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7,500 | Suppose that you have an abstract for a scientific paper: we present a detailed physical analysis of the dynamical glass - jamming transition which occurs for the so called knight models recently introduced and analyzed in a joint work with d.s.fisher@xcite .
furthermore , we review some of our previous works on kinetically constrained models .
the knights models correspond to a new class of kinetically constrained models which provide the first example of finite dimensional models with an _ ideal glass - jamming transition_. this is due to the underlying percolation transition of particles which are mutually blocked by the constraints .
this _ jamming percolation _ has unconventional features : it is discontinuous ( i.e. the percolating cluster is compact at the transition ) and the typical size of the clusters diverges faster than any power law when @xmath0 .
these properties give rise for knight models to an ergodicity breaking transition at @xmath1 : at and above @xmath2 a finite fraction of the system is frozen . in turn , this finite jump in the density of frozen sites leads to a two step relaxation for dynamic correlations in the unjammed phase , analogous to that of glass forming liquids .
also , due to the faster than power law divergence of the dynamical correlation length , relaxation times diverge in a way similar to the vogel - fulcher law .
* keywords : * kinetically constrained lattice gases , glassy dynamics , bootstrap percolation , jamming transition . .
And you have already written the first three sentences of the full article: the formation of amorphous solids as glasses and granular media , i.e the _ glass and jamming transitions _ , are still unsettled and fascinating questions in condensed matter physics despite all the works that have been devoted to this subject .
these phenomena occur in a variety of systems which , even if microscopically very different , share common features . among the others we recall supercooled liquids , colloidal suspensions and non - thermal jamming systems ( e.g. vibrated granular materials ) @xcite .
basic _ glassy properties _ include a dramatic slowing down of dynamics when a proper external parameter is tuned ( e.g. temperature is lowered for liquids ) and the occurrence of a complicated relaxation : non exponential and spatially heterogeneous @xcite ..
Please generate the next two sentences of the article | when relaxation times become longer than experimental scales , equilibrium can no more be achieved and the systems freeze into an amorphous phase .
even the basic issues in understanding these phenomena remain unsolved . in particular |
7,501 | Suppose that you have an abstract for a scientific paper: recently the agile @xmath0-ray telescope has reported the enhanced @xmath0-ray emission above 100 mev from the direction of the crab nebula during a period of a few days .
this intriguing observation has been confirmed by the fermi - lat telescope .
this emission does not show evidences of pulsations with the crab pulsar .
it seems that it originates at the shock region created as a result of the interaction of the pulsar wind with the nebula .
we propose that such variable @xmath0-ray emission originate in the region behind the shock when the electrons can be accelerated as a result of the reconnection of the magnetic field compressed by the decelerating pulsar wind .
the natural consequence of such interpretation is the prediction that the crab nebula @xmath0-ray spectrum produced by electrons as a result of the inverse compton scattering of soft radiation to multi - tev energies should also show synchronous variability on the time scales as observed at gev energies by the agile and fermi - lat telescopes .
we calculate how the end of the ic component of the crab nebula @xmath0-ray spectrum should look like during the quiescent and the flare gev @xmath0-ray emission .
we conclude that the variability of the multi - tev @xmath0-ray spectrum from the crab nebula might in principle be responsible for the differences between the spectral features reported by the hegra and hess collaborations at the multi - tev energies .
[ firstpage ] neutron stars : nebulae individual : crab nebula radiation mechanisms : non - thermal gamma - rays : theory .
And you have already written the first three sentences of the full article: the crab nebula @xmath0-ray emission has been established as a standard candle for the @xmath0-ray astronomy ( e.g. meyer et al .
this conclusion based mainly on the observations at energy ranges between @xmath1 mev and a few gev ( satellite telescopes ) and between @xmath1 gev and @xmath2 tev ( cherenkov telescopes ) .
the theoretical interpretation of the emission from the crab nebula suggests that this may not be exactly the case . the @xmath0-ray spectrum is widely interpreted in the two component radiation model in which the lower energy emission is due to the synchrotron process and the higher energy emission results as a consequence of the inverse compton ( ic ) process ..
Please generate the next two sentences of the article | it has been argued that the ends of the synchrotron and ic components can flicker due to the non - stationary acceleration of leptons at the pulsar wind shock .
first evidences of the variability of the end of synchrotron component has been reported based on the analysis of the egret data ( de jager et al . |
7,502 | Suppose that you have an abstract for a scientific paper: we have investigated the in - plane thermal conductivity @xmath0 of large single crystals of optimally oxygen - doped ( y@xmath1,sm@xmath2)ba@xmath3cu@xmath4o@xmath5 ( @xmath6=0 , 0.1 , 0.2 and 1.0 ) and yba@xmath3(cu@xmath7zn@xmath8)@xmath4o@xmath5 ( @xmath9=0.0071 ) as functions of temperature and magnetic field ( along the @xmath10 axis ) . for comparison ,
the temperature dependence of @xmath11 for as - grown crystals with the corresponding compositions are presented .
the nonlinear field dependence of @xmath11 for all crystals was observed at relatively low fields near a half of @xmath12 .
we make fits of the @xmath13 data to an electron contribution model , providing both the mean free path of quasiparticles @xmath14 and the electronic thermal conductivity @xmath15 , in the absence of field . the local lattice distortion due to the sm substitution for y suppresses both the phonon and electron contributions . on the other hand
, the light zn doping into the cuo @xmath3 planes affects solely the electron component below @xmath12 , resulting in a substantial decrease in @xmath14 . .
And you have already written the first three sentences of the full article: since the discovery of high-@xmath12 cuprate with its perovskite structure , a large number of measurements of thermal conductivity @xmath16 have been reported up to date , giving crucial information about transport properties in the superconducting and normal states@xcite .
the thermal conductivity of solids is usually separated into the phonon and electronic components @xmath17 and @xmath18 @xcite . for high-@xmath12 copper oxide superconductors yba@xmath3cu@xmath4o@xmath5(ybco ) ,
bi@xmath3sr@xmath3cacu@xmath3o@xmath19 and tl@xmath3sr@xmath3cacu@xmath3o@xmath19 , a rapid enhancement in @xmath20 is observed below @xmath12 , with decreasing @xmath21 , then @xmath20 reaches a maximum around a half of @xmath12 and finally shows a monotonous decrease at low temperatures ..
Please generate the next two sentences of the article | tewordt et al .
ascribed the origin of the anomaly to the phonon contribution @xmath17 on the basis of the classical theory of thermal transport in superconductors @xcite . on the contrary , yu et al . |
7,503 | Suppose that you have an abstract for a scientific paper: quantum state can be teleported to a remote site by only local measurement and classical communication if the prior einstein - podolsky - rosen quantum channel is available between the sender and the receiver .
those quantum channels shared by multiple nodes can constitute a quantum network .
yet , studies on the efficiency of quantum communication between nodes of quantum networks remain limited , which differs from classical case in that the quantum channel will be consumed if teleportation is performed . here
, we introduce the exclusive quantum channels ( eqc ) as the measure of efficiency of quantum information transmission .
it quantifies the amount of quantum information which can be teleported between nodes in a quantum network .
we show that different types of eqc are local quantities with effective circles .
significantly , capacity of quantum communication of quantum networks quantified by eqc is independent of distance for the communicating nodes .
thus , the quantum network can be dealt as the isotropic medium where quantum communication is no - decaying .
eqc are studied by both analytical and numerical methods .
the eqc can be enhanced by transformations of lattices of quantum network via entanglement swapping .
our result opens the avenue in studying the quantum communication of the quantum networks .
quantum information processing offers quantum algorithms which may surpass their classical counterparts .
recently , quantum network and its extension , quantum internet which might potentially be the next generation internet , have been attracting a great deal of interests @xcite .
the quantum networks are constituted by quantum nodes where quantum information can be produced , stored and processed locally .
those nodes are supposed to be linked by both quantum channels and classical channels so that quantum states can be teleported between different nodes .
this feature is also essential if each individual node in quantum network is restricted to finite size of....
And you have already written the first three sentences of the full article: we consider a quantum network which constitutes a periodic two - dimensional lattice , see fig .
the nodes are located at lattice sites , and each bond connecting nearest neighboring sites correspond a pure entangled state shared by two nodes , @xmath0 , where @xmath1 and @xmath2 is assumed .
suppose we need to transmit some qubits from alice at node @xmath3 in the network to bob at node @xmath4 ..
Please generate the next two sentences of the article | we follow the standard protocol : first , we convert each entangled state represented by a bond to a maximally entangled state .
the optimal conversion probability is @xmath5 , @xcite . |
7,504 | Suppose that you have an abstract for a scientific paper: in the context of the sensational results concerning superluminal velocities , announced recently by the opera collaboration , we have proposed a classical model yielding a statistically calculated measured velocity of a beam , higher than the velocity of the particles constituting the beam .
the two key elements of our model , necessary and sufficient to obtain this curious result , are a time - dependent `` transmission '' function and statistical method of the maximum - likelihood estimation . opera neutrino anomaly , superluminal neutrinos 06.30.gv velocity , acceleration , and rotation , 06.20.dk measurement and error theory , 07.05.kf data analysis : algorithms and implementation ; data management , 13.15.+g neutrino interactions , 14.60.lm ordinary neutrinos , 03.30.+p special relativity inspired by the amazing results of the opera collaboration @xcite , claiming that the velocity of light @xmath0 has been beaten by a beam of neutrinos , we propose a simple classical model , which yields the curious effect of a seeming increase of `` effective '' velocity ( see @xcite , for an earlier independent approach , and also @xcite , for a wave version ) .
there are dozens of papers , which have recently appeared , adopting various attitudes towards the results presented by the opera collaboration , for example @xcite ( see also an example of an older work on superluminal velocities @xcite ) .
the attitude of our paper is definitely skeptical . in view of the fact that we have found a ( `` mathematical '' ) model providing an `` artificial '' increase of real velocity , we are forced to put the results announced by the opera collaboration in doubt .
moreover , we have also proposed a simple working example , such that appropriately fitting its parameters one can simulate the controversial results of the opera collaboration .
strictly speaking , our paper does not indisputably invalidates the conclusions drawn by the opera collaboration , but it seriously weakens their argumentation ,....
And you have already written the first three sentences of the full article: for the reader s convenience , we present here analytical form of the expressions used in the main part of the paper . for @xmath5 given by ( [ eq : gauss ] ) and @xmath17 given by ( [ eq : nontrivialtransmission ] )
, we obtain the integral @xmath41.
Please generate the next two sentences of the article | |
7,505 | Suppose that you have an abstract for a scientific paper: we investigate the charge transfer characteristics of one and two excess charges in a dna base - pair dimer using a model hamiltonian approach .
the electron part comprises diagonal and off - diagonal coulomb matrix elements such a correlated hopping and the bond - bond interaction , which were recently calculated by starikov [ e. b. starikov , phil . mag .
lett . * 83 * , 699 ( 2003 ) ] for different dna dimers .
the electronic degrees of freedom are coupled to an ohmic or a super - ohmic bath serving as dissipative environment .
we employ the numerical renormalization group method in the nuclear tunneling regime and compare the results to marcus theory for the thermal activation regime . for realistic parameters ,
the rate that at least one charge is transferred from the donor to the acceptor in the subspace of two excess electrons significantly exceeds the rate in the single charge sector .
moreover , the dynamics is strongly influenced by the coulomb matrix elements .
we find sequential and pair transfer as well as a regime where both charges remain self - trapped .
the transfer rate reaches its maximum when the difference of the on - site and inter - site coulomb matrix element is equal to the reorganization energy which is the case in a gc - gc dimer .
charge transfer is completely suppressed for two excess electrons in at - at in an ohmic bath and replaced by damped coherent electron - pair oscillations in a super - ohmic bath . a finite bond - bond interaction @xmath0
alters the transfer rate : it increases as function of @xmath0 when the effective coulomb repulsion exceeds the reorganization energy ( inverted regime ) and decreases for smaller coulomb repulsion . .
And you have already written the first three sentences of the full article: understanding charge transfer dynamics in dna is of fundamental importance for biochemistry and molecular electronics . @xcite it can generate chemical reactions over long distances and has biological relevance in the formation of oxidative damage .
charge transfer in dna also plays an important role in anti - cancer drugs,@xcite electrochemical readout of micro arrays and molecular - electronic devices .
whereas dna conductivity is still disputed , there is no doubt that electron transfer through dna double strands takes place ..
Please generate the next two sentences of the article | @xcite it is generally believed that the electron or hole migrates by super - exchange tunneling or multistep hopping in a donor - bridge - acceptor system depending on the energy difference between the bridge and donor / acceptor @xcite and the fluctuation of the environment .
@xcite most of the current understanding of electron transfer is derived from a single - excess charge where only two states are needed to model a donor - acceptor system . at high temperatures |
7,506 | Suppose that you have an abstract for a scientific paper: mesons constructed from the quark propagators without the lowest - lying eigenmodes of the dirac operator reveal not only restored @xmath0 chiral and @xmath1 symmetries , but actually a higher symmetry .
all possible chiral and @xmath1 multiplets for the states of the same spin are degenerate , i.e. , the energy of the observed quantum levels does not depend on the spin orientation of quarks in the system and their parities .
the quark - spin independence of the energy levels implies absence of the magnetic interactions in the system .
the ultrarelativistic quark - antiquark system with only the color - electric interactions can be interpreted ( or defined ) as a dynamical qcd string . .
And you have already written the first three sentences of the full article: with the static color charges one observes on the lattice a color - electric flux tube @xcite , which , if the distance between the static quarks is large , can be approximated as a string .
this string is nondynamical ( in the sense that its ends are fixed ) . in the light quark systems
a crucial aspect is a relativistic motion of quarks at the ends of a possible string ..
Please generate the next two sentences of the article | there is no consistent theory of the dynamical qcd string with quarks at the ends .
it is even apriori unclear whether such a picture has something to do with reality . in this case |
7,507 | Suppose that you have an abstract for a scientific paper: we analyze in detail the discrete time quantum walk on the line by separating the quantum evolution equation into markovian and interference terms . as a result of this separation ,
it is possible to show analytically that the quadratic increase in the variance of the quantum walker s position with time is a direct consequence of the coherence of the quantum evolution .
if the evolution is decoherent , as in the classical case , the variance is shown to increase linearly with time , as expected .
furthermore we show that this system has an evolution operator analogous to that of a resonant quantum kicked rotor . as this rotator
may be described through a quantum computational algorithm , one may employ this algorithm to describe the time evolution of the quantum walker .
hadamard walk ; markovian process ; quantum information + pacs : 03.65.yz ; 03.67.lx ; 05.40.fb .
And you have already written the first three sentences of the full article: the study of computational devices based upon quantum mechanics , _ i.e. _ quantum computation , has drawn the attention of researchers in the last few decades @xcite .
the recent advances in technology that allow to construct and preserve almost perfectly quantum states , have opened the possibility of building useful quantum computing devices . however , relatively few quantum algorithms that outperform classical ones have been found @xcite .
the classical random walk is an example of stochastic motion that has found classical applications in many fields ..
Please generate the next two sentences of the article | the quantum version of this problem has several features which are markedly different from the classical walk @xcite . as some classical algorithms
are based on random walks , it seems natural to ask whether quantum random walks might be a useful tool for quantum computation @xcite . |
7,508 | Suppose that you have an abstract for a scientific paper: in this work we study spherical shell dark soliton states in three - dimensional atomic bose - einstein condensates .
their symmetry is exploited in order to analyze their existence , as well as that of topologically charged variants of the structures , and , importantly , to identify their linear stability bogolyubov - de gennes spectrum .
we compare our effective 1d spherical and 2d cylindrical computations with the full 3d numerics .
an important conclusion is that such spherical shell solitons can be stable sufficiently close to the linear limit of the isotropic condensates considered herein .
we have also identified their instabilities leading to the emergence of vortex line and vortex ring cages .
in addition , we generalize effective particle pictures of lower dimensional dark solitons and ring dark solitons to the spherical shell solitons concerning their equilibrium radius and effective dynamics around it . in this case too , we favorably compare the resulting predictions such as the shell equilibrium radius , qualitatively and quantitatively , with full numerical solutions in 3d . .
And you have already written the first three sentences of the full article: the pristine setting of atomic bose - einstein condensates ( becs ) has offered a significant playground for the examination of numerous physical concepts @xcite .
one of the flourishing directions has been at the interface of the theory of nonlinear waves and such atomic ( as well as optical ) systems , concerning , in particular , the study of matter - wave solitons @xcite .
such coherent nonlinear structures have been observed in experiments and studied extensively in theory ..
Please generate the next two sentences of the article | prototypical examples of pertinent studies include but are not limited to bright @xcite , dark @xcite and gap @xcite matter - wave solitons , as well as vortices @xcite , solitonic vortices and vortex rings @xcite . among these diverse excitations , dark solitons in repulsive becs
have enjoyed a considerable amount of attention in effectively one - dimensional settings due to numerous experiments leading ( especially , more recently ) to their well - controlled creation @xcite . moreover , numerous works considered dark solitons in higher - dimensional settings in order to experimentally explore their instability leading to the formation of vortex rings and vortex lines , as illustrated , e.g. , in refs . @xcite . more recently , such excitations have also been observed in fermionic superfluids @xcite . |
7,509 | Suppose that you have an abstract for a scientific paper: the _ sandwiched _ surface singularities are those rational surface singularities which dominate birationally smooth surface singularities . de jong and van straten showed that one can reduce the study of the deformations of a sandwiched surface singularity to the study of deformations of a 1-dimensional object , a so - called _ decorated _ plane curve singularity . in particular , the milnor fibers corresponding to their various smoothing components may be reconstructed up to diffeomorphisms from those deformations of associated decorated curves which have only ordinary singularities .
part of the topology of such a deformation is encoded in the _ incidence matrix _ between the irreducible components of the deformed curve and the points which decorate it , well - defined up to permutations of columns . extending a previous theorem ofours , which treated the case of cyclic quotient singularities ,
we show that the milnor fibers which correspond to deformations whose incidence matrices are different up to permutations of columns are not diffeomorphic in a strong sense .
this gives a lower bound on the number of stein fillings of the contact boundary of a sandwiched singularity . .
And you have already written the first three sentences of the full article: in our previous paper @xcite , we proved a conjecture of lisca @xcite , establishing a bijective correspondence between the milnor fibers of the smoothing components of a cyclic quotient singularity and the stein fillings of the corresponding contact lens space , the boundary of the singularity .
as a particular case of our results , the milnor fibers corresponding to distinct smoothing components of the reduced miniversal base space of the cyclic quotient singularity are pairwise non - diffeomorphic . here
one has to understand the diffeomorphisms _ in a strong sense _ : namely , there are natural identifications of the boundaries of the milnor fibers up to isotopy , and we showed that there are no diffeomorphisms extending those identifications . having in mind the construction of de jong and van straten in @xcite regarding the milnor fibers of sandwiched singularites , it is natural to try to extend the above result for such singularities ..
Please generate the next two sentences of the article | one of the main obstructions of this program is that at the present moment the precise description of all the smoothing components of sandwiched singularities ( or / and the classification of all stein fillings of the corresponding contact boundaries ) is out of hope .
nevertheless , we will prove a slightly weaker version of the above result . in order to explain it we need some preparation . |
7,510 | Suppose that you have an abstract for a scientific paper: in this work we study the properties of the atomic entanglement in the eigenstates spectrum of the inhomogeneous tavis - cummings model .
the inhomogeneity is present in the coupling among the atoms with quantum electromagnetic field .
we calculate analytical expressions for the concurrence and we found that this exhibits a strong dependence on the inhomogeneity . .
And you have already written the first three sentences of the full article: quantum correlations have played a central role from the very beginning of quantum mechanics , and currently the concept of entanglement has become a key resource in the research on quantum information and quantum computation @xcite .
the availability of entangled quantum states and their characterization are among the most important questions in quantum information . in this sense
, there have been a considerable number of theoretical works that have allowed for characterizing quantum entanglement . from a mathematical point of view ,.
Please generate the next two sentences of the article | a quantum state of a pair of particles is separable if this can be written as a convex sum of product states @xcite , @xmath0 , where @xmath1 and @xmath2 correspond to different particles in the pair and @xmath3 .
actually , separability criteria @xcite provides us with necessary and sufficient conditions to state if a bipartite quantum state is separable or not . |
7,511 | Suppose that you have an abstract for a scientific paper: this review gives a rather general discussion of high temperature superconductors as an example of a strongly correlated material .
the argument is made that in view of the many examples of unconventional superconductors discovered in the past twenty years , we should no longer be surprised that superconductivity emerges as a highly competitive ground state in systems where coulomb repulsion plays a dominant role .
the physics of the cuprates is discussed , emphasizing the unusual pseudogap phase in the underdoped region .
it is argued that the resonating valence bond ( rvb ) picture , as formulated using gauge theory with fermionic and bosonic matter fields , gives an adequate physical understanding , even though many details are beyond the powers of current calculational tools .
the recent discovery of quantum oscillations in a high magnetic field is discussed in this context . meanwhile ,
the problem of the quantum spin liquid ( a spin system with antiferromagnetic coupling which refuses to order even at zero temperature ) is a somewhat simpler version of the high @xmath0 problem where significant progress has been made recently .
it is understood that the existence of matter fields can lead to de - confinement of the @xmath1 gauge theory in @xmath2 dimensions , and novel new particles ( called fractionalized particles ) , such as fermionic spinons which carry spin @xmath3 and no charge , and gapless gauge bosons can emerge to create a new critical state at low energies .
we even have a couple of real materials where such a scenario may be realized experimentally .
the article ends with answers to questions such as : what limits @xmath0 if pairing is driven by an electronic energy scale ?
why is the high @xmath0 problem hard ?
why is there no consensus ? and
why is the high @xmath0 problem important ? .
And you have already written the first three sentences of the full article: high temperature superconductivity was discovered in cuprates in 1986.@xcite the rapid raising of the transition temperature to well above the melting point of nitrogen @xcite shattered the old record of 23 k. furthermore , the fact that high @xmath0 superconductivity was discovered in a rather unexpected material , a transition metal oxide , made it clear that some novel mechanism must be at work .
the intervening years have seen great strides in high @xmath0 research .
the growth and characterization of cuprate single crystals and thin films have advanced to the point where sample quality and reproducibility problems which plagued the field in the early days are no longer issues . at the same time , basically all conceivable experimental tools have been applied to the cuprates ..
Please generate the next two sentences of the article | indeed , the need for more and more refined data has spurred the development of experimental techniques such as angle resolved photoemission spectroscopy ( arpes ) and low temperature scanning tunneling microscopy ( stm ) .
today the cuprate is arguably the best studied material outside of the semiconductor family and a great deal of facts are known . |
7,512 | Suppose that you have an abstract for a scientific paper: high - frequency ultrasonic pulses at 36 mhz are used to measure velocity profiles in a complex fluid sheared in the couette geometry .
our technique is based on time - domain cross - correlation of ultrasonic speckle signals backscattered by the moving medium .
post - processing of acoustic data allows us to record a velocity profile in 0.022 s with a spatial resolution of 40 @xmath0 m over 1 mm . after a careful calibration using a newtonian suspension ,
the technique is applied to a sheared lyotropic lamellar phase seeded with polystyrene spheres of diameter 310 @xmath0 m .
time - averaged velocity profiles reveal the existence of inhomogeneous flows , with both wall slip and shear bands , in the vicinity of a shear - induced `` layering '' transition .
slow transient regimes and/or temporal fluctuations can also be resolved and exhibit complex spatio - temporal flow behaviors with sometimes more than two shear bands . .
And you have already written the first three sentences of the full article: accurate measurements of flow velocities are essential for exploring and understanding fluid dynamics .
such measurements raise important technical problems whenever one needs them to be nonintrusive .
indeed , many applications where direct access to the fluid is impossible perclude the use of local probes such as miniature piezoelectric pressure probes , hot films or hot wires ..
Please generate the next two sentences of the article | in other cases , the introduction of a probe inside the fluid may perturb the flow or even the fluid structure itself , and may lead to incorrect interpretations of the measurements .
thus , in general , much insight can be gained from some remote , noninvasive sensing of the flow field . in the following , |
7,513 | Suppose that you have an abstract for a scientific paper: we present a method to measure the weak phase @xmath0 in the three - body decay of neutral @xmath1 mesons to the final states @xmath2 .
these decays are mediated by interfering amplitudes which are color - allowed and hence relatively large . as a result , large cp violation effects can be observed with high statistical significance .
in addition , the three - body decay helps to resolve discrete ambiguities present in measurements of the weak phase .
the experimental implications of conducting these measurements are discussed , and the sensitivity of the method is evaluated using a simulation . .
And you have already written the first three sentences of the full article: the violation of the cp symmetry is now established in the b meson sector and the parameter @xmath3 is measured with precision by babar @xcite and belle @xcite . however , the measurement of the other angles of the unitarity triangle are necessary for a more comprehensive study of cp violation .
these measurements suffer from several difficulties related to the uncertainties of the theory , the limited statistics and/or ambibuities in their extraction .
we have recently proposed a new method @xcite involving three - body b meson decays , which circumvent these problems and allows to determine the angle @xmath4 . in this paper.
Please generate the next two sentences of the article | we extend this method to the weak phase @xmath5 , which can be identified to the combination @xmath6 of the unitarity triangle angles @xcite .
important constraints on the theory will be obtained from the measurement of this phase . in the following , |
7,514 | Suppose that you have an abstract for a scientific paper: we investigate transitions between topologically ordered phases in two spatial dimensions induced by the condensation of a bosonic quasiparticle . to this end
, we formulate an extension of the theory of symmetry breaking phase transitions which applies to phases with topological excitations described by quantum groups or modular tensor categories .
this enables us to deal with phases whose quasiparticles have non - integer quantum dimensions and obey braid statistics .
many examples of such phases can be constructed from two - dimensional rational conformal field theories and we find that there is a beautiful connection between quantum group symmetry breaking and certain well - known constructions in conformal field theory , notably the coset construction , the construction of orbifold models and more general conformal extensions .
besides the general framework , many representative examples are worked out in detail . .
And you have already written the first three sentences of the full article: in both high energy and condensed matter physics , there is a long tradition of studying systems which exhibit topological excitations .
recently , this field has received a new impetus , since it has been realized that such topological excitations may permit fault tolerant storage and manipulation of quantum information @xcite . in connection with this , there are current experimental efforts to prove the existence of nontrivial topological phases in the fractional quantum hall effect@xcite and to construct such phases in josephson junction networks @xcite .
topological excitations are usually introduced at the classical level as solutions to the equations of motion and the observables that distinguish them are directly linked to topologically invariant properties of these solutions . this places topological particles in marked contrast to the more usual perturbative ( quasi)particles . the latter are described as low energy quantum fluctuations over a given vacuum state ..
Please generate the next two sentences of the article | the group of symmetries of the system that fixes the vacuum state will act on the fluctuations and cause them to organize into multiplets . as a result these perturbative particle states form irreducible representations of the symmetry group . for topological particles
no such labeling is obviously present . |
7,515 | Suppose that you have an abstract for a scientific paper: we investigate the possible corrections to the linear regge trajectories for the light - quark meson sector by matching two - point correlators of quark currents to the operator product expansion .
we find that the allowed modifications to the linear behavior must decrease rapidly with the principal quantum number . after fitting the lightest states in each channel and certain low - energy constants the whole spectrum for meson masses and residues
is obtained in a satisfactory agreement with phenomenology . the perturbative corrections to our results
are discussed .
the observed masses squared of mesons with given quantum numbers form linear trajectories @xcite depending on the number of radial excitation @xmath0 .
this is a strong indication that qcd admits an effective string description , as this type of spectrum is characteristic e.g. of the bosonic string . in the bosonic string model
the slope of all trajectories must be equal since this quantity is proportional to the string tension depending on gluedynamics only .
however , there exist sizeable deviations from the string picture . in the present analysis we examine possible corrections to the linear trajectories in the vector ( v ) , axial - vector ( a ) , scalar ( s ) , and pseudoscalar ( p ) channels @xcite .
our method is based on the consideration of the two - point correlators of v , a , s , p quark currents in the large-@xmath1 limit of qcd @xcite . on the one hand , by virtue of confinement
they are saturated by an infinite set of narrow meson resonances , that is , they can be represented by the sum of related meson poles in euclidean space : @xmath2 expressing the quark - hadron duality@xcite . here @xmath3 ; @xmath4 .
further we denote @xmath5 . on the other hand ,
their high - energy asymptotics is provided by the perturbation theory and the operator product expansion ( ope ) with condensates @xcite .
matching these two approaches results in the chiral symmetry restoration sum rules representing a set of....
And you have already written the first three sentences of the full article: this work is supported by rfbr , grant 05 - 02 - 17477 , grant ur 02.01.299 and infn , grant is / pi13 .
work of s. a. and d. e. is partially supported by cyt fpa , grant 2004 - 04582-c02 - 01 and by cirit gc , grant 2001sgr-00065 .
9 a. bramon , e. etim and m. greco , _ phys ..
Please generate the next two sentences of the article | lett . _ * b41 * , 609 ( 1972 ) ; m. greco , _ nucl .
phys . _ * b63 * , 398 ( 1973 ) ; j. j. sakurai , _ phys . lett . _ * b46 * , 207 ( 1973 ) . |
7,516 | Suppose that you have an abstract for a scientific paper: we present results on the rates of interlayer energy transfer between excitons in two - dimensional transition metal dichalcogenides ( tmds ) .
we consider both radiative ( mediated by real photons ) and non - radiative ( mediated by virtual photons ) mechanisms of energy transfer using a unified green s function approach that takes into account modification of the exciton energy dispersions as a result of interactions .
the large optical oscillator strengths associated with excitons in tmds result in very fast energy transfer rates .
the energy transfer times depend on the exciton momentum , exciton linewidth , and the interlayer separation and can range from values less than 100 femtoseconds to more than tens of picoseconds . whereas inside the light cone the energy transfer rates of longitudinal and transverse excitons are comparable , outside the light cone
the energy transfer rates of longitudinal excitons far exceed those of transverse excitons .
average energy transfer times for a thermal ensemble of longitudinal and transverse excitons is temperature dependent and can be smaller than a picosecond at room temperature for interlayer separations smaller than 10 nm .
energy transfer times of localized excitons range from values less than a picosecond to several tens of picoseconds .
when the exciton scattering and dephasing rates are small , energy transfer dynamics exhibit coherent oscillations .
our results show that electromagnetic interlayer energy transfer can be an efficient mechanism for energy exchange between tmd monolayers . .
And you have already written the first three sentences of the full article: the optoelectronic properties of 2d transition metal dichalcogenide ( tmd ) monolayers are dominated by excitons @xcite . distinguishing features of the excitons in 2d metal dichalcogenides are the large exciton binding energies and the strong exciton - photon interactions @xcite .
recently , exciton - polaritons have been also studied experimentally and theoretically in these materials @xcite .
the strong exciton - photon coupling results in spontaneous emission radiative lifetimes in the hundreds of femtoseconds range @xcite ..
Please generate the next two sentences of the article | the strong exciton - photon coupling suggests that the rates for interlayer energy transfer between excitons in parallel tmd monolayers would also be fast . in electronically coupled 2d tmd monolayers , ultrafast energy transfer via
interlayer charge transfer has been observed @xcite . in this work |
7,517 | Suppose that you have an abstract for a scientific paper: we investigate the charge excitations of a weyl semimetal in the axionic charge density wave ( axionic cdw ) state .
while it has been shown that the topological response ( anomalous hall conductivity ) is protected against the cdw state , we find that the long wavelength plasmon excitation is radically influenced by the dynamics of the cdw order parameter . in the normal state , we show that an undamped collective mode should exist at @xmath0 if there is an attractive interaction favoring the formation of the cdw state .
the undamped nature of this collective mode is attributed to a gap - like feature in the particle - hole continuum at @xmath0 due to the chirality of the weyl nodes , which is not seen in other materials with cdw instability . in the cdw state ,
the long wavelength plasmon excitations become more dispersive due to the additional interband scattering not allowed in the normal state . moreover , because the translational symmetry is spontaneously broken , umklapp scattering , the process conserving the total momentum only up to @xmath1 with @xmath2 an integer and @xmath3 the ordering wave vector , emerges in the cdw state .
we find that the plasmon excitation couples to the phonon mode of the cdw order via the umklapp scattering , leading to two branches of resonant collective modes observable in the density - density correlation function at @xmath4 and @xmath0 .
based on our analysis , we propose that measuring these resonant plasmon - axion excitations around @xmath4 and @xmath0 by the momentum - resolved electron energy loss spectroscopy ( m - eels ) could serve as a reliable way to detect the axionic cdw state in weyl semimetals .
_ introduction_ the weyl semimetal@xcite is a new gapless state of matter attracting a lot of attention in the past few years due to its rich topological properties.@xcite in the wake of the study on topological insulators@xcite , the search for semimetals exhibiting linear band dispersion near the fermi energy has been one of the most active....
And you have already written the first three sentences of the full article: following eq . 6 in the main text ,
the time - ordered bare susceptibility is a @xmath49 matrix @xmath110 defined as , ^0_i , j(,)=_i(,)^_j(,0 ) , where the density operators are defined in eq .
3 in the main text ..
Please generate the next two sentences of the article | first , we perform the wicks decomposition and then convert the @xmath111 operators to the band basis , c_r(,)=_u_r_()a _ ( , ) .
after we perform a fourier transformation to matsubara space , sum over the internal matsubara frequency , and do the analytic continuation , we obtain the final expression of retarded bare susceptibility as |
7,518 | Suppose that you have an abstract for a scientific paper: we consider a quantum scalar field with @xmath0 interaction in curved spacetimes .
the quantum effects are taken into account nonperturbatively using the hartree approximation to the 2pi effective action .
although this approximation has been considered in many previous works , we reconsider it using a consistent nonperturbative renormalization procedure , which we extend to general curved spacetimes .
we obtain the renormalized equations for the mean field and for the propagator of the fluctuations , showing explicitly their independence on the arbitrary scale introduced by the regularization scheme .
we apply our results to the particular case of de sitter spacetime and discuss spontaneous symmetry breaking .
the results depend strongly on the renormalization procedure . .
And you have already written the first three sentences of the full article: in the last years there has been a renewed interest in the analysis of interacting field theories in de sitter spacetimes .
on the one hand , there is observational evidence that supports the existence of periods of exponential or quasi - exponential expansion of the universe , both during the inflationary era before the radiation dominated period in the early universe , and in the present accelerated expansion .
quantum fields may play a relevant role during both periods . on the other hand , the high degree of symmetry of de sitter spacetime ,.
Please generate the next two sentences of the article | make it a very interesting arena to analyze conceptual problems of semiclassical and quantum gravity .
there are several unsettled questions regarding interacting quantum fields in de sitter spacetime . |
7,519 | Suppose that you have an abstract for a scientific paper: we analyze the current matrix elements in the general collinear ( breit ) frames and find the relation between the ordinary ( or canonical ) helicity amplitudes and the light - front helicity amplitudes . using the conservation of angular momentum , we derive a general angular condition which should be satisfied by the light - front helicity amplitudes for any spin system .
in addition , we obtain the light - front parity and time - reversal relations for the light - front helicity amplitudes . applying these relations to the spin-1 form factor analysis , we note that the general angular condition relating the five helicity amplitudes is reduced to the usual angular condition relating the four helicity amplitudes due to the light - front time - reversal condition .
we make some comments on the consequences of the angular condition for the analysis of the high-@xmath0 deuteron electromagnetic form factors , and we further apply the general angular condition to the electromagnetic transition between spin-1/2 and spin-3/2 systems and find a relation useful for the analysis of the n-@xmath1 transition form factors .
we also discuss the scaling law and the subleading power corrections in the breit and light - front frames . .
And you have already written the first three sentences of the full article: a relativistic treatment is one of the essential ingredients that should be incorporated in describing hadronic systems .
the hadrons have an intrinsically relativistic nature since the quantum chromodynamics ( qcd ) governing the quarks and gluons inside the hadrons has _ a priori _ a strong interaction coupling and the characteristic momenta of quarks and gluons are of the same order , or even very much larger , than the masses of the particles involved .
it has also been realized that a parametrization of nuclear reactions in terms of non - relativistic wave functions must fail . in principle , a manifestly covariant framework such as the bethe - salpeter approach and its covariant equivalents can be taken for the description of hadrons . however , in practice , such tools are intractable because of the relative time dependence and the difficulty of systematically including higher order kernels ..
Please generate the next two sentences of the article | a different and more intuitive framework is the relativistic hamiltonian approach . with the recent advances in the hamiltonian renormalization program , a promising technique to impose
the relativistic treatment of hadrons appears to be light - front dynamics ( lfd ) , in which a fock - space expansion of bound states is made at equal light - front time @xmath2 . the reasons that make lfd so attractive to solve bound - state problems in field theory |
7,520 | Suppose that you have an abstract for a scientific paper: we consider two types of multilinear pseudodifferential operators .
first , we prove the boundedness of multilinear pseudodifferential operators with symbols which are only measurable in the spatial variables in weighted lebesgue spaces .
these results generalise earlier work of the present authors concerning linear pseudo - pseudodifferential operators .
secondly , we investigate the boundedness of bilinear pseudodifferential operators with symbols in the hrmander @xmath0 classes .
these results are new in the case @xmath1 , that is , outwith the scope of multilinear caldern - zygmund theory . .
And you have already written the first three sentences of the full article: the study of multilinear pseudodifferential operators goes back to the pioneering works of r. coifman and y. meyer , @xcite , @xcite , @xcite and @xcite .
since then , there has been a large amount of work on various generalisations of their results , as well as studies of bilinear operators with symbols satisfying different conditions to those in the standard bilinear coifman - meyer classes .
the literature in this area of research is vast and any brief summary of it here would not do the authors justice ..
Please generate the next two sentences of the article | therefore we confine ourselves to mention only those works with a direct connection to the present paper .
r. coifman and y. meyer , in @xcite and @xcite , proved the boundedness from @xmath2 to @xmath3 of multilinear pseudodifferential operators with symbols in the class @xmath4 ( see definition [ bilinear multiplier defn ] below ) for @xmath5 and @xmath6 with @xmath7 . in the seminal paper @xcite , l. grafakos and r. torres systematically developed the theory of multilinear caldern - zygmund operators . |
7,521 | Suppose that you have an abstract for a scientific paper: digital technologies are constantly changing , and with it criminals are finding new ways to abuse these technologies .
cybercrime investigators , then , must also keep their skills and knowledge up to date .
this work proposes a holistic training development model specifically focused on cybercrime investigation that is based on improving investigator capability while also considering the capacity of the investigator or unit .
along with a training development model , a cybercrime investigation capacity assessment framework is given for attempting to measure capacity throughout the education process .
first , a training development model is proposed that focuses on the expansion of investigation capability as well as capacity of investigators and units .
next , a capacity assessment model is given to evaluate the effectiveness of the training program .
a description of how the proposed model is being applied to the development of training programs for cybercrime investigators in developing countries will then be given , as well as already observed challenges .
finally , concluding remarks as well as proposed future work is discussed .
* keywords : * _ cybercrime investigation capacity assessment , cybercrime investigation capability , training development , education , law enforcement _ .
And you have already written the first three sentences of the full article: continuous development of information communication technology and large scale proliferation is leading to an increase in victims of digital crime , as well as tools and evidence in criminal investigations [ 1 ] .
many crimes , even traditionally non - digital crimes such as murder , now normally have some sort of digital component [ 2,3 ] .
even so much so that some law enforcement agencies claim that there are rarely cases that do not involve some sort of digital device [ 4 ] ..
Please generate the next two sentences of the article | because of this , the ability of law enforcement to handle electronic evidence is vital during entire investigative procedure .
a survey recently conducted by the united nations ( u.n . ) reported that more than 90% of respondent countries have at least some capability to conduct digital investigations [ 5 ] . |
7,522 | Suppose that you have an abstract for a scientific paper: in this work we show that the gravitational chern - simons term , aside from being a key ingredient in inflationary baryogenesis , modifies super - horizon gravitational waves produced during inflation .
we compute the super - hubble gravitational power spectrum in the slow - roll approximation and show that its overall amplitude is modified while its spectral index remains unchanged ( at leading order in the slow - roll parameters ) .
then , we calculate the correction to the tensor to scalar ratio , @xmath0 . we find a correction of @xmath0 which is dependent on @xmath1 ( more precisely quadratic in @xmath2 ) , the parameter characterizing the amplitude of the chern - simons terms . in a stringy embedding of the leptogenesis mechanism , @xmath1 is the ratio between the planck scale and the fundamental string scale .
thus , in principle , we provide a direct probe of leptogenesis due to stringy dynamics in the cosmic microwave background ( cmb ) .
however , we demonstrate that the corresponding correction of @xmath0 is in fact very small and not observable in the regime where our calculations are valid . to obtain a sizable effect
, we argue that a non - linear calculation is necessary . .
And you have already written the first three sentences of the full article: cosmic baryogenesis stands as one of the unresolved problems of particle cosmology .
most models address baryogenesis after the inflationary epoch .
recently the authors of ref ..
Please generate the next two sentences of the article | @xcite demonstrated that the baryon asymmetry can be generated during inflation from gravity waves . in this model
the lepton number was generated by a quantum expectation value of the chern - simons density from ultra - violet ( uv ) , birefringent gravitational waves during the inflationary epoch . in a subsequent paper |
7,523 | Suppose that you have an abstract for a scientific paper: we consider filters for the detection and extraction of compact sources on a background .
we make a one - dimensional treatment ( though a generalization to two or more dimensions is possible ) assuming that the sources have a gaussian profile whereas the background is modeled by an homogeneous and isotropic gaussian random field , characterized by a scale - free power spectrum .
local peak detection is used after filtering .
then , a bayesian generalized neyman - pearson test is used to define the region of acceptance that includes not only the amplification but also the curvature of the sources and the a priori probability distribution function of the sources .
we search for an optimal filter between a family of matched - type filters ( mtf ) modifying the filtering scale such that it gives the maximum number of real detections once fixed the number density of spurious sources .
we have performed numerical simulations to test theoretical ideas . .
And you have already written the first three sentences of the full article: the detection of compact signals ( sources ) embedded in a background is a recurrent problem in many fields of science .
some common examples in astronomy are the separation of individual stars in a crowded optical image , the identification of local features ( lines ) in noisy one - dimensional spectra or the detection of faint extragalactic objects in microwave frequencies . regarding the detection of point sources on maps of the cosmic microwave background radiation ( cmb ) , several techniques based on different linear filters
have been proposed in the literature : the mexican hat wavelet ( mhw cayn et al.@xcite , vielva et al.@xcite ) , the classic _ matched _ filter ( mf , tegmark and de oliveira - costa@xcite ) , the adaptive top hat filter ( athf , chiang et al.@xcite ) and the scale - adaptive filter ( saf , sanz et al.@xcite , herranz et al.@xcite ) . a certain deal of controversy has appeared about which one , if any , of the previous filters is _ optimal _ for the detection of point sources in cmb data . in order to answer that question it is necessary to consider first a more fundamental issue , the concept of _ detection _ itself ..
Please generate the next two sentences of the article | the detection process can be posed as follows : given an observation , the problem is to _ decide _ whether or not a certain signal was present at the input of the receiver .
the decision is not obvious since the observation is corrupted by a random process that we call ` noise ' or ` background ' . |
7,524 | Suppose that you have an abstract for a scientific paper: the production of electron - positron pairs in time - dependent electric fields ( schwinger mechanism ) depends non - linearly on the applied field profile .
accordingly , the resulting momentum spectrum is extremely sensitive to small variations of the field parameters . owing to this non - linear dependence
it is so far unpredictable how to choose a field configuration such that a predetermined momentum distribution is generated .
we show that quantum kinetic theory along with optimal control theory can be used to approximately solve this inverse problem for schwinger pair production .
we exemplify this by studying the superposition of a small number of harmonic components resulting in predetermined signatures in the asymptotic momentum spectrum . in the long run
, our results could facilitate the observation of this yet unobserved pair production mechanism in quantum electrodynamics by providing suggestions for tailored field configurations .
dynamically assisted schwinger mechanism , inverse problem , optimal control theory .
And you have already written the first three sentences of the full article: the vacuum breakdown in external electric fields by the emission of the lightest charged particle - antiparticle pairs ( schwinger effect ) is an unobserved prediction of quantum electrodynamics ( qed ) @xcite . until recently
, this pair production mechanism seemed to be a mere academic problem owing to the required electric field strength of the order of @xmath0 .
recent efforts have raised the hopes that a direct observation might become feasible at ultra - high intensity laser facilities @xcite ..
Please generate the next two sentences of the article | alternatively , there have been suggestions to study the schwinger effect in graphene @xcite or to quantum simulate it in analogue cold atom systems @xcite . the pair production problem in qed
can not be solved in full glory but requires an approximate treatment . |
7,525 | Suppose that you have an abstract for a scientific paper: relativistic effects on the precision of quantum metrology for particle detectors , such as two - level atoms are studied .
the quantum fisher information is used to estimate the phase sensitivity of atoms in non - inertial motions or in gravitational fields .
the unruh - dewitt model is applicable to the investigation of the dynamics of a uniformly accelerated atom weakly coupled to a massless scalar vacuum field .
when a measuring device is in the same relativistic motion as the atom , the dynamical behavior of quantum fisher information as a function of rindler proper time are obtained .
it is found out that monotonic decrease in phase sensitivity is characteristic of dynamics of relativistic quantum estimation . to improve relativistic quantum metrology ,
we reasonably take into account two reflecting plane boundaries perpendicular to each other .
keywords : phase quantum estimation , relativistic effects , unruh - dewitt model , quantum fisher information pacs : 03.67.-a , 03.65.yz , 42.50.ex .
And you have already written the first three sentences of the full article: the combination of relativity and quantum theory contributes to a fruitful area of research , which in particular includes relativistic quantum information theory and technology @xcite . in information processing ,
particle detectors or observers moving along relativistic trajectories , can send and receive signals which are relevant to internal degrees of freedom of detectors .
the role of detectors is to locate and label events in curved spacetimes ..
Please generate the next two sentences of the article | recently , the use of non - inertial motions to perform quantum computing has been investigated by means of accelerated optical cavities @xcite or atoms in relativistic regimes @xcite .
the relativistic technology contributes to ultra - fast quantum computation which can overcome some obstacles from decoherence . in this letter |
7,526 | Suppose that you have an abstract for a scientific paper: the digital signal processing has greatly simplified the process of phase noise measurements , especially in oscillators , but its applications are largely confined to the frequencies below 400 mhz .
we propose a novel transpose frequency technique , which extends the frequency range of digital noise measurements to the microwave domain and beyond .
we discuss two basic variations of the proposed noise measurement technique , one of which enables characterization of phase fluctuations added to the passing signal by the particular microwave component , for example by an amplifier , while another one is intended for measurements of phase fluctuations of the incoming signal itself .
shell : bare demo of ieeetran.cls for journals phase noise , phase measurement , phase spectrum , allan deviation , short - term frequency stability .
And you have already written the first three sentences of the full article: symmetricom test set has become a useful instrument for phase noise and frequency stability measurements that allows one to compare a signal from a device under test ( dut ) against a reference signal and as a result measure the relative phase noise and frequency stability between the two signals @xcite .
the manufacturer supplies a few models but currently the maximum input bandwidth is 400 mhz ( model 5125a ) while the highest performance unit ( model 5120 - 01 ) , with the lowest phase noise measurement noise floor , only has a measurement bandwidth of 30 mhz .
so how would one measure the additive or residual phase noise of a device under test which has an operating frequency much higher than 30 mhz or even 400 mhz ?.
Please generate the next two sentences of the article | one method to achieve this is to take a beat note between two oscillators , and , by engineering a relatively low noise reference through frequency division of a signal derived from one of the oscillators , one can make a measurement on oscillators operating at x - band frequencies @xcite . if the oscillators have similar phase noise 3 db can be subtracted for their individual performance .
however this method is limited to the case where the beat note between the signals from two oscillators being compared falls within the measurement bandwidth of the test set being used . |
7,527 | Suppose that you have an abstract for a scientific paper: we have used the supercosmos h@xmath0 survey to look for faint outer structures such as halos , ansae and jets around known planetary nebulae across 4000 square degrees of the southern milky way .
our search will contribute to a more accurate census of these features in the galactic pn population .
candidate common - envelope pne have also been identified on the basis of their microstructures .
we also intend to determine more reliable distances for these pne , which should allow a much better statistical basis for the post - agb total mass budget .
our survey offers fresh scope to address this important issue . .
And you have already written the first three sentences of the full article: one of the longest standing astrophysical problems is the exact relationship between the birth mass of stars and the mass left when they die .
unequal estimates of these masses have led to the planetary nebula `` missing mass''problem .
a typical pn progenitor star of mass 2.5@xmath1 sheds its envelope at the end of the agb phase in a terminal superwind.
Please generate the next two sentences of the article | . however , most pne have an ionized mass of only 0.20.6@xmath1 while the residual white dwarf may be only 0.6@xmath1 . until this mass discrepancy is reconciled , the gaps in our knowledge of the late evolution of intermediate - mass stars impacts on our ability to model the evolution and chemical enrichment of our own galaxy .
a typical agb halo provides a visible fossil record of the agb mass - loss history ( e.g. sandin et al . 2010 ) , but has a mean h@xmath0 brightness @xmath210@xmath3 fainter than the main pn shell , so a deep survey is needed . |
7,528 | Suppose that you have an abstract for a scientific paper: in general relativity , the energy conditions are invoked to restrict general energy - momentum tensors @xmath0 on physical grounds .
we show that in the standard friedmann lematre
robertson
walker ( flrw ) approach to cosmological modelling where the equation of state of the cosmological fluid is unknown , the energy conditions provide model - independent bounds on the behavior of the distance modulus of cosmic sources as a function of the redshift .
we use both the _ gold _ and the _ legacy _ samples of current type ia supenovae to carry out a model - independent analysis of the energy conditions violation in the context of standard cosmology . .
And you have already written the first three sentences of the full article: the standard approach to cosmological modelling commences with the assumption that our @xmath1dimensional space is homogeneous and isotropic at large scales .
the most general spacetime metric consistent with the existence of a cosmic time @xmath2 and the principle of spatial homogeneity and isotropy is the flrw metric @xmath3,\ ] ] where the function @xmath4 , @xmath5 , @xmath6 depends on the sign of the constant spatial curvature ( @xmath7 ) , @xmath8 is the cosmological scale factor , and we have set the speed of light @xmath9 .
a third assumption in this approach is that the large scale structure of the universe is essentially determined by gravitational interactions , and hence can be described by a metrical theory of gravitation such as general relativity ( gr ) , which we assume in this work . under these very general premises , the total density @xmath10 and the total pressure @xmath11 of the cosmological fluid as a function of scale factor @xmath12.
Please generate the next two sentences of the article | are given by @xmath13\ ; , \label{rho - eq } \\ p & = & - \frac{1}{8\pi g}\left[\ , 2\,\frac{\ddot{a}}{a } + \frac{\dot{a}^2}{a^2 } + \frac{k}{a^2 } \,\right ] \ ; , \label{p - eq}\end{aligned}\ ] ] where @xmath14 is the newton constant .
note that if now one wishes to constrain the physical properties that hold for the matter fields in the universe it is convenient to impose the so - called _ energy conditions _ |
7,529 | Suppose that you have an abstract for a scientific paper: suppose that we are given two independent sets @xmath0 and @xmath1 of a graph such that @xmath2 , and imagine that a token is placed on each vertex in @xmath0 .
then , the sliding token problem is to determine whether there exists a sequence of independent sets which transforms @xmath0 into @xmath1 so that each independent set in the sequence results from the previous one by sliding exactly one token along an edge in the graph .
the sliding token problem is one of the reconfiguration problems that attract the attention from the viewpoint of theoretical computer science .
the reconfiguration problems tend to be pspace - complete in general , and some polynomial time algorithms are shown in restricted cases .
recently , the problems that aim at finding a shortest reconfiguration sequence are investigated . for the 3sat problem
, a trichotomy for the complexity of finding the shortest sequence has been shown ; that is , it is in p , np - complete , or pspace - complete in certain conditions . in general , even if it is polynomial time solvable to decide whether two instances are reconfigured with each other , it can be np - complete to find a shortest sequence between them .
namely , finding a shortest sequence between two independent sets can be more difficult than the decision problem of reconfigurability between them . in this paper
, we show that the problem for finding a shortest sequence between two independent sets is polynomial time solvable for some graph classes which are subclasses of the class of interval graphs . more precisely
, we can find a shortest sequence between two independent sets on a graph @xmath3 in polynomial time if either @xmath3 is a proper interval graph , a trivially perfect graph , or a caterpillar .
as far as the authors know , this is the first polynomial time algorithm for the shortest sliding token problem for a graph class that requires detours . .
And you have already written the first three sentences of the full article: recently , the _ reconfiguration problems _ attract the attention from the viewpoint of theoretical computer science .
the problem arises when we wish to find a step - by - step transformation between two feasible solutions of a problem such that all intermediate results are also feasible and each step abides by a fixed reconfiguration rule , that is , an adjacency relation defined on feasible solutions of the original problem .
the reconfiguration problems have been studied extensively for several well - known problems , including independent set @xcite , satisfiability @xcite , set cover , clique , matching @xcite , vertex - coloring @xcite , shortest path @xcite , and so on ..
Please generate the next two sentences of the article | the reconfiguration problem can be seen as a natural `` puzzle '' from the viewpoint of recreational mathematics .
the _ 15 puzzle _ is one of the most famous classic puzzles , that had the greatest impact on american and european society of any mechanical puzzle the word has ever known in 1880 ( see @xcite for its rich history ) . |
7,530 | Suppose that you have an abstract for a scientific paper: this paper proposes a new phenomenology for strong incompressible mhd turbulence with nonzero cross helicity .
this phenomenology is then developed into a quantitative fokker - planck model that describes the time evolution of the anisotropic power spectra of the fluctuations propagating parallel and anti - parallel to the background magnetic field @xmath0 .
it is found that in steady state the power spectra of the magnetic field and total energy are steeper than @xmath1 and become increasingly steep as @xmath2 increases , where @xmath3 is the cross helicity , @xmath4 is the fluctuation energy , and @xmath5 is the wavevector component perpendicular to @xmath0 .
increasing @xmath6 with fixed @xmath4 increases the time required for energy to cascade to smaller scales , reduces the cascade power , and increases the anisotropy of the small - scale fluctuations .
the implications of these results for the solar wind and solar corona are discussed in some detail . .
And you have already written the first three sentences of the full article: much of our current understanding of incompressible magnetohydrodynamic ( mhd ) turbulence has its roots in the pioneering work of iroshnikov ( 1963 ) and kraichnan ( 1965 ) .
these studies emphasized the important fact that alfvn waves travelling in the same direction along a background magnetic field do not interact with one another and explained how one can think of the cascade of energy to small scales as resulting from collisions between oppositely directed alfvn wave packets .
they also argued that in the absence of a mean magnetic field , the magnetic field of the energy - containing eddies at scale @xmath7 affects fluctuations on scales @xmath8 much in the same way as would a truly uniform mean magnetic field ..
Please generate the next two sentences of the article | another foundation of our current understanding is the finding that mhd turbulence is inherently anisotropic .
montgomery & turner ( 1981 ) and shebalin , matthaeus , & montgomery ( 1983 ) showed that a strong uniform mean magnetic field @xmath0 inhibits the cascade of energy to small scales measured in the direction parallel to @xmath0 . |
7,531 | Suppose that you have an abstract for a scientific paper: in this paper , we explore a connection between binary hierarchical models , their marginal polytopes and codeword polytopes , the convex hulls of linear codes . the class of linear codes that are realizable by hierarchical models is determined .
we classify all full dimensional polytopes with the property that their vertices form a linear code and give an algorithm that determines them . .
And you have already written the first three sentences of the full article: in theoretical statistics the marginal polytope plays an important role . it is the polytope of possible values that a sufficient statistics can take .
it encodes in its face lattice the combinatorial structure of the boundary of the exponential family defined by the statistics . for a model on discrete random variables
it can be represented with vertices that have only components 0 or 1 , commonly called a 0/1 polytope . in coding theory when decoding binary linear codes one can apply techniques from linear programming and optimize a linear function over the convex hull of the code words , known as the codeword polytope @xcite . observing that for certain choices of sufficient statistics on binary random variables these two notions coincide ,.
Please generate the next two sentences of the article | our main contribution is a characterization of the corresponding polytopes .
we do not address problems that are directly linked to coding theory . |
7,532 | Suppose that you have an abstract for a scientific paper: according to the walecka mean field theory of nuclear interaction the collective mutual deceleration of the colliding nuclei gives rise to the bremsstrahlung of real and virtual @xmath0mesons .
it is shown that decays of these mesons may give a noticeable contribution to the observed yields of the baryon
antibaryon pairs , dileptons and pions .
excitation functions and rapidity distributions of particles produced by this mechanism are calculated under some simplifying assumptions about the space
time variation of meson fields in nuclear collisions .
the calculated multiplicities of coherently produced particles grow fast with the bombarding energy , reaching a saturation above the rhic bombarding energy . in the case of central au+au collisions
the bremsstrahlung mechanism becomes comparable with particle production in incoherent hadron
hadron collisions above the ags energies .
the rapidity spectra of antibaryons and pions exhibit a characteristic two hump structure which is a consequence of incomplete projectile target stopping at the initial stage of the reaction .
the predicted distribution of e@xmath1e@xmath2 pairs has a strong peak at invariant masses gev
. 0.5 cm -1 cm # 1@xmath3 # 1eq .
( [ # 1 ] ) # 1 # 1#2 + # 2 # 1#2#3#4#1 * # 2 * , # 3 ( # 4 ) * particle production by time
dependent meson fields + in relativistic heavy ion collisions * + * i.n .
mishustin@xmath4 , l.m .
satarov@xmath5 , h. stcker@xmath6 and w. greiner@xmath6 * = @xmath7_the kurchatov institute , 123182 moscow ,
_ + @xmath8 + @xmath9 + .
And you have already written the first three sentences of the full article: as follows from the relativistic mean field model @xcite strong time
dependent meson fields are generated in the course of relativistic heavy
ion collisions . within the framework of this model several new collective phenomena were predicted : the filamentation instability of interpenetrating nuclei @xcite and the spontaneous creation of the baryon antibaryon ( @xmath10 ) pairs in a superdense baryon .
Please generate the next two sentences of the article | rich matter @xcite . using the approach developed in papers on the pion @xcite and photon @xcite bremsstrahlung
we suggested recently @xcite a new mechanism of the @xmath10 pair production by the collective bremsstrahlung of meson fields in relativistic heavy ion collisions . |
7,533 | Suppose that you have an abstract for a scientific paper: the processes responsible for the broad - band radiation of the young supernova remnant cas a are explored using a new code which is designed for a detailed treatment of the diffusive shock acceleration of particles in nonlinear regime .
the model is based on spherically symmetric hydrodynamic equations complemented with transport equations for relativistic particles .
electrons , protons and the oxygen ions accelerated by forward and reverse shocks are included in the numerical calculations .
we show that the available multi - wavelength observations in the radio , x - ray and gamma - ray bands can be best explained by invoking particle acceleration by both forward and reversed shocks .
although the tev gamma - ray observations can be interpreted by interactions of both accelerated electrons and protons / ions , the measurements by fermi lat at energies below 1 gev give a tentative preference to the hadronic origin of gamma - rays .
then , the acceleration efficiency in this source , despite the previous claims , should be very high ; 25 % of the explosion energy ( or approximately @xmath0 erg ) should already be converted to cosmic rays , mainly by the forward shock . at the same time
, the model calculations do not provide extension of the maximum energy of accelerated protons beyond 100 tev . in this model ,
the acceleration of electrons is dominated by the reverse shock ; the required @xmath1 erg can be achieved under the assumption that the injection of electrons ( positrons ) is supported by the radioactive decay of @xmath2ti . .
And you have already written the first three sentences of the full article: the mechanism of diffusive shock acceleration ( dsa ) of relativistic particles ( krymsky @xcite , axford et al .
@xcite , bell @xcite , blandford & ostriker @xcite ) is generally accepted as the most likely paradigm for production of galactic cosmic rays ( cr ) in supernova remnants ( snrs ) . over the last 30 years a significant progress has been achieved in the development of theoretical models and understanding of the basic features of dsa ( see e.g. malkov & drury @xcite , schure et al .
@xcite for a review ) . on the other hand.
Please generate the next two sentences of the article | , the recent detailed studies of spectral and morphological features of young snrs , first of all in the x - ray and very - high - energy ( or tev ) gamma - ray band , provide excellent observational material for development of detailed numerical models of acceleration and radiation of relativistic electrons and protons in young snrs .
these observations generally confirm in general terms the predictions of dsa . |
7,534 | Suppose that you have an abstract for a scientific paper: the effect of out - of - plane orientational freedom on the orientational ordering properties of a monolayer of hard ellipsoids is studied using parsons - lee scaling approach and replica exchange monte carlo computer simulation .
prolate and oblate ellipsoids exhibit very different ordering properties , namely , the axes of revolution of prolate particles tend to lean out , while those of oblate ones prefer to lean into the confining plane .
the driving mechanism of this is that the particles try to maximize the available free area on the confining surface , which can be achieved by minimizing the cross section areas of the particles with the plane . in the lack out - of - plane orientational freedom
the monolayer of prolate particles is identical to a two - dimensional hard ellipse system , which undergoes an isotropic - nematic ordering transition with increasing density . with gradually switching on the out - of - plane orientational freedom
the prolate particles lean out from the confining plane and a destabilisation of the in - plane isotropic - nematic phase transition is observed .
the system of oblate particles behaves oppositely to that of prolates .
it corresponds to a two - dimensional system of hard disks in the lack of out - of - plane freedom , while it behaves similar to that of hard ellipses in the freely rotating case . .
And you have already written the first three sentences of the full article: phase behavior of non - spherical hard bodies with their centers of mass confined in planar geometry is receiving considerable attention due to the recent development of the preparation of colloidal particles with various shapes and new experimental techniques .
nowadays it is possible to prepare colloids with several geometrical shapes such as cubes , polyhedrons , octopods , ellipsoids and helices [ 1 - 6 ] .
the anisotropic colloids can be confined at the interfaces [ 7 - 11 ] , between two parallel solid walls [ 12,13 ] , at the bottom of the sample holder [ 14 ] , at a substrate surface [ 15 ] and into a lamellar matrix of surfactants [ 16,17 ] ..
Please generate the next two sentences of the article | the confinement can be so strong that even colloidal monolayers can be realized experimentally .
ordering properties of two - dimensional and quasi two - dimensional ( q2d ) non- spherical colloids has been the subject of several experimental and theoretical studies [ 17 - 36 ] . |
7,535 | Suppose that you have an abstract for a scientific paper: it is argued that the discovery of cosmic acceleration could have been anticipated on thermodynamic grounds , namely , the generalized second law and the approach to equilibrium at large scale factor .
therefore , the existence of dark energy -or equivalently , some modified gravity theory- should have been expected . in general , cosmological models that satisfy the above criteria
show compatibility with observational data . .
And you have already written the first three sentences of the full article: the standard cold dark matter ( scdm ) model @xcite was in good health until around the last decade of the previous century when it became apparent that the fractional density of matter falls well below the einstein - de sitter value , @xmath0 -see e.g. @xcite .
the death blow came at the close of the century with the discovery of the current cosmic acceleration @xcite , something the said model can not accommodate by any means .
however , to account for the acceleration in homogeneous and isotropic models one must either introduce some exotic energy component with a huge negative pressure ( dubbed dark energy ) or , more drastically , devise some theory of gravity more general than einstein relativity @xcite ..
Please generate the next two sentences of the article | thus , both solutions appear somewhat forced and not very aesthetical . here
we argue that dark energy ( or something equivalent ) is demanded on thermodynamic grounds . |
7,536 | Suppose that you have an abstract for a scientific paper: we prove that if a simplicial complex @xmath0 is shellable , then the intersection lattice @xmath1 for the corresponding diagonal arrangement @xmath2 is homotopy equivalent to a wedge of spheres .
furthermore , we describe precisely the spheres in the wedge , based on the data of shelling .
also , we give some examples of diagonal arrangements @xmath3 where the complement @xmath4 is @xmath5 , coming from rank @xmath6 matroids . .
And you have already written the first three sentences of the full article: consider @xmath7 with coordinates @xmath8 . a _
diagonal subspace _ @xmath9 is a linear subspace of the form @xmath10 .
a _ diagonal arrangement _ ( or a _ hypergraph arrangement _ ) @xmath3 is a finite set of diagonal subspaces of @xmath7 . throughout this paper.
Please generate the next two sentences of the article | , we assume that for any @xmath11 , @xmath12 is not included in @xmath13 . for a simplicial complex @xmath0 on a vertex set @xmath14 :
= \{1 , 2 , \dots , n \}$ ] such that @xmath15 , one can associate a diagonal arrangement @xmath2 in @xmath7 as follows . for a facet @xmath16 of @xmath0 , let @xmath17 be the diagonal subspace @xmath10 where @xmath18-f = \ { i_1 , \dots , i_r \}$ ] . |
7,537 | Suppose that you have an abstract for a scientific paper: we perform a linear stability analysis of magnetized rotating cylindrical jet flows in the approximation of zero thermal pressure .
we focus our analysis on the effect of rotation on the current driven mode and on the unstable modes introduced by rotation .
we find that rotation has a stabilizing effect on the current driven mode only for rotation velocities of the order of the alfvn velocity .
rotation introduces also a new unstable centrifugal buoyancy mode and the `` cold '' magnetorotational instability .
the first mode is analogous to the parker instability with the centrifugal force playing the role of effective gravity .
the magnetorotational instability can be present , but only in a very limited region of the parameter space and is never dominant .
the current driven mode is characterized by large wavelenghts and is dominant at small values of the rotational velocity , while the buoyancy mode becomes dominant as rotation is increased and is characterized by small wavelenghts . [ firstpage ] galaxies : jets , mhd , instabilities .
And you have already written the first three sentences of the full article: an important step for understanding the dynamics and phenomenology of astrophysical jets is the study of their instabilities .
instabilities have a substantial importance , on one hand for the formation and evolution of various observed structures and , on the other hand , for dissipating part of the jet energy and leading to the observed radiation .
there are several possible sources of instabilities , like the velocity shear between the jet and the ambient medium , which drives the kelvin - helmholtz instability , the current flowing along magnetic field lines , which drives the current driven instability ( cdi ) and rotation that can drive several kinds of instabilities . since the most promising models for the acceleration and collimation of jets involve the presence of a magnetic field with footpoints anchored to a rotating object ( an accretion disk or a spinning star or black hole ) , the presence of a toroidal field component and of rotation seems to be a natural consequence and both cdi and rotation driven instabilities may play an important role in the jet propagation ..
Please generate the next two sentences of the article | cdi have been , for example , suggested as being responsible for the conversion from poynting to kinetic energy flux in the first phases of jet propagation @xcite .
khi have been extensively studied in several different configurations both in the newtonian ( see e.g. * ? ? ? |
7,538 | Suppose that you have an abstract for a scientific paper: the anisotropy associated with the initial dipole asymmetry in heavy ion collisions is studied via the two - particle relative azimuthal azimuthal angle ( @xmath0 ) correlations , within a multi - phase transport model . for a broad selection of centrality , transverse momenta ( @xmath1 ) and pseudorapidity ( @xmath2 ) ,
a fitting method is used to decompose the anisotropy into a rapidity - even component , characterized by the fourier coefficient @xmath3 , and a global momentum conservation component .
the extracted @xmath3 values are negative for @xmath4 gev , reach a maximum at 2 - 3 gev , and decreases at higher @xmath5 .
the @xmath3 values vary weakly with @xmath6 and centrality , but increases with collision energy and parton cross - section .
the extracted global momentum conservation component is found to depend on @xmath7 for @xmath8 . .
And you have already written the first three sentences of the full article: a large azimuthal anisotropy is observed for particle production in heavy ion collisions at the relativistic heavy ion collider ( rhic ) and the large hadron collider ( lhc ) .
this anisotropy has been successfully described in terms of pressure - driven collective flow , which converts the spatial asymmetries of the initially created matter into transverse momentum ( @xmath5 ) space @xcite .
such anisotropy can be expressed as fourier series in azimuthal angle ( @xmath9 ) : @xmath10 where @xmath11 and @xmath12 represent the magnitude and direction of @xmath13-order flow respectively ..
Please generate the next two sentences of the article | asymmetries giving rise to non - zero @xmath11 are associated with either an average shape ( for @xmath14 ) or shapes due to the spatial fluctuations of the participating nucleons @xcite ; the @xmath15 term is known as dipole asymmetry . due to the approximate boost invariance of the created matter , the @xmath11
are expected to be even functions in rapidity ( rapidity - even ) @xcite . however , |
7,539 | Suppose that you have an abstract for a scientific paper: field theoretical models with first order lagrangean can be formulated in a covariant hamiltonian formalism . in this article , the geometrical construction of the gerstenhaber structure that encodes the equations of motion is explained for arbitrary fibre bundles .
special emphasis has been put on naturality of the constructions .
further , the treatment of symmetries is explained .
finally , the canonical field theoretical 2-form is obtained by pull back and integration of the polysymplectic form over space like hypersurfaces .
* key words : * geometric field theory , multisymplectic geometry , hamiltonian formulation , gerstenhaber algebra .
And you have already written the first three sentences of the full article: it has turned out that field theories can be described best in the jet bundle formalism . for first order theories , i.e.
when the lagrange density is a function of the fields and their first derivatives only , the description can be reduced to the first jet bundle .
this description is an extension of the lagrangean formulation of mechanics in the following sense . in particle mechanics ,.
Please generate the next two sentences of the article | particles are described by curves in the tangent space @xmath0 , i.e. by sections of the ( trivial ) bundle @xmath1 . in field theory ,
physical fields are sections of some bundle over space - time , i.e. higher dimensional curves . |
7,540 | Suppose that you have an abstract for a scientific paper: in this article it is shown how optimized and dedicated microarray experiments can be used to study the thermodynamics of dna hybridization for a large number of different conformations in a highly parallel fashion . in particular ,
free energy penalties for mismatches are obtained in two independent ways and are shown to be correlated with values from melting experiments in solution reported in the literature .
the additivity principle , which is at the basis of the nearest - neighbor model , and according to which the penalty for two isolated mismatches is equal to the sum of the independent penalties , is thoroughly tested .
additivity is shown to break down for a mismatch distance below @xmath0 nt .
the behavior of mismatches in the vicinity of the helix edges , and the behavior of tandem mismatches are also investigated . finally , some thermodynamic outlying sequences are observed and highlighted .
these sequences contain combinations of ga mismatches .
the analysis of the microarray data reported in this article provides new insights on the dna hybridization parameters and can help to increase the accuracy of hybridization - based technologies . .
And you have already written the first three sentences of the full article: hybridization of single - stranded nucleic acids to form a duplex is a reversible chemical reaction , which is at the basis of many processess and techniques currently used in biotechnology , as for instance pcr @xcite . due to its central importance
, hybridization has been intensively studied in experiments ( focusing on the thermodynamics @xcite or kinetics of the process ) and also in computer simulations @xcite .
the thermodynamics of dna hybridization is usually described by the nearest - neighbor ( nn ) model @xcite ..
Please generate the next two sentences of the article | this model assumes that the free energy of a duplex can be expressed as a sum of dinucleotide stability parameters ; it is therefore based on the principle of additivity . from the nn parameters one can
, for instance , estimate melting temperatures , compute melting curves and predict secondary structures in which rna molecules fold @xcite . in the folding problem , many different local conformations arise as single nucleotide mismatches , bulges , stem - loop structures , etc . describing these conformations in the framework of |
7,541 | Suppose that you have an abstract for a scientific paper: we report on a surface - electrode trap with smco magnets arranged in a quadrupole configuration underneath the trap electrode .
because the distance between the magnets and the trapped ions can be as little as several hundred micrometers , a large magnetic field is produced without any heat management .
the magnetic - field gradient was measured using the zeeman splitting of a single trapped @xmath0ca@xmath1 ion at several positions , and a field gradient of 36 t / m was obtained .
such a field gradient is useful for the generation of a state - dependent force , which is important for quantum simulation and/or quantum gate operation using radio - frequency or microwave radiation .
_ keywords _ : ion trap , magnetic - field gradient , quantum simulation .
And you have already written the first three sentences of the full article: trapped atomic ions have been regarded as a very promising physical system in quantum information processing .
they have been used for many proof - of - principle experiments such as fundamental quantum gate operations@xcite , generation of entangled states@xcite , and quantum simulation of coupled spins@xcite . in these pioneering studies , the quantized motional and internal states of trapped ions
were controlled using laser radiation . in spite of such successful works ,.
Please generate the next two sentences of the article | the use of laser radiation for coherent manipulation has a few issues .
if two levels are coupled by a raman transition , spontaneous emission causes the destruction of quantum coherence@xcite . on the other hand , |
7,542 | Suppose that you have an abstract for a scientific paper: we present a search for variable stars in the fornax dwarf galaxy covering an area of 1/2 a square degree .
we have @xmath0 epochs of @xmath1 data .
we found and determined periods for more than 500 rr lyrae , 17 anomalous cepheids , 6 population ii cepheids .
in addition we have 85 candidate long period variables , the majority of which were previously unknown .
we estimated that the average metal abundance of rr lyrae stars is @xmath2 } \simeq -1.6 $ ] dex . .
And you have already written the first three sentences of the full article: several studies have found variable stars in fornax or have detected variability ( light et al .
1986 , demers & irwin 1987 , buonanno et al . 1985 ,
stetson et al . 1998 ) ..
Please generate the next two sentences of the article | however they all suffered from some limitations .
for instance @xcite cover a large area with deep photometry but they do nt have enough epochs to determine periods for their candidate variables . |
7,543 | Suppose that you have an abstract for a scientific paper: we initiate a systematic investigation of the space of 2 + 1 dimensional quiver gauge theories , emphasising a succinct `` forward algorithm '' .
few `` order parametres '' are introduced such as the number of terms in the superpotential and the number of gauge groups .
starting with two terms in the superpotential , we find a generating function , with interesting geometric interpretation , which counts the number of inequivalent theories for a given number of gauge groups and fields .
we demonstratively list these theories for some low numbers thereof .
furthermore , we show how these theories arise from m2-branes probing toric calabi - yau 4-folds by explicitly obtaining the toric data of the vacuum moduli space . by observing equivalences of the vacua between markedly different theories ,
we see a new emergence of `` toric duality '' .
imperial / tp/08/ah/10 + 0.25 in m2-branes and quiver chern - simons : @xmath0 a taxonomic study + amihay hanany@xmath1 and yang - hui
he@xmath2 + + [ cols= " < , < " , ] .
And you have already written the first three sentences of the full article: recent advances in studying the world - volume theory of m2-branes @xcite have allowed new perspectives on the ads / cft correspondence . indeed , the three - dimensional theory on the m2-branes is now understood as an ordinary gauge theory of chern - simons ( cs ) type @xcite .
the investigation of ads@xmath3/cft@xmath4 subsequently took flight , ever augmenting our arsenal of dual pairs of theories .
one strand of development has been the extension of the elaborate structure of the ads@xmath5/cft@xmath3 situation wherein the d3-brane world - volume gauge theory and the corresponding calabi - yau cone over sasaki - einstein 5-folds have been probed in great detail over the past decade.
Please generate the next two sentences of the article | . of particular interest had been the cases where the calabi - yau threefold admits toric description . there , a rich tapestry , enabled by the abundant techniques of toric geometry , had been woven over such themes as toric duality @xcite , dimer models and brane tilings @xcite . along this vein , the parallel story for m2-branes probing toric calabi - yau 4-fold singularities met with rapid progress @xcite , addressing such issues as tiling or its 3-dimensional counter - part of crystal models , toric duality , as well as partition functions in the light of the plethystic programme @xcite etc .
thus inspired , especially by the fortitude to attack the general singularity @xcite , it is expedient for us to take a synthetic approach . |
7,544 | Suppose that you have an abstract for a scientific paper: direct detection dark matter experiments looking for wimp - nucleus elastic scattering will soon be sensitive to an irreducible background from neutrinos which will drastically affect their discovery potential . here
we explore how the neutrino background will affect future ton - scale experiments considering both spin - dependent and spin - independent interactions .
we show that combining data from experiments using different targets can improve the dark matter discovery potential due to target complementarity .
we find that in the context of spin - dependent interactions , combining results from several targets can greatly enhance the subtraction of the neutrino background for wimp masses below 10 gev / c@xmath0 and therefore probe dark matter models to lower cross - sections . in the context of target complementarity , we also explore how one can tune the relative exposures of different target materials to optimize the wimp discovery potential . .
And you have already written the first three sentences of the full article: numerous independent surveys have demonstrated evidence on both cosmological and galactic scales that about 30% of the matter energy density of the universe consists of non - baryonic , non - luminous matter . a leading candidate for this dark matter
is a yet - to - be - discovered weakly interactive massive particle ( wimp ) which could directly interact with detectors based on earth leading to kev - scale nuclear recoils .
direct dark matter detection experiments are now probing well - motivated models of extensions to the standard model such as supersymmetry which naturally predict dark matter candidates @xcite . as the exposures of direct dark matter detection experiments continue to improve , they will soon have enough sensitivity to detect neutrinos from several astrophysical sources such as the sun , the atmosphere , and diffuse supernovae @xcite ..
Please generate the next two sentences of the article | for example , a 1 kev threshold xe based experiment with a 1 ton - year exposure will detect about 100 @xmath1 solar neutrino events via coherent neutrino - nucleus scattering ( cns ) .
in fact for some wimp masses , such neutrino backgrounds can almost perfectly mimic a wimp signal . |
7,545 | Suppose that you have an abstract for a scientific paper: we perform extended numerical simulation of the dynamics of dry friction , based on a model derived from the phenomenological description proposed by t. baumberger et al . @xcite . in the case of small deviation from the steady sliding motion ,
the model is shown to be equivalent to the state- and rate - dependent friction law which was first introduced by rice and ruina @xcite on the basis of experiments on rocks .
we obtain the dynamical phase diagram that agrees well with the experimental results on the paper - on - paper systems .
in particular , the bifurcation between stick - slip and steady sliding are shown to change from a direct ( supercritical ) hopf type to an inverted ( subcritical ) one as the driving velocity increases , in agreement with the experiments .
pacs numbers : 05.45.+b , 46.30.pa , 62.20.hg , 91.30.px .
And you have already written the first three sentences of the full article: it is well - known that the frictional resistance is independent of the apparent area of the sliding surface and it is proportional to the normal load with a proportional constant @xmath0 , which is known as the friction coefficient . traditionally , the friction coefficient has two distinct values : the static friction coefficient @xmath1 , determined from the minimum force needed to move a slider at rest , and the dynamic friction coefficient @xmath2 , used for the friction force when a steady sliding motion is established .
friction is often described using the well - known amontons - coulomb s laws : ( @xmath3 ) both @xmath1 and @xmath2 are independent of the apparent area of the contacting surfaces and the normal load ; ( @xmath4 ) both @xmath1 and @xmath2 depend on the shear characteristics of the contacting materials @xcite ; ( @xmath5 ) for most cases , @xmath2 is appreciably lower than @xmath1 .
this standard picture is still widely accepted nowadays ; however , in many cases , significant refinements must be taken into account for the explanation of the observed friction ..
Please generate the next two sentences of the article | our common experiences tell us that the sliding of contact bodies subjected to a steady pulling velocity sometimes proceeds in an alternation of periods of rest and slide rather than moving steadily ( this is the reason , for example , for the occurrence of squeaking noises ) .
this unstable motion consists of periods of a stick state followed by a sudden slip is known as stick - slip oscillations . |
7,546 | Suppose that you have an abstract for a scientific paper: we examined the vsnet light curve of the unusual su uma - type dwarf nova v503 cyg which is known to show a short ( 89 d ) supercycle length and exceptionally small ( a few ) normal outbursts within a supercycle . in 19992000 , v503 cyg displayed frequent normal outbursts with typical recurrence times of 79 d. the behavior during this period is characteristic to an usual su uma - type dwarf nova with a short supercycle length . on the other hand ,
v503 cyg showed very infrequent normal outbursts in 20012002 .
some of the superoutbursts during this period were observed shorter than usual .
the remarkable alternations of the outbursting states in v503 cyg support the presence of mechanisms of suppressing normal outbursts and premature quenching superoutbursts , which have been proposed to explain some unusual su uma - type outbursts .
the observed temporal variability of the suppressing / quenching mechanisms in the same object suggests that these mechanisms are not primarily governed by a fixed system parameter but more reflect state changes in the accretion disk . .
And you have already written the first three sentences of the full article: er uma stars are a still enigmatic small subgroup of su uma - type dwarf novae [ for a review of dwarf novae , see @xcite ] , which have extremely short supercycle lengths ( @xmath0 the interval between successive superoutbursts ) of 1950 d [ for a review , see @xcite ] and regular occurrence of superoutbursts .
only five definite members have been recognized up to now : er uma ( @xcite , @xcite , @xcite ) ; v1159 ori ( @xcite , @xcite ) ; rz lmi ( @xcite , @xcite ) ; di uma ( @xcite ) ; and ix dra ( @xcite ) .
some helium - transferring cataclysmic variables have become recognized as helium counterparts " of er uma stars [ cr boo : @xcite ; v803 cen : @xcite , @xcite ] . from a theoretical side ,.
Please generate the next two sentences of the article | er uma stars have been understood as a smooth extension of normal su uma - type dwarf nova toward higher mass - transfer rates ( @xmath1 ) @xcite .
the exact origin of such a high mass - transfer rate is still a mystery . even considering a higher mass - transfer rate , the shortest period systems ( rz lmi and di uma ) are difficult to explain without a special mechanism of prematurely quenching a superoutburst @xcite . in recent years |
7,547 | Suppose that you have an abstract for a scientific paper: models of the universe with arbitrary ( non gravitational ) interaction between the components of the cosmic fluid : the phantom energy and the background , are investigated .
a general form of the interaction that is inspired in scalar - tensor theories of gravity is considered .
no specific model for the phantom fluid is assumed .
we concentrate our investigation on solutions that are free of the coincidence problem .
we found a wide region in the parameter space where the solutions are free of the big rip singularity also .
physical arguments , together with arguments based on the analysis of the observational evidence , suggest that phantom models without big rip singularity might be preferred by nature . .
And you have already written the first three sentences of the full article: recently it has been argued that astrophysical observations might favor a dark energy ( de ) component with `` supernegative '' equation - of - state ( eos ) parameter @xmath0 @xcite , where @xmath1 is the pressure and @xmath2 the energy density of the i - th component of the cosmic fluid .
sources sharing this property violate the null dominant energy condition ( ndec ) .
otherwise , well - behaved energy sources ( positive energy density ) that violate ndec ( necessarily negative pressure ) , have eos parameter less than minus unity @xcite ..
Please generate the next two sentences of the article | ndec - violating sources are being investigated as possible dark energy ( de ) candidates and have been called as `` phantom '' components @xcite . since ndec prevents instability of the vacuum or propagation of energy outside the light cone , then
, phantom models are intrinsically unstable . nevertheless , if thought of as effective field theories ( valid up to a given momentum cutoff ) , these models could be phenomenologically viable @xcite . |
7,548 | Suppose that you have an abstract for a scientific paper: we show that , under the right conditions , one can make highly accurate polarization - based measurements without knowing the absolute polarization state of the probing light field .
it is shown that light , passed through a randomly varying birefringent material has a well - defined orbit on the poincare sphere , which we term a generalized polarization state , that is preserved .
changes to the generalized polarization state can then be used in place of the absolute polarization states that make up the generalized state , to measure the change in polarization due to a sample under investigation .
we illustrate the usefulness of this analysis approach by demonstrating fiber - based ellipsometry , where the polarization state of the probe light is unknown , and , yet , the ellipsometric angles of the investigated sample ( @xmath0 and @xmath1 ) are obtained with an accuracy comparable to that of conventional ellipsometry instruments by measuring changes to the generalized polarization state . .
And you have already written the first three sentences of the full article: polarization - based measurements are increasingly important , both as a fundamental tool for scientific research @xcite , and as a vital tool for applications in the chemical , food , and pharmaceutical industries .
indeed , proposed classical communications systems , fluorescence measurements , non - invasive blood - sugar measurements , lidar , imaging through scattering media , strain , and temperature sensors all have implementations that rely on polarization based measurements @xcite . in surface science , it is well known that polarization based measurements are very sensitive .
for instance , ellipsometry has been used to measure sub - monolayer changes in surface coverage @xcite . as such.
Please generate the next two sentences of the article | , it is a nearly - ideal technique for monitoring modern epitaxial fabrication techniques @xcite and for contamination monitoring of vacuum components ( e.g. , synchrotron optics ) @xcite .
the sensitivity of ellipsometry comes from the ability to set and measure polarization states with a high degree of accuracy . as a result |
7,549 | Suppose that you have an abstract for a scientific paper: the influence of broken structural homology , and the implied broken dynamical homology , is examined for the fundamental plane ( fp ) . requiring a symmetrical treatment of the fp variables , a bisector method of linear regression
was applied , in 3-dimensions , to derive the best fp .
a bootstrapping procedure has been used to estimate the uncertainties associated with the slope of the fp . for 25 e and s0 virgo galaxies ,
the ` standard ' fp , constructed using @xmath0 model parameters for the effective radii ( @xmath1 ) and the mean surface brightness within this radius ( @xmath2 ) and using central velocity dispersion ( cvd ) measurements ( @xmath3 ) , gave a relation described by @xmath4 . using sersic @xmath5 light profile model parameters and
the projected , infinite aperture , velocity dispersion ( @xmath6 ) , derived from application of the jeans equation to the observed intensity profiles , gave an ` improved ' fp described by the relation @xmath7 .
this result , based on independent data , supports the previous finding by graham & colless ( 1997a ) that assumptions of structural and dynamical homology are partly responsible for the departure of the observed fp from the plane expected by the virial theorem , which predicts @xmath8 . upon removal of the known s0 galaxies from the sample of virgo galaxies , the above planes
were observed to change to @xmath9 and @xmath10 .
the perpendicular rms residuals about these planes are 0.084 and 0.050 dex , respectively .
the fornax cluster was similarly treated , although removal of the s0 galaxies left a sample of only 7 ellipticals which had published cvd measurements . treating the range of structural and dynamical profiles present in this sample
produced a fp given by the relation @xmath11 , in tantalizing agreement with the plane expected from the virial theorem , but with discouragingly large errors due to the small sample size . similarly to virgo , the perpendicular rms residuals about this plane is 0.050 dex .
the fp was....
And you have already written the first three sentences of the full article: our knowledge about the structure of elliptical galaxies has progressed considerably in the last decade .
no longer are we satisfied with fitting a de vaucouleurs ( 1948,1953 ) @xmath0 intensity distribution to the light profiles of elliptical galaxies .
modern imaging techniques are providing ever - more precise measurements , revealing a range of light profile shapes which have been shown to be better described by the sersic ( 1968 ) @xmath5 model ( capaccioli 1989 ; caon , capaccioli & donofrio 1993 ; graham et al ..
Please generate the next two sentences of the article | 1996 , and references within ) . through varying the parameter @xmath17 in the sersic model
, one can reproduce an exponential light distribution ( @xmath17=1 ) , the classic de vaucouleurs profile ( @xmath17=4 ) , approximate a power - law for large values of @xmath17 ( approximately @xmath1815 ) , or any of the intermediate forms which galaxies exhibit ( michard 1985 ; schombert 1986 ; binggeli & cameron 1991 ; caon et al . |
7,550 | Suppose that you have an abstract for a scientific paper: the recent discovery of an x - ray jet in the z=4.3 quasar gb 1508 + 5714 by yuan et al .
( astro - ph/0309318 ) and siemiginowska et al .
( astro - ph/0310241 ) prompted a search for its radio counterpart .
here , we report the successful discovery of faint radio emission from the jet at 1.4 ghz using archival vla data .
the x - ray emission is best interpreted as inverse compton ( ic ) emission off the cmb as discussed by the previous investigators . in this scenario ,
its high x - ray to radio monochromatic luminosity ratio , compared to previously detected ic / cmb x - ray jets at lower redshift , is a natural consequence of its high redshift . .
And you have already written the first three sentences of the full article: since its launch in 1999 , the chandra x - ray observatory has been used to detect a large number of x - ray jets in active galactic nuclei ( agn ) , where prominent radio jets were previously known to exist ( see e.g. , * ? ? ? * and associated website ) .
the recent report @xcite of an extended x - ray jet originating from the z=4.3 quasar gb 1508 + 5714 , where previous observations showed no obvious sign of extended radio emission , presents an interesting case .
the x - ray feature is strong well over 100 counts were detected from it in the @xmath090 ksec chandra exposure ..
Please generate the next two sentences of the article | an archival hst image helps rule out the possibility that it is due to a foreground galaxy or a gravitationally lensed image of the quasar @xcite . based on deep x - ray source counts
, it has a low probability of being a random unassociated x - ray field source . |
7,551 | Suppose that you have an abstract for a scientific paper: it was shown in a previous work that the data combinations canceling laser frequency noise constitute a module - the module of syzygies .
the cancellation of laser frequency noise is crucial for obtaining the requisite sensitivity for lisa . in this work
we show how the sensitivity of lisa can be optimised for a monochromatic source - a compact binary - whose direction is known , by using appropriate data combinations in the module .
a stationary source in the barycentric frame appears to move in the lisa frame and our strategy consists of _ coherently tracking _
the source by appropriately _ switching _ the data combinations so that they remain optimal at all times . assuming that the polarisation of the source is not known
, we average the signal over the polarisations .
we find that the best statistic is the ` network ' statistic , in which case lisa can be construed of as two independent detectors .
we compare our results with the michelson combination , which has been used for obtaining the standard sensitivity curve for lisa , and with the observable obtained by optimally switching the three michelson combinations .
we find that for sources lying in the ecliptic plane the improvement in snr increases from 34@xmath0 at low frequencies to nearly 90@xmath0 at around 20 mhz .
finally we present the signal - to - noise ratios for some known binaries in our galaxy .
we also show that , if at low frequencies snrs of both polarisations can be measured , the inclination angle of the plane of the orbit of the binary can be estimated . .
And you have already written the first three sentences of the full article: the goal of the lisa mission @xcite is to detect and analyze low frequency gravitational signals essentially in the range from 0.1 mhz to 0.1 hz . in this frequency range ,
sources of gravitational waves are mainly the wide population of galactic compact binaries , and interactions between black holes with a range of complexity .
the study of the emission of gw from known binaries could be extremely useful for firstly , direct determination of distances , and secondly , possible small general relativistic effects , if the signal to noise ratio ( snr ) is large enough . for this reason ,.
Please generate the next two sentences of the article | we focus on optimising the sensitivity of lisa for a given astrophysical source with known direction .
the sensitivity of lisa can be improved by solving technological problems , but it can also be improved by employing certain optimal data analysis strategies . in this paper , we show how algebraic methods previously developed in @xcite , henceforth referred to as paper i , can be used to design optimal strategies for combining data with appropriate time - delays . |
7,552 | Suppose that you have an abstract for a scientific paper: in this paper we briefly introduce the quantum methods for computations of the drag coefficients for flows around a body , using the flows around a rigid sphere as an example , and we aim for comparing the wake under quantized environment and the classical computational strategies for finding the drag force .
this paper however does nt provide discussion on the pressure distribution over the surfaces of a spherical body and neither the analytical solution for the flows around an airfoil due to the greatly limited computational capacities and resources . .
And you have already written the first three sentences of the full article: the fundamental problem of aerodynamics is to find the action force allocated along with the surface of a body in the flow ( such as the lift and drag force on airfoils , etc ) , thus we shall first study how the physical quantities distribute in the entire flow field .
the relevant theory development peaked at the time shortly after joukowski and prandtl dedicated their effort .
however navier - stoke equation and reynolds equation had become to their fellow researchers formidable mathematical obstacles ahead of them . in order to attain accurate data records in a flow field.
Please generate the next two sentences of the article | , we have to be aware of the complete figure of the field with great details , such as the regulatory development routine for the boundary layer , the laminar - turbulent transition , the development of the separation region , and the mechanism of turbulence energy dissipation in all sections . only through unveiling the mysteries of these principles
, can we learn more about the pressure distribution as well as the appropriate circumstances for applying euler equations . |
7,553 | Suppose that you have an abstract for a scientific paper: we calculate the fluxes and energy spectra of high - energy ( @xmath0 ) neutrinos from the annihilations of supermassive ( @xmath1 ) , strongly interacting dark matter particles in the core of the sun .
we take all significant aspects of neutrino propagation through matter into account , as well as oscillations in matter and vacuum .
we also calculate the resulting event rates in an idealized @xmath2 ice detector .
we find that the signal should be well above background and easily observed by next - generation neutrino detectors such as icecube . .
And you have already written the first three sentences of the full article: the identity of the non - baryonic dark matter , believed to account for about @xmath3 of the total density of the universe @xcite , is one of the major unanswered questions in cosmology today .
there is much speculation that the dark matter consists of massive non - standard model elementary particles .
the so - called `` wimps , '' or weakly interacting massive particles , are the best known such candidate ..
Please generate the next two sentences of the article | these are often taken as the lightest supersymmetric particle , with a mass of no more than about @xmath4 @xcite .
any dark matter particle which is a thermal relic can not have a mass of more than about @xmath5 @xcite . |
7,554 | Suppose that you have an abstract for a scientific paper: we have developed a 4-channel multi - anode mcp - pmt , sl10 , which exhibits a performance of @xmath0 ps for single photons with @xmath1 and @xmath2 under a magnetic field of b @xmath3 .
the cross - talk among anodes has been extensively studied .
we have taken two measures to suppress it : one is to configure the sl10 to an effectively independent 4 small pieces of mcp - pmt s by segmenting an electrode of the second mcp - layer ; the other is to use a constant fractional discriminator .
remarkable improvement has been achieved . , , , , , , , , , , , , , , , mcp - pmt , cross - talk , top counter .
And you have already written the first three sentences of the full article: a micro - channel plate ( mcp ) photo - multiplier tube ( pmt ) provides a good time response .
our r&d work had obtained a transit time spread ( tts ) of @xmath4 ps for single photons with a channel - hole size of @xmath5 10 @xmath6m@xmath7 without a magnetic field ( b ) or with [email protected] t strength @xcite .
such an mcp - pmt made it possible to realize @xmath9 ps of a tof counter for 4 gev / c pion beams @xcite ..
Please generate the next two sentences of the article | furthermore , an mcp - pmt with a multi - alkali photocathode maintains its timing performance up to an integrated irradiation of @xmath10 photons/@xmath11 or an integrated output charge amount of @xmath12 c/@xmath11 under an irradiation rate of @xmath13 photons/@xmath11/s @xcite .
the mcp - pmt having these superb properties lets us develop a new type of cherenkov ring imaging counter , a time - of - propagation ( top ) counter @xcite , for particle identification at a planned super - kekb factory with an expected luminosity of @xmath14 /@xmath15sec , which is 50-times as intense as the achieved luminosity of the current kekb factory , and is expected to survive for more than 14 years under this situation . |
7,555 | Suppose that you have an abstract for a scientific paper: we report a @xmath0sr study of licro@xmath1 , which has a magnetic lattice made up of a stacking of triangular heisenberg antiferromagnetic ( cr@xmath2 , @xmath3 ) layers .
a static magnetically ordered state is observed below the transition temperature @xmath4 k , while the expected peak of the relaxation rate is slightly shifted downward by a few kelvins below @xmath5 .
we draw a comparison with the isostructural compound nacro@xmath1 , where an exotic broad fluctuating regime has been observed [ a. olariu , p. mendels , f. bert , b. g. ueland , p. schiffer , r. f. berger , and r. j. cava , phys .
rev .
lett . * 97 * , 167203 ( 2006 ) ] and was suggested to originate from topological excitations of the triangular lattice . replacing na by li strongly narrows the exotic fluctuating regime formerly observed in nacro@xmath1 , which we attribute to a more pronounced inter - plane coupling in licro@xmath1 . .
And you have already written the first three sentences of the full article: geometrical frustration of antiferromagnetic interactions is the object of intense research as a route to generate novel exotic ground states .
first proposed by anderson for the triangular lattice @xcite , spin - liquid - like behavior is now commonly observed in many compounds with corner - shared triangular lattices .
archetypes are the kagome or the pyrochlore lattices @xcite ..
Please generate the next two sentences of the article | the surge of interest for such weakly connected lattices in the 1990s came from ( i ) the lack of good experimental realizations of heisenberg triangular antiferromagnets and ( ii ) the idea that a weaker connectivity offers an additional ingredient to destabilize nel states and generate novel exotic physics . only very recently , the discovery of new experimental systems revived the interest in the pure triangular lattice . from the theoretical point of view , there was an early consensus that the heisenberg triangular antiferromagnet with nearest - neighbor coupling orders at @xmath6 in the so - called 120@xmath7 configuration of spins @xcite .
however , to date , there has been little theoretical exploration in the dynamics associated with the triangular topology . kawamura and miyashita proposed in the 1980s that , even though no magnetic transition is possible at a finite temperature , the system goes through a cross - over regime due to the proliferation of topological defects z@xmath1 |
7,556 | Suppose that you have an abstract for a scientific paper: in december 1924 wolfgang pauli proposed the idea of an inner degree of freedom of the electron , which he insisted should be thought of as genuinely quantum mechanical in nature .
shortly thereafter ralph kronig and , independently , samuel goudsmit and george uhlenbeck took up a less radical stance by suggesting that this degree of freedom somehow corresponded to an inner rotational motion , though it was unclear from the very beginning how literal one was actually supposed to take this picture , since it was immediately recognised ( already by goudsmit and uhlenbeck ) that it would very likely lead to serious problems with special relativity if the model were to reproduce the electron s values for mass , charge , angular momentum , and magnetic moment .
however , probably due to the then overwhelming impression that classical concepts were generally insufficient for the proper description of microscopic phenomena , a more detailed reasoning was never given . in this contribution
i shall investigate in some detail what the restrictions on the physical quantities just mentioned are , if they are to be reproduced by rather simple classical models of the electron within the framework of special relativity .
it turns out that surface stresses play a decisive role and that the question of whether a classical model for the electron does indeed contradict special relativity can only be answered on the basis of an _ exact _ solution , which has hitherto not been given . .
And you have already written the first three sentences of the full article: the discovery of electron spin is one of the most interesting stories in the history of quantum mechanics ; told e.g. in van der waerden s contribution to the pauli memorial volume ( @xcite , pp.199 - 244 ) , in tomonaga s book @xcite , and also in various first - hand reports @xcite@xcite @xcite .
this story also bears fascinating relations to the history of understanding special relativity .
one such relation is given by thomas discovery of what we now call `` thomas precession '' @xcite@xcite , which explained for the first time the correct magnitude of spin - orbit coupling and hence the correct magnitude of the fine - structure split of spectral lines , and whose mathematical origin can be traced to precisely that point which marks the central difference between the galilei and the lorentz group ( this is e.g. explained in detail in sects.4.3 - 4.6 of @xcite ) . in the present paper.
Please generate the next two sentences of the article | i will dwell a little on another such connection to special relativity . as is widely appreciated , wolfgang pauli is a central figure , perhaps _ the _ most central figure , in the story of spin .
being the inventor of the idea of an inner ( quantum mechanical ) degree of freedom of the electron , he was at the same time the strongest opponent to attempts to relate it to any kind of interpretation in terms of kinematical concepts that derive from the picture of an extended material object in a state of rotation . to my knowledge , |
7,557 | Suppose that you have an abstract for a scientific paper: an efficient method is proposed for numerical solutions of nonlinear schrdinger equations in an unbounded domain . through approximating the kinetic energy term by a one - way equation and uniting it with the potential energy equation , absorbing
boundary conditions are designed to truncate the unbounded domain , which are in nonlinear form and can perfectly absorb the waves outgoing from the truncated domain .
we examine the stability of the induced initial boundary value problems defined on the computational domain with the boundary conditions by a normal mode analysis .
numerical examples are given to illustrate the stable and tractable advantages of the method . .
And you have already written the first three sentences of the full article: in this paper , we consider the construction of absorbing boundary conditions ( abcs ) for the nonlinear schrdinger equation ( nls ) , @xmath0\psi,\label{nls}\ ] ] where @xmath1 is the atomic mass , @xmath2 represents the planck constant , and @xmath3 is the potential function .
this equation appears in many different applications @xcite , such as the gravity waves on deep water in fluid dynamics , the pulse propagations in optics fibers , and the bose - einstein condensation . for the cubic nonlinear term @xmath4 , eq .
( [ nls ] ) reduced to gross - pitaevskii equation , which be numerically studied by @xcite and references therein . for a quintic nonlinearity.
Please generate the next two sentences of the article | , one can see @xcite .
a current challenge for the numerical solutions of this kind of problems is due to the unboundedness of the physical domain . |
7,558 | Suppose that you have an abstract for a scientific paper: the difference in formation process between binary stars and planetary systems is reflected in their composition as well as their orbital architecture , particularly orbital eccentricity as a function of orbital period .
it is suggested here that this difference can be used as an observational criterion to distinguish between brown dwarfs and planets .
application of the orbital criterion suggests that with three possible exceptions , all of the recently - discovered substellar companions discovered to date may be brown dwarfs and not planets .
these criterion may be used as a guide for interpretation of the nature of sub - stellar mass companions to stars in the future . .
And you have already written the first three sentences of the full article: it is not unusual in science to find that the initial early detection of a phenomenon is followed by a rapidly increasing discovery rate as interest intensifies and new technology is developed .
such has been the case with the search for substellar companions to stars in the solar neighborhood . while there have been claims of detections of companions to stars with masses less than the lower limit for the mass of a star
, most have not stood the test of time . however , that has changed following the announcement of the detection of a companion to the star hd 114762 ( latham et al ..
Please generate the next two sentences of the article | 1989 ) . during the interval of time from 1995 to early 1997 there have been reported detections of 20 substellar mass companions to nearby stars .
the recent avalanche of detections began with the paper announcing the discovery of a companion to the star 51 pegasi ( mayor and queloz 1995 ) . |
7,559 | Suppose that you have an abstract for a scientific paper: we derive horizontal fluid motions on the solar surface over large areas covering the quiet - sun magnetic network from local correlation tracking of convective granules imaged in continuum intensity and doppler velocity by the helioseismic and magnetic imager ( hmi ) onboard the solar dynamics observatory ( sdo ) . from these
we calculate horizontal divergence , vertical component of vorticity , and kinetic helicity of fluid motions .
we study the correlations between fluid divergence and vorticity , and that between vorticity ( kinetic helicity ) and magnetic field .
we find that the vorticity ( kinetic helicity ) around small - scale fields exhibits a hemispherical pattern ( in sign ) similar to that followed by the magnetic helicity of large - scale active regions ( containing sunspots ) .
we identify this pattern to be a result of the coriolis force acting on supergranular - scale flows ( both the outflows and inflows ) , and is consistent with earlier studies using local helioseismology .
further , we show that the magnetic fields cause transfer of vorticity from supergranular inflow regions to outflow regions , and that they tend to suppress the vortical motions around them when magnetic flux densities exceed about 300 g ( hmi ) .
we also show that such action of magnetic fields leads to marked changes in the correlations between fluid divergence and vorticity .
these results are speculated to be of importance to local dynamo action if present , and to the dynamical evolution of magnetic helicity at the small - scale . .
And you have already written the first three sentences of the full article: interactions between turbulent convection and magnetic field at the photospheric layers play central roles in structuring and driving varied forms of dynamical phenomena in the atmospheric layers above , and hence in the energetics ( see , _ e.g. _ @xcite and references therein ) .
these interactions in the near - surface layers are also basic to local dynamo action @xcite , which , if present , could explain the large amount of quiet - sun magnetic flux inferred from high - resolution observations @xcite .
an important aspect of these interactions is the role of helical or swirly fluid motions which can similarly twist or inject helicity to the magnetic field , and vice versa ..
Please generate the next two sentences of the article | helicity of a vector field , in general , is defined as the volume integral of the scalar product of the field vector and its curl ( or rotation ) and it quantifies the amount of twistedness in the vector field @xcite . for fluid flow ,
the kinetic helicity , @xmath0 , is such a quantity derived from velocity @xmath1 and its curl or vorticity , @xmath2 : @xmath3 , where @xmath4 is the volume element . for magnetic fields |
7,560 | Suppose that you have an abstract for a scientific paper: we study the properties of strange and charm mesons in hot and dense matter within a self - consistent coupled - channel approach for the experimental conditions of density and temperature expected for the cbm experiment at fair / gsi .
the in - medium solution at finite temperature accounts for pauli blocking effects , mean - field binding of all the baryons involved , and meson self - energies .
we analyze the behaviour in this hot and dense environment of dynamically - generated baryonic resonances together with the evolution with density and temperature of the strange and open - charm meson spectral functions .
we test the spectral functions for strange mesons using energy - weighted sum rules and finally discuss the implications of the properties of charm mesons on the @xmath0 and the predicted @xmath1 scalar resonances . .
And you have already written the first three sentences of the full article: over the last decades strangeness has been a matter of extensive study in connection to exotic atoms @xcite as well as heavy - ion collisions at sis / gsi energies @xcite .
phenomenology of antikaonic atoms shows that the @xmath2 feels an attractive potential at low densities .
this attraction results from the modified @xmath3-wave @xmath4 resonance in the medium due to pauli blocking effects @xcite together with the self - consistent consideration of the @xmath2 self - energy @xcite and the inclusion of self - energies of the mesons and baryons in the intermediate states @xcite.
Please generate the next two sentences of the article | . attraction of the order of -50 mev at normal nuclear matter density , @xmath5 , is obtained by different approaches , such as unitarizated theories in coupled channels based on meson - exchange models @xcite or chiral dynamics @xcite .
higher - partial waves beyond the s - wave contribution have been also studied @xcite as they become relevant for heavy - ion collisions at beam energies below 2agev @xcite . |
7,561 | Suppose that you have an abstract for a scientific paper: i review the interpretation of solar and atmospheric neutrino data in terms neutrino oscillations and describe some ways to account for the required neutrino masses and mixing angles from first principles , both within top - down and bottom - up approaches .
i also discuss non - oscillation phenomena such as which may probe the absolute scale of neutrino mass , and also reveal its majorana nature .
i note that leptonic cp violation induced by `` majorana '' phases drop from oscillations but play a role in the leptogenesis scenario for the baryon asymmetry of the universe .
direct tests of leptonic cp violation in oscillation experiments , such as neutrino factories , will be a tough challenge , due to the hierarchical neutrino mass splittings and the smallness of @xmath0 indicated by reactors .
the large solar mixing angle @xmath1 offers a way to probe otherwise inaccessible features of supernova physics .
finally , i note that in low - scale models of neutrino mass , one may probe ` all ` mixing angles , including the atmospheric @xmath2 , at high energy accelerator experiments such as the lhc or nlc .
a neat example is supersymmetry with bilinear breaking of r parity , where the lsp decay branching ratios are directly correlated to the neutrino mixing angles .
i also discuss non - oscillation solutions to the solar neutrino problem in terms of spin - flavor precession and non - standard neutrino interactions , which will be crucially tested at kamland . .
And you have already written the first three sentences of the full article: solar neutrinos have now been detected with the geochemical method @xcite via the + @xmath3cl @xmath4ar + @xmath5 reaction at homestake , and via the + @xmath6ga @xmath7ge + @xmath5 reaction at the gallex , sage and gno experiments .
direct detection with cherenkov techniques using @xmath8 scattering on water at super - k @xcite , and heavy water at sno @xcite have given a robust confirmation that the number of solar neutrinos detected in underground experiments is less than expected from theories of energy generation in the sun @xcite .
especially relevant is the sensitivity of the sno experiment to the neutral current ( nc ) ..
Please generate the next two sentences of the article | altogether these experiments provide a solid evidence for solar neutrino conversions and , as a result , imply that an extension of the standard model of particle physics in the lepton sector is needed .
although not yet unique , the most popular explanation of solar neutrino experiments is provided by the neutrino oscillations hypothesis . |
7,562 | Suppose that you have an abstract for a scientific paper: we prove that one - way quantum computations have the same computational power as quantum circuits with unbounded fan - out .
it demonstrates that the one - way model is not only one of the most promising models of physical realisation , but also a very powerful model of quantum computation .
it confirms and completes previous results which have pointed out , for some specific problems , a depth separation between the one - way model and the quantum circuit model .
since one - way model has the same computational power as unbounded quantum fan - out circuits , the quantum fourier transform can be approximated in constant depth in the one - way model , and thus the factorisation can be done by a polytime probabilistic classical algorithm which has access to a constant - depth one - way quantum computer .
the extra power of the one - way model , comparing with the quantum circuit model , comes from its classical - quantum hybrid nature .
we show that this extra power is reduced to the capability to perform unbounded classical parity gates in constant depth . .
And you have already written the first three sentences of the full article: the one - way quantum computational model , proposed by raussendorf and briegel @xcite , is remarkable in many aspects .
it represents an approach to quantum computation very different to more conventional `` circuit - based '' approaches which were derived in close analogy to classical logic circuits . in the one - way model ,
computation proceeds by the generation of a particular entangled multi - qubit state - a cluster state - followed by the adaptive measurement of individual qubits ..
Please generate the next two sentences of the article | the choice of basis for the measurements , and their adaptive dependency encodes the computation .
the dependancy of the bases upon the outcome of previous measurements is a necessary part of the model . |
7,563 | Suppose that you have an abstract for a scientific paper: we present spectroscopic observations of two halo m subdwarfs which have @xmath0 emission lines .
we show that in both cases close companions are the likely cause of the chromospheric activity in these old , metal - poor stars .
we argue that gl 781 a s unseen companion is most likely a cool helium white dwarf .
gl 455 is a near - equal - mass m subdwarf ( sdm ) system .
gl 781 a is rapidly rotating with @xmath1 km s@xmath2 . the properties of the chromospheres and x - ray coronae of these systems are compared to m dwarfs with emission ( dme ) .
the x - ray hardness ratios and optical chromospheric line emission ratios are consistent with those seen in dme stars .
comparison to active near - solar metallicity stars indicates that despite their low metallicity ( @xmath3 \approx -1.2 $ ] ) , the sdme stars are roughly as active in both x - rays and chromospheric emission .
measured by @xmath4 , the activity level of gl 781 a is no more than a factor of 2.5 subluminous with respect to near - solar metallicity stars . .
And you have already written the first three sentences of the full article: it has long been noted that most old halo stars show little magnetic activity relative to young disk stars indeed , joy ( 1947 ) used `` a weakening of emission lines '' as one of the criteria for identifying m subdwarfs . for disk stars ,
magnetic activity has been extensively studied from the onset of the convective envelope amongst f stars down to the hydrogen burning limit ( as reviewed by @xcite ) .
comparatively little is known about the activity of population ii stars recent studies of population ii stars have addressed chromospheric activity of single stars ( @xcite ) and x - ray emission in binary systems ( @xcite , hereafter ofp ) , but these studies targeted near - solar mass stars rather than very - low - mass stars ..
Please generate the next two sentences of the article | nevertheless , the population ii m subdwarfs are worthy of study because stars with @xmath5 are thought to be fully convective for all metallicities ( @xcite ) , and therefore may have a different dynamo mechanism than solar mass stars which have radiative / convective zone boundaries ( @xcite ; @xcite )
. moderate resolution spectra of very - low - mass stars allow the identification of high activity ( `` dme '' ) stars by the presence of @xmath0 emission lines while at the same time allowing the classification ( @xcite , hereafter g97 ) of metal - poor stars as sdm ( m subdwarfs ) and esdm ( extreme m subdwarfs ) . in our recent palomar / michigan state university ( pmsu ) |
7,564 | Suppose that you have an abstract for a scientific paper: we extend the study of long mode perturbations to other large scale observables such as cosmic rulers , galaxy number counts and halo bias .
the long mode is a pure gradient mode that is still outside observer s horizon .
we insist that gradient mode effects on observables vanish .
it is also crucial that the expressions for observables are relativistic .
this allows us to show that the effects of a gradient mode on the large scale observables vanishes identically in a relativistic frame work . to study the potential modulation effect of the gradient mode on halo bias , we derive a consistency condition to the first order in gradient expansion .
we find that the matter variance at a fixed physical scale is not modulated by the long gradient mode perturbations when the consistency condition holds .
this shows that the contribution of long gradient modes to bias vanishes in this frame work . .
And you have already written the first three sentences of the full article: latest developments in cosmology are provided by deep redshift surveys for cosmological structures .
these structures develop from evolution of primordial perturbations generated during inflation .
originally , quantum fluctuations of the inflation field set the seeds of curvature perturbations at primordial epochs ..
Please generate the next two sentences of the article | the nature of these fluctuations are well studied in the cosmic microwave background ( cmb ) .
the fingerprints of these fluctuations on large scale structures ( lss ) are also important since the current and future galaxy surveys will take high precision measurements of galaxy clustering . |
7,565 | Suppose that you have an abstract for a scientific paper: let @xmath0 be a banach lie group with involutive automorphism @xmath1 , @xmath2 be the @xmath1-eigenspaces in the lie algebra @xmath3 of @xmath4 , and @xmath5 be the identity component of its group of fixed points .
an olshanski semigroup is a semigroup @xmath6 of the form @xmath7 , where @xmath8 is an open @xmath9-invariant convex cone in @xmath10 and the polar map @xmath11 is a diffeomorphism .
any such semigroup carries an involution @xmath12 satisfying @xmath13 . our central result , generalizing the lscher mack theorem for finite dimensional groups , asserts that any locally bounded @xmath12-representation @xmath14 with a dense set of smooth vectors defines by `` analytic continuation '' a unitary representation of the simply connected lie group @xmath15 with lie algebra @xmath16 .
we also characterize those unitary representations of @xmath15 obtained by this construction . with similar methods , we further show that semibounded unitary representations extend to holomorphic representations of complex olshanski semigroups . .
And you have already written the first three sentences of the full article: there are many important results in the unitary representation theory of lie groups related to analytic continuation . here
a key ingredient is the special case where @xmath17 is a strongly continuous unitary one - parameter group and @xmath18 its self - adjoint infinitesimal generator , i.e. , @xmath19 in the sense of measurable functional calculus .
then the unitary one - parameter group @xmath20 extends to a holomorphic one - parameter semigroup @xmath21 if and only if @xmath18 is bounded below ..
Please generate the next two sentences of the article | this extension then restricts to a locally bounded non - degenerate hermitian one - parameter semigroup @xmath22 .
conversely , any such hermitian one - parameter group has a self - adjoint infinitesimal generator @xmath23 and @xmath24 then yields an extension to @xmath25 , where the boundary values form a unitary one - parameter group . |
7,566 | Suppose that you have an abstract for a scientific paper: we present deep composite luminosity functions in @xmath0 , @xmath1 , @xmath2 , @xmath3 , @xmath4 and @xmath5 for six clusters at @xmath6 observed with the hubble space telescope advanced camera for surveys .
the luminosity functions reach to absolute magnitude of @xmath7 mag . and
are well fitted by a single schechter function with @xmath8 mag . and @xmath9 ( in all bands ) .
the observations suggest that the galaxy luminosity function is dominated by objects on the red sequence to at least 6 mags . below the @xmath10 point .
comparison with local data shows that the red sequence is well established at least at @xmath11 down to @xmath12 of the luminosity of the milky way and that galaxies down to the regime of dwarf spheroidals have been completely assembled in clusters at this redshift .
we do not detect a steepening of the luminosity function at @xmath13 as is observed locally .
if the faint end upturn is real , the steepening of the luminosity function must be due to a newly infalling population of faint dwarf galaxies . .
And you have already written the first three sentences of the full article: the galaxy luminosity function ( hereafter lf ) provides a @xmath14 order description of the gross properties of galaxy populations .
although it may be regarded as somewhat simplistic , in reducing galaxy properties to the two numbers ( @xmath15 and @xmath16 ) that describe the lf in the @xcite form , reproducing the observed lf is a fundamental test for any viable theory of galaxy formation , and one that has proven surprisingly complex to achieve until relatively recently ( e.g. , @xcite ) .
clusters of galaxies are , in several ways , ideal laboratories to study the lf and its evolution ..
Please generate the next two sentences of the article | cluster galaxies may be considered as a volume limited sample of objects observed at the same cosmic epoch and occupy a relatively ` constant ' environment corresponding to the highest density peaks at the redshift of observation .
operationally , cluster members have a much higher surface density on the sky than the surrounding field and often exhibit distinctive morphologies and colors ( see fig . 1 below ) . |
7,567 | Suppose that you have an abstract for a scientific paper: in this paper , we develop a theory of redshift distortion of the galaxy power spectrum in the discrete wavelet transform ( dwt ) representation . because the dwt power spectrum is dependent of both the scale and shape ( configuration ) of the decomposition modes , it is sensitive to distortion of shape of the field . on the other hand ,
the redshift distortion causes a shape distortion of distributions in real space with respect to redshift space .
therefore , the shape - dependent dwt power spectrum is useful to detect the effect of redshift distortion .
we first established the mapping between the dwt power spectra in redshift and real space .
the mapping depends on the redshift distortion effects of ( 1 ) bulk velocity , ( 2 ) selection function and ( 3 ) pairwise peculiar velocity .
we then proposed @xmath0-estimators using the dwt off - diagonal power spectra .
these @xmath0-estimators are model - free even when the non - linear redshift distortion effect is not negligible . moreover
, these estimators do not rely on the assumption of whether the pairwise velocity dispersion being scale - dependent .
the tests with n - body simulation samples show that the proposed @xmath0-estimators can yield reliable measurements of @xmath0 with about 20% uncertainty for all popular dark matter models .
we also develop an algorithm for reconstruction of the power spectrum in real space from the redshift distorted power spectrum .
the numerical test also shows that the real power spectrum can be well recovered from the redshift distorted power spectrum . .
And you have already written the first three sentences of the full article: in three previous papers we have developed a method of measuring galaxy power spectrum with discrete wavelet transform ( dwt ) decomposition , which is an alternative of the fourier power spectrum detection ( fang & feng , 2000 ( paper i ) , yang et al 2001a ( paper ii ) , 2001b ( paper iii ) ) .
the dwt power spectrum estimator is information - loseless , and optimized in the sense that the spatial resolution is adaptive automatically to the scale to be studied .
a test with observed sample of the lcrs galaxies showed that the dwt estimator can give a robust measurement of the power spectrum . in this paper.
Please generate the next two sentences of the article | , we continue our effort in this direction .
the topic this time is to develop theory and algorithm of redshift distortion in the dwt representation . in terms of power spectrum measurement , |
7,568 | Suppose that you have an abstract for a scientific paper: andromeda ii ( and ii ) has been known for a few decades but only recently observations have unveiled new properties of this dwarf spheroidal galaxy .
the presence of two stellar populations , the bimodal star formation history ( sfh ) and an unusual rotation velocity of and ii put strong constrains on its formation and evolution .
following @xcite , we propose a detailed model to explain the main properties of and ii involving ( 1 ) a gas - rich major merger between two dwarf galaxies at high redshift in the field and ( 2 ) a close interaction with m31 about 5 gyr ago .
the model is based on @xmath0-body / hydrodynamical simulations including gas dynamics , star formation and feedback .
one simulation is designed to reproduce the gas - rich major merger explaining the origin of stellar populations and the sfh .
other simulations are used to study the effects of tidal forces and the ram pressure stripping during the interaction between and ii and m31 .
the model successfully reproduces the sfh of and ii including the properties of stellar populations , its morphology , kinematics and the lack of gas .
further improvements to the model are possible via joint modelling of all processes and better treatment of baryonic physics .
[ firstpage ] galaxies : individual : andromeda ii galaxies : local group galaxies : dwarf galaxies : kinematics and dynamics galaxies : evolution galaxies : interactions .
And you have already written the first three sentences of the full article: the local group ( lg ) is composed of two massive spiral galaxies , the milky way ( mw ) and m31 , and a smaller one , m33 .
in addition to these normal galaxies , more and more dwarf galaxies are discovered ( see * ? ? ? * for an updated review of the lg dwarf galaxies ) .
the new discoveries came as a result of the sdss @xcite , the pandas survey @xcite , the pan - starrs1 @xmath1 survey @xcite and most recently the dark energy survey @xcite ..
Please generate the next two sentences of the article | most of these objects are dwarf spheroidal ( dsph ) galaxies : spheroidal in shape , devoid of gas and current star formation and typically located close to the mw or m31 ( @xmath2 kpc ) . except for a few ellipticals , the remaining lg dwarf galaxies are dwarf irregulars ( dirr ) : gas - rich , with high star formation rates and located rather far from the mw and m31 ( @xmath3 kpc ) , with a notable exception of the magellanic clouds . in the context of the @xmath4cdm paradigm ,
dwarf galaxies are understood as remnants of primordial galaxies , full of dark matter , which have not yet merged with other objects to build massive galaxies @xcite . |
7,569 | Suppose that you have an abstract for a scientific paper: conditional independence models in the gaussian case are algebraic varieties in the cone of positive definite covariance matrices .
we study these varieties in the case of bayesian networks , with a view towards generalizing the recursive factorization theorem to situations with hidden variables . in the case when the underlying graph is a tree , we show that the vanishing ideal of the model is generated by the conditional independence statements implied by graph . we also show that the ideal of any bayesian network is homogeneous with respect to a multigrading induced by a collection of upstream random variables .
this has a number of important consequences for hidden variable models .
finally , we relate the ideals of bayesian networks to a number of classical constructions in algebraic geometry including toric degenerations of the grassmannian , matrix schubert varieties , and secant varieties . .
And you have already written the first three sentences of the full article: a bayesian network or directed graphical model is a statistical model that uses a directed acyclic graph ( dag ) to represent the conditional independence structures between collections of random variables .
the word bayesian is used to describe these models because the nodes in the graph can be used to represent random variables that correspond to parameters or hyperparameters , though the basic models themselves are not a priori bayesian .
these models are used throughout computational statistics to model complex interactions between collections of random variables ..
Please generate the next two sentences of the article | for instance , tree models are used in computational biology for sequence alignment @xcite and in phylogenetics @xcite .
special cases of bayesian networks include familiar models from statistics like factor analysis @xcite and the hidden markov model @xcite . |
7,570 | Suppose that you have an abstract for a scientific paper: we show that the slopes between @xmath0extrema of the drifted 1d brownian motion form a stationary alternating marked point process , extending the result of j. neveu and j. pitman for the non drifted case .
our analysis covers the results on the statistics of @xmath0extrema obtained by p. le doussal , c. monthus and d. fisher via a renormalization group analysis and gives a complete description of the slope between @xmath0extrema covering the origin by means of the palm khinchin theory .
moreover , we analyze the behavior of the brownian motion near its @xmath0extrema . _
2000 mathematics subject classification : _
60j65 , 60g55 .
_ key words : _ brownian motion , marked point processes , palm
khinchin theory , fluctuation theory . .
And you have already written the first three sentences of the full article: let @xmath1 be a two sided standard brownian motion with drift @xmath2 .
given @xmath3 we say that @xmath1 admits an _ @xmath0minimum _ at @xmath4 , and that @xmath5 is a point of @xmath0minimum , if there exist @xmath6 such that @xmath7 for all @xmath8 $ ] , @xmath9 and @xmath10 .
similarly , we say that @xmath1 admits an _ @xmath0maximum _ at @xmath11 , and that @xmath5 is a point of @xmath0maximum , if there exist @xmath6 such that @xmath12 for all @xmath8 $ ] , @xmath13 and @xmath14 ..
Please generate the next two sentences of the article | we say that @xmath1 admits an _ @xmath0extremum _ at @xmath4 , and that @xmath5 is a point of @xmath0extremum , if @xmath5 is a point of @xmath0minimum or a point of @xmath0maximum .
finally , the truncated trajectory @xmath1 going from an @xmath0minimum to an @xmath0maximum will be called upward @xmath0slope , while the truncated trajectory @xmath1 going from an @xmath0maximum to an @xmath0minimum will be called downward @xmath0slope . |
7,571 | Suppose that you have an abstract for a scientific paper: we give a proposal to generalize the concept of the differential equations on time scales @xcite , such that they can be more appropriate for the analysis of real world problems , and give more opportunities to increase the theoretical depth of investigation .
differential equations on time scales ; transition condition ; modeling .
And you have already written the first three sentences of the full article: let us remind the differential equations on time scales , proposed by hilger @xcite .
the main element of the equations is the time scale , which is understood as a nonempty closed subset , @xmath0 of the real numbers . on a time scale
@xmath1 the functions @xmath2 and @xmath3 are called the forward and backward jump operators , respectively ..
Please generate the next two sentences of the article | the point @xmath4 is called right - scattered if @xmath5 and right - dense if @xmath6 similarly , it is called left - scattered if @xmath7 and left - dense if @xmath8 the @xmath9derivative of a continuous function @xmath10 at a right - scattered point is defined as @xmath11 and at a right - dense point it is defined as @xmath12 if the limit exists .
a differential equation @xmath13 is said to be a differential equation on time scale , where function @xmath14 in ( [ tsde ] ) is assumed to be rd - continuous on @xmath15 @xcite . |
7,572 | Suppose that you have an abstract for a scientific paper: finding the electromagnetic ( em ) counterpart is critically important for a gravitational wave event .
although many efforts have been made to search for the purported em counterpart of gw150914 , the first gravitational wave event detected by ligo , only fermi / gbm reported an excess above background ( i.e. gw150914-gbm ) at 0.4 s after the ligo trigger time , that is possibly associated with this gw event @xcite . however , since there is no significant detection by the integral / spi - acs around the time of gw150914-gbm , a great debate has been raised about whether gw150914-gbm is of astrophysical origin and associated with the gw150914 @xcite . in order to answer this question ,
we re - analyzed the gbm data with a straightforward but sophisticated method .
we find that the excess of gw150914-gbm mostly comes from those detectors with bad viewing angles to the gw event , whereas the good viewing detectors see nothing significant beyond background fluctuation around the trigger time of gw150914 .
this finding suggests that gw150914-gbm is very unlikely associated with the gw150914 .
given that gw150914-gbm is the only event found by gbm that is possibly associated with this gw event in a comprehensive search , we conclude that gbm did not detect any electromagnetic radiation from the gw150914 . .
And you have already written the first three sentences of the full article: the era of gravitational wave ( gw ) astronomy has come since the laser interferometer gravitational - wave observatory ( ligo ) detected the first gw event , gw150914 , which is thought to be produced by the merging of a stellar mass binary black hole system @xcite . finding the electromagnetic ( em ) counterpart of the gw event is critically important in many aspects , such as identification of the gw event , study of the progenitor and its environment , fundamental physics and cosmology .
although many efforts have been made to search for the purported em counterpart of gw150914 @xcite , only the gamma - ray burst monitor ( gbm ) onboard fermi @xcite recorded an excess ( denoted as gw150914-gbm ) at 0.4 s after the ligo trigger time , which is claimed to be possibly associated with this gw event @xcite .
however , since there is no significant signal detected by the integral / spi - acs around the time of gw150914-gbm @xcite , a great debate has been raised about whether gw150914-gbm is of astrophysical origin and associated with the gw150914 ..
Please generate the next two sentences of the article | @xcite reported that gw150914-gbm is likely associated with the gw150914 based on the following reasons : ( a ) its time is only 0.4 s after the ligo trigger time of the gw event .
( b ) its localization is not inconsistent with ligo locations of gw150914 , although quite poor due to the weakness and unfavorable incident angles to gbm detectors . |
7,573 | Suppose that you have an abstract for a scientific paper: we study the predictions for the direct cp violation parameter in a class of string inspired model with non
universal soft @xmath0terms .
we show that the non universality of the @xmath0terms plays an important rule in enhancing the supersymmetric contributions to the cp violation . in particular , the supersymmetric contribution to can be of order the ktev result , @xmath1 .
# 1#2 # 1#2#3 _ ann .
phys .
( ny ) _ * # 1 * ( # 2 ) # 3 # 1#2#3 _ ann .
rev .
nucl . part .
sci . _ * # 1 * ( # 2 ) # 3 # 1#2#3 _ nucl .
phys . _
* b # 1 * ( # 2 ) # 3 # 1#2#3 _ nucl .
phys . _
( proc .
suppl.)*b # 1 * ( # 2 ) # 3 # 1#2#3 _ phys .
lett . _
* b # 1 * ( # 2 ) # 3 # 1#2#3 _ phys .
rev . _
* d # 1 * ( # 2 ) # 3 # 1#2#3 _ phys .
rep . _ * # 1 * ( # 2 ) # 3 # 1#2#3 _ phys .
rev .
lett . _ * # 1 * ( # 2 ) # 3 # 1#2#3 _ prog .
theor .
phys . _ * # 1 * ( # 2 ) # 3 # 1#2#3 _ rev .
mod .
phys . _ * # 1 * ( # 2 ) # 3 # 1#2#3 _ zeit .
fr physik _ * c # 1 * ( # 2 ) # 3 # 1#2#3 _ mod .
phys .
lett . _ * a # 1 * ( # 2 ) # 3 # 1#2#3 _ sov .
j. nucl .
phys .
_ * # 1 * ( # 2 ) # 3 # 1#2#3 _ yad . fiz . _
* # 1 * ( # 2 ) # 3 # 1#2#3 _ nuovo cim . _ * # 1 * ( # 2 ) # 3 # 1#2#3 _ jetp lett . _ * # 1 * ( # 2 ) # 3 # 1#2#3 _ ibid .
_ * # 1 * ( # 2 ) # 3 .
And you have already written the first three sentences of the full article: the most recent results of , which measures the size of the direct cp violation in @xmath2 , reported by ktev @xcite and na48 @xcite lead to a world average of re = @xmath3 @xcite . this result is higher than the standard model ( sm ) predictions @xcite , opening the way to the interpretation that it may be a signal of new physics beyond the sm .
the sm predictions for suffer from large theoretical uncertainties @xcite such that one can not draw a definite conclusion if this observed high value of can be accommodated in the sm . in any case , one may wonder if the supersymmetry ( susy ) can be responsible for enhancing . in the minimal supersymmetric extension of the sm ( mssm )
there is no way of generating a siable susy contribution to even if one assume that the susy cp violating phases are large and the electric dipole moments ( edm ) of the electron and neutron are less than the experimental bounds due to the cancellation between the different contributions ..
Please generate the next two sentences of the article | this is mainly due to the assumption of universal boundary conditions of the soft - breaking terms @xcite .
it has been shown that , without new flavor structure beyond the usual yukawa couplings , general susy models with phases of the soft terms of order @xmath4 ( but with a vanishing ckm phase @xmath5 ) can not give a sizeable contribution to the cp violating processes @xcite . |
7,574 | Suppose that you have an abstract for a scientific paper: an implicit hydrodynamic code following the explosion of classical novae , from the accretion phase up to the final ejection of the envelope , has been coupled to a monte - carlo code able to simulate their gamma - ray emission .
carbon - oxygen ( co ) and oxygen - neon ( one ) novae have been studied and their gamma - ray spectra have been obtained , as well as the gamma - ray light curves for the important lines ( e@xmath0e@xmath1 annihilation line at 511 kev , @xmath2be decay - line at 478 kev and @xmath3na decay - line at 1275 kev ) .
the detectability of the emission by cgro instruments has been analyzed .
it is worth noticing that the @xmath4-ray signature of a co nova is different from that of an one one . in the co case
, the 478 kev line is very important , but lasts only for @xmath52 months . in the one case
, the 1275 kev line is the dominant one , lasting for @xmath5 4 years . in both cases ,
the 511 kev line is the most intense line at the beginning , but its short duration ( @xmath52 days ) makes it very difficult to be detected .
it is shown that the negative results from the observations made by comptel up to now are consistent with the theoretical predictions .
predictions of the future detectability by the integral mission are also made .
7@xmath2be 13@xmath6n 14@xmath7o 15@xmath8o 17@xmath9f 18@xmath10f 22@xmath3na 26@xmath11al .
And you have already written the first three sentences of the full article: nova explosions are caused by thermonuclear runaways on white dwarfs accreting hydrogen from a main sequence companion in a cataclysmic variable .
the explosive burning of hydrogen on the top of a co or an one degenerate core leads to the synthesis of some @xmath12 unstable nuclei , such as 13 , 14 , 15 , 17 and 18 .
these nuclei have short lifetimes ( @xmath51 - 2 minutes for 14 , 15 and 17 , @xmath515 min for 13 and @xmath53 hours for 18 ) , and they emit a positron when they decay . these positrons annihilate with electrons leading to the emission of photons with energy less or equal to 511 kev . furthermore , other medium- and long - lived radiocative nuclei are synthesized in classical novae : 7 ( @xmath13=77days ) , whichs emits a photon of 478 kev after an electron capture , 22 ( @xmath13=3.75yr ) and 26 ( @xmath13=1.04@xmath14 yr ) , which experience a @xmath12-decay emitting photons of 1275 and 1809 kev , respectively ..
Please generate the next two sentences of the article | thus , classical novae are potential @xmath4-ray emitters , as was pointed out in previous works ( clayton & hoyle @xcite , clayton @xcite , leising & clayton @xcite )
. there are also some previous works concerning nucleosynthesis in classical novae ( see politano et al @xcite , prialnik & kovetz @xcite and references therein for nucleosynthesis in one and co novae , respectively , as well as hernanz et al @xcite , jos et al @xcite , jos & hernanz @xcite and @xcite ) . |
7,575 | Suppose that you have an abstract for a scientific paper: recent theoretical and empirical studies have focused on the structural properties of complex relational networks in social , biological and technological systems . here
we study the basic properties of twenty 1-square - mile samples of street patterns of different world cities .
samples are represented by spatial ( planar ) graphs , i.e. valued graphs defined by metric rather than topologic distance and where street intersections are turned into nodes and streets into edges .
we study the distribution of nodes in the 2-dimensional plane .
we then evaluate the local properties of the graphs by measuring the meshedness coefficient and counting short cycles ( of three , four and five edges ) , and the global properties by measuring global efficiency and cost . as normalization graphs , we consider both minimal spanning trees ( mst ) and greedy triangulations ( gt ) induced by the same spatial distribution of nodes .
the results indicate that most of the cities have evolved into networks as efficienct as gt , although their cost is closer to the one of a tree .
an analysis based on relative efficiency and cost is able to characterize different classes of cities . .
And you have already written the first three sentences of the full article: during the last decade , the growing availability of large databases , the increasing computing powers , as well as the development of reliable data analysis tools , have constituted a better machinery to explore the topological properties of several complex networks from the real world @xcite .
this has allowed to study a large variety of systems as diverse as social , biological and technological .
the main outcome of this activity has been to reveal that , despite the inherent differences , most of the real networks are characterized by the same topological properties , as for instance relatively small characteristic path lengths and high clustering coefficients ( the so called _ small - world property _ ) @xcite , _ scale - free _ degree distributions @xcite , degree correlations @xcite , and the presence of motifs @xcite and community structures @xcite ..
Please generate the next two sentences of the article | all such features make real networks radically different from regular lattices and random graphs , the standard topologies usually used in modeling and computer simulations .
this has led to a large attention towards the comprehension of the evolution mechanisms that have shaped the topology of a real network , and to the design of new models retaining the most significant properties observed empirically . |
7,576 | Suppose that you have an abstract for a scientific paper: this paper is concerned with the asymptotic expansions of the amplitude of the solution of the helmholtz equation .
the original expansions were obtained using a pseudo - differential decomposition of the dirichlet to neumann operator .
this work uses first and second order approximations of this operator to derive new asymptotic expressions of the normal derivative of the total field .
the resulting expansions can be used to appropriately choose the ansatz in the design of high - frequency numerical solvers , such as those based on integral equations , in order to produce more accurate approximation of the solutions around the shadow and deep shadow regions than the ones based on the usual ansatz . .
And you have already written the first three sentences of the full article: studying the helmholtz equation at the high - frequency regime is fundamental in both the theoretical understanding of the corresponding solutions and the derivation of appropriate numerical schemes .
the well - know asymptotic expansions developed by melrose and taylor @xcite have significantly contributed in this matter and were the key in the design of several high - frequency integral equation methods . indeed , integral equation methods are very efficient and widely used in the solution of acoustic scattering problems ( see e.g. @xcite and the references therein )
. however , the resulting linear systems are dense , ill - conditioned and with large size in particular when the frequency increases ..
Please generate the next two sentences of the article | several effective strategies have been proposed to overcome these difficulties @xcite . despite this significant progress ,
integral formulations are limited at higher frequencies since the numerical resolution of field oscillations can easily lead to impractical computational times . |
7,577 | Suppose that you have an abstract for a scientific paper: the standard analysis of the cmb data assumes that the distance to the last scattering surface can be calculated using the distance - redshift relation as in the friedmann model .
however , in the inhomogeneous universe , even if @xmath0 , the distance relation is not the same as in the unperturbed universe .
this can be of serious consequences as a change of distance affects the mapping of cmb temperature fluctuations into the angular power spectrum @xmath1 .
in addition , if the change of distance is relatively uniform no new temperature fluctuations are generated .
it is therefore a different effect than the lensing or isw effects which introduce additional cmb anisotropies .
this paper shows that the accuracy of the cmb analysis can be impaired by the accuracy of calculation of the distance within the cosmological models .
since this effect has not been fully explored before , to test how the inhomogeneities affect the distance - redshift relation , several methods are examined : the dyer roeder relation , lensing approximation , and non - linear swiss - cheese model . in all cases ,
the distance to the last scattering surface is different than when homogeneity is assumed
. the difference can be as low as 1% and as high as 80% . excluding extreme cases , the distance changes by about 20 30% .
since the distance to the last scattering surface is set by the position of the cmb peaks , in order to have a good fit , the distance needs to be adjusted . after correcting the distance , the cosmological parameters change .
therefore , a not properly estimated distance to the last scattering surface can be a major source of systematics .
this paper shows that if inhomogeneities are taken into account when calculating the distance then models with positive spatial curvature and with @xmath2 are preferred . the @xmath3cdm model ( i.e. a flat friedmann solution with the cosmological constant ) , in most cases , is at odds with the current data . .
And you have already written the first three sentences of the full article: it has been said that we entered the era of precision cosmology .
this is mainly due to observations of the cosmic microwave background radiation ( cmb ) .
as the cmb power spectrum is very sensitive to cosmological parameters it provides very tight constraints ..
Please generate the next two sentences of the article | currently the errors are at the level of a few percent @xcite .
the cmb power spectrum is shaped by several processes that can be divided into two groups . |
7,578 | Suppose that you have an abstract for a scientific paper: for chaotic classical systems , the distribution of return times to a small region of phase space is universal .
we propose a simple tool to investigate multiple returns in quantum systems .
numerical evidence for the baker map and kicked top points , also in the quantum case , at a universal distribution .
+ _ pacs _ : 05.45.mt,05.45.pq + _ keywords _ : return times , baker map , kicked top .
And you have already written the first three sentences of the full article: in classical dynamical systems , one may study how long it takes a system to return to the phase space region it occupied at time zero .
in general , this time will increase when the phase space area under consideration is decreased .
m. kac has shown that , for an ergodic dynamical system , the average return time , assuming that the system starts in a set @xmath0 , is given by @xmath1 where the average is taken over the ergodic measure @xmath2 ..
Please generate the next two sentences of the article | related to this are results about asymptotically rare events . consider a sequence @xmath3 of subsets of phase space such that @xmath4 .
if the time for a point @xmath5 in phase space to visit @xmath3 is denoted by @xmath6 , then the question arises how the product @xmath7 behaves . |
7,579 | Suppose that you have an abstract for a scientific paper: we study the structural correlations and the nonlinear response to a driving force of a two - dimensional phase - field - crystal model with random pinning .
the model provides an effective continuous description of lattice systems in the presence of disordered external pinning centers , allowing for both elastic and plastic deformations .
we find that the phase - field crystal with disorder assumes an amorphous glassy ground state , with only short - ranged positional and orientational correlations even in the limit of weak disorder . under increasing driving force
, the pinned amorphous - glass phase evolves into a moving plastic - flow phase and then finally a moving smectic phase .
the transverse response of the moving smectic phase shows a vanishing transverse critical force for increasing system sizes . .
And you have already written the first three sentences of the full article: pinning and sliding of lattice systems , which can form periodic structures in the absence of perturbations , are subjects of considerable interest . in the presence of pinning disorder and driving forces , they can exhibit a wide variety of interesting equilibrium and non - equilibrium behavior with partially ordered and glassy structures .
important examples in two dimensions include vortex lattices in superconducting films @xcite , atomic layers adsorbed between sliding surfaces @xcite or on oscillating substrates @xcite , and colloidal crystals on a rough substrate @xcite .
although in three dimensions a topological ordered phase , the bragg glass @xcite , with quasi - long range positional order is possible in the weak disorder regime , the two - dimensional limit is qualitatively different due to the proliferation of thermally and disorder - induced dislocations even in the weak - disorder regime ..
Please generate the next two sentences of the article | analytical and numerical studies for the equilibrium behavior @xcite have shown that , in two dimensions , positional and orientational order are both destroyed by weak pinning disorder and topological defects at any nonzero temperature leading to a liquid - like phase in the thermodynamic limit . in the absence of thermal fluctuations ( zero temperature ) an amorphous glass is expected @xcite . for the system under a driving force moving at high velocities ,
it has been shown analytically that some components of the disorder remain static in the co - moving reference frame , leading to a moving glass phase @xcite . in three - dimensional systems , |
7,580 | Suppose that you have an abstract for a scientific paper: comprehensive neutron scattering studies were carried out on a series of high - quality single crystals of cu@xmath0zn@xmath1geo@xmath2 .
the zn concentration , @xmath3 , was determined for each sample using electron probe micro - analysis .
the measured zn concentrations were found to be 40 - 80% lower than the nominal values .
nevertheless the measured concentrations cover a wide range which enables a systematic study of the effects due to zn - doping .
we have confirmed the coexistence of spin - peierls ( sp ) and antiferromagnetic ( af ) orderings at low temperatures and the measured phase diagram is presented .
most surprisingly , long - range af ordering occurs even in the lowest available zn concentration , x=0.42% , which places important constraints on theoretical models of the af - sp coexistence .
magnetic excitations are also examined in detail .
the af excitations are sharp at low energies and show no considerable broadening as @xmath3 increases indicating that the af ordering remains long ranged for @xmath3 up to 4.7% .
on the other hand , the sp phase exhibits increasing disorder as @xmath3 increases , as shown from the broadening of the sp excitations as well as the dimer reflection peaks . .
And you have already written the first three sentences of the full article: in 1993 the discovery of an inorganic spin - peierls ( sp ) compound , cugeo@xmath2 , was first reported by hase _
@xcite this material has chains of cu@xmath4 ( @xmath5 ) along its @xmath6-axis which distort into dimers below the sp transition temperature , @xmath7k.@xcite the dimerized structure has a singlet ground state and a triplet excited state ; singlet - to - triplet excitations were demonstrated by nishi _
et al._@xcite using inelastic neutron scattering ..
Please generate the next two sentences of the article | cugeo@xmath2 is interesting not only because it is the first known inorganic spin - peierls system , but also because evidence is mounting that it does not behave like a typical sp system .
it has been believed that good one - dimensionality was needed for a material to undergo a spin - peierls transition . |
7,581 | Suppose that you have an abstract for a scientific paper: we study the ground - state ( gs ) properties of the frustrated spin-@xmath0 @xmath1@xmath2@xmath3 heisenberg model on the two - dimensional honeycomb lattice with ferromagnetic nearest - neighbor ( @xmath4 ) exchange and frustrating antiferromagnetic next - nearest - neighbor ( @xmath5 ) and next - next - nearest - neighbor ( @xmath6 ) exchanges , for the case @xmath7 .
we use the coupled - cluster method implemented to high orders of approximation , complemented by the lanczos exact diagonalization of a large finite lattice with 32 sites , in order to calculate the gs energy , magnetic order parameter , and spin - spin correlation functions . in one scenario
we find a quantum phase transition point between regions characterized by ferromagnetic order and a form of antiferromagnetic ( `` striped '' ) collinear order at @xmath8 , which is below the corresponding hypothetical transition point at @xmath9 ( @xmath10 ) for the classical version of the model , in which we momentarily ignore the intervening noncollinear spiral phase in the region @xmath11 .
hence we see that quantum fluctuations appear to stabilize somewhat the collinear antiferromagnetic order in preference to the ferromagnetic order in this model .
we compare results for the present ferromagnetic case ( with @xmath4 ) to previous results for the corresponding antiferromagnetic case ( with @xmath12 ) .
the magnetic order parameter is found to behave similarly for the ferromagnetic and the antiferromagnetic models for large values of the frustration parameter @xmath2 . however , there are considerable differences in the behavior of the order parameters for the two models for @xmath13 . for example
, the quasiclassical collinear magnetic long - range order for the antiferromagnetic model ( with @xmath12 ) breaks down at @xmath14 , whereas the `` equivalent '' point for the ferromagnetic model ( with @xmath4 ) occurs at @xmath15 .
unlike in the antiferromagnetic model ( with @xmath12 ) , where a plaquette valence - bond crystal phase....
And you have already written the first three sentences of the full article: in recent years frustrated quantum spin systems on regular two - dimensional ( 2d ) lattices have aroused a great deal of research interest .
@xcite in particular the interplay of magnetic frustration and quantum fluctuations has been seen to be a very effective route to destabilize or destroy magnetic order and thereby to create new quantum phases .
such 2d magnetic systems can thus in turn develop a diverse array of phases with widely different ordering properties , such as antiferromagnets with quasiclassical nel ordering , quantum `` spirals '' , valence - bond crystals / solids , phases with nematic ordering , and spin liquids ..
Please generate the next two sentences of the article | other factors that influence the ground - state ( gs ) phase structures are the nature of the underlying crystallographic lattice , the number and nature of the bonds on this lattice , and the spin quantum numbers of the atoms localized to the sites on the lattice .
the theoretical investigation of these models has proceeded hand in hand with the discovery and experimental investigation of ever more quasi-2d magnetic materials with novel properties . |
7,582 | Suppose that you have an abstract for a scientific paper: perturbing a g model towards a realistic protein hamiltonian by adding non - native interactions , we find that the folding rate is in general enhanced as ruggedness is initially increased , as long as the protein is sufficiently large and flexible .
eventually the rate drops rapidly towards zero when ruggedness significantly slows conformational transitions .
energy landscape arguments for thermodynamics and kinetics are coupled with a treatment of non - native collapse to elucidate this effect .
= -1.6 cm = -0.05 in = 0.4 cm = 6.6 in 0 _ * abstract * .
And you have already written the first three sentences of the full article: theorists seek to capture the essence of protein folding with simple models of a self - interacting polymer chain @xcite .
there are two distinct limits pertaining to the nature of the interactions in this minimalist approach .
one is that of purely random interactions , and is considered too frustrated to describe real proteins ..
Please generate the next two sentences of the article | another is the g model @xcite , where the polymer is self - attractive only for those parts of it in their native configurations .
this is considered too unfrustrated to describe real proteins , and also impossible to achieve in practice . as these two models bracket the behavior of real proteins , we consider perturbing from the g model towards real protein interactions by adding some non - native heterogeneity . |
7,583 | Suppose that you have an abstract for a scientific paper: we report on a search for evidence of binarity in _ far - ultraviolet spectroscopic explorer _ ( _ fuse _ ) observations of dao white dwarfs .
spectra recorded by _ fuse _ are built up from a number of separate exposures .
observation of changes in the position of photospheric heavy element absorption lines between exposures , with respect to the stationary interstellar medium lines , would reveal radial velocity changes - evidence of the presence of a binary system .
this technique is successful in picking out all the white dwarfs already known to be binaries , which comprise 5 out of the sample of 16 , but significant radial velocity shifts were found for only one additional star , ton320 .
this object is also known to have an infrared excess @xcite .
daos can be separated broadly into low or normal mass objects .
low mass white dwarfs can be formed as a result of binary evolution , but it has been suggested that the lower mass daos evolve as single stars from the extended horizontal branch @xcite , and we find no evidence of binarity for 8 out of the 12 white dwarfs with relatively low mass . the existence of higher mass daos can also be explained if they are within binary systems , but of the four higher mass stars in the sample studied , pg1210 + 533 and lb2 do not exhibit significant radial velocity shifts , although there were only two exposures for the former object and the latter has an infrared excess @xcite .
[ firstpage ] stars : atmospheres - white dwarfs - ultraviolet : stars . .
And you have already written the first three sentences of the full article: dao white dwarfs , the prototype of which is hz34 @xcite , are a group of white dwarfs that are observed to have both hydrogen and helium lines in their optical spectra , in contrast to the more common das , which exhibit only hydrogen absorption .
hence , the presence of detectable he must arise from the existence of a thin overlying h envelope or there must be a mixing process , dredging up he from the deeper layers of the stellar photosphere .
radiative forces appear to be too low to support sufficient quantities of helium to be able to produce the observed lines @xcite ..
Please generate the next two sentences of the article | a thin h envelope might arise through float up of residual h in a he - rich do atmosphere as objects transfer between the helium and hydrogen cooling channels @xcite .
however , the discovery by @xcite that the heii line in the optical spectra of one dao was better reproduced by a homogeneous rather than a layered atmospheric model was contrary to this view . |
7,584 | Suppose that you have an abstract for a scientific paper: gravitational - wave detectors with sensitivities sufficient to measure the radiation from astrophysical sources are rapidly coming into existence . by the end of this decade
, there will exist several ground - based instruments in north america , europe , and japan , and the joint american - european space - based antenna lisa should be either approaching orbit or in final commissioning in preparation for launch .
the goal of these instruments will be to open the field of _ gravitational - wave astronomy _ : using gravitational radiation as an observational window on astrophysics and the universe . in this article , we summarize the current status of the various detectors currently being developed , as well as future plans . we also discuss the scientific reach of these instruments , outlining what gravitational - wave astronomy is likely to teach us about the universe . .
And you have already written the first three sentences of the full article: a common misconception outside of the gravitational - wave research community is that the primary purpose of observatories such as ligo is to detect directly gravitational waves .
although the first unambiguous direct detection will certainly be a celebrated event , the real excitement will come when gravitational - wave detection can be used as an observational tool for astronomy . because the processes which drive gravitational - wave emission are fundamentally different from processes that radiate electromagnetically
, gravitational - wave astronomy will provide a view of the universe that is rather different from our `` usual '' views . because they arise from fundamentally different physical processes , the information carried by gravitational radiation is `` orthogonal '' to.
Please generate the next two sentences of the article | that carried by electromagnetic radiation .
consider the following differences : * electromagnetic waves are oscillations of electric and magnetic fields that propagate through spacetime . |
7,585 | Suppose that you have an abstract for a scientific paper: we use a microscopic density functional theory based on wertheim s first order thermodynamic perturbation theory to study wetting behavior of athermal mixtures of colloids and excluded - volume polymers . in opposition to the wetting behavior of the asakura - oosawa - vrij model we find the polymer - rich phase to wet a hard wall .
the wetting transition is of the first order and is accompanied by the prewetting transition .
we do not find any hints for the layering transitions in the partial wetting regime .
our results resemble the wetting behavior in athermal polymer solutions .
we point out that an accurate , monomer - resolved theory for colloid - polymer mixtures should incorporate the correct scaling behavior in the dilute polymer regime and an accurate description of the reference system . .
And you have already written the first three sentences of the full article: mixtures of nonadsorbing polymers and colloidal particles often exhibit rich phase behavior @xcite . for certain polymer - to - colloid size ratios @xmath0 ( where @xmath1 is the radius of gyration of the polymer and @xmath2 is the radius of colloid ) entropy - driven effective interactions may lead to stable colloidal gas , liquid and solid phases even if all bare interactions are purely repulsive @xcite .
a simple theoretical model giving an insight into this phenomenon is the asakura - oosawa - vrij ( aov ) model of colloid - polymer mixtures in which the polymers ( modeled as spheres ) are ideal and can overlap freely , but the polymer - colloid and colloid - colloid interactions are of the hard sphere type @xcite .
effective attractive interactions in such systems arise due to a tendency to decrease the volume excluded to the polymer coils @xcite . the aov model has attracted much attention due to its simplicity @xcite , however when comparing to experiments the agreement is only qualitative ..
Please generate the next two sentences of the article | this is due to the fact that the real polymers are nonideal .
the incorporation of the polymer nonideality can be tackled at the monomer - resolved @xcite or coarse - grained @xcite levels of description . |
7,586 | Suppose that you have an abstract for a scientific paper: we provide a characterization and analysis of the effects of dissipation on oscillator assisted ( qubus ) quantum gates . the effects can be understood and minimized by looking at the dynamics of the signal coherence and its entanglement with the continuous variable probe . adding loss in between successive interactions we obtain the effective quantum operations , providing a novel approach to loss analysis in such hybrid settings .
we find that in the presence of moderate dissipation the gate can operate with a high fidelity .
we also show how a simple iteration scheme leads to independent single qubit dephasing , while retaining the conditional phase operation regardless of the amount of loss incurred by the probe . .
And you have already written the first three sentences of the full article: quantum information processing can potentially provide a considerable speedup over classical information processing for certain problems @xcite along with the ability to efficiently simulate physical systems that can not be done classically @xcite . in view of this , much work has been done on finding a viable physical implementation of a quantum computer and many different realizations have been proposed @xcite , some of which explored experimentally on a small scale @xcite .
most large scale architectures rely on protocols enabling the transport of quantum systems or distributed schemes to perform logical gates on isolated qubits .
such schemes make use of ` flying ' qubits @xcite or more generally of quantum bus concepts @xcite ..
Please generate the next two sentences of the article | decoherence effects on the bus are crucial and being able to overcome them will bring us one step closer to true scalability .
most of the results in quantum information theory were developed in a discrete setting , making use of qubits . |
7,587 | Suppose that you have an abstract for a scientific paper: testing procedures for predictive regressions with lagged autoregressive variables imply a suboptimal inference in presence of small violations of ideal assumptions . we propose a novel testing framework resistant to such violations , which is consistent with nearly integrated regressors and applicable to multi - predictor settings , when the data may only approximately follow a predictive regression model .
the monte carlo evidence demonstrates large improvements of our approach , while the empirical analysis produces a strong robust evidence of market return predictability hidden by anomalous observations , both in- and out - of - sample , using predictive variables such as the dividend yield or the volatility risk premium .
* keywords : * predictive regression , stock return predictability , bootstrap , subsampling , robustness .
* jel : * c12 , c13 , g1 . .
And you have already written the first three sentences of the full article: a large literature has investigated whether economic variables such as , e.g. , the price - dividend ratio , proxies of labour income , or the interest rate can predict stock returns . the econometric approach to test for predictability is mostly based on a predictive regression of stock returns onto a set of lagged financial variables ; see , e.g. , stambaugh ( 1999 ) .
important differences between testing approaches in the literature arise because of the different test statistics , asymptotic theories or resampling approaches used to test the null hypothesis of no predictability .
these differences lead in a number of cases to diverging results and conclusions ..
Please generate the next two sentences of the article | mankiw and shapiro ( 1986 ) and stambaugh ( 1986 ) note that in a setting with endogenous predictor and correlated innovations standard asymptotic theory causes small sample biases that may imply an overrejection of the hypothesis of no predictability . to mitigate the problem ,
recent studies propose tests based on bias - corrected estimators of predictive regressions . |
7,588 | Suppose that you have an abstract for a scientific paper: modular categories are a well - known source of quantum 3manifold invariants . in this paper
we study structures on modular categories which allow to define refinements of quantum 3manifold invariants involving cohomology classes or generalized spin and complex spin structures . a crucial role in our construction is played by objects which are invertible under tensor product .
all known examples of cohomological or spin type refinements of the witten - reshetikhin - turaev 3manifold invariants are special cases of our construction . in addition
, we establish a splitting formula for the refined invariants , generalizing the well - known product decomposition of quantum invariants into projective ones and those determined by the linking matrix . .
And you have already written the first three sentences of the full article: in the late 80 s , inspired by witten s ideas @xcite , reshetikhin and turaev @xcite came up with a construction of new 3manifold invariants , known as wrt quantum invariants .
few years later , turaev @xcite formalized this construction by introducing the notion of _ modular category_. his main result is that any modular category gives rise to a quantum @xmath0manifold invariant .
a modular category is a special kind of ribbon category which has a finite set of simple objects @xmath1 , including the unit object @xmath2 , satisfying duality , domination and non - degeneracy axioms ..
Please generate the next two sentences of the article | a ribbon category is a monoidal category with braiding , twist and compatible duality .
ribbon categories are universal receivers for invariants of ribbon graphs @xcite . |
7,589 | Suppose that you have an abstract for a scientific paper: in this paper , we present a new approach to the discrete version of the wormlike chain model ( wcm ) of semiflexible polymers . our solution to the model
is based on a new computational technique called the generalized borel transform ( gbt ) which we use to study the statistical mechanics of semiflexible polymer chains .
specifically , we evaluate the characteristic function of the model approximately .
afterward , we compute the polymer propagator of the model using the gbt and find an expression valid for polymers with any number of segments and values of the semiflexibility parameter .
this expression captures the limits of flexible and infinitely stiff polymers exactly . in between ,
a smooth and approximate crossover behavior is predicted .
another property of our propagator is that it fulfills the condition of finite extensibility of the polymer chain .
we have also calculated the single chain structure factor .
this property is a decreasing function of the wave vector , @xmath0 until a plateau is reached .
our computations clearly show that the structure factor decreases faster with increasing wave vector when the semiflexibility parameter is increased .
furthermore , when the wave vector is large enough , there is a regime where the structure factor follows an approximate power law of the form @xmath1 even for short polymer chains .
@xmath2 is equal to two for flexible polymers and to one for rigid chains .
we also compare our results to the predictions of other models . .
And you have already written the first three sentences of the full article: in recent years , experimental studies of biological macromolecules have motivated intense research in the field of statistical mechanics of single semiflexible polymer chains .
indeed , studies like force - elongation measurements of different biological ( dna , titin , tenascin ) and synthetic ( polyethylene glycol , polyvinyl alcohol ) polymers using atomic force microscopes , optical tweezers and other recently developed tools are abundant@xcite .
the measured force - elongation curve is generally fitted to the prediction of the wormlike chain model ( wcm ) of semiflexible chains@xcite , originally proposed by kratky and porod@xcite . from this fit ,.
Please generate the next two sentences of the article | parameters like the persistence length of the biopolymer are extracted .
another kind of experiments has targeted the mechanical properties of eukaryotic cells@xcite . |
7,590 | Suppose that you have an abstract for a scientific paper: a striking feature of the atmosphere of titan is that no heavy noble gases other than argon were detected by the gas chromatograph mass spectrometer ( gcms ) aboard the huygens probe during its descent to titan s surface in january 2005 .
here we provide an explanation of the mysterious absence or rarity of these noble gases in titan s atmosphere : the thermodynamic conditions prevailing at the surface - atmosphere interface of the satellite allow the formation of multiple guest clathrates that preferentially store some species , including all heavy noble gases , over others . the clean water ice needed for formation of these clathrates
could be delivered by successive episodes of cryovolcanic lavas that have been hypothesized to regularly cover the surface of titan .
the formation of clathrates in the porous lavas and their propensity for trapping ar , kr and xe would progressively remove these species from the atmosphere of titan over its history . in some circumstances ,
a global clathrate crust with an average thickness not exceeding a few meters could be sufficient on titan for a complete removal of the heavy noble gases from the atmosphere . .
And you have already written the first three sentences of the full article: a striking feature of the atmosphere of titan is that no heavy noble gases other than argon were detected by the gas chromatograph mass spectrometer ( gcms ) aboard the huygens probe during its descent to titan s surface in january 2005 ( niemann et al .
2005 , 2010 ) .
the detected argon includes primordial @xmath0ar , present in subsolar abundance in titan s atmosphere ( @xmath0ar/@xmath1n is found to be about six orders of magnitude lower than the solar value ) , and the radiogenic isotope @xmath2ar , which is a decay product of @xmath2k ( niemann et al ..
Please generate the next two sentences of the article | the other primordial noble gases @xmath3ar , kr and xe were not detected by the gcms instrument , yielding upper limits of 10@xmath4 for their atmospheric mole fractions ( niemann et al .
2005 , 2010 ) . in order to interpret this deficiency |
7,591 | Suppose that you have an abstract for a scientific paper: typical models with composite higgs bosons are briefly reviewed .
we also introduce the isospin symmetric higgs model recently proposed in ref . @xcite . .
And you have already written the first three sentences of the full article: recently , the atlas and the cms collaborations at the large hadron collider ( lhc ) discovered a new boson @xmath0 in the mass range 125126 gev @xcite .
in addition , the standard model ( sm ) higgs boson has been excluded at 95% c.l . in the mass range 110149 gev , except for the narrow region 122.8127.8 gev @xcite . the mass range from 127 to 600 gev
was previously excluded @xcite ..
Please generate the next two sentences of the article | it is also noticeable that the mass @xmath1@xmath2 gev perfectly agrees with the lep precision measurements @xcite . on the other hand ,
the contact interactions in the processes of @xmath3 and @xmath4 are severely constrained , i.e. , the compositeness scale @xmath5 should be larger than , say , 10 tev @xcite . against this situation , is there still a room for some strong dynamics responsible for the electroweak symmetry breaking ( ewsb ) ? |
7,592 | Suppose that you have an abstract for a scientific paper: we study the dynamics of the front separating a spatio - temporally chaotic region from a stable steady region using a simple model applicable to periodically forced systems . in particular , we investigate both the coarsening of the front induced by the inherent ` noise ' of the chaotic region , and the long wavelength dynamics causing the front to develop cusps . ] .
And you have already written the first three sentences of the full article: in this paper we study the dynamics of the front separating a spatio - temporally chaotic state from a stable steady ordered state .
such situations occur in many experimental settings . in an experiment on a vertically vibrating granular monolayer of spheres @xcite
both a state at rest on the plate and a chaotically bouncing state are stable . when a small perturbation is applied to the stationary state , the chaotic state.
Please generate the next two sentences of the article | is observed to invade the stable state through a propagating front . in a rayleigh - bnard convection experiment @xcite both straight rolls and spiral defect chaos are stable under some conditions and it is observed that a region of straight rolls is invaded by a region of spiral defect turbulence . for our study
we employ a type of model called a continuum coupled map ( ccm ) introduced in ref . |
7,593 | Suppose that you have an abstract for a scientific paper: we study an predictive radiative seesaw model at one - loop level with a flavor dependent gauge symmetry @xmath0 , in which we consider bosonic dark matter .
we obtain a specific two zero texture with inverse mass matrix that provides us several predictions such as a specific pattern of dirac cp phase .
we also analyze the constraint of lepton flavor violations , muon @xmath1 , relic density of dark matter , and collider physics , have numerical analysis and show allowed region to satisfy all the constraints .
kias - p17013 .
And you have already written the first three sentences of the full article: the observation of neutrino oscillation confirms at least two non - zero masses of active neutrinos indicating physics beyond the standard model ( sm ) to generate the neutrino masses .
radiative seesaw models are one of the attractive candidate to generate the neutrino masses where a neutrino mass matrix is induced at loop level and a dark matter ( dm ) candidate can be included as a particle propagating inside a loop diagram for generating neutrino mass .
it is also interesting to include flavor dependent gauge symmetry with which we can obtain predictive structure of neutrino mass matrix @xcite ..
Please generate the next two sentences of the article | one of the interesting flavor dependent @xmath2 gauge symmetry is the @xmath3 which can induce sizable deviation of muon anomalous magnetic dipole moment from sm prediction , @xmath4 , where experimental observation indicates @xmath5 suggesting discrepancy from the sm value .
in addition , some interesting phenomenologies regarding the @xmath3 are investigated , e.g. in refs . |
7,594 | Suppose that you have an abstract for a scientific paper: we report on the observation of a quenched moment of inertia as resulting from superfluidity in a strongly interacting fermi gas .
our method is based on setting the hydrodynamic gas in slow rotation and determining its angular momentum by detecting the precession of a radial quadrupole excitation .
the measurements distinguish between the superfluid and collisional origins of hydrodynamic behavior , and show the phase transition . .
And you have already written the first three sentences of the full article: superfluidity is a striking property of quantum fluids at very low temperatures . for bosonic systems , important examples are liquids and clusters of @xmath0he and atomic bose - einstein condensates . in fermionic systems , superfluidity is a more intricate phenomenon as it requires pairing of particles .
fermionic superfluidity is known to occur in atomic nuclei and @xmath1he liquids and it is also at the heart of superconductivity , thus being of great technological importance .
recent advances with ultracold fermi gases have opened up unprecedented possibilities to study the properties of strongly interacting fermionic superfluids @xcite ..
Please generate the next two sentences of the article | early experiments on ultracold fermi gases with resonant interparticle interactions compiled increasing evidence for superfluidity @xcite until the phenomenon was firmly established by the observation of vortex lattices @xcite . here we report on the manifestation of superfluidity in a quenched moment of inertia ( moi ) in a strongly interacting fermi gas that undergoes slow rotation .
the basic idea of a quenched moi as a signature of superfluidity dates back to more than 50 years ago in nuclear physics , where mois below the classical , rigid - body value were attributed to superfluidity @xcite . |
7,595 | Suppose that you have an abstract for a scientific paper: lageos is an accurately - tracked , dense spherical satellite covered with 426 retroreflectors .
the tracking accuracy is such as to yield a medium term ( years to decades ) inertial reference frame determined via relatively inexpensive observations .
this frame is used as an adjunct to the more difficult and data intensive vlbi absolute frame measurements .
there is a substantial secular precession of the satellite s line of nodes consistent with the classical , newtonian precession due to the non - sphericity of the earth .
ciufolini has suggested the launch of an identical satellite ( lageos-3 ) into an orbit supplementary to that of lageos-1 : lageos-3 would then experience an equal and opposite classical precession to that of lageos-1 . besides providing a more accurate real - time measurement of the earth s length of day and polar wobble
, this paired - satellite experiment would provide the first direct measurement of the general relativistic frame - dragging effect .
of the five dominant error sources in this experiment , the largest one involves surface forces on the satellite , and their consequent impact on the orbital nodal precession .
the surface forces are a function of the spin dynamics of the satellite .
consequently , we undertake here a theoretical effort to model the spin ndynamics of lageos . in this paper
we present our preliminary results . .
And you have already written the first three sentences of the full article: the laser geodynamic satellite experiment ( lageos-3 ) is a joint usaf , nasa , and asi proposed program to measure , for the first time , a quasi - stationary property of the earth
its gravitational magnetic dipole moment ( gravitomagnetism ) as predicted by einstein s theory of general relativity .
this gravitomagnetic field causes local inertial frames to be dragged around with the earth at a rate proportional to the angular momentum of the earth , and inversely proportional to the cube of the distance from the center of the earth ..
Please generate the next two sentences of the article | thus the line of nodes of the orbital plane of lageos-3 precesses eastward at @xmath0 .
although in this example the frame dragging effect is small compared to the torque on the orbital plane due to the oblateness of the earth , it is an essential ingredient in the dynamics of accretion disks , binary systems , and other astrophysical phenomena @xcite . today , almost eighty years after einstein introduced his geometric theory of gravity , we have just begun to measure to verify his gravitation theory . of no less stature than the `` tide producing '' |
7,596 | Suppose that you have an abstract for a scientific paper: it is known that the sphere packing problem and the number variance problem ( closely related to an optimization problem in number theory ) can be posed as energy minimizations associated with an infinite number of point particles in @xmath0-dimensional euclidean space @xmath1 interacting via certain repulsive pair potentials .
we reformulate the covering and quantizer problems as the determination of the ground states of interacting particles in @xmath1 that generally involve single - body , two - body , three - body , and higher - body interactions .
this is done by linking the covering and quantizer problems to certain optimization problems involving the void " nearest - neighbor functions that arise in the theory of random media and statistical mechanics .
these reformulations , which again exemplifies the deep interplay between geometry and physics , allow one now to employ theoretical and numerical optimization techniques to analyze and solve these energy minimization problems .
the covering and quantizer problems have relevance in numerous applications , including wireless communication network layouts , the search of high - dimensional data parameter spaces , stereotactic radiation therapy , data compression , digital communications , meshing of space for numerical analysis , and coding and cryptography , among other examples . in the first three space dimensions , the best known solutions of the sphere packing and number variance problems ( or their dual " solutions ) are directly related to those of the covering and quantizer problems , but such relationships may or may not exist for @xmath2 , depending on the peculiarities of the dimensions involved .
our reformulation sheds light on the reasons for these similarities and differences .
we also show that disordered saturated sphere packings provide relatively thin ( economical ) coverings and may yield thinner coverings than the best known lattice coverings in sufficiently large dimensions . in the case of the quantizer problem ,
we....
And you have already written the first three sentences of the full article: there are certain scientific problems that provide deep connections between many different scientific fields .
the study of the low - energy states of classical interacting many - particle systems is an exemplar of a class of such problems because of its manifest importance in physics , materials science , communication theory , cryptography , mathematics and computer science .
such many - particle systems have been used with great success to model liquids , glasses and crystals when quantum effects are negligible @xcite ..
Please generate the next two sentences of the article | the total potential energy @xmath3 of @xmath4 identical particles with positions @xmath5 in some large volume in @xmath0-dimensional euclidean space @xmath1 can be resolved into separate one - body , two - body , @xmath6 , @xmath4-body contributions : @xmath7 where @xmath8 represents the intrinsic @xmath9-body interaction in excess to the interaction energy for @xmath10 particles . to make the statistical - mechanical problem more tractable , the exact many - body potential ( [ full ] )
is usually replaced by a mathematically simpler form . |
7,597 | Suppose that you have an abstract for a scientific paper: since mid-2007 we have carried out a dedicated long - term monitoring programme at 15 ghz using the owens valley radio observatory 40 meter telescope ( ovro 40 m ) .
one of the main goals of this programme is to study the relation between the radio and gamma - ray emission in blazars and to use it as a tool to locate the site of high energy emission . using this large sample of objects we are able to characterize the radio variability , and study the significance of correlations between the radio and gamma - ray bands .
we find that the radio variability of many sources can be described using a simple power law power spectral density , and that when taking into account the red - noise characteristics of the light curves , cases with significant correlation are rare .
we note that while significant correlations are found in few individual objects , radio variations are most often delayed with respect to the gamma - ray variations .
this suggests that the gamma - ray emission originates upstream of the radio emission .
because strong flares in most known gamma - ray - loud blazars are infrequent , longer light curves are required to settle the issue of the strength of radio - gamma cross - correlations and establish confidently possible delays between the two .
for this reason continuous multiwavelength monitoring over a longer time period is essential for statistical tests of jet emission models . .
And you have already written the first three sentences of the full article: although the general picture of synchrotron emission at low energies and inverse compton at high energies is well established , important aspects of blazars are not well understood . in particular , the location of the gamma - ray emission region is not clearly established .
there are models and observations that argue for a location close to central engine ( @xmath0 pc , e.g. , * ? ? ?
* ; * ? ? ?.
Please generate the next two sentences of the article | * ) , and also another set of models and observations pointing to a location further down the jet , at tens of parsecs ( e.g. , * ? ? ?
* ; * ? ? ? |
7,598 | Suppose that you have an abstract for a scientific paper: we consider the late - time tails of spherical waves propagating on even - dimensional minkowski spacetime under the influence of a long range radial potential . we show that in six and higher even dimensions there exist exceptional potentials for which the tail has an anomalously small amplitude and fast decay . along the way we clarify and amend some confounding arguments and statements in the literature of the subject . .
And you have already written the first three sentences of the full article: it is well known that sharp propagation of free waves along light cones in even - dimensional flat spacetimes , known as huygens property , is blurred by the presence of a potential .
physically , the spreading of waves inside the light cone is caused by the backscattering off the potential .
if the potential falls off exponentially or faster at spatial infinity , then the backscattered waves decay exponentially in time , while the long range potentials with an algebraic fall - off give rise to tails which decay polynomially in @xmath0 ..
Please generate the next two sentences of the article | the precise description of these tails is an important issue in scattering theory .
there are two main approaches to this problem in the literature . on the one hand , there are mathematical results in the form of various decay estimates . |
7,599 | Suppose that you have an abstract for a scientific paper: the work treats dynamical systems given by ordinary differential equations in the form @xmath0 where fast motions @xmath1 depend on the slow motion @xmath2 ( coupled with it ) and they are either given by another differential equation @xmath3 or perturbations of an appropriate parametric family of markov processes with freezed slow variables . in the first case
we assume that the fast motions are hyperbolic for each freezed slow variable and in the second case we deal with markov processes such as random evolutions which are combinations of diffusions and continuous time markov chains .
first , we study large deviations of the slow motion @xmath2 from its averaged ( in fast variables @xmath1 ) approximation @xmath4 the upper large deviation bound justifies the averaging approximation on the time scale of order @xmath5 , called the averaging principle , in the sense of convergence in measure ( in the first case ) or in probability ( in the second case ) but our real goal is to obtain both the upper and the lower large deviations bounds which together with some markov property type arguments ( in the first case ) or with the real markov property ( in the second case ) enable us to study ( adiabatic ) behavior of the slow motion on the much longer exponential in @xmath5 time scale , in particular , to describe its fluctuations in a vicinity of an attractor of the averaged motion and its rare ( adiabatic ) transitions between neighborhoods of such attractors . when the fast motion @xmath1 does not depend on the slow one we arrive at a simpler averaging setup studied in numerous papers but the above fully coupled case , which better describes real phenomena ,
leads to much more complicated problems
. 0.1 cm [ part1 ] .
And you have already written the first three sentences of the full article: many real systems can be viewed as a combination of slow and fast motions which leads to complicated double scale equations . already in the 19th century in applications to celestial mechanics it was well understood ( though without rigorous justification ) that a good approximation of the slow motion can be obtained by averaging its parameters in fast variables .
later , averaging methods were applied in signal processing and , rather recently , to model climate weather interactions ( see @xcite , @xcite , @xcite and @xcite ) .
the classical setup of averaging justified rigorously in @xcite presumes that the fast motion does not depend on the slow one and most of the work on averaging treats this case only . on the other hand , in real systems.
Please generate the next two sentences of the article | both slow and fast motions depend on each other which leads to the more difficult fully coupled case which we study here .
this setup emerges , in particular , in perturbations of hamiltonian systems which leads to fast motions on manifolds of constant energy and slow motions across them . in this work |
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