8 higher than the latter ..
Please generate the next two sentences of the article | it therefore provides the tightest reliable lower bound on the maximum mass of neutron stars .
compact stars provide the perfect astrophysical environment for testing theories of cold and dense matter . |
5,722 | Suppose that you have an abstract for a scientific paper: in olfactory search an immobile target emits chemical molecules at constant rate .
the molecules are transported by the medium which is assumed to be turbulent . considering a searcher able to detect such chemical signals and
whose motion follows the infotaxis strategy , we study the statistics of the first - passage time to the target when the searcher moves on a finite two - dimensional lattice of different geometries .
far from the target , where the concentration of chemicals is low the direction of the searcher s first movement is determined by the geometry of the domain and the topology of the lattice , inducing strong fluctuations on the average search time with respect to the initial position of the searcher .
the domain is partitioned in well defined regions characterized by the direction of the first movement . if the search starts over the interface between two different regions , large fluctuations in the search time are observed . .
And you have already written the first three sentences of the full article: optimal olfactory searches are essential for the survival of insects and animals in search for food and mating . these searches are based on the capacity of these organisms to detect the chemical signals emitted by the target , usually at distances that are further away to be visually located . in recent years several olfactory search strategies
have been proposed to model the way in which such organisms are capable of finding their targets @xcite . to accomplish a successful search the strategy has to be reliable to reach the target most of the times , robust against errors and efficient in the sense of exhibiting reasonably short search times . from a mathematical point of view ,
an optimal strategy is one that minimizes the search time , failure probability or any appropriate cost function ..
Please generate the next two sentences of the article | the complexity of an olfactory search is in general a consequence of the complexity of the transport of the chemical signals through the environment .
it is natural to expect that organisms using optimal strategies will have a survival advantage with respect to other competitors that do not . |
5,723 | Suppose that you have an abstract for a scientific paper: the nucleus of the milky way is known to harbour regions of intense star formation activity as well as a super - massive black hole@xcite .
recent fermi space telescope observations have revealed regions of @xmath0-ray emission reaching far above and below the galactic centre , the so - called fermi bubbles@xcite .
it is uncertain whether these were generated by nuclear star formation or by quasar - like outbursts of the central black hole@xcite and no information on the structures magnetic field has been reported . here
we report on the detection of two giant , linearly - polarized radio lobes , containing three ridge - like sub - structures , emanating from the galactic centre .
the lobes each extend @xmath1 , bear a close correspondence to the fermi bubbles , are located in the galactic bulge , and are permeated by strong magnetic fields of up to 15 @xmath2 g .
our data signal that the radio lobes originate in a bi - conical , star - formation ( rather than black hole ) driven outflow from the galaxy s central 200 pc that transports a massive magnetic energy of @xmath3 erg into the galactic halo .
the ridges wind around this outflow and , we suggest , constitute a ` phonographic ' record of nuclear star formation activity over at least 10 myr . ettore carretti,@xmath4 roland m. crocker,@xmath5 lister staveley - smith@xmath6 , marijke haverkorn@xmath7 , cormac purcell@xmath8 , b. m. gaensler@xmath8 , gianni bernardi@xmath9 , michael j. kesteven@xmath10 , and sergio poppi@xmath11 csiro astronomy and space science , po box 276 , parkes , nsw 2870 , australia max - planck - institut f " ur kernphsik , p.o .
box 103980 heidelberg , germany research school of astronomy & astrophysics , australian national university , weston creek , act 2611 , australia international centre for radio astronomy research , m468 , university of western australia , crawley , wa 6009 , australia arc centre of excellence for all - sky astrophysics department of astrophysics / imapp , radboud....
And you have already written the first three sentences of the full article: * figure 1 : linearly polarized intensity @xmath29 at 2.3 ghz from s - pass * ( @xmath30 ) .
the thick dashed lines delineate the radio lobes reported in this letter , while the thin dashed lines delimit the @xmath0-ray fermi bubbles@xcite .
the map is in galactic coordinates , centred at the galactic centre with galactic east to the left and galactic north up ; the galactic plane runs horizontally across the centre of the map ..
Please generate the next two sentences of the article | the polarized flux density is indicated by the scale bar given in unit of jy / beam with a beam size of 10.75 ( 1 jy @xmath31 w m@xmath32hz@xmath33 ) .
the lobe edges follow the @xmath0-ray border up to @xmath34 where the radio emission extends beyond . |
5,724 | Suppose that you have an abstract for a scientific paper: we investigate the prospects for determining the accelerating history of the universe from upcoming measurements of the expansion rate @xmath0 . in our analyses , we use monte carlo simulations based on @xmath1cdm models to generate samples with different characteristics and calculate the evolution of the deceleration parameter @xmath2 .
we show that a cosmographic ( and , therefore , model - independent ) evidence for cosmic acceleration ( @xmath3 , where @xmath4 is the transition redshift ) will only be possible with an accuracy in @xmath0 data greater than the expected in current planned surveys . a brief discussion about the prospects for reconstructing the dark energy equation of state from the parameters @xmath0 and @xmath2
is also included . .
And you have already written the first three sentences of the full article: the determination of cosmographic parameters , such as @xmath5 and @xmath6 , has a long and interesting history in cosmology ( see , e.g. , @xcite ) . in particular
, the evolution of such parameters provides a unique and direct method to map the expansion history of the universe in a model - independent way .
since all evidence we have so far for the current cosmic acceleration are indirect @xcite , extracting the evolution of these two parameters from future redshift surveys constitutes one of the major challenges in observational cosmology may also reduce the so - called smearing effect that makes constraining the dark energy equation of state ( eos ) @xmath1 extremely difficult @xcite . ] . in this paper.
Please generate the next two sentences of the article | , we investigate how well cosmography may provide a model - independent way to check the reality of cosmic acceleration .
specifically , we study the evolution of the deceleration parameter from the @xmath0 data which are to become available by some planned projects . to this end |
5,725 | Suppose that you have an abstract for a scientific paper: decoherence is the main obstacle to the realization of quantum computers . until recently it was thought that quantum error correcting codes are the only complete solution to the decoherence problem . here
we present an alternative that is based on a combination of a decoherence - free subspace encoding and the application of strong and fast pulses : `` encoded recoupling and decoupling '' ( erd ) .
this alternative has the advantage of lower encoding overhead ( as few as two physical qubits per logical qubit suffice ) , and direct application to a number of promising proposals for the experimental realization of quantum computers . .
And you have already written the first three sentences of the full article: in the quest to construct large - scale quantum information processors , in particular quantum computers , decoherence is still the main obstacle to realization .
decoherence is the degradation of quantum information due to inevitable interactions with the environment .
early skepticism @xcite concerning the viability of quantum computation ( qc ) in the presence of decoherence was overcome by the discovery of quantum error correcting codes ( qeccs),@xcite that flourished into a comprehensive theory that incorporates all elements of quantum computation.@xcite a qecc relies on an encoding of quantum information into the state of several quantum bits ( qubits ) , and a closed - loop , active error diagnosis and correction procedure.@xcite in principle , it is possible to correct arbitrary errors using sufficiently large qeccs.@xcite in practice , however , this may require a very large overhead , especially in terms of qubit resources.@xcite this is troubling in light of the substantial difficulties associated with generating and controlling systems with very large numbers of qubits ..
Please generate the next two sentences of the article | in addition , the theory of qeccs is rather abstract , in that it presumes that one can execute certain logical operations , but does not refer to the underlying hamiltonians governing specific physical systems .
hence it is of interest to explore alternatives to qeccs , that are more economical in qubit resources , and that are direcly tailored to specific quantum computer proposals . |
5,726 | Suppose that you have an abstract for a scientific paper: this paper reports on the learning computational grammars ( lcg ) project , a postdoc network devoted to studying the application of machine learning techniques to grammars suitable for computational use .
we were interested in a more systematic survey to understand the relevance of many factors to the success of learning , esp .
the availability of annotated data , the kind of dependencies in the data , and the availability of knowledge bases ( grammars ) .
we focused on syntax , esp .
noun phrase ( np ) syntax . .
And you have already written the first three sentences of the full article: this paper reports on the still preliminary , but already satisfying results of the learning computational grammars ( lcg ) project , a postdoc network devoted to studying the application of machine learning techniques to grammars suitable for computational use .
the member institutes are listed with the authors and also included issco at the university of geneva .
we were impressed by early experiments applying learning to natural language , but dissatisfied with the concentration on a few techniques from the very rich area of machine learning ..
Please generate the next two sentences of the article | we were interested in a more systematic survey to understand the relevance of many factors to the success of learning , esp .
the availability of annotated data , the kind of dependencies in the data , and the availability of knowledge bases ( grammars ) . |
5,727 | Suppose that you have an abstract for a scientific paper: the computer code decay4 is developed to generate initial energy , time and angular distributions of particles emitted in radioactive decays of nuclides and nuclear ( atomic ) deexcitations .
data for description of nuclear and atomic decay schemes are taken from the ensdf and eadl database libraries .
the examples of use of the decay4 code in several underground experiments are described . -10pt
-10pt 0.4 cm * o.a .
ponkratenko , v.i .
tretyak and yu.g .
zdesenko * _ institute for nuclear research , prospect nauki 47 , msp 03680 kiev , ukraine _ .
And you have already written the first three sentences of the full article: despite the fact that effect to background ratio is the central problem of all experimental physics , there is a certain class of experiments for which this problem is so crucial that even the possibility of their performance itself depends strongly on the reached background level of the used detectors .
these are so called underground experiments devoted to investigation of the very rare or forbidden decays and processes like , for instance , double beta decay , proton decay , dark matter particles search , solar neutrino study and so on .
the ultimate sensitivity of such experiments is determined mainly ( except the available source strengths ) by the detector background ..
Please generate the next two sentences of the article | the first origin of background is due to cosmic rays and can be eliminated by the proper underground site for the set up .
the second ( and the most crucial for sensitivity ) source of the background is the decays of the nuclides from the radioactive impurities in the detector itself , in the materials used for detector mounting and shielding , and in the surroundings . |
5,728 | Suppose that you have an abstract for a scientific paper: the darwin approximation is investigated for its possible use in simulation of electromagnetic effects in large size , high frequency capacitively coupled discharges .
the approximation is utilized within the framework of two different fluid models which are applied to typical cases showing pronounced standing wave and skin effects . with the first model it is demonstrated that darwin approximation is valid for treatment of such effects in the range of parameters under consideration .
the second approach , a reduced nonlinear darwin approximation - based model , shows that the electromagnetic phenomena persist in a more realistic setting .
the darwin approximation offers a simple and efficient way of carrying out electromagnetic simulations as it removes the courant condition plaguing explicit electromagnetic algorithms and can be implemented as a straightforward modification of electrostatic algorithms .
the algorithm described here avoids iterative schemes needed for the divergence cleaning and represents a fast and efficient solver , which can be used in fluid and kinetic models for self - consistent description of technical plasmas exhibiting certain electromagnetic activity . .
And you have already written the first three sentences of the full article: low temperature plasmas play a crucial role in materials processing @xcite . particularly capacitive
radio frequency discharges are important .
such plasmas , which were first introduced in the 1960s , have undergone a continuous development keeping up with the increasing requirements of the hitech industry ..
Please generate the next two sentences of the article | one trend is the attempt to increase productivity by increasing the size of the processed wafers or substrates . in microelectronics , wafer sizes of @xmath0 mm
are now state of the art , the transition to @xmath1 mm is envisioned @xcite . |
5,729 | Suppose that you have an abstract for a scientific paper: detached eclipsing binaries are very useful objects for calibrating theoretical stellar models and checking their predictions .
detached eclipsing binaries in open clusters are particularly important because of the additional constraints on their age and chemical composition from their membership of the cluster .
i compile a list containing absolute parameters of well - studied eclipsing binaries in open clusters , and present new observational data on the b - type systems v1481cyg and v2263cyg which are members of the young open cluster ngc7128 . .
And you have already written the first three sentences of the full article: theoretical stellar evolution models are of huge importance to stellar and galactic astrophysics because they are basically the only way of deriving the age , internal structure and composition of stars and galaxies from simple observational data ( e.g. meynet et al . 2005 ;
nordstrm et al .
the accuracy of the results depends on the predictive power of the models , but this is severely limited by the parameteric treatment of several effects , including convective core overshooting ( @xmath0 ) , the efficiency of convective energy transport ( @xmath1 ) , the effects of rotation , magnetic fields and mass loss , and the need to use theoretically - calculated opacities ..
Please generate the next two sentences of the article | the main offender is @xmath0 , changes in which cause major modifications to the predicted lifetimes , chemical yields and luminosities of massive stars ( e.g. maeder & meynet 1989 ) .
this in turn has a large effect on the predicted properties and formation rates of evolved objects such as core - collapse supernovae ( eldridge & tout 2004 ) and black holes . |
5,730 | Suppose that you have an abstract for a scientific paper: the conditions for occurrence of the efimov effect is briefly described using hyperspherical coordinates .
the strength of the effective hyperradial @xmath0 potential appearing for two or three large scattering lengths is computed and discussed as function of two independent mass ratios of the three constituent particles .
the effect is by far most pronounced for asymmetric systems with three very different masses .
one efimov state may by chance appear in nuclei .
many states could be present for systems with one electron and two neutral atoms or molecules .
estimates of the number of states and their sizes and energies are given . .
And you have already written the first three sentences of the full article: more than 30 years ago efimov realized that a three - body system could have a large number of bound states when two or three of the two - body subsystems simultaneously have ( virtual or bound ) @xmath1-states sufficiently close to zero energy @xcite .
this effect has been discussed in a number of subsequent publications @xcite .
external fields can be used to tune the effective two - body interaction aiming at approaching the zero energy condition @xcite ..
Please generate the next two sentences of the article | the picture describing the efimov effect is that one particle effectively has large - distance interaction simultaneously with both the other two particles building up a coherent wave function fully exploiting the interactions .
when only one scattering length is large the effect does not occur since the effective large - distance interactions only involve two of the particles while the third can avoid contributing by being far away without interacting . |
5,731 | Suppose that you have an abstract for a scientific paper: finite group theorists have established many formulas that express interesting properties of a finite group in terms of sums of characters of the group .
an obstacle to applying these formulas is lack of control over the dimensions of representations of the group . in particular , the representations of small dimensions tend to contribute the largest terms to these sums , so a systematic knowledge of these small representations could lead to proofs of important conjectures which are currently out of reach . despite the classification by lusztig of the irreducible representations of finite groups of lie type , it seems that this aspect remains obscure . in this note
we develop a language which seems to be adequate for the description of the * * `` small '' * * representations of finite classical groups and puts in the forefront the notion of * * rank * * _ _ _ _ of a representation .
we describe a method , the * `` eta correspondence '' , * to construct small representations , and we conjecture that our construction is exhaustive . we also give a strong estimate on the dimension of small representations in terms of their rank . for the sake of clarity , in this note
we describe in detail only the case of the finite symplectic groups . .
And you have already written the first three sentences of the full article: finite group theorists have established formulas that enable expression of interesting properties of a group @xmath0 in terms of quantitative statements on sums of values of its characters .
there are many examples @xcite .
we describe a representative one ..
Please generate the next two sentences of the article | consider the commutator map@xmath1 : g\times g\rightarrow g;\text { \ \ } [ x , y]=xyx^{-1}y^{-1 } , \label{cm}\]]and for @xmath2 denote by @xmath3 _ { g}$ ] the set @xmath3 _ { g}=\{(x , y)\in g\times g;$ ] @xmath4=g\}.$ ] in @xcite ore conjectured that for a finite non - commutative simple group @xmath0 the map ( [ cm ] ) is onto , i.e. , @xmath5 _
{ g}\neq 0,$ ] for every @xmath6 the quantity @xmath5 _ { g}$ ] is a class function on @xmath0 and frobenius developed the formula for its expansion as a linear combination of irreducible characters . |
5,732 | Suppose that you have an abstract for a scientific paper: we study the average density of resonances ( dor ) for a semi - infinite disordered chain , coupled to the outside world by a ( semi - infinite ) perfect lead .
a set of equations is derived , which provides the general framework for calculating the average dor , for an arbitrary disorder and coupling strength .
these general equations are applied to the case of weak coupling and an asymptotically exact expression for the averaged dor is derived , in the limit of small resonance width .
this expression is universal , in the sense that it holds for any degree of disorder and everywhere in the ( unperturbed ) energy band .
21 cm 16 cm -0.15 cm .
And you have already written the first three sentences of the full article: open quantum systems often exhibit the phenomenon of resonances .
resonances correspond to quasi - stationary states which have a long life - time but eventually decay into the continuum .
( a particle , initially within the system , escapes to infinity . ).
Please generate the next two sentences of the article | one approach to the problem of resonances is based on the study of the analytic properties of the scattering matrix , @xmath0 , in the complex energy plane .
resonances correspond to the poles , @xmath1 , of @xmath0 on the unphysical sheet @xcite . |
5,733 | Suppose that you have an abstract for a scientific paper: a hypersurface @xmath0 , @xmath1 , has the central ovaloid property , or _ cop _ , if * @xmath2 meets some hyperplane transversally along an ovaloid , and *
every such ovaloid on @xmath2 has central symmetry .
generalizing work of b. solomon to higher dimensions , we show that a complete , connected , smooth hypersurface with _ cop _ must either be a cylinder over a central ovaloid , or else quadric . .
And you have already written the first three sentences of the full article: a central set in a euclidean space has symmetry with respect to reflection through a point , called its center .
a closed embedded smooth hypersurface of @xmath3 is called an ovaloid if all its principal curvatures , with respect to the outer unit normal , are positive everywhere .
an ovaloid of dimension one is also called an oval . the compact transverse cross - sections of a cylinder over a central ovaloid in @xmath3 , @xmath4 , with hyperplanes are central ovaloids ..
Please generate the next two sentences of the article | a similar result holds also for quadrics , which are the level sets of quadratic polynomials in @xmath3 , @xmath4 .
their compact transverse cross - sections with hyperplanes are ellipsoids , which are central ovaloids . |
5,734 | Suppose that you have an abstract for a scientific paper: the subtle interplay between local and global charges for topological semimetals exactly parallels that for singular vector fields .
part of this story is the relationship between cohomological semimetal invariants , euler structures , and ambiguities in the torsion of manifolds .
dually , semimetal invariants can be represented by euler chains from which the surface fermi arc connectivity can be deduced .
these dual pictures , and the link to insulators , are organised using geometric exact sequences .
we go beyond dirac - type hamiltonians and introduce new classes of semimetals whose local charges are subtle atiyah
dupont
thomas invariants globally constrained by the kervaire semicharacteristic , leading to the prediction of torsion fermi arcs . .
And you have already written the first three sentences of the full article: as theoretically predicted in @xcite and experimentally discovered in @xcite , two - band solid state systems in 3d can host topologically protected `` weyl semimetallic phases '' in which the quasiparticle excitations at the band crossings ( `` weyl points '' ) share some features with weyl fermions from relativistic quantum mechanics .
the experimental signature , namely `` fermi arcs '' of surface states which connect the projected weyl points in the surface brillouin zone , is just as remarkable .
based on this initial success , much effort has been put into the general study of topological semimetallic phases in the hope of predicting and eventually realising new exotic fermionic quasiparticles in condensed matter systems ..
Please generate the next two sentences of the article | most proposals have focused on _ local _ aspects in the sense of finding new types of topological obstructions to locally opening up gaps in semimetal band crossings .
staying in the two - band case , there are generalisations of the basic weyl semimetal phase to `` type - ii '' ones @xcite , as well as `` quadratic '' ones @xcite . |
5,735 | Suppose that you have an abstract for a scientific paper: the primordial abundances of deuterium , helium , and lithium probe the baryon density of the universe only a few minutes after the big bang . of these relics from the early universe , deuterium is the baryometer of choice . after reviewing the current observational status ( a moving target ! ) ,
the bbn baryon density is derived and compared to independent estimates of the baryon density several hundred thousand years after the big bang ( as inferred from cmb observations ) and at present , more than 10 billion years later .
the excellent agreement among these values represents an impressive confirmation of the standard model of cosmology , justifying indeed , demanding more detailed quantitative scrutiny . to this end ,
the corresponding bbn - predicted abundances of helium and lithium are compared with observations to further test and constrain the standard , hot , big bang cosmological model . .
And you have already written the first three sentences of the full article: as progress is made towards a new , precision era of cosmology , _ redundancy _ will play an increasingly important role .
as cosmology is an _
observational _ science , it will be crucial to avail ourselves of multiple , independent tests of , and constraints on , competing cosmological models and their parameters ..
Please generate the next two sentences of the article | furthermore , such redundancy may provide the only window on systematic errors which can impede our progress or send us off in unprofitable directions . to illustrate the efficacy of such an approach in modern cosmology , i ll track the baryon density of the universe as revealed early on ( first few minutes ) by big bang nucleosynthesis ( bbn ) , later ( few hundred thousand years ) as coded in the fluctuation spectrum of the cosmic microwave background ( cmb ) radiation , and up to the present , approximately 10 gyr after the expansion began .
as theory suggests and terrestrial experiments confirm , baryon number should be preserved throughout these epochs in the evolution of the universe , so that the number of baryons ( @xmath0 nucleons ) in a comoving volume _ should _ be unchanged from bbn to today . as a surrogate for identifying a comoving volume , we may compare the baryon / nucleon density to the density of cmb relic photons . |
5,736 | Suppose that you have an abstract for a scientific paper: the zero - temperature phase diagram of @xmath0-orbital two - component fermionic system loaded into a one - dimensional optical lattice is mapped out by means of analytical and numerical techniques .
it is shown that the @xmath0-band model away from half - filling hosts various competing superconducting phases for attractive and repulsive interactions . at quarter filling , we analyze the possible formation of incompressible mott phases and in particular for repulsive interactions , we find the occurrence of a mott transition with the formation of fully gapped bond - ordering waves . .
And you have already written the first three sentences of the full article: ladder systems have been the focus of much theoretical and experimental work over more than two decades .
one theoretical motivation was to investigate the dimensional crossover between the well - known one - dimensional ( 1d ) physics and the two - dimensional ( 2d ) case , in the search of 2d non - fermi liquid physics .
a second reason stems from experiments and the study of ladder compounds , such as the famous telephone number one sr@xmath1ca@xmath2cu@xmath3o@xmath4 which has a superconducting phase at high pression and for a small hole density ..
Please generate the next two sentences of the article | @xcite the simplest ladder model is that of a two - leg ladder , made of two coupled fermionic chains . in stark contrast to the single chain case , the two - leg ladder system displays a superconducting phase with @xmath5-wave superconductivity for repulsive interactions which stems from the doping of a spin - gapped mott insulating phase at half - filling .
@xcitethis gave the belief that the two - leg ladder problem already contains seeds of the rich physics of the cuprates . |
5,737 | Suppose that you have an abstract for a scientific paper: the preliminary na49 results on the energy dependence of transverse momentum fluctuations over the whole super proton synchrotron ( sps ) energy range exhibit an unexpected effect .
the @xmath0 fluctuation measure - used by the na49 experiment - manifests a different behavior for different charge combinations .
whereas the @xmath0 is consistent with zero and independent of energy for negatively charged particles , it significantly increases for both all charged and positively charged particles at lower sps energies .
the string - hadronic ultrarelativistic quantum molecular dynamics model ( urqmd ) is applied here to explain this effect .
the urqmd simulations show that the number of protons is strongly correlated with impact parameter and that the event - by - event impact parameter fluctuations are responsible for the event - by - event transverse momentum fluctuations of positively charged and all charged particles where protons are included .
the observations presented in this article are important for all experiments measuring event - by - event fluctuations , especially for those using all charged particles in the analysis .
the results can be also crucial for detectors with acceptances extending to the beam / target spectator domains .
* influence of impact parameter fluctuations * * on transverse momentum fluctuations * * katarzyna grebieszkow * + warsaw university of technology + e - mail : .
And you have already written the first three sentences of the full article: event - by - event fluctuations of kinematic characteristics and particle yields are believed to be one of the important probes to study the dynamics of heavy - ion collisions .
transverse momentum and multiplicity fluctuations are expected to be modified when the system approaches the phase boundary between hadron gas and quark - gluon plasma ( qgp ) .
it has been also argued that significant transverse momentum and multiplicity fluctuations should appear for systems hadronizing near the second - order critical qcd end - point @xcite ..
Please generate the next two sentences of the article | the qcd phase diagram - ( @xmath1 ) , where @xmath2 is the temperature and @xmath3 bariochemical potential - can be scanned both by varying the system size / centrality and energy and therefore a possible nonmonotonic evolution of event - by - event ( @xmath4 and multiplicity ) fluctuations with beam energy , system size , or centrality may be used as an indication of the phase transition and the qcd critical point @xcite .
the na49 experiment at the cern sps studied both the system size dependence and the energy dependence of transverse momentum fluctuations . in the analysis of the na49 data |
5,738 | Suppose that you have an abstract for a scientific paper: the w - boson mass has been measured using the aleph detector at lep .
preliminary results from data taken in 1998 are added to previous measurements to give @xmath0
= 80.411 @xmath1 0.064(stat . )
@xmath1 0.037(syst . )
@xmath1 0.022(be - cr ) @xmath1 0.018(lep ) gev/@xmath2 .
glas - ppe/199919november 1999 .
And you have already written the first three sentences of the full article: in this paper we discuss the measurement of the w mass from direct reconstruction of the invariant mass of the decay products in the channels ww@xmath3qqqq ( 4q ) and ww@xmath4qq .
preliminary results are presented for data collected in aleph@xcite during 1998 with an integrated luminosity of 174.2@xmath5 at 188.63gev .
events are preselected to remove radiative returns to the z and clustered into four jets using the ` durham - pe ` algorithm , defining @xmath6 ..
Please generate the next two sentences of the article | events are vetoed if a charged track in a jet carries more than 90% of the jet energy or if there is more than 95% of electromagnetic energy in a @xmath7 cone around any particle .
a neural network with fourteen input variables ( nn14 ) is used to perform the final selection . |
5,739 | Suppose that you have an abstract for a scientific paper: seeger s semi - empirical mass formula is revisited for two of its constants ( bulk constant @xmath0 and neutron - proton asymmetry constant @xmath1 ) readjusted to obtain the ground - state ( g.s . )
binding energies of nuclei within a precision of @xmath21.5 mev and for nuclei up to z=118 .
the aim is to include the temperature t - dependence on experimental binding energies , and not to obtain the new parameter set of seeger s liquid drop energy @xmath3 .
our proceedure is to define the g.s .
binding energy @xmath4 , as per strutinsky renormalization procedure , and using the empirical shell corrections @xmath5 of myers and swiatecki , fit the constants of @xmath3 to obtain the experimental binding energy @xmath6 or theoretically calculated @xmath7 if data were not available .
the t - dependence of the constants of @xmath3 , is introduced as per the work of davidson _ et al .
_ , where the pairing energy @xmath8 is modified as per new calculations on compound nucleus decays .
the newly fitted constants of @xmath3 at t=0 are made available here for use of other workers interested in nuclear dynamics of hot and rotating nuclei . .
And you have already written the first three sentences of the full article: seeger s mass formula @xcite was given in 1961 , with its constants fitted to ground - state ( g.s ) binding energies of some 488 nuclei available at that time .
the temperature t - dependence of these constants was later introduced by davidson _
@xcite on the basis of thermodynamical considerations of the nucleus ..
Please generate the next two sentences of the article | these constants , however , need be fitted again since a large amount of data on experimental g.s .
binding energies @xcite , and their theoretically calculated values @xcite for , not - yet observed , neutron- and proton - rich nuclei have now become available . |
5,740 | Suppose that you have an abstract for a scientific paper: we consider scalar perturbations in the time - dependent horava - witten model in order to probe its stability .
we show that during the non - singular epoque the model evolves without instabilities until it encounters the curvature singularity where a big crunch is supposed to occur .
we compute the frequencies of the scalar field oscillation during the stable period and show how the oscillations can be used to prove the presence of such a singularity .
= 1000 pacs numbers : 04.50.-h @xmath0 04.60.cf @xmath0 11.25.wx @xmath0 11.25.yb .
And you have already written the first three sentences of the full article: the classical big - bang model based on einstein s general relativity does not explain the origin of the initial singularity , which is expected to be understood at a higher dimensional string theory model .
it is known that the horava - witten theory @xcite relates 11-dimensional supergravity on the orbifold @xmath1 with strongly coupled heterotic @xmath2 string theory .
then , this link suggests that as one probes higher energies , our 4-dimensional universe would first go through an intermediate regime where the orbifold dimension becomes visible , thus making our world appear 5-dimensional @xcite , and only at energies of order the string scale the universe would look 11-dimensional ..
Please generate the next two sentences of the article | the intermediate 5-dimensional energy regime has led to the conjecture that our universe is a brane in a higher dimensional world .
these horava - witten inspired `` braneworlds '' have a topology defined by a line times a non - compact space with two branes at the boundaries of the line element , which is usually characterized as the orbifold @xmath1 . due to the compactness of the orbifold direction , |
5,741 | Suppose that you have an abstract for a scientific paper: = 0.55 cm we present the exact @xmath0 correction to the process @xmath1 , @xmath2 , for isr@xmath3fsr at and beyond lep2 energies .
we give explicit formulas for the completely differential cross section . as an important application ,
we compute the size of the respective sub - leading corrections of @xmath4 to the @xmath5 cross section , where @xmath6 is the respective big logarithm in the renormalization group sense so that it is identifiable as @xmath7 when @xmath8 is the squared @xmath9 cms energy .
comparisons are made with the available literature .
we show explicitly that our results have the correct infrared limit , as a cross - check .
some comments are made about the implementation of our results in the framework of the monte carlo event generator mc .
= 0.6 cm currently , the final lep2 data analysis is in its beginning stages , and the desired total precision tags on the important lep2 physics processes @xmath10 , @xmath2 , are already called out in the lep2 mc workshop in ref . @xcite .
it has been demonstrated in ref .
@xcite that the monte carlo ( mc ) event generator program @xmath11
@xcite , hereafter referred to as mc , and the semi - analytical program zfitter @xcite realize these precisions ( @xmath12 ) in most channels for inclusive cross sections and that for the fully differential distributions , the mc again meets most of the requirements for the lep2 final data analysis . in this paper , we present exact results on the @xmath0 correction to the single hard bremsstrahlung processes @xmath13 , @xmath2 .
this correction is an important contribution to the differential distributions as they are realized in the mc which allows the very demanding precisions just cited to be achieved .
specifically , the exact results for the @xmath0 corrections to @xmath8-channel annihilation hard bremsstrahlung processes under study here were also considered in refs .
@xcite .
we differ from these results as follows .
concerning ref .
@xcite , the....
And you have already written the first three sentences of the full article: in this section we set our notational conventions .
we will use the conventions of refs .
@xcite for our spinors ..
Please generate the next two sentences of the article | these conventions are based on the kleiss - stirling @xcite weyl spinors augmented as described in refs .
@xcite with the rules for controlling their complex phases , or equivalently , the three axes of the fermion rest frame in which the spin of that fermion is quantized . |
5,742 | Suppose that you have an abstract for a scientific paper: the 3d heisenberg model is studied from a dual point of view in terms of 2d solitons ( vortices ) .
it is shown that the disordered phase corresponds to condensation of vortices in the vacuum , and the critical indices are computed from the corresponding disorder parameter . .
And you have already written the first three sentences of the full article: the heisenberg ferromagnet is defined by the partition function @xmath0 = \int \prod [ d \omega(x ) \exp(-s)\label{eq:1}\ ] ] where @xmath1 ^ 2 \qquad \vec n^2(x ) = 1\label{eq:2}\ ] ] and @xmath2 is the element of solid angle for the orientation of @xmath3 in colour space .
the model presents a 2nd order phase transition at @xmath4@xcite . for @xmath5
there is an ordered phase , with order parameter the magnetization @xmath6 ; for @xmath7 , @xmath8 ( disordered phase ) ..
Please generate the next two sentences of the article | we shall describe the system from a dual point of view , and show that in the disordered phase vortices condense .
the model will be viewed as a @xmath9 dimensional euclidean field theory . |
5,743 | Suppose that you have an abstract for a scientific paper: this poster discusses a possible explanation for the relationship between the mass of the central supermassive black hole and the velocity dispersion in the bulge of the host galaxy .
we suppose that the black hole and the dark matter halo are forming simultaneously as matter falls in , and a self - similar system then exists in which the mass and the velocities of the system evolve as power - law functions of time .
this leads naturally to a relationship between the black hole mass and the velocities in the halo which , with a reasonable choice of cosmological parameters , is in good agreement with the observed relationship .
we also confirm this relationship with more robust numerical results .
[ 1996/06/01 ] a&a .
And you have already written the first three sentences of the full article: supermassive black holes ( bhs ) are now considered to be a common feature of galaxies which have a bulge .
furthermore , a number of observational properties of the host galaxy correlate with the bh mass . among the strongest of these correlations
is the relationship between the bh mass and velocity dispersion within the galactic bulge ( ferrarese & merritt 2000 ; gebhardt et al . 2000 ) : @xmath1 , where @xmath2 ( tremaine et al . 2002 ) ..
Please generate the next two sentences of the article | since the velocity dispersion is measured well outside of the bh `` influence , '' this correlation indicates that an intimate relationship exists between the bh and the dynamical structure of the host galaxy .
we assume that a galaxy forms by the extended collapse of a `` halo '' composed of collisionless matter and that simultaneously the central black hole is growing proportionally to the halo as matter continues to fall in . |
5,744 | Suppose that you have an abstract for a scientific paper: semi - classical description of bh , as it was originally introduced by hawking and bekenstein in the early seventies , where classical solutions of the einstein equations are coupled to quantum matter fields , opened for the first time a window with a glance on the quantum aspects of gravity .
the surprising properties showed by semi - classical description of black holes ( bhs ) called for a full quantum description for such objects . in particular , the understanding of bh entropy in terms of micro - states , as well as the behavior during the final phase of evaporation , can not be properly described in semi - classical terms .
quantum gravity has a long story of doomed attempts to cure the theory from non - renormalizability and quantum anomalies . in the eighties
green and schwarz brilliantly solved these problems in the framework of @xmath0 or @xmath1 super - symmetric quantum string theories . up to now
, string theory is the best candidate for a grand unified theory including gravity at the quantum level in a consistent way . accepting that the building blocks of matter are one - dimensional extended objects , characterized by a length scale of order @xmath2 , still the relation between fundamental strings and bhs remains to be determined .
the exponential increase of string states degeneracy with the string excitation energy resembles the exponential increase of bh states with the increase of bh mass .
this and other results suggest a correspondence between bhs and highly excited strings , or string balls .
however , a more precise stringy formulation of bhs requires a non - perturbative formulation of the theory itself , including the interaction with higher dimensional objects , i.e. d - branes .
so far , this approach provides the correct entropy counting bh micro - states only in a limited number of cases , but not in general . in this chapter
we would like to review a `` phenomenological '' approach taking into account the most fundamental feature of string theory or....
And you have already written the first three sentences of the full article: the description of radiating bhs by hawking @xcite offered the first physically relevant `` peep '' on the mysteries of quantum gravity .
after more than forty years of intensive research in this field ( see @xcite and @xcite for a recent review with an extensive reference list ) various aspects of the problem still remain to be properly explained .
for example , a satisfactory description of the terminal stage of bh evaporation remains still to be understood ..
Please generate the next two sentences of the article | so far , the string theory seems to be the best candidate for self - consistent , ultraviolet completion of gravity at the planck scale . on the other hand , following bekenstein s idea , the bh entropy is formally identified with the area of the event horizon in planck units .
thus , combining hawking s definition of bh temperature with the area law gives a consistent thermodynamical description of semi - classical bhs dynamics . |
5,745 | Suppose that you have an abstract for a scientific paper: deep x - ray surveys have shown that the cosmic x - ray background ( xrb ) is largely due to accretion onto supermassive black holes , integrated over cosmic time .
however , the characteristic hard spectrum of the xrb can only be explained if most agn spectra are heavily absorbed .
the absorbed agn will suffer severe extinction and therefore , unlike classical qsos , will not be prominent at optical wavelengths .
most of the accretion power is being absorbed by gas and dust and will have to be reradiated in the fir / sub - mm band .
agn could therefore contribute a substantial fraction to the recently discovered cosmic fir / sub - mm background .
here it is shown that a number of high - redshift absorbed x - ray sources selected in the _ rosat _ deep survey of the lockman hole have broad - band spectral energy distributions very similar to the local ulirg ngc6240 , lending additional support to the background models for the obscured universe . .
And you have already written the first three sentences of the full article: all cosmic processes like the big bang , the formation and evolution of galaxies , the creation and the growth of massive black holes and the heating of the universe due to large - scale clustering will imprint characteristic radiation patterns on the electromagnetic spectrum of the universe .
the structure of the universe at the epoch of decoupling is frozen into the 2.7 k cosmic microwave background ( cmb ) .
star and galaxy light , produced after the dark ages by thermonuclear fusion , is mainly confined to the near - infrared , optical and ultraviolet spectral bands ..
Please generate the next two sentences of the article | active black holes in galactic nuclei ( agn ) , which accrete matter and efficiently convert gravitational energy into radiation , typically shine in a very broad energy band , from radio to gamma wavelengths . the role of dust is also very important : it absorbs optical , uv and x - ray light , is warmed up and re - radiates the energy in the far - infrared band .
the extragalactic background radiation , i.e. the total cosmic energy density spectrum , therefore gives a fossil record of all radiation processes in the universe , integrated over cosmic time . |
5,746 | Suppose that you have an abstract for a scientific paper: we consider the problem of photon creation from vacuum inside an ideal cavity with vibrating walls in the resonance case , taking into account the interaction between the resonant field mode and a detector modeled by a quantum harmonic oscillator .
the frequency of wall vibrations is taken to be twice the cavity normal frequency , modified due to the coupling with the detector .
the dynamical equations are solved with the aid of the multiple scales method .
analytical expressions are obtained for the photon mean numbers and their variances for the field and detector modes , which are supposed to be initially in the vacuum quantum states .
we analyze different regimes of excitation , depending on the ratio of the modulation depth of the time - dependent cavity eigenfrequency to the coupling strength between the cavity mode and detector .
we show that statistical properties of the detector quantum state ( variances of the photon numbers , photon distribution function , and the degree of quadrature squeezing ) can be quite different from that of the field mode . besides , the mean number of quanta in the detector mode increases with some time delay , compared with the field mode . .
And you have already written the first three sentences of the full article: the effect of photon creation from vacuum in a cavity with rapidly varying geometrical or material properties , called nowadays as dynamical casimir effect ( dce ) , attracted attention of many researchers for a long time : see recent reviews @xcite .
the first experimental results for the open strip - line waveguide with time - dependent boundary conditions , simulating a single oscillating ideal mirror in the one - dimensional space , were reported recently in @xcite .
it is quite probable that new experiments in other geometries will be done soon , too ..
Please generate the next two sentences of the article | therefore , the problem of the back action of different detectors on the rate of photon generation becomes actual .
the very first studies were performed in @xcite under the condition that the field - detector coupling is much stronger than the effective coupling between the selected resonance field mode in the cavity and moving boundary ( due to strong limitations on the attainable amplitude of surface oscillations in real materials ) . however , since that time there were proposed several schemes on simulating the dce by means of changing not the positions of boundaries but their material properties @xcite . in such cases the effective velocity of boundaries can be increased by several orders of magnitude , therefore the situations where the modulation depth of the instantaneous cavity eigenfrequency is bigger than the normalized field - detector coupling coefficient can be considered now quite realistic , as well . |
5,747 | Suppose that you have an abstract for a scientific paper: we present a new code allowing to evolve three - dimensional self - gravitating collisionless systems with a large number of particles @xmath0 . *
fly * ( fast level - based n - body code ) is a fully parallel code based on a tree algorithm .
it adopts periodic boundary conditions implemented by means of the ewald summation technique .
fly is based on the one - side communication paradigm to share data among the processors that access remote private data avoiding any kind of synchronism .
the code was originally developed on a cray t3e system using the _ shmem _ library and it was ported on sgi origin 2000 and on ibm sp ( on the latter making use of the _ lapi _ library ) .
version 1.1 is an open source _ freely available code_. + fly data output can be analysed with astromd , an analysis and visualization tool specifically designed to deal with the visualization and analysis of astrophysical data .
astromd can manage different physical quantities
. it can find out structures without well defined shape or symmetries , and perform quantitative calculations on selected regions .
is a _ freely available _ code . .
And you have already written the first three sentences of the full article: fly is the tree n - body code we design , develop and use to run very big simulations of the large scale structure of the universe using parallel systems mpp and smp .
fly uses the leapfrog numerical integration scheme for performance reasons , and incorporates fully periodic boundary conditions using the ewald method .
the i / o data format is integrated with the astromd package ..
Please generate the next two sentences of the article | + astromd is an analysis and visualization tool specifically designed to deal with the visualization and analysis of astrophysical data .
astromd can find structures having a not well defined shape or symmetries , and performs quantitative calculations on a selected region or structure . |
5,748 | Suppose that you have an abstract for a scientific paper: we present a summary of recent @xmath0 , @xmath1 , and @xmath2 measurements carried out in @xmath3 tev at the tevatron .
the observation of rare @xmath2 events and the precise measurement of the @xmath0 cross section in fully leptonic decay modes are described .
results in semi - leptonic decay modes where one boson decays to two quarks are also presented .
the measurements described are all in good agreement with the standard model and are relevant to searches for the higgs boson at the tevatron . .
And you have already written the first three sentences of the full article: measurements of diboson production cross sections at the tevatron test the electroweak sector of the standard model and have been used to place limits on models of physics beyond the standard model @xcite .
diboson measurements are also useful in the context of searches for the standard model higgs boson at the tevatron . in this presentation
we focus on recent diboson results that are relevant to the higgs searches . the search for the higgs boson at the tevatron involves searching for a very small signal in overwhelming backgrounds ..
Please generate the next two sentences of the article | sophisticated analysis techniques are often used to exploit small differences between signal and background events .
the searches also gain power from increasing signal acceptance and dividing events into several regions depending on their signal - to - background ratios . |
5,749 | Suppose that you have an abstract for a scientific paper: we prove landen s transformation by direct elementary transformation of infinite series . .
And you have already written the first three sentences of the full article: our paper contains a direct elementary proof of the following series transformation : ( * landen s transformation * ) if @xmath0 , then@xmath1{x}}{1+\sqrt{x}}\right)^{2}-\frac{1^{2}\cdot 3}{2^{2}\cdot 4^{2}}\left(\frac{2\sqrt[4]{x}}{1+\sqrt{x}}\right)^{4}-\frac{1^{2}\cdot 3^{2}\cdot 5}{2^{2}\cdot 4^{2}\cdot 6^{2}}\left(\frac{2\sqrt[4]{x}}{1+\sqrt{x}}\right)^{6}-\cdots\right\}= & \\ & \\={\displaystyle}1+\left(\frac{1}{2}\right)^{2}x+\left(\frac{1\cdot 1}{2\cdot 4}\right)^{2}x^{2}+\left(\frac{1\cdot 1\cdot 3}{2\cdot 4\cdot 6}\right)^{2}x^{3}+\left(\frac{1\cdot 1\cdot 3\cdot 5}{2\cdot 4\cdot
6\cdot 8}\right)^{2}x^{4}+\cdots & \\\end{array } $ } \ ] ] @xmath2 the interest in this theorem is that it gives a direct proof the equality of the following two formulas for the perimeter of an ellipse with semi - axes @xmath3 and @xmath4 .
( * the perimeter of an ellipse * ) the perimeter , @xmath5 , of an ellipse with semi - major axes @xmath3 and @xmath4 and eccentricity @xmath6 is:@xmath7@xmath2 the first formula for @xmath5 is due to maclaurin @xcite in 1742 while the second is due to ivory @xcite in 1796 ..
Please generate the next two sentences of the article | berndt ( @xcite , p. 147 ) points out that ivory s formula can be obtained from a form of landen s transformation to be found in erdlyi s compendium ( @xcite , p.111 , formula ( 5 ) ) , but we have not been able to encounter a direct elementary proof in the literature which transforms the first of the two formulas for @xmath5 into the second one , and which does not appeal to general transformation formulas .
ivory s own proof cleverly finesses this difficulty by showing that both series are equal to an integral . |
5,750 | Suppose that you have an abstract for a scientific paper: spectra of comet c/2014 q2 ( lovejoy ) were taken with a low resolution spectrograph mounted on the 0.5 m telescope at the mount abu infrared observatory ( miro ) , india during january to may 2015 covering the perihelion and post - perihelion periods .
the spectra showed strong molecular emission bands ( c@xmath0 , c@xmath1 and cn ) in january , close to perihelion .
we have obtained the scale lengths for these molecules by fitting the haser model to the observed column densities .
the variation of gas production rates and production rate ratios with heliocentric distance were studied .
the extent of the dust continuum using the @xmath2 parameter and its variation with the heliocentric distance were also investigated .
the comet is seen to become more active in the post - perihelion phase , thereby showing an asymmetric behaviour about the perihelion .
[ firstpage ] comet : general - comet : individual : c/2014 q2 - methods : observational - techniques : spectroscopic - telescopes - oort cloud .
And you have already written the first three sentences of the full article: comets are cold icy bodies in the solar system that were formed in the solar nebula and are considered to be the signature bodies to understand the formation of the solar system .
as the comet nucleus makes its journey towards its parent star , the ices start sublimating giving rise to a mixture of gas and dust which form the coma . for comets at heliocentric distances less than 3 au ,
the visible band spectrum shows strong molecular emission bands riding on the continuum radiation scattered by the cometary dust ..
Please generate the next two sentences of the article | studying these molecular emission bands has been an important part of the cometary study .
+ comet c/2014 q2 ( lovejoy ) , an oort cloud comet , was discovered by terry lovejoy in august 2014 using an 8 inch telescope when the comet had a visual magnitude of 15 . |
5,751 | Suppose that you have an abstract for a scientific paper: we present a new empirical fitting method for the optical light curves of type ia supernovae ( sne ia ) .
we find that a variant broken - power - law function provides a good fit , with the simple assumption that the optical emission is approximately the blackbody emission of the expanding fireball .
this function is mathematically analytic and is derived directly from the photospheric velocity evolution . applying it to the case study of sn 2011fe gives a surprisingly good fit that can describe the light curves from explosion to a few weeks after peak brightness , as well as over a large range of fluxes ( @xmath0 mag , and even @xmath1mag in the @xmath2 band ) .
since sne ia share similar light - curve shapes , this fitting method has the potential to fit most other sne ia and characterize their properties in large statistical samples such as those already gathered and in the near future as new facilities become available . .
And you have already written the first three sentences of the full article: type ia supernovae ( sne ia ) are believed to be thermonuclear runaway explosions of carbon / oxygen white dwarfs ( see , e.g. , hillebrandt & niemeyer 2000 for a review ) .
observationally , sne ia share similar light - curve shapes ; thus , traditionally the fitting of sn ia light curves is conducted with templates constructed from well - observed sne ia ( e.g. , jha et al .
2007 ; guy et al . 2007 ) ..
Please generate the next two sentences of the article | some other attempts have also been proposed to characterize sn ia light curves with different techniques .
for example , kessler et al . ( |
5,752 | Suppose that you have an abstract for a scientific paper: we propose a scheme for generating squeezed states in solid state circuits consisting of a nanomechanical resonator ( nmr ) , a superconducting cooper - pair box ( cpb ) and a superconducting transmission line resonator ( stlr ) .
the nonlinear interaction between the nmr and the stlr can be implemented by setting the external biased flux of the cpb at certain values .
the interaction hamiltonian between the nmr and the stlr is derived by performing fr@xmath0hlich transformation on the total hamiltonian of the combined system . just by adiabatically keeping the cpb at the ground state
, we get the standard parametric down - conversion hamiltonian .
the cpb plays the role of nonlinear media " , and the squeezed states of the nmr can be easily generated in a manner similar to the three - wave mixing in quantum optics .
this is the three - wave mixing in a solid - state circuit . .
And you have already written the first three sentences of the full article: mechanical harmonic oscillator plays an important role in the historical development of quantum mechanics .
the harmonic oscillator problem was one of the few completely solvable problems when one began to learn quantum mechanics . due to the macroscopic nature , the experiments of mechanical harmonic oscillators did nt achieve much progress for a quite long time , however .
recently , with the development in quantum information processing , people are now searching for possible applications of mechanical harmonic oscillator in this field , and evidence for quantized displacement in a nanomechanical harmonic oscillator has been observed @xcite ..
Please generate the next two sentences of the article | many good physical ideas about the harmonic oscillator came up , though this system is rather simple .
squeezed state was one of them . |
5,753 | Suppose that you have an abstract for a scientific paper: we present high - resolution infrared echelle spectroscopy for the globular clusters palomar 6 and m71 .
our mean heliocentric radial velocity of palomar 6 is + 180.6 @xmath0 3.2 km sec@xmath1 and is 20 km sec@xmath1 lower than that found by minniti in 1995 .
contrary to the previous metallicity estimates using low - resolution spectroscopy , our results show that palomar 6 has an intermediate metallicity with [ fe / h ] = @xmath21.0 @xmath0 0.1 and is slightly more metal - poor than m71 .
reasonable changes in the surface temperature or the microturbulent velocity of the model atmospheres do not affect [ fe / h ] at more than @xmath0 0.2 dex . in spite of its high metallicity , based on the spectrum of a single cluster member the [ si / fe ] and [ ti / fe ] ratios of palomar 6 appear to be enhanced by 0.4 dex and 0.5 dex , respectively , suggesting that the galactic inner halo may have experienced a very rapid chemical enrichment history . .
And you have already written the first three sentences of the full article: the measurement of [ @xmath3/fe ] ratios of globular clusters provides important information regarding relative ages .
the @xmath3-elements ( c , o , ne , mg , si , s , ar , ca , and ti ) are synthesized predominantly by massive stars , and ejected into the interstellar medium by type ii supernovae ( sne ii ) explosions . on the other hand ,
iron - peak elements are produced by both sne ii and type ia supernovae ( sne ia ) ..
Please generate the next two sentences of the article | enhanced values of [ @xmath3/fe ] ratios in globular clusters indicate the domination of sne ii nucleosynthesis , while lower ratios indicate increasing contribution of sne ia , which are thought to appear 10@xmath4 or more years later .
therefore , the measurement of the behavior of [ @xmath3/fe ] versus [ fe / h ] tells us how rapidly chemical enrichment proceeded in our galaxy ( wheeler , sneden , & truran 1989 ) . |
5,754 | Suppose that you have an abstract for a scientific paper: this paper proposes a new class of copulas which characterize the set of all twice continuously differentiable copulas .
we show that our proposed new class of copulas is a new generalized copula family that include not only asymmetric copulas but also all smooth copula families available in the current literature .
spearman s rho and kendall s tau for our new fourier copulas which are asymmetric are introduced .
furthermore , an approximation method is discussed in order to optimize spearman s rho and the corresponding kendall s tau . corresponding author ] .
And you have already written the first three sentences of the full article: recently , a study of dependence by using copulas has been getting more attention in the areas of finance , actuarial science , biomedical studies and engineering because a copula function does not require a normal distribution and independent , identical distribution assumptions .
furthermore , the invariance property of copula has been attractive in the finance area .
but most copulas including archimedean copula family are symmetric functions so that the copula model fitting for asymmetric data is not appropriate . liebscher ( @xcite ) introduced two methods for the construction of asymmetric multivariate copulas . the first is connected with products of copulas ..
Please generate the next two sentences of the article | the second approach generalizes the archimedean copulas .
the resulting copulas are asymmetric but are little extension of the parametric families of copulas . |
5,755 | Suppose that you have an abstract for a scientific paper: we give a new , manifestly spacetime - supersymmetric method for calculating superstring scattering amplitudes , using the ghost pyramid , that is simpler than all other known methods .
no pictures nor non - vertex insertions are required other than the usual @xmath0 and @xmath1 ghosts of the bosonic string .
we evaluate some tree and loop amplitudes as examples .
march 28 , 2006 yitp - sb-06 - 5 .5 in * simpler superstring scattering * + kiyoung lee and warren siegel + _ c. n. yang institute for theoretical physics + state university of new york , stony brook , ny 11794 - 3840 _ + many formalisms have been introduced for calculating scattering amplitudes for superstrings .
the most practical of these have been ( covariant ) ramond - neveu - schwarz ( rns ) @xcite , ( lightcone ) green - schwarz ( gs ) @xcite , hybrid rns - gs ( h ) @xcite , and pure spinor ( ps ) @xcite .
all of these have ( at least ) two important defects : \(1 ) some kind of insertion is required .
it may be separate from the vertices , or may be combined with some vertices to put them into different pictures " .
the result is to complicate the calculations or destroy manifest symmetry .
( the only exception is tree graphs with external bosons only , where such methods make cyclic symmetry more obscure but avoid producing extra terms that cancel . )
\(2 ) supersymmetry is not completely manifest .
the most serious case is rns , where fermion vertices are much more complicated than boson ( because the spinors are not free fields , so in practice noncovariant exponentials of bosons must be used ) , and sums over spin structures ( periodic / antiperiodic boundary conditions ) must be performed in loops . in the gs and h cases
there is partial supersymmetry ( and partial 10d lorentz invariance ) , which complicates vertices for the longitudinal " directions , which are required for general higher - point calculations ; for this reason we will not consider gs and h in detail .
the most symmetric is ps ,....
And you have already written the first three sentences of the full article: w.s . thanks brenno carlini vallilo and nathan berkovits for discussions , and nathan berkovits for explaining the modern covariant description of the @xmath6 picture . in our previous paper
we constructed the brst operator for the superparticle and superstring in a super yang - mills background @xcite . from the brst operator
we can get the gauge fixed hamiltonian : @xmath208 where @xmath209 and @xmath210 are the graded covariant derivatives ..
Please generate the next two sentences of the article | notice that @xmath26 and @xmath19 are shorthand notation for @xmath211 and @xmath212 , where @xmath213 is the ghost number and @xmath214 is the ghost level .
( even level and odd level correspond to fermion and boson respectively . ) |
5,756 | Suppose that you have an abstract for a scientific paper: we study the quantum behaviour of a binary mixture of bose - einstein condensates ( bec ) in a double - well potential starting from a two - mode bose - hubbard hamiltonian .
we focus on the small tunneling amplitude regime and apply perturbation theory up to second order .
analytical expressions for the energy eigenvalues and eigenstates are obtained .
then the quantum evolution of the number difference of bosons between the two potential wells is fully investigated for two different initial conditions : completely localized states and coherent spin states . in the first case
both the short and the long time dynamics is studied and a rich behaviour is found , ranging from small amplitude oscillations and collapses and revivals to coherent tunneling . in the second case the short - time scale evolution of number difference
is determined and a more irregular dynamics is evidenced . finally , the formation of schroedinger cat states is considered and shown to affect the momentum distribution . .
And you have already written the first three sentences of the full article: the experimental discovery of bose - einstein condensation @xcite in dilute systems of trapped alkali - metal atoms , such as rubidium ( @xmath0 ) , lithium ( @xmath1 ) , sodium ( @xmath2 ) and ytterbium ( @xmath3 ) , has spurred a renewed interest into the investigation of macroscopic quantum phenomena and interference effects , allowing for a deeper understanding of the conceptual foundations of quantum mechanics @xcite .
this fascinating research area has been growing up thanks to the high degree of experimental manipulation and control @xcite .
interference between condensates released in a potential with a barrier was first observed in 1997 @xcite and that paved the way for further investigations on the problem of bose condensates in a double well potential ..
Please generate the next two sentences of the article | then josephson oscillations have been observed in one dimensional optical potential arrays @xcite .
a single bosonic josephson junction was produced for the first time in 2005 with @xmath0 atoms and its dynamics was experimentally investigated both within tunneling as well as self - trapping regime @xcite@xcite@xcite . |
5,757 | Suppose that you have an abstract for a scientific paper: the so - called is generally characterized by the quasi - periodic oscillatory evolution of the photospheric spots number .
this quasi - periodic pattern has always been an intriguing question .
several physical models were proposed to explain this evolution and many mathematical data analysis were employed to determine the principal frequencies noticeable in the measured data .
both approaches try to predict the future evolution of the solar activity and to understand the physical phenomena producing these cycles . here
we present the analysis of the sunspots number evolution using the time - delay approach .
our results show than the solar cycle can also be characterized by this behavior implying the influence of the past evolution over the present one , suggesting an histeresis mechanism , linked probably with magnetic activity . .
And you have already written the first three sentences of the full article: solar activity can be seen through the evolution of sunspots number in quasi - periodic oscillatory series with periods going from 8 to 15 years and with a mean period of 11 years . due to the change of magnetic field polarity in solar hemispheres alternatively
each cycle , the period is rather 22 years .
the quasi - periodic evolution of many activity phenomena is still a unsolved key problem in solar physics ( along with , e.g. , heating of the solar chromosphere and corona , and solar flares ) ..
Please generate the next two sentences of the article | an important issue of this understanding is due to the influence of solar activity over the terrestrial climate ( ( * ? ? ?
* archibald 2006 ) ) . |
5,758 | Suppose that you have an abstract for a scientific paper: the present paper is devoted to the study of resonances for one - dimensional quantum systems with a potential that is the restriction to some large box of an ergodic potential . for discrete models
both on a half - line and on the whole line , we study the distributions of the resonances in the limit when the size of the box where the potential does not vanish goes to infinity . for periodic and random potentials ,
we analyze how the spectral theory of the limit operator influences the distribution of the resonances .
.5 cm rsum .
dans cet article , nous tudions les rsonances dun systme unidimensionnel plong dans un potentiel qui est la restriction un grand intervalle dun potentiel ergodique .
pour des modles discrets sur la droite et la demie droite , nous tudions la distribution des rsonances dans la limite de la taille de bote infinie .
pour des potentiels priodiques et alatoires , nous analysons linfluence de la thorie spectrale de loprateur limite sur la distribution des rsonances . .
And you have already written the first three sentences of the full article: on @xmath0 , consider @xmath1 a bounded potential and the schrdinger operator @xmath2 defined by , for @xmath3 , @xmath4 the potentials @xmath1 we will deal with are * @xmath1 periodic ; * @xmath5 random e.g. anderson model i.e. the entries of the diagonal matrix @xmath1 are independent identically distributed non constant random variable .
the spectral theory of such models has been studied extensively ( see e.g. @xcite ) and it is well known that * when @xmath1 is periodic , the spectrum of @xmath6 is purely absolutely continuous ; * when @xmath5 is random , the spectrum of @xmath6 is almost surely pure point i.e. the operator only has eigenvalues ; moreover , the eigenfunctions decay exponentially at infinity .
pick @xmath7 ..
Please generate the next two sentences of the article | the main object of our study is the operator @xmath8 when @xmath9 becomes large . here
, @xmath10 is the integer interval @xmath11 and @xmath12 if @xmath13 and @xmath14 if not . |
5,759 | Suppose that you have an abstract for a scientific paper: we calculate the system - size - over - wave - length ( @xmath0 ) dependence of sample - to - sample conductance fluctuations , using the open kicked rotator to model chaotic scattering in a ballistic quantum dot coupled by two @xmath1-mode point contacts to electron reservoirs .
both a fully quantum mechanical and a semiclassical calculation are presented , and found to be in good agreement .
the mean squared conductance fluctuations reach the universal quantum limit of random - matrix - theory for small systems . for large systems
they increase @xmath2 at fixed mean dwell time @xmath3 .
the universal quantum fluctuations dominate over the nonuniversal classical fluctuations if @xmath4 .
when expressed as a ratio of time scales , the quantum - to - classical crossover is governed by the ratio of ehrenfest time and ergodic time . .
And you have already written the first three sentences of the full article: sample - to - sample fluctuations of the conductance of disordered systems have a universal regime , in which they are independent of the mean conductance . the requirement for these universal conductance fluctuations
@xcite is that the sample size should be small compared to the localization length .
the mean conductance is then much larger than the conductance quantum @xmath5 ..
Please generate the next two sentences of the article | the same condition applies to the universality of conductance fluctuations in ballistic chaotic quantum dots @xcite , although there is no localization in these systems .
random - matrix - theory ( rmt ) has the universal limit @xmath6 for the variance of the conductance @xmath7 in units of @xmath5 . here |
5,760 | Suppose that you have an abstract for a scientific paper: we study the dimensional crossover from 1d to 2d in half - filled and lightly doped , weakly interacting @xmath0-leg hubbard ladders . in this case
, the hubbard ladders are equivalent to a @xmath0-band model . using renormalization group techniques , we find , that the half - filled ladders exhibit ( in the spin - sector ) an odd - even effect only below a crossover energy @xmath1 $ ] ( @xmath2 and @xmath3 depend on the interaction strength and on the hopping matrix elements ) : below @xmath4 , the dominant interactions take place within band pairs @xmath5 [ and within the band @xmath6 for @xmath0 odd ] , such that even - leg ladders are an insulating spin - liquid , while odd - leg ladders have one gapless spinon - mode .
in contrast , above the energy - scale @xmath4 , all bands are interacting with each other and the system is a 2d - like ( insulating ) antiferromagnet ; we obtain an analytical expression for the hamiltonian which is similar to the 2d heisenberg antiferromagnet .
bosonization techniques show , that in the charge - sector the mott insulator is as well below and above @xmath4 of the same type as in @xmath7 half - filled two - leg ladders .
doping away from half - filling , we find that the effect of an increasing doping @xmath8 is very similar to decreasing the number of legs @xmath0 : in both cases interactions between unpaired bands are suppressed and thereby the antiferromagnetic correlations reduced .
the resulting band pairs form then insulating spin - liquids and when doped , there is a spin - gap , but phase coherence exists only within the band pairs . at higher doping levels @xmath9 ,
phase coherence between all band pairs sets in and the system becomes a 2d - like @xmath10-wave superconductor [ @xmath11 for @xmath12 . 2 .
And you have already written the first three sentences of the full article: the physical properties of ( quasi-)one - dimensional electron systems are often very different from their 2d counterpart , for example , in ( spin-@xmath13 ) heisenberg antiferromagnets ( afm ) : the ( quasi-1d ) ladders exhibit in the groundstate an odd - even effect , i.e. , odd - leg ladders have one gapless spinon - mode , while even - leg ladders have a spin - gap @xcite .
the 2d heisenberg model however , has two gapless magnon - modes and long - range order @xcite .
similarly , ( quasi-)1d conductors are generally luttinger liquids ( ll ) @xcite , while 2d and 3d electron systems are ( usually ) fermi liquids ( fl ) . for the afm heisenberg model , the dimensional crossover from 1d to 2d has been studied in ref . @xcite . via the correspondence between number of legs @xmath0 and temperature @xmath14 , @xmath15.
Please generate the next two sentences of the article | , the nonlinear sigma - model allows one in this case to calculate various physical properties ; in particular , the spin - gap present in even - leg ladders vanishes exponentially as a function of the number @xmath0 of coupled spin - chains .
coupled lls @xcite and the dimensional crossover to 2d have been investigated by many different authors @xcite . |
5,761 | Suppose that you have an abstract for a scientific paper: in this article we discuss some general results on the covariant picard groupoid in the context of differential geometry and interpret the problem of lifting lie algebra actions to line bundles in the picard groupoid approach .
* keywords : * morita equivalence , @xmath0-algebras , picard groupoid , hopf algebra actions .
* msc ( 2000 ) : * 16d90 , 16w30 , 16w10 , 53d55 .
And you have already written the first three sentences of the full article: in this work we would like to illustrate and exemplify some general results from @xcite where the general framework of a morita theory which is covariant under a given hopf algebra was studied .
one main motivation to do so is coming from ( deformation ) quantization theory @xcite , see e.g @xcite for recent reviews . here
morita equivalence provides an important notion of equivalence of observable algebras @xcite ..
Please generate the next two sentences of the article | in particular , on cotangent bundles the condition for star products to be morita equivalent is shown to coincide with dirac s integrality condition for magnetic charges of a background magnetic field @xcite leading to a natural interpretation of morita equivalence also in more general situations . from the differential geometric point of view , it is a natural question whether all these techniques as developed in @xcite can be made compatible with a certain given symmetry of the underlying manifold . on the purely algebraic level ,
a fairly general notion of ` symmetry ' is that of a hopf algebra action of a given hopf algebra . in @xcite |
5,762 | Suppose that you have an abstract for a scientific paper: we consider a class of non - homogeneous , continuous , centered gaussian random fields @xmath0 where @xmath1 denotes a rescaled smooth manifold , i.e. @xmath2 and study the limit behavior of the extreme values of these gaussian random fields when @xmath3 tends to zero , which means that the manifold is growing .
our main result can be thought of as a generalization of a classical result of bickel and rosenblatt ( 1973a ) , and also of results by mikhaleva and piterbarg ( 1997 ) .
+ this research was partially support by the nsf - grant dms 1107206 + _ ams 2000 subject classifications . _
primary 60g70 , 60g15 .
+ _ keywords and phrases . _ local stationarity , extreme values , triangulation of manifolds .
And you have already written the first three sentences of the full article: extreme value behavior of gaussian processes is an important topic in probability theory and a crucial ingredient to many statistical inference procedures .
see for instance chernozhukov et al .
( 2014 ) for a very recent , general contribution to this topic . here.
Please generate the next two sentences of the article | we are considering the extreme value behavior of gaussian fields on manifolds , which plays an important role in statistical inference .
in fact there is recent growing interest in the statistical literature in inference for manifolds such as integral curves ( koltchinskii et al . , 2007 ) , ridges or filaments ( hall et al . , 1992 , genovese et al |
5,763 | Suppose that you have an abstract for a scientific paper: dynamic fluctuations in the local density of non - identified hadron tracks reconstructed in the star tpc are studied using the discrete wavelet transform power spectrum technique which involves mixed event reference sample comparison .
the two - dimensional event - by - event analysis is performed in pseudo - rapidity @xmath0 and azimuthal angle @xmath1 .
hijing simulations indicate that jets and mini - jets result in signals , visible without high @xmath2 selection , when the dynamic texture analysis is applied . scanning a broad range of event multiplicities , we study the dependence of the signals on the initial conditions .
event structures are studied separately with positive and negative tracks , as well as both charges .
a change of regime is observed in auau collisions at @xmath3 gev as event multiplicity is increased : a long range @xmath0 correlation ( or suppressed fluctuation vis - a - vis mixed events ) is seen in same charge data .
this effect is qualitatively similar to one of the predicted manifestations of the color glass condensate . .
And you have already written the first three sentences of the full article: bulk properties of strongly interacting matter under extreme conditions are the focus of the on - going rhic program .
deconfinement and chiral symmetry restoration@xcite are expected to take place in collisions of ultra - relativistic nuclei . because these phase transitions are multiparticle phenomena , a promising , albeit challenging , approach is the study of dynamics of large groups of final state particles .
the dynamics shows itself in the correlations and fluctuations ( texture ) on a variety of distance scales in momentum space ..
Please generate the next two sentences of the article | the multi - resolution dynamic texture approach ( applied for the first time@xcite at sps ) uses discrete wavelet transform @xcite(dwt ) to extract such information . at present stage ,
the information is extracted in a comprehensive way , without any built - in assumptions or filters . |
5,764 | Suppose that you have an abstract for a scientific paper: ngc2359 is an optical nebula excited by the powerful wind and the radiation of the wolf
rayet star hd56925 .
we have investigated the interaction between this massive star and the surrounding neutral gas by analyzing the large - scale 21cm - hi emission and by mapping the nebula in the j = @xmath0 and the j = @xmath1 lines of co. we found a conspicuous ( @xmath2 pc ) hi shell , expanding at 12 km s@xmath3 , likely produced during the main - sequence phase of the star .
the molecular gas towards ngc2359 shows three velocity components .
two of these components , a1 and a2 , have narrow linewidths ( 12 km s@xmath3 ) and radial velocities of 3538 and 6468 km s@xmath3 , respectively .
the third component is detected at radial velocities between 50 and 58 km s@xmath3 and has a broader profile ( up to 5.5 km s@xmath3 ) .
furthermore , this component is morphologicaly related with the nebula and has a velocity gradient of a few km s@xmath3 . we have also estimated the physical parameters of the molecular gas by means of a lvg modelling of the co emission .
the gas projected onto the southern hiiregion of the nebula has low co column density and is rather hot , probably up to 80k .
several profiles of the @xmath4co j = @xmath0 line near the peak of the emission , together with a weak emission bridge between the broad and one of the narrow components ( component a2 ) , suggest the presence of a shock front acting in the southern part of the nebula .
this shock was likely produced in a previous rsg / lbv phase of hd56925 . .
And you have already written the first three sentences of the full article: the different evolutive stages of massive stars have strong influence on their surroundings and , consequently , on the galactic evolution . during their lives ,
the massive stars inject large amounts of matter , energy and momentum into the interstellar medium ( ism ) . in the pre - main sequence ,
massive stars undergo a phase of very energetic mass loss giving rise to molecular outflows ..
Please generate the next two sentences of the article | uv radiation , expansion of hii regions and fast stellar winds are present in the main sequence stage . in the short lived red supergiant ( rsg ) and
luminous blue variable ( lbv ) stages , the winds become slower and denser and ejections of up to some solar masses may be produced . |
5,765 | Suppose that you have an abstract for a scientific paper: we present preliminary results of our work on blazar unification .
we assume that all blazars have a broad line region ( blr ) and that the size of the blr scales with the power of the source in a manner similar to that derived through reverberation mapping in radio quiet active galactic nuclei ( agns ) . using a self - consistent emission model that includes particle acceleration
we show that according to this scaling , in weak sources like mkn 421 , the inverse compton ( ic ) scattering losses are dominated by synchrotron - self compton scattering ( ssc ) , while in powerful sources , like 3c 279 , they are dominated by external compton ( ec ) scattering of blr photons . in agreement with other workers , we show that even in the powerful sources that are dominated by ec scattering , the hard x - ray emission is due to ssc . finally , we show that this scaling reproduces well the observed sequence of blazar properties with luminosity . .
And you have already written the first three sentences of the full article: blazars have been shown to exhibit a sequence of properties as a function of source power ( fossati et al .
1998 ) . as the source power increases , the emission line luminosity and the ratio of compton to synchrotron luminosity increase , while the synchrotron peak frequency @xmath0 and the ic peak frequency decrease .
recent multiwavelength studies support this scheme ( e.g. kubo et al ..
Please generate the next two sentences of the article | 1998 ) , although the result that the ratio of the compton to synchrotron luminosity increases with source luminosity suffers from limited statistics , and should be only considered tentative .
the initial division of blazars into flat spectrum radio quasars ( fsrqs ) and bl lacertae objects ( bls ) was based on the equivalent width ( ew ) of the broad emission lines . |
5,766 | Suppose that you have an abstract for a scientific paper: we present a simple derivation of the energy formula found by tan , relative to the single channel hamiltonian relevant for ultracold fermi gases .
this derivation is generalized to particles with different masses , to arbitrary mixtures , and to two - dimensional space .
we show how , in a field theoretical approach , the @xmath0 tail in the momentum distribution and the energy formula arise in a natural way . as a specific example
, we consider quantitative calculations of the energy , from different formulas within the ladder diagrams approximation in the normal state .
the comparison of the results provides an indication on the quality of the approximation . .
And you have already written the first three sentences of the full article: the remarkable progress in the field of ultracold atomic gases has provided access to a number of systems which may display quite new physical properties .
one of the most striking example is provided by ultracold fermionic gases @xcite and the bec - bcs crossover . while the physics of bose - einstein condensates ( bec ) is known from superfluid @xmath1he ( and from ultracold bosonic atomic gases ) , and the one of bcs condensates from superconductors , fermionic gases provide systems which display a smooth continuous evolution between these two extremes .
this is made possible by the existence of feshbach resonances which allow to control the value of the scattering length @xmath2 merely by changing the applied magnetic field ..
Please generate the next two sentences of the article | for ultracold gases the kinetic energy of the atoms is so small that only s - wave scattering is relevant , and it is fully characterized by the scattering length . since pauli principle forbids s - wave scattering between identical atoms , the scattering length corresponds in most of the experiments performed so far to scattering between atoms in different hyperfine states of a same element .
these hyperfine states are often called for convenience `` spin up '' and `` spin down '' . in the case of a wide feshbach resonance ( as it occurs for example for @xmath3li and @xmath4k ) , the closed channel responsible for the feshbach resonance may be omitted and the system is described by a single open channel hamiltonian , where the interaction is characterized by the single parameter @xmath2 . with the densities produced in experiments |
5,767 | Suppose that you have an abstract for a scientific paper: the determination of the size of the convective core of main - sequence stars is usually dependent on the construction of models of stars .
here we introduce a method to estimate the radius of the convective core of main - sequence stars with masses between about 1.1 and 1.5 @xmath0 from observed frequencies of low - degree p - modes .
a formula is proposed to achieve the estimation .
the values of the radius of the convective core of four known stars are successfully estimated by the formula .
the radius of the convective core of kic 9812850 estimated by the formula is @xmath1 @xmath2 . in order to confirm this prediction ,
a grid of evolutionary models were computed .
the value of the convective - core radius of the best - fit model of kic 9812850 is @xmath3 @xmath2 , which is in good agreement with that estimated by the formula from observed frequencies .
the formula aids in understanding the interior structure of stars directly from observed frequencies .
the understanding is not dependent on the construction of models . .
And you have already written the first three sentences of the full article: by matching the luminosity , atmospheric parameters , and oscillation frequencies of models with the observed ones , asteroseismology is used to determine fundamental parameters of stars .
asteroseismology is also used to probe physical processes in stars and diagnose internal structures of stars @xcite .
asteroseismology is a powerful tool for studying the structure and evolution of stars ..
Please generate the next two sentences of the article | stars with a mass larger than @xmath4 are considered to have a convective core during their main sequence ( ms ) stage . due to the fact that the overshooting of the convective core can bring more hydrogen - rich material into the core
, the evolution of a star could be significantly affected by the overshooting . thus determining the size of the convective core including the overshooting region is important for understanding the structure and evolution of stars . |
5,768 | Suppose that you have an abstract for a scientific paper: magic sand , a hydrophobic toy granular material , is widely used in popular science instructions because of its non - intuitive mechanical properties .
a detailed study of the failure of an underwater column of magic sand shows that these properties can be traced to a single phenomenon : the system self - generates a cohesive _ skin _ that encapsulates the material inside . the _ skin _ , consists of pinned air - water - grain interfaces , shows multi - scale mechanical properties : they range from contact - line dynamics in the intra - grain roughness scale , plastic flow at the grain scale , all the way to the sample - scale mechanical responses . with decreasing rigidity of the _ skin _ , the failure mode transforms from brittle to ductile ( both of which are collective in nature ) to a complete disintegration at the single grain scale . .
And you have already written the first three sentences of the full article: dry granular systems are known to exhibit both liquid and solid - like properties . while there are many instances where a granular assembly exhibits liquid - like properties @xcite , examples of granular systems illustrating solid - like properties are rare with one exception : the typical conical sandpile shape @xcite . to craft more complex shapes , e.g. , sand art
, it is necessary to add additional constraints .
these constraints can be added in the bulk or at the boundary . adding a small quantity of water to the sand introduces constraints in the bulk in the form of capillary bridges @xcite ..
Please generate the next two sentences of the article | conversely , encapsulating dry grains in a container is an example of constraints that are applied at the boundary @xcite .
in general , encapsulation requires isolating materials from their surroundings and it is achieved either by ( i ) introducing another material in the interfacial region or ( ii ) facilitating processes at the interface that create self - encapsulation . |
5,769 | Suppose that you have an abstract for a scientific paper: ohba has conjectured @xcite that if the graph @xmath0 has @xmath1 or fewer vertices then the list chromatic number and chromatic number of @xmath0 are equal . in this paper
we prove that this conjecture is asymptotically correct .
more precisely we obtain that for any @xmath2 , there exist an @xmath3 such that the list chromatic number of @xmath0 equals its chromatic number , provided @xmath4 4.5 mm * 2000 mathematics subject classification : * 05c15 , 05d40 . * keywords and phrases : * probabilistic method , graph coloring , list - chromatic number . .
And you have already written the first three sentences of the full article: -5 mm recently , a host of important results on graph colouring have been obtained via the probabilistic method .
the first author presented an invited lecture at the 2002 international congress of mathematicians surveying a number of these results .
the recent monograph @xcite provides a more in depth survey of the topic ..
Please generate the next two sentences of the article | this paper presents one example of a result proven using the method .
an instance of list colouring consists of a graph @xmath0 and a list @xmath5 of colours for each vertex @xmath6 of @xmath0 . |
5,770 | Suppose that you have an abstract for a scientific paper: in considering the college admissions problem , almost fifty years ago , gale and shapley came up with a simple abstraction based on preferences of students and colleges .
they introduced the concept of stability and optimality ; and proposed the _ deferred acceptance _ ( da ) algorithm that is proven to lead to a stable and optimal solution .
this algorithm is simple and computationally efficient .
furthermore , in subsequent studies it is shown that the da algorithm is also strategy - proof , which means , when the algorithm is played out as a mechanism for matching two sides ( e.g. colleges and students ) , the parties ( colleges or students ) have no incentives to act other than according to their true preferences . yet , in practical college admission systems , the da algorithm is often not adopted . instead , an algorithm known as the _ boston mechanism _ ( bm ) or its variants are widely adopted . in bm
, colleges accept students without deferral ( considering other colleges decisions ) , which is exactly the opposite of gale - shapley s da algorithm . to explain and rationalize this reality ,
we introduce the notion of _ reciprocating preference _ to capture the influence of a student s interest on a college s decision .
this model is inspired by the actual mechanism used to match students to universities in hong kong .
the notion of reciprocating preference defines a class of matching algorithms , allowing different degrees of reciprocating preferences by the students and colleges .
da and bm are but two extreme cases ( with zero and a hundred percent reciprocation ) of this set .
this model extends the notion of stability and optimality as well . as in gale - shapley s original paper
, we discuss how the analogy can be carried over to the stable marriage problem , thus demonstrating the model s general applicability . * * jel classification**@xmath0c78
@xmath1 i23 @xmath1 i31 .
And you have already written the first three sentences of the full article: one of the main features of many market and social processes is their bilateral structure and the need to match agents from one side of the market with the other side , e.g. students and schools in college admissions , employees and companies in the job market ( see * ? ? ?
* ) , men and women in online dating sites , advertisers and advertising slots in sponsored search ( see * ? ? ?
* ) . a class of `` two - sided matching model '' for studying such problems was first introduced by gale and shapley in 1962 in their seminal paper @xcite , in the context of college admissions and the marriage problem ..
Please generate the next two sentences of the article | yet , the original model is quite general and can be easily adapted for other two - sided markets , such as the well - known national resident matching program ( nrmp ) for assigning medical students to residency positions in us . in gale and shapley s seminal paper ,
the college admissions problem is formulated as follows . |
5,771 | Suppose that you have an abstract for a scientific paper: we present an extensive numerical study of the hubbard model on the doped ab@xmath0 chain , both in the weak coupling and the infinite - u limit . due to the special unit cell topology
, this system displays a rich variety of phases as function of hole doping ( @xmath1 ) away from half - filling . near half - filling ,
spiral states develop in the weak coupling regime , while nagaoka itinerant ferromagnetism is observed in the infinite - u limit . for higher doping the system
phase - separates before reaching a mott insulating phase of short - range rvb states at @xmath2 .
moreover , for @xmath3 we observe a crossover , which anticipates the luttinger liquid behavior for @xmath4 . .
And you have already written the first three sentences of the full article: low - dimensional strongly correlated electron systems have attracted great attention in the last two decades .
the reason dates back to anderson s proposal @xcite that the @xmath5 version of the hubbard model might carry the basic mechanisms underlying the high - tc superconductivity observed in cuo@xmath0 compounds . despite
that this remains an open issue , the above suggestion fertilized intensive investigations on many related fundamental topics , such us itinerant electron magnetism , mott metal - insulator transitions and quantum critical phenomena . amongst several features of interest , we mention the possibility of realization of spiral @xcite , nagaoka @xcite and resonating - valence - bond ( rvb ) states @xcite , spatially separated phases @xcite and luttinger liquid behavior @xcite , which may present strong deviations from the landau fermi liquid theory ..
Please generate the next two sentences of the article | in this work , we report numerical results of the hubbard model on the doped ab@xmath0 chain away from half filling , which show that its special unit cell topology greatly enriches the phase diagram found in the doped standard linear chain .
in fact , all features mentioned above are shown to be associated with well defined ground state ( gs ) phases of this doped chain . doped ab@xmath0-hubbard chains were previously studied through hartree - fock , quantum monte carlo and exact diagonalization ( ed ) techniques both in the weak and strong coupling limits @xcite , including also the @xmath5 model @xcite using density matrix renormalization group ( dmrg ) and recurrent variational anstzes , and the infinite - u limit @xcite using ed . in particular , these chains represent an alternative route to reaching two - dimensional quantum physics from one - dimensional systems @xcite . at half filling the ab@xmath0-hubbard chain exhibits a quantum ferrimagnetic gs @xcite , whose magnetic excitations have been studied in detail both in the weak and strong coupling limits @xcite , and in the light of the quantum heisenberg model @xcite . |
5,772 | Suppose that you have an abstract for a scientific paper: the understanding of language competition helps us to predict extinction and survival of languages spoken by minorities .
a simple agent based model of a sexual population , based on the penna model , is built in order to find out under which circumstances one language dominates other ones .
this model considers that only young people learn foreign languages .
the simulations show a first order phase transition where the ratio between the number of speakers of different languages is the order parameter and the mutation rate is the control one . .
And you have already written the first three sentences of the full article: recently , increasing attention has been paid on the understanding of linguistic systems by computational and analytical methods .
physicists , mathematicians , computer scientists and biologists apply their tools on the investigation of language capability , language change and language competition@xcite .
especially the similarity to biological systems opens the field of linguistics to methods of the far better understood evolutionary systems . for an overview.
Please generate the next two sentences of the article | see refs.@xcite .
it is believed that a concept of `` universal grammar '' is fixed by some way in our genetic code enabling humans to learn languages fast during our childhood@xcite . |
5,773 | Suppose that you have an abstract for a scientific paper: we show that steady - state ab initio laser theory ( salt ) can be applied to find the stationary multimode lasing properties of an @xmath0-level laser .
this is achieved by mapping the @xmath0-level rate equations to an effective two - level model of the type solved by the salt algorithm .
this mapping yields excellent agreement with more computationally demanding @xmath0-level time domain solutions for the steady state .
99 h. haken , _ light : laser dynamics _ vol . 2 ( north - holland phys .
publishing , new york , 1985 ) .
a. e. siegman , _ lasers _ ( university science books , mill valley - california , 1986 ) .
a. s. nagra and r. a. york , `` fdtd analysis of wave propagation in nonlinear absorbing and gain media , '' ieee trans .
antennas propag .
* 46 * , 334 - 340 ( 1998 ) . k. s. yee , `` numerical solution of the initial boundary value problems involving maxwell s equations in isotropic media , '' ieee trans antennas propag .
* 14 * , 302 - 307 ( 1966 ) .
h. e. treci , a. d. stone , and b. collier , `` self - consistent multimode lasing theory for complex or random lasing media , '' phys .
rev .
a * 74 * , 043822 ( 2006 ) .
h. e. treci , a. d. stone , and l. ge , `` theory of the spatial structure of nonlinear lasing modes , '' phys . rev .
a * 76 * , 013813 ( 2007 ) .
h. e. treci , l. ge , s. rotter , and a. d. stone , `` strong interactions in multimode random lasers , '' science * 320 * , 643 - 646 ( 2008 ) .
l. ge , y. d. chong , and a. d. stone , `` steady - state ab initio laser theory : generalizations and analytic results , '' phys . rev .
a * 82 * , 063824 ( 2010 ) .
h. cao , `` review on the latest developments in random lasers with coherent feedback , '' j. phys .
a * 38 * , 10497 - 10535 ( 2005 ) .
o. painter , r. k. lee , a. scherer , a. yariv , j. d. obrien , p. d. dapkus , and i. kim , `` two - dimensional photonic band - gap defect mode laser , '' science * 284 * , 1819 - 1821 ( 1999 ) .
s. chua , y. d.....
And you have already written the first three sentences of the full article: semiclassical laser theory , which neglects the quantum fluctuations of the electromagnetic field , is widely used to describe and simulate lasers @xcite . in principle
, it correctly describes the laser thresholds and frequencies , the spatial pattern of the lasing modes , and the laser output power , including all classical non - linear effects , such as spatial hole - burning , gain saturation , and mode and phase locking .
essentially the theory describes maxwell s equations in an open cavity , coupled to the non - linear polarization of the gain medium ..
Please generate the next two sentences of the article | the gain polarization can be described using either a classical non - linear oscillator model @xcite , or a quantum - mechanical model of @xmath0 atomic levels in which the polarization and level populations obey the equations of motion of the quantum density matrix .
the simplest version of the theory , used widely in textbooks , is the two - level maxwell - bloch ( mb ) model @xcite ; however , most design and characterization simulations of lasers use models with @xmath1 or more levels . in addition , most theoretical solutions for the semiclassical laser equations employ a large number of simplifying assumptions in order to make them analytically tractable , most notably neglecting the openness of the cavity and/or treating only simple one - dimensional ( 1d ) or ring cavities , as well as approximating the non - linear interactions to cubic order . the results are typically not useful for quantitative modeling . until recently , |
5,774 | Suppose that you have an abstract for a scientific paper: we use the method of thermal qcd sum rules to investigate the effects of temperature on the neutron electric dipole moment @xmath0 induced by the vacuum @xmath1-angle
. then , we analyze and discuss the thermal behaviour of the ratio @xmath2 in connection with the restoration of the cp - invariance at finite temperature . 22.5cm16.8cm-.4cm-.9 cm = 6pt plus 2pt minus 1pt addtoresetequationsection = 18.6pt plus 0.2pt minus 0.1pt addtoresetequationsection .
And you have already written the first three sentences of the full article: the cp symmetry is , without doubt , one of the fundamental symmetries in nature .
its breaking still carries a cloud of mystery in particle physics and cosmology .
indeed , cp symmetry is intimately related to theories of interactions between elementary particles and represents a cornerstone in constructing grand unified and supersymmetric models ..
Please generate the next two sentences of the article | it is also necessary to explain the matter - antimatter asymmetry observed in universe .
the first experimental evidence of cp violation was discovered in the @xmath3 mixing and kaon decays @xcite . according to the cpt theorem , cp violation implies t violation . |
5,775 | Suppose that you have an abstract for a scientific paper: quantum counterparts of certain simple classical systems can exhibit chaotic behaviour through the statistics of their energy levels and the irregular spectra of chaotic systems are modelled by eigenvalues of infinite random matrices .
we use known bounds on the distribution function for eigenvalue spacings for the gaussian orthogonal ensemble ( goe ) of infinite random real symmetric matrices and show that gamma distributions , which have an important uniqueness property , can yield an approximation to the goe distribution . that has the advantage that then both chaotic and non chaotic cases fit in the information geometric framework of the manifold of gamma distributions , which has been the subject of recent work on neighbourhoods of randomness for general stochastic systems .
additionally , gamma distributions give approximations , to eigenvalue spacings for the gaussian unitary ensemble ( gue ) of infinite random hermitian matrices and for the gaussian symplectic ensemble ( gse ) of infinite random hermitian matrices with real quaternionic elements , except near the origin .
gamma distributions do not precisely model the various analytic systems discussed here , but some features may be useful in studies of qualitative generic properties in applications to data from real systems which manifestly seem to exhibit behaviour reminiscent of near - random processes .
+ * keywords : random matrices , goe , gue , gse , quantum chaotic , eigenvalue spacing , statistics , gamma distribution , randomness , information geometry * .
And you have already written the first three sentences of the full article: berry introduced the term quantum chaology in his 1987 bakerian lecture @xcite as the study of semiclassical but non - classical behaviour of systems whose classical motion exhibits chaos .
he illustrated it with the statistics of energy levels , following his earlier work with tabor @xcite and related developments from the study of a range of systems .
in the regular spectrum of a bound system with @xmath0 degrees of freedom and @xmath1 constants of motion , the energy levels are labelled by @xmath1 quantum numbers , but the quantum numbers of nearby energy levels may be very different . in the case of an irregular spectrum , such as for an ergodic system where only energy is conserved , we can not use quantum number labelling ..
Please generate the next two sentences of the article | this prompted the use of energy level spacing distributions to allow comparisons among different spectra @xcite .
it was known , eg from the work of porter @xcite , that the spacings between energy levels of complex nuclei and atoms with @xmath1 large are modelled by the spacings of eigenvalues of random matrices and that the wigner distribution @xcite gives a very good fit . |
5,776 | Suppose that you have an abstract for a scientific paper: we summarize the current view on parton - hadron duality as it applies to @xmath0 meson decays .
it is emphasized that an ope treatment is essential for properly formulating duality and its limitations .
duality violations are unlikely to become the limiting factor in describing semileptonic @xmath0 width vis - a - vie higher order corrections .
the consistent extraction of the @xmath1 quark mass from @xmath0 production and decays provides a striking example of the theoretical control achieved . * parton hadron duality in @xmath0 meson decays * and thomas mannel + _ institut fr theoretische teilchenphysik , + universitt karlsruhe , d76128 karlsruhe , germany _ + _ contribution to the ckm workshop , + held at cern , geneva , feb.15.-18.2002 _ .
And you have already written the first three sentences of the full article: parton - hadron duality or duality for short is one of the central concepts in contemporary particle physics .
it is invoked to connect quantities evaluated on the quark - gluon level to the ( observable ) world of hadrons .
it is used all the time , more often than not without explicit reference to it ..
Please generate the next two sentences of the article | a striking example of the confidence the hep community has in the asymptotic validity of duality was provided by the discussion of the width @xmath2 .
there was about a 2% difference in the predicted and measured decay width , which lead to lively debates on its significance vis - a - vis the _ experimental _ error . |
5,777 | Suppose that you have an abstract for a scientific paper: a study of the @xmath0li(@xmath1be,@xmath2he@xmath1be)@xmath3h reaction at @xmath4=70 mev has been performed using resonant particle spectroscopy techniques and provides a measurement of @xmath5-decaying states in @xmath6c .
excited states are observed at 12.0 , 13.4 , 14.1 , 14.6 , 15.2 , 16.8 , 17.9 , 18.7 , 21.3 and 23.9 mev .
this study provides the first measurement of the three highest energy states .
angular distribution measurements have been performed and have been employed to indicate the transferred angular momentum for the populated states .
these data are compared with recent speculations of the presence of chain - like structures in @xmath6c . , , , , , , , ,
, , nuclear reactions , @xmath0li+@xmath1be , @xmath6c levels deduced , @xmath2he+@xmath1be decay , angular distributions , molecular structure .
And you have already written the first three sentences of the full article: the structure of light nuclei has always provided a certain fascination , given that a full range of structural properties are displayed from spherical shell model like structure via deformation to clustering . in particular
even - even nuclei , composed of equal numbers of protons and neutrons offer the possibility that the nucleus may be decomposed into a collection of @xmath5-particles .
this was the picture developed by ikeda @xcite , who speculated that at the point that the @xmath7 decay threshold was encountered the associated cluster degree of freedom should be liberated ..
Please generate the next two sentences of the article | correspondingly , this picture would suggest that the @xmath8be ground state should possess an @xmath5-@xmath5 cluster structure , and the 3@xmath5 cluster structure should appear at an excitation energy close to 7.3 mev in @xmath9c .
indeed , it has been recently speculated that certain states above the 3@xmath5 decay threshold in @xmath9c ( e.g. the 7.65 mev state ) , or the 4@xmath5 decay threshold in @xmath10o , should possess properties reminiscent of a bose gas @xcite . |
5,778 | Suppose that you have an abstract for a scientific paper: we study the effect of the electron - phonon coupling on vibrational eigenmodes of nano- and micro - mechanical systems made of semiconductors with equivalent energy valleys .
we show that the coupling can lead to a strong mode nonlinearity .
the mechanism is the lifting of the valley degeneracy by the strain .
the redistribution of the electrons between the valleys is controlled by a large ratio of the electron - phonon coupling constant to the electron chemical potential or temperature .
we find the quartic in the strain terms in the electron free energy , which determine the amplitude dependence of the mode frequencies .
this dependence is calculated for silicon micro - systems .
it is significantly different for different modes and the crystal orientation , and can vary nonmonotonously with the electron density and temperature . .
And you have already written the first three sentences of the full article: the electron - phonon coupling strongly affects vibrational modes of nano- and micro - electro - mechanical systems .
much interest have attracted the effects of this coupling related to the reduced dimensionality of the electron system , as they make it possible to reveal interesting consequences of the electron correlations at the nanoscale , the coulomb blockade being a simple example , cf .
@xcite and references therein ..
Please generate the next two sentences of the article | much less attention has been paid to the consequences of the electron - phonon coupling , which are related to the discreteness of the vibrational spectrum of a nanosystem , but emerge in the absence of size quantization of the electron motion .
one of such consequences , which we study in this paper , is the coupling - induced change of the vibration nonlinearity . |
5,779 | Suppose that you have an abstract for a scientific paper: we have made a precise measurement of the inclusive jet cross section at @xmath0=1800 gev . the result is based on an integrated luminosity of 92 pb@xmath1 collected at the fermilab tevatron @xmath2 collider with the d detector .
the measurement is reported as a function of jet transverse energy ( 60 gev @xmath3 500 gev ) , and in the pseudorapidity intervals @xmath4 0.5 and [email protected] .
a preliminary measurement of the pseudorapidity dependence of inclusive jet production ( @xmath4 1.5 ) is also discussed .
the results are in good agreement with predictions from next to leading order ( nlo ) quantum chromodynamics ( qcd ) .
d has also determined the ratio of jet cross sections at @xmath0=630 gev and @xmath0=1800 gev ( @xmath6 ) .
this preliminary measurement differs from nlo qcd predictions . .
And you have already written the first three sentences of the full article: within the framework of quantum chromodynamics ( qcd ) , inelastic scattering between a proton and antiproton is described as a hard collision between their constituents ( partons ) .
after the collision , the outgoing partons manifest themselves as localized streams of particles or `` jets '' . predictions for the inclusive jet cross section have improved in the early nineties with next - to - leading order ( nlo ) perturbative qcd calculations @xcite and new , accurately measured parton density functions ( pdf)@xcite .
d has recently measured and published @xcite the cross section for the production of jets as a function of the jet energy transverse to the incident beams , @xmath7 ..
Please generate the next two sentences of the article | the measurement is based on an integrated luminosity of about 92 pb@xmath1 of @xmath2 hard collisions collected with the d detector @xcite at the fermilab tevatron collider .
this result allows a stringent test of qcd , with a total uncertainty substantially reduced relative to previous results @xcite . |
5,780 | Suppose that you have an abstract for a scientific paper: we study the adiabatic time evolution of quantum resonances over time scales which are small compared to the lifetime of the resonances .
we consider three typical examples of resonances : the first one is that of shape resonances corresponding , for example , to the state of a quantum - mechanical particle in a potential well whose shape changes over time scales small compared to the escape time of the particle from the well .
our approach to studying the adiabatic evolution of shape resonances is based on a precise form of the time - energy uncertainty relation and the usual adiabatic theorem in quantum mechanics .
the second example concerns resonances that appear as isolated complex eigenvalues of spectrally deformed hamiltonians , such as those encountered in the n - body stark effect .
our approach to study such resonances is based on the balslev - combes theory of dilatation - analytic hamiltonians and an adiabatic theorem for nonnormal generators of time evolution .
our third example concerns resonances arising from eigenvalues embedded in the continuous spectrum when a perturbation is turned on , such as those encountered when a small system is coupled to an infinitely extended , dispersive medium .
our approach to this class of examples is based on an extension of adiabatic theorems without a spectral gap condition .
we finally comment on resonance crossings , which can be studied using the last approach . *
key words : * adiabatic theorem , quantum resonances . .
And you have already written the first three sentences of the full article: there are many physically interesting examples of quantum resonances in atomic physics and quantum optics . to mention one , the state of a cold gas of atoms localized in a trap may be metastable , since the trap may be not strictly confining . in typical bose - einstein condensation experiments ,
the shape of the trap usually varies slowly over time scales small compared to the lifetime of the metastable state , yet larger than a typical relaxation time ( see for example @xcite ) .
this is an example of an adiabatic evolution of shape resonances ..
Please generate the next two sentences of the article | while there has been much progress in a time - independent theory of quantum resonances ( see @xcite ) , there has been relatively little work on a time - dependent theory of quantum resonances ( see @xcite ) .
surprisingly , and inspite of its relevance to the interpretation of many experiments and phenomena in atomic physics , the problem of adiabatic evolution of quantum resonances received very litte attention , so far ; ( but see @xcite ) . in this paper , we study the adiabatic evolution of three general types of quantum resonances . |
5,781 | Suppose that you have an abstract for a scientific paper: we propose to observe and manipulate topological edge spins in 1d optical lattice based on currently available experimental platforms . coupling the atomic spin states to a laser - induced periodic zeeman field
, the lattice system can be driven into a symmetry protected topological ( spt ) phase , which belongs to the chiral unitary ( aiii ) class protected by particle number conservation and chiral symmetries .
in free - fermion case the spt phase is classified by a @xmath0 invariant which reduces to @xmath1 with interactions .
the zero edge modes of the spt phase are spin - polarized , with left and right edge spins polarized to opposite directions and forming a topological spin - qubit ( tsq ) .
we demonstrate a novel scheme to manipulate the zero modes and realize single spin control in optical lattice .
the manipulation of tsqs has potential applications to quantum computation .
_ introduction._@xmath2since the discovery of the quantum hall effect in two - dimensional ( 2d ) electron gas @xcite , the search for nontrivial topological states has become an exciting pursuit in condensed matter physics @xcite .
the recently observed time - reversal ( tr ) invariant topological insulators ( tis ) have opened a new chapter in the study of topological phases ( tps ) , attracting great efforts in both theory and experiments @xcite . depending on whether the ground states have long - range or short - range entanglement
, the tps can be classified into intrinsic or symmetry - protected topological ( spt ) orders @xcite .
being protected by the bulk gap , the intrinsic tps are robust against any local perturbations , and the spt phases are robust against those respecting given symmetries @xcite .
this property may be applied to the fault - tolerant quantum computation @xcite .
while in theory there are numerous types of tps , the existing topological orders in nature are rare .
the recent great advancement in realizing effective spin - orbit ( so ) interaction in cold atoms @xcite....
And you have already written the first three sentences of the full article: in this supplementary material we provide the details of some results in the main text .
k atoms . ] in this section we provide details of deriving the tight - binding hamiltonian for the @xmath42-band model .
as mentioned in the main text , only two lasers @xmath14 , with @xmath191 and @xmath192 used to induce the two - photon raman transition , are needed to generate simultaneously the periodic transverse zeeman term and the 1d optical lattice ..
Please generate the next two sentences of the article | this further greatly simplifies the set - up for the experimental realization .
[ p - band ] shows the realistic transitions for @xmath178k atoms induced by @xmath14 . |
5,782 | Suppose that you have an abstract for a scientific paper: we present a spectroscopically identified catalogue of 72 da white dwarfs from the lamost pilot survey .
35 are found to be new identifications after cross - correlation with the eisenstein et al . and
villanova catalogues . the effective temperature and gravity of these white dwarfs are estimated by balmer lines fitting .
most of them are hot white dwarfs . the cooling times and masses of these white dwarfs
are estimated by interpolation in theoretical evolution tracks .
the peak of mass distribution is found to be @xmath0 0.6 @xmath1 which is consistent with prior work in the literature .
the distances of these white dwarfs are estimated using the method of synthetic spectral distances .
all of these wds are found to be in the galactic disk from our analysis of space motions .
our sample supports the expectation white dwarfs with high mass are concentrated near the plane of galactic disk . .
And you have already written the first three sentences of the full article: white dwarfs ( wds ) are the final stage for the the evolution of majority of low and medium mass stars with initial masses @xmath2 @xmath3 .
since there are no fusions reaction , the evolution of wds is primarily determined by a well understood cooling process ( fontaine et al . 2001 ; salaris et al . 2000 ) .
thus , they can be used for cosmochronology , an independent age - dating method ..
Please generate the next two sentences of the article | also , the luminosity function of wds provides firm constraints on the local star formation rate and history of the galactic disk ( krzesinski et al .
2009 ) . |
5,783 | Suppose that you have an abstract for a scientific paper: period - colour ( pc ) and amplitude - colour ( ac ) relations at maximum , mean and minimum light are constructed from a large grid of full amplitude hydrodynamic models of cepheids with a composition appropriate for the smc ( small magellanic cloud ) .
we compare these theoretical relations with those from observations .
the theoretical relations are in general good agreement with their observational counterparts though there exist some discrepancy for short period ( @xmath0 < 1 $ ] ) cepheids .
we outline a physical mechanism which can , in principle , be one factor to explain the observed pc / ac relations for the long and short period cepheids in the galaxy , lmc and smc .
our explanation relies on the hydrogen ionization front - photosphere interaction and the way this interaction changes with pulsation period , pulsation phase and metallicity .
since the pc relation is connected with the period - luminosity ( pl ) relation , it is postulated that such a mechanism can also explain the observed properties of the pl relation in these three galaxies .
cepheids stars : fundamental parameters .
And you have already written the first three sentences of the full article: the papers in this series are devoted to a study of the period - colour ( pc ) and amplitude - colour ( ac ) relations for classical cepheid variables , the physics behind the connections of pc and ac relations , and the implication for cepheid period - luminosity ( pl ) relations .
the connection between the pc and ac relations was derived by @xcite , who applied the stefan - boltzmann law at the optical maximum and minimum light together with the fact that radial variations are small in the optical @xcite . specifically : @xmath1 where @xmath2 and @xmath3 are the effective temperature at the maximum and minimum light , respectively .
if @xmath2 , and hence the colour at maximum light , is independent of period , then equation ( 1 ) implies there is a relation between the temperature at minimum light and the optical amplitudes , and vice versa ..
Please generate the next two sentences of the article | @xcite found that at the maximum light , the spectral type of galactic cepheids is independent of pulsating period .
convincing observational support for a flat ( i.e. zero slope ) maximum light pc relation has been documented by @xcite , ( * ? ? ? |
5,784 | Suppose that you have an abstract for a scientific paper: if an unruh - dewitt detector operates for an infinite proper time along the trajectory of a uniformly accelerated observer in fock space then induced transition rate of the detector is proportional to planck distribution . for a realistic detector which operates only for a finite period , the instantaneous transition rate contains both transient and non - transient terms . in particular , the non - transient term contains a _ residue _ evaluated at the pole of the two - point function .
we show here by considering a massless scalar field that unlike in fock quantization , the short - distance two - point function contains no pole in polymer quantization , the quantization techniques used in loop quantum gravity .
consequently , corresponding transition rate of the unruh - dewitt detector contains only transient terms .
thus , the result presented here provides an alternative evidence for absence of unruh effect in polymer quantization which was shown earlier by the authors using methods of bogoliubov transformation and kubo - martin - schwinger condition . .
And you have already written the first three sentences of the full article: the fock vacuum state with respect to a uniformly accelerating observer , behaves as a _
thermal _ state of a given temperature which is proportional to the magnitude , say @xmath0 , of the acceleration 4-vector .
this phenomena is referred as unruh effect @xcite ..
Please generate the next two sentences of the article | the corresponding temperature is called _ unruh temperature _ given by @xmath1 where @xmath2 is the _ boltzmann constant_. this result follows from the application of standard quantum field theory techniques in a curved background @xcite .
the existence of unruh effect can be seen using many different methods . |
5,785 | Suppose that you have an abstract for a scientific paper: we present a study of the vortex lattice in untwinned yba@xmath0cu@xmath1o@xmath2 crystals , using a combination of muon spin rotation and neutron small angle scattering measurements .
both methods show a very sharp melting temperature consistent with a first order transition . the dependence of the melting temperature on the angle of the field with respect to the crystallographic @xmath3-axis is studied .
the results are compared to thermal measurements .
-1 cm 2 .
And you have already written the first three sentences of the full article: due to their short coherence length , long penetration depth and high anisotropy , the high - t@xmath4 superconductors ( hts ) , show very unusual behaviour . apart from a proposed vortex - glass phase @xcite , which has probably been observed in the highly anisotropic bi@xmath0sr@xmath0cacu@xmath0o@xmath5 ( bscco ) at high fields @xcite ,
there is also the exciting phenomenon of vortex - lattice melting in these compounds . unlike in bscco ,
the vortex lattice melting transition in yba@xmath0cu@xmath1o@xmath2 ( ybco ) takes place at sufficiently high fields to be studied using thermal measurements such as differential thermal analysis ( dta ) @xcite and specific heat @xcite ..
Please generate the next two sentences of the article | this is mainly due to the much lower anisotropy of ybco ( @xmath6 5 ) .
apart from this phenomenological difference , there are however also more fundamental differences between ybco and bscco in the crystallographic symmetry , which is orthorhombic in the former , while it is tetragonal in the latter . |
5,786 | Suppose that you have an abstract for a scientific paper: the production of @xmath0 and @xmath1 is studied in @xmath2 collisions at @xmath3 tev with the lhcb detector .
the results of these measurements are compared with different theoretical models .
results and prospects are also shown for exotics : the mass measurement of the @xmath4 and the search of the @xmath5 .
most of the presented results are based on the 2010 lhcb dataset ( 35 pb@xmath6 ) . .
And you have already written the first three sentences of the full article: heavy quarkonium production remains a challenging problem for the understanding of quantum chromodynamics ( qcd ) . at the centre - of mass energies for proton - proton collisions at the large hadron collider ,
@xmath0 pairs are expected to be produced predominantly via leading order gluon gluon interactions , which can be computed using perturbative qcd , followed by the formation of the bound charmonium states described by non perturbative models .
recent approaches make use of non - relativistic qcd factorization ( nrqcd ) which assumes a combination of the colour - singlet and colour - octet @xmath0 as it evolves towards the final bound state via the exchange of soft gluons @xcite . next - to - leading order ( nlo ) qcd corrections in charmonium and bottomonium production.
Please generate the next two sentences of the article | are also essential for the description of the experimental data @xcite .
studies of @xmath7 , @xmath8 and @xmath9 production cross sections are presented . |
5,787 | Suppose that you have an abstract for a scientific paper: we develop a new perturbation theory ( pt ) treatment that can describe gravitational dynamics of large - scale structure after shell - crossing in the one - dimensional cosmological case . starting with cold initial conditions ,
the motion of matter distribution follows at early stages the single - stream regime , which can , in one dimension , be described exactly by the first - order lagrangian perturbation , i.e. the zeldovich solution .
however , the single - stream flow no longer holds after shell - crossing and a proper account of the multi - stream flow is essential for post - collapse dynamics . in this paper , extending previous work by ( * ? ? ?
* mnras 446 , 2902 ) , we present a perturbative description for the multi - stream flow after shell - crossing in a cosmological setup . in addition , we introduce an adaptive smoothing scheme to deal with the bulk properties of phase - space structures .
the filtering scales in this scheme are linked to the next - crossing time in the post - collapse region , estimated from our pt calculations .
our pt treatment combined with adaptive smoothing is illustrated in several cases .
predictions are compared to simulations and we find that post - collapse pt with adaptive smoothing reproduces the power spectrum and phase - space structures remarkably well even at small scales , where zeldovich solution substantially deviates from simulations .
[ firstpage ] large - scale structure cosmology vlasov - poisson equation .
And you have already written the first three sentences of the full article: it is currently admitted that processes of structure formation in the universe are mainly dominated at large scale by an invisible component called dark matter .
although the microscopic origin of dark matter is still unclear , it is macroscopically described as a self - gravitating collisionless fluid following the collisionless boltzmann or vlasov equation in a cosmological background , @xmath0 f({\mbox{\boldmath$x$}},{\mbox{\boldmath$v$}},t ) = 0 , \label{eq : vp_3d}\end{aligned}\ ] ] supplemented with the poisson equation for the newton potential @xmath1 , @xmath2 , \label{eq : poisson_3d}\end{aligned}\ ] ] where @xmath3 is the phase - space density at comoving position @xmath4 , peculiar velocity @xmath5 and time @xmath6 , @xmath7 is the expansion factor of the universe , @xmath1 is the gravitational potential and @xmath8 is the average dark matter density . in the standard picture of structure formation ,
dark matter was initially cold i.e. with a virtually null local velocity dispersion , so the six - dimensional phase - space distribution is effectively reduced to a three - dimensional hyper - surface and this remains true at all times thanks to the hamiltonian nature of the system . at early times ,.
Please generate the next two sentences of the article | dark matter thus follows the single - stream flow regime , with a velocity field @xmath9 uniquely determined as a function of position , and its evolution is that of a pressure - less fluid with a phase - space distribution function given by @xmath10 , \label{eq : df_single - stream}\end{aligned}\ ] ] where @xmath11 is the density contrast of the dark matter distribution , initially of very small magnitude , as well as @xmath9 . substituting eq .
( [ eq : df_single - stream ] ) into eqs . |
5,788 | Suppose that you have an abstract for a scientific paper: the ratios of the codon usage in the quartets and sextets for the vertebrate series exhibit a correlated behaviour which fits naturally in the framework of the crystal basis model of the genetic code @xcite . moreover the observed universal behaviour of these suitably normalized ratios can be easily explained . * symmetry and codon usage correlations * * in the genetic code * l. frappat , p. sorba _ laboratoire de physique thorique lapth , ura 1436 , _ + _ chemin de bellevue , bp 110 , + f-74941 annecy - le - vieux , france _
+ _ e - mail : _ ` frappat(sorba)@lapp.in2p3.fr ` a. sciarrino _ dipartimento di scienze fisiche , universit di napoli `` federico ii '' _ + _ and i.n.f.n .
, sezione di napoli , italy _ + _ mostra doltremare pad .
20 , 80125 napoli , italy _
+ _ e - mail : _ ` [email protected] ` .
And you have already written the first three sentences of the full article: it is a well known and intriguing fact that , in the genetic code , 64 codons code the biosynthesis of 20 amino - acids ( a.a . ) with a structure in multiplets reported in table [ tablerep ] .
+ it is also a well known and , at our knowledge , unexplained fact that the frequency rate of usage ( codon usage ) of the different codons inside a multiplet is not the same .
+ it is the aim of this paper to emphasize for the vertebrate series a correlation in the codon usage , in the quartets and sextets , which is naturally explained in the framework of the mathematical model of the genetic code recently proposed by the authors @xcite ..
Please generate the next two sentences of the article | moreover we put in evidence an universal function behaviour connected with the codon usage , which also finds a justification in the model .
2 we recall the essential features of the model and in sec . |
5,789 | Suppose that you have an abstract for a scientific paper: we study the magnetic interaction between two superconducting concentric mesoscopic al loops , close to the superconducting / normal phase transition . the phase boundary is measured resistively for the two - loop structure as well as for a reference single loop . in both systems little - parks oscillations ,
periodic in field are observed in the critical temperature @xmath0 versus applied magnetic field @xmath1 . in the fourier spectrum of the @xmath2 oscillations ,
a weak low frequency response shows up , which can be attributed to the inner loop supercurrent magnetic coupling to the flux of the outer loop .
the amplitude of this effect can be tuned by varying the applied transport current . .
And you have already written the first three sentences of the full article: in 1962 , little and parks@xcite measured a mesoscopic superconducting cylinder in an axial magnetic field .
the superconducting critical temperature @xmath3 showed oscillations periodic in the normalized flux , with the period corresponding to the superconducting flux quantum @xmath4 .
these oscillations in @xmath3 are a straightforward consequence of the fluxoid quantization constraint , which was introduced by f. london@xcite ..
Please generate the next two sentences of the article | fluxoid quantization can be easily understood by integrating the second ginzburg - landau ( gl ) equation for the supercurrent@xcite @xmath5 along a closed contour . here , @xmath6 is the supercurrent density , @xmath7 is the superfluid velocity , @xmath8 is the phase of the complex order parameter @xmath9 , and @xmath10 is the magnetic vector potential .
integration along an arbitrary closed contour yields the following equation : @xmath11 where the fluxoid @xmath12 is quantized in units of @xmath13 and @xmath14 is the applied flux threading the area inside the contour . the integer number @xmath15 is the phase winding number , or also called the fluxoid quantum number , counting the number of flux quanta @xmath16 penetrating the enclosed area . when the applied flux @xmath14 is not equal to integer times the flux quantum @xmath16 , a supercurrent @xmath17 has to be generated in order to fulfill eq . |
5,790 | Suppose that you have an abstract for a scientific paper: thz time - domain spectroscopy was used to directly probe the low - energy ( 0.55 mev ) electrodynamics of the charge - ordered manganite pr@xmath0ca@xmath1mno@xmath2 .
we revealed the existence of a finite peak structure around 23 mev well below the charge gap @xmath3 mev .
in analogy to the low - energy optical properties of the well - studied low - dimensional materials , we attributed this observed structure to the collective excitation mode arising from the charge - density - wave condensate .
this finding provides the importance role of the quasi - one dimensional nature of the charge and orbital ordering in pr@xmath0ca@xmath1mno@xmath2 . .
And you have already written the first three sentences of the full article: the tendency toward for the formation of the charge ordering is a common characteristic of the transition metal oxides with a perovskite structure including high - temperature superconducting cuprates and colossal magnetoresistive manganites .
@xcite in particular , various kind of the manganites with the doping level @xmath4 of 1/2 show the charge - exchange ( ce)-type charge ordering , @xcite in which mn@xmath5 and mn@xmath6 ions by the ratio of 1:1 regularly distribute in the underlying lattice below the charge and orbital ordering temperature @xmath7 [ fig .
[ fig1](a ) ] ..
Please generate the next two sentences of the article | such a real - space charge ordering is characterized by a single - particle excitation across the charge gap @xmath8 . using the light of frequency @xmath9 , the single - particle excitation spectrum of the charge - ordered ( co ) manganites
have been extensively investigated in recent years ; @xcite for example , okimoto _ |
5,791 | Suppose that you have an abstract for a scientific paper: in this work we study the formation and dynamics of polarons in a system with a few impurities in a lattice immersed in a bose - einstein condensate ( bec ) .
this system has been experimentally realized using ultracold atoms and optical lattices . here
, we consider a two - band model for the impurity atoms , along with a bogoliubov approximation for the bec , with phonons coupled to impurities via both intraband and interband transitions .
we decouple this frhlich - type term by an extended two - band lang - firsov polaron transformation using a variational method .
the new effective hamiltonian with two ( polaron ) bands differs from the original hamiltonian by modified coherent transport , polaron energy shifts , and induced long - range interaction .
a lindblad master - equation approach is used to take into account residual incoherent coupling between polaron and bath .
this polaronic treatment yields a renormalized inter - band relaxation rate compared to fermi s golden rule . for a strongly coupled two - band frhlich hamiltonian
, the polaron is tightly dressed in each band and can not tunnel between them , leading to an _ inter - band self - trapping _ effect . .
And you have already written the first three sentences of the full article: the field of ultracold atom physics has explored a wide variety of phenomena since its relatively recent accessibility , with a major feature being the tunability of experiments across wide parameter regimes @xcite , to easily access and probe phase transitions @xcite , as well as excitation spectra and dynamics of systems analog to condensed matter @xcite .
even features such as artificial gauge fields can be implemented for neutral atomic particles , allowing for the investigation of topological phases @xcite . within this ultracold toolbox
, one ingredient is becoming of increasing interest in recent years which is of vital importance to real solid - state systems : phonons and atom - phonon coupling @xcite ..
Please generate the next two sentences of the article | such a coupling provides many interesting possibilities @xcite . for one , it can lead to effective hamiltonians , such as extended hubbard models or the holstein model @xcite , as well as dissipative two - level system @xcite .
polaronic effects from electron - phonon interactions have also long been suggested to be the proponent behind high-@xmath0 superconductivity in one- and two - band solid - state systems @xcite . in ultracold quantum gases , |
5,792 | Suppose that you have an abstract for a scientific paper: we study the evolution and observability of young compact star clusters within @xmath0pc of the galactic center .
calculations are performed using direct integration on the grape-4 , including the effects of both stellar and binary evolution and the external influence of the galaxy .
the results of these detailed calculations are used to calibrate a simplified model applicable over a wider range of cluster initial conditions .
we find that clusters within 200pc of the galactic center dissolve within @xmath1 myr .
however , their projected densities drop below the background density in the direction of the galactic center within @xmath2myr , effectively making these clusters undetectable after that time .
clusters farther from the galactic center but at the same projected distance are more strongly affected by this selection effect , and may go undetected for their entire lifetimes .
based on these findings , we conclude that the region within 200 pc of the galactic center could easily harbor some 50 clusters with properties similar to those of the arches or the quintuplet systems .
# 1 # 1*[#1 steve ] * # 1*[#1 steve ] * # 1*[#1 simon ] * # 1*[#1 simon ] * # 1*[#1 piet ] * # 1*[#1 piet ] * # 1*[#1 jun ] * # 1*[#1 jun ] * @xmath3 massachusetts institute of technology , cambridge , ma 02139 , usa , _ hubble fellow _
+ @xmath4 department of astronomy , university of tokyo , 7 - 3 - 1 hongo , bunkyo - ku , tokyo 113 - 0033 , japan + @xmath5 dept . of physics , drexel university , philadelphia , pa 19104 , usa + @xmath6 institute for advanced study , princeton , nj 08540 , usa + subject headings : gravitation methods : n - body simulations stellar dynamics stars : evolution globular clusters : individual ( arches , quintuplet ) .
And you have already written the first three sentences of the full article: two young compact star clusters have been observed within a few tens of parsecs of the galactic center : the arches cluster ( object 17 , nagata et al .
1995 ) and the quintuplet cluster ( afgl2004 , nagata et al . 1990
; okuda et al . 1990 ) , for which excellent observational data are available . in terms of structural parameters size , mass , density profile and ages , these systems may represent the galactic counterparts to ngc2070 ( r136 ) , the central star cluster in the 30doradus region in the large magellanic could ( massey & hunter 1998 ) . the arches and quintuplet clusters lie behind thick layers of absorbing material , hinting that many more such systems may exist ..
Please generate the next two sentences of the article | recently , dutra & bica ( 2000 ) have reported from the 2mass survey a total of 58 star cluster candidates within @xmath7pc ( in projection ) of the galactic center .
a number of important questions make these clusters worthy of detailed study , among them : ( 1 ) how are such clusters related to globular clusters ? ( 2 ) how do they contribute to the total star formation rate in the galaxy ? ( 3 ) are their mass functions in reality intrinsically flat , as is suggested by observations ? ( 4 ) how far are these clusters from the galactic center ? ( 5 ) how many are hidden , still waiting to be discovered ? in this letter |
5,793 | Suppose that you have an abstract for a scientific paper: a systematic approach to the non - markovian quantum dynamics of open systems is given by the projection operator techniques of nonequilibrium statistical mechanics .
combining these methods with concepts from quantum information theory and from the theory of positive maps , we derive a class of correlated projection superoperators that take into account in an efficient way statistical correlations between the open system and its environment .
the result is used to develop a generalization of the lindblad theory to the regime of highly non - markovian quantum processes in structured environments . .
And you have already written the first three sentences of the full article: the theoretical description of relaxation and decoherence processes in open quantum systems often leads to a non - markovian dynamics which is determined by pronounced memory effects @xcite .
strong system - environment couplings @xcite , correlations and entanglement in the initial state @xcite , interactions with environments at low temperatures and with spin baths @xcite , finite reservoirs @xcite , and transport processes in nano - structures @xcite can lead to long memory times and to a failure of the markovian approximation .
a systematic approach to non - markovian dynamics is provided by the projection operator techniques @xcite which are extensively used in nonequilibrium thermodynamics and statistical mechanics @xcite ..
Please generate the next two sentences of the article | these techniques are based on the introduction of a certain projection superoperator @xmath0 which acts on the states of the total system .
the superoperator @xmath0 is the mathematical expression for the idea of the elimination of degrees of freedom from the complete description of the states of the total system : if @xmath1 is the full density matrix of the composite system , the projection @xmath2 represents a certain approximation of @xmath1 which leads to a simplified effective description of the dynamics through a reduced set of variables . |
5,794 | Suppose that you have an abstract for a scientific paper: for the gls and bjorken dis sum rules we compare fixed - order nnlo perturbative qcd estimates , and all - orders resummed estimates , with the available data , in order to assess the reliability of fixed - order perturbation theory at rather small @xmath0 values .
fits are also performed for non - perturbative power corrections using a recently proposed model . .
And you have already written the first three sentences of the full article: the perturbative series for qcd observables is not convergent , the @xmath1-order coefficients exhibiting @xmath2 growth at large @xmath3 . in the borel plane
there are singularities along the real axis : ultraviolet ( uv ) renormalons along the negative real semi - axis , and infrared ( ir ) renormalons lying on the integration contour , along the positive real semi - axis .
the latter render the borel integral ambiguous , the ambiguity being structurally identical to ambiguities arising in the non - perturbative operator product expansion ( ope ) @xcite ..
Please generate the next two sentences of the article | consequently , all - orders perturbation theory is only well - defined if supplemented by the non - perturbative ope , allowing the ambiguities to cancel . in practice
all - orders calculations are only possible in the `` leading-@xmath4 approximation '' , in which the @xmath1-order perturbative coefficient is recast as an expansion in powers of @xmath5 , the first beta - function coefficient ( in su@xmath6 qcd , with @xmath7 active quark flavours ) . the `` leading-@xmath4 '' term ( proportional to @xmath8 ) |
5,795 | Suppose that you have an abstract for a scientific paper: we initiate the development of a theory of the elasticity of nanoscale objects based upon new physical concepts which remain properly defined on the nanoscale .
this theory provides a powerful way of understanding nanoscale elasticity in terms of local group contributions and gives insight into the breakdown of standard continuum relations .
we also give two applications . in the first ,
we show how to use the theory to derive a new relation between the bending and stretching properties of nanomechanical resonators and to prove that it is much more accurate than the continuum - based relations currently employed in present experimental analyses . in the second
, we use the new approach to link features of the underlining electronic structure to the elastic response of a silicon nanoresonator . .
And you have already written the first three sentences of the full article: the recent development of artificial free - standing structures of nanometer dimensions has led to great interest in their mechanical properties .
a wealth of experimental information is now available for nanowires @xcite and nanotubes@xcite , and a computational literature is developing on the subject@xcite .
many of these works make use of results from the continuum theory of elasticity to analyze the behavior of nanometer structures ..
Please generate the next two sentences of the article | however , the applicability of continuum theories to nanoscale objects , where atomic - level inhomogeneities come to the fore , has yet to be explored in depth .
rigorous understanding of the elastic properties of nanoscale systems is crucial in understanding their mechanical behavior and presents an intriguing theoretical challenge lying at the cross - over between the atomic level and the continuum . in the absence of an appropriate theoretical description at this cross - over , |
5,796 | Suppose that you have an abstract for a scientific paper: we consider the important problem of estimating parameter sensitivities for stochastic models of reaction networks that describe the dynamics as a continuous - time markov process over a discrete lattice .
these sensitivity values are useful for understanding network properties , validating their design and identifying the pivotal model parameters .
many methods for sensitivity estimation have been developed , but their computational feasibility suffers from the critical bottleneck of requiring time - consuming monte carlo simulations of the exact reaction dynamics . to circumvent this problem one needs to devise methods that speed up the computations while suffering acceptable and quantifiable loss of accuracy .
we develop such a method by first deriving a novel integral representation of parameter sensitivity and then demonstrating that this integral may be approximated by any convergent tau - leap method .
our method is easy to implement , works with any tau - leap simulation scheme and its accuracy is proved to be similar to that of the underlying tau - leap scheme .
we demonstrate the efficiency of our methods through numerical examples .
we also compare our method with the tau - leap versions of certain finite - difference schemes that are commonly used for sensitivity estimations .
+ [ section ] [ theorem]lemma [ theorem]condition [ theorem]proposition [ theorem]remark [ theorem]definition [ theorem]hypothesis [ theorem]corollary [ theorem]example [ theorem]description [ theorem]assumption
| * keywords : * parameter sensitivity ; reaction networks ; markov process ; tau - leap simulations + * mathematical subject classification ( 2010 ) : * 60j22 ; 60j27 ; 60h35 ; 65c05 . .
And you have already written the first three sentences of the full article: the study of chemical reaction networks is an essential component of the emerging fields of systems and synthetic biology @xcite .
traditionally chemical reaction networks were modeled in the deterministic setting , where the dynamics is represented by a set of ordinary differential equations ( odes ) or partial differential equations ( pdes ) . in the study of intracellular chemical reactions , some chemical species are present in low copy numbers .
since the behavior of individual molecules is best described by a stochastic process , in the low molecular copy number regime , the copy numbers of the molecular species itself is better modeled by a stochastic process than by odes @xcite . only in the limit of large molecular copy numbers ,.
Please generate the next two sentences of the article | one expects the deterministic models to be accurate @xcite .
while our work in this paper is focused on biochemical reaction networks as primary examples , we emphasize that the mathematical framework of reaction networks can also be used to describe a wide range of other phenomena in fields such as epidemiology @xcite and ecology @xcite . |
5,797 | Suppose that you have an abstract for a scientific paper: we study an individual - based predator - prey model of biological coevolution , using linear stability analysis and large - scale kinetic monte carlo simulations .
the model exhibits approximate @xmath0 noise in diversity and population - size fluctuations , and it generates a sequence of quasi - steady communities in the form of simple food webs .
these communities are quite resilient toward the loss of one or a few species , which is reflected in different power - law exponents for the durations of communities and the lifetimes of species .
the exponent for the former is near @xmath1 , while the latter is close to @xmath2 .
statistical characteristics of the evolving communities , including degree ( predator and prey ) distributions and proportions of basal , intermediate , and top species , compare reasonably with data for real food webs . .
And you have already written the first three sentences of the full article: biological evolution presents many problems concerning interacting multi - entity systems far from equilibrium that are well suited for methods from nonequilibrium statistical physics @xcite . among these are questions concerning the dynamics of the emergence and extinction of species on macroevolutionary timescales @xcite .
traditionally it has been common to treat ecological and evolutionary processes on very different timescales . however , it has recently been realized that evolution often can take place on short timescales , comparable to those of ecological processes @xcite . a well - known example of very rapid evolution is provided by the cichlid fishes of east africa @xcite .
several models have therefore been proposed that , while spanning disparate scales of temporal and taxonomic resolution , consider the complex problem of coevolution of species in a fitness landscape that constantly changes with the composition of the community ..
Please generate the next two sentences of the article | early contributions were simulations of parapatric and sympatric speciation @xcite and the coupled @xmath3 model with population dynamics @xcite .
more recent work includes the webworld model @xcite , the tangled - nature model @xcite and simplified versions of the latter @xcite , as well as network models @xcite . |
5,798 | Suppose that you have an abstract for a scientific paper: we study the pair - production of charginos in the cp - violating minimal supersymmetric standard model at center - of - mass energies around the heavy neutral higgs boson resonances .
if these resonances are nearly degenerate , as it can happen in the higgs decoupling limit , radiatively induced scalar - pseudoscalar transitions can be strongly enhanced .
the resulting mixing in the higgs sector leads to large cp - violating effects , and a change of their mass spectrum . for longitudinally polarized muon beams ,
we analyze cp asymmetries which are sensitive to the interference of the two heavy neutral higgs bosons .
we present a detailed numerical analysis of the cross sections , chargino branching ratios , and the cp observables .
we obtain sizable cp asymmetries , which would be accessible in future measurements at a muon collider . especially for intermediate values of the parameter @xmath0 , where the largest branching ratios of higgs bosons into charginos are expected
, this process allows to analyze the higgs sector properties and its interaction to supersymmetric fermions .
bonn - th-2008 - 06 + * cp - violating higgs boson mixing in chargino production at the muon collider * olaf kittel _ physikalisches
institut der universitt bonn , nussallee 12 , d-53115 bonn , germany _ _ instituto de fsica de cantabria ( csic - uc ) , e-39005 santander , spain _ .
And you have already written the first three sentences of the full article: the cp - conserving minimal supersymmetric standard model ( mssm ) contains three neutral higgs bosons @xcite , the lighter and heavier cp - even scalars @xmath1 and @xmath2 , respectively , and the cp - odd pseudoscalar @xmath3 . in the presence of cp phases ,
the mssm higgs sector is still cp - conserving at born level .
however loop effects , dominantly mediated by third generation squarks , can generate significant cp - violating scalar - pseudoscalar transitions ..
Please generate the next two sentences of the article | thus the neutral cp - odd and cp - even higgs states mix and form the mass eigenstates @xmath4 , @xmath5 , @xmath6 , with no definite cp parities @xcite .
a detailed knowledge of their mixing pattern will be crucial for the understanding of the mssm higgs sector in the presence of cp - violating phases . |
5,799 | Suppose that you have an abstract for a scientific paper: when an isolated system is brought in contact with a heat bath its final energy is random and follows the gibbs distribution a cornerstone of statistical physics .
the system s energy can also be changed by performing non - adiabatic work using a cyclic process .
almost nothing is known about the resulting energy distribution in this setup , which is especially relevant to recent experimental progress in cold atoms , ions traps , superconducting qubits and other systems . here
we show that when the non - adiabatic process comprises of many repeated cyclic processes the resulting energy distribution is universal and different from the gibbs ensemble .
we predict the existence of two qualitatively different regimes with a continuous second order like transition between them .
we illustrate our approach performing explicit calculations for both interacting and non - interacting systems .
understanding equilibrium and non - equilibrium properties of thermally _ isolated _ systems has become a forefront of research due to experimental developments over the past decade , particularly in cold atom systems @xcite , trapped ions @xcite , and nuclear spins @xcite and superconducting qubits @xcite . in these systems the coupling to external dissipative degrees of freedom is strongly suppressed and irrelevant on accessible time scales .
these systems provide a new and very clean playground where one can investigate fundamental questions in statistical and quantum physics .
moreover , they point to new practical applications , in particular in the context of quantum information .
the experimental studies inspired intensive theoretical research on a variety of topics .
these include equilibration in isolated systems initially driven out of equilibrium by a sudden change in a coupling constant ( a quench ) ; defect ( or energy ) generation during slow nearly adiabatic processes in gapless phases or near singularities , such as quantum phase transitions ( for a review see refs .
@xcite ) ; non -....
And you have already written the first three sentences of the full article: first , we consider a system of non - interacting and weakly interacting particles in a deforming cavity . then we analyze a single particle in a harmonic potential , which is a part of a larger system , and subject to a time - dependent external force .
two additional examples of a classical one - dimensional xy - model and a quantum one - dimensional transverse field ising model will be discussed in the supplementary material . _ single particle in a deforming cavity _ :
let us first consider a very simple system - a single particle bouncing elastically in a cavity ..
Please generate the next two sentences of the article | when the cavity is stationary the energy of the particle is conserved . if the cavity is chaotic there are no other conserved quantities so that in the long - time limit the particle relaxes to a uniform position distribution and an isotropic momentum distribution .
we consider a process where the system is repeatedly driven by deforming the cavity . at the end of each cycle |
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