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5,200 | Suppose that you have an abstract for a scientific paper: the reaction @xmath0si + @xmath1ta has been studied at e@xmath2=125 and 135 mev .
coincidences between high energy particles and various x- and @xmath3-rays from abnormally long - lived states were observed .
e.g. 7.8 - 8.6 mev @xmath4-particles with @xmath3-rays of a superdeformed band , 5.1 - 5.5 mev @xmath4-particles with x- and @xmath3-rays of w , re , and pt , and 3.88 mev particles ( interpreted as protons ) with 185.8 kev @xmath3-rays .
the data are interpreted in terms of the production of long - lived ( t@xmath5 of several months ) high spin isomeric states in the second well of the potential in the parent nuclei , which decay to the normal states in the daughters , and in the third well of the potential , which decay to the second well .
pacs numbers : 23.60.+e , 21.10.re , 21.10.tg , 27.80.+w .
And you have already written the first three sentences of the full article: the first evidence for a new kind of long - lived isomeric states was obtained in actinide fractions @xcite produced via secondary reactions in a cern w target which had been irradiated with 24-gev protons @xcite .
isomeric states with t@xmath5 @xmath6 0.6 y and @xmath7 30 d ( 10@xmath8 - 10@xmath9 times longer than the expected half - lives of the corresponding ground states ) were found in neutron - deficient @xmath10am and @xmath10bk nuclei , respectively . about 3x10@xmath9 atoms of @xmath10am and 4x10@xmath8 atoms of @xmath10bk
were produced in the isomeric states , and decayed by the @xmath11 or electron capture processes ..
Please generate the next two sentences of the article | the character of these states was not clear : they are far from closed shells where high spin isomers are usually found , and they have very long lifetimes as compared to the known shape isomers .
in addition @xcite , some new particle groups were found in the decay of various actinide fractions separated from the same w target . |
5,201 | Suppose that you have an abstract for a scientific paper: it has been established for some time that high - power pump can trap a probe beam of lower intensity that is simultaneously propagating in a kerr - type optical medium , inducing a focusing of the probe with the emergence of modes displaying solitonic properties . to understand the mechanism by which such self - sustained modes are generated , and mainly the changes on probe spectrum induced by the cross - phase - modulation effect for an harmonic probe trapped by a multiplex of temporal pulses , a linear equation ( for the probe ) and a nonlinear schrdinger equation ( for the pump ) both coupled by a cross - phase - modulation term , are considered simultaneously . in general
the set of coupled probe - pump equations is not exactly tractable at any arbitrary value of the ratio of the cross - phase to the self - phase modulation strengths .
however , for certain values of this ratio , the probe modulation wavector develops into @xmath0 _ quantum states _ involving @xmath1 soliton - shaped eigenfunctions which spectral properties can be characterized unambiguously .
solutions of the probe equation give evidence that the competition between the self - phase and cross - phase modulations leads to a broadband spectrum , with the possibility of a quasi - continuum of soliton modes when the cross - phase - modulation coupling is strong enough . .
And you have already written the first three sentences of the full article: in two classic papers @xcite , by solving the master - slave optical system @xmath2 the author predicted that ultrafast pulses with energies lower than that required to self - sustain soliton shape in the anomalous dispersion regime of an optical medium may preserve their shape , provided an intense copropagating pump of a different color ( i.e. wavelength ) and a longer duration typical of soliton is present . since this key input as well as
the subsequent experimental evidences reported in @xcite it has become evident that besides their most common applications in long - distance transmission of high - power signals @xcite , solitons could be prime candidates for controlling light by light @xcite .
more advanced studies have been carried out in recent years based on numerical simulations , and revealed that due to their unique stability properties solitons provide excellent and reliable guiding structures for reconfigurable low - power signals and re - routinable high - power pulses @xcite ..
Please generate the next two sentences of the article | particularly attracting is the possibility to construct soliton networks that can be used as nonlinear waveguide arrays , as established in the landscape of recent experiments @xcite emphasizing the outstanding robustness of the periodic lattices of optical solitons with flexible ( hence controllable ) refractive index modulation depth and period that are induced all - optically . in general , these periodic optical - soliton structures form in continuous nonlinear media where they develop into optically imprinted modulations with some effective refractive index . given the tunable character of the effective refractive index as well as the flexible modulation period , a great number of new opportunities for all - optical manipulation of light can be envisaged since in this case , periodic optical - soliton waveguides can operate in both weak and strong - coupling regimes depending on the depth of refractive index modulation .
transmission techniques exploiting optically - induced waveguiding configurations with solitons are now common in several communication media such as laser @xcite , photon @xcite systems and photorefractive semiconductor @xcite media . |
5,202 | Suppose that you have an abstract for a scientific paper: we provide an extension to lattice systems of the reptation quantum monte carlo ( rqmc ) algorithm , originally devised for continuous hamiltonians . for systems affected by the sign problem , a method to systematically improve upon the so - called fixed - node approximation
is also proposed .
the generality of the method , which also takes advantage of a canonical worm algorithm scheme to measure off - diagonal observables , makes it applicable to a vast variety of quantum systems and eases the study of their ground - state and excited - states properties . as a case study
, we investigate the quantum dynamics of the one - dimensional heisenberg model and we provide accurate estimates of the ground - state energy of the two - dimensional fermionic hubbard model . .
And you have already written the first three sentences of the full article: the path - integral formulation of quantum mechanics is the foundation of many numerical methods that allow one to study with great accuracy the rich physics of interacting quantum systems . at finite temperature ,
a path - integral monte carlo ( pimc ) technique for continuous systems has been developed and applied by ceperley and pollock.@xcite recently , this approach has been renovated in a new class of methods known as _ worm algorithms_.
@xcite the zero - temperature counterparts of the pimc algorithm are the reptation quantum monte carlo ( rqmc ) @xcite and the path - integral ground state ( pigs ) methods , @xcite which have been demonstrated useful to simulate coupled electron - ion systems , @xcite as well as to infer spectral properties from imaginary time dynamics ..
Please generate the next two sentences of the article | @xcite a number of important physical problems particularly in the fields of strongly correlated fermions and cold atoms can be fruitfully modeled by lattice hamiltonians .
a first application of path - integral techniques to ( boson ) lattice models was proposed by krauth _ |
5,203 | Suppose that you have an abstract for a scientific paper: chaotic deterministic dynamics of a particle can give rise to diffusive brownian motion .
in this paper , we compute analytically the diffusion coefficient for a particular two - dimensional stochastic layer induced by the kicked harper map .
the variations of the transport coefficient as a parameter is varied are analyzed in terms of the underlying classical trajectories with particular emphasis in the appearance and bifurcations of periodic orbits .
when accelerator modes are present , anomalous diffusion of the lvy type can occur .
the exponent characterizing the anomalous diffusion is computed numerically and analyzed as a function of the parameter .
ipno / th 96 - 50 novembre 1996 + .
And you have already written the first three sentences of the full article: transport properties of deterministic chaotic hamiltonian dynamics can exhibit a rich variety of phenomena . in many situations where chaos is strong ,
transport through phase space tends to be uniform and can imitate random processes of the brownian type . the motion on average is a normal diffusion .
however , in more generic situations where regular as well as chaotic behaviour coexist the phase space has a fractal structure , and this structure can induce important variations of the transport process . in this paper.
Please generate the next two sentences of the article | our purpose is to investigate transport properties of a deterministic two - dimensional area preserving map whose dynamics can be either mixed or strongly chaotic as a parameter is varied .
it is defined by the time - dependent hamiltonian @xmath0 called the kicked harper model . |
5,204 | Suppose that you have an abstract for a scientific paper: we propose a novel algorithm for compressive imaging that exploits both the sparsity and persistence across scales found in the 2d wavelet transform coefficients of natural images . like other recent works ,
we model wavelet structure using a hidden markov tree ( hmt ) but , unlike other works , ours is based on loopy belief propagation ( lbp ) . for lbp , we adopt a recently proposed `` turbo '' message passing schedule that alternates between exploitation of hmt structure and exploitation of compressive - measurement structure . for the latter , we leverage donoho , maleki , and montanari s recently proposed approximate message passing ( amp ) algorithm .
experiments with a large image database suggest that , relative to existing schemes , our turbo lbp approach yields state - of - the - art reconstruction performance with substantial reduction in complexity . .
And you have already written the first three sentences of the full article: in compressive imaging @xcite , we aim to estimate an image @xmath0 from @xmath1 noisy linear observations @xmath2 , @xmath3 assuming that the image has a representation @xmath4 in some wavelet basis @xmath5 ( i.e. , @xmath6 ) containing only a few ( @xmath7 ) large coefficients ( i.e. , @xmath8 ) . in ( [ eqn : system ] ) , @xmath9 is a known measurement matrix and @xmath10 is additive white gaussian noise .
though @xmath11 makes the problem ill - posed , it has been shown that @xmath12 can be recovered from @xmath13 when @xmath7 is adequately small and @xmath14 is incoherent with @xmath5 @xcite .
the wavelet coefficients of natural images are known to have an additional structure known as _ persistence across scales _ ( pas ) @xcite , which we now describe . for 2d images ,.
Please generate the next two sentences of the article | the wavelet coefficients are naturally organized into quad - trees , where each coefficient at level @xmath15 acts as a parent for four child coefficients at level @xmath16 .
the pas property says that , if a parent is very small , then all of its children are likely to be very small ; similarly , if a parent is large , then it is likely that some ( but not necessarily all ) of its children will also be large . |
5,205 | Suppose that you have an abstract for a scientific paper: we give an exponential upper and a quadratic lower bound on the number of pairwise non - isotopic simple closed curves can be placed on a closed surface of genus @xmath0 such that any two of the curves intersects at most once . although the gap is large , both bounds are the best known for large genus . in genus one and two , we solve the problem exactly .
our methods generalize to variants in which the allowed number of pairwise intersections is odd , even , or bounded , and to surfaces with boundary components .
= 1 .
And you have already written the first three sentences of the full article: [ sec : intro ] the classical area of _ combinatorial designs _ ( see , e.g. , @xcite ) asks about extremal subset systems of a finite set that have specified intersection patterns . in this paper , we are interested in extremal families of curves in a closed , orientable surface with specified intersection patterns . more specifically , benson farb and chris leininger brought the following topological variant to our attention : [ farbq ] let @xmath1 be a closed oriented surface of genus @xmath0 , and let @xmath2 be a collection of pairwise non - isotopic essential simple closed curves @xmath3 such that @xmath4 intersects @xmath5 at most once for any @xmath6 .
how large can @xmath2 be ?
in fact , this question goes back further , to work of juvan , malni , and mohar @xcite , which we learned about after circulating an earlier version @xcite of the present paper ..
Please generate the next two sentences of the article | juvan , et al .
@xmath7-system _ of curves on a genus @xmath0 closed , oriented surface to be a collection of non - isotopic , essential , simple closed curves @xmath8 such that each of the @xmath4 intersects any @xmath5 , @xmath9 at most @xmath7 times . |
5,206 | Suppose that you have an abstract for a scientific paper: the analysis of the shear induced by a single cluster , acting as a gravitational lens , on the images of a large number of background galaxies is all centered around the curl - free character of a well - known vector field that can be derived from the data ; in particular , the mass reconstruction methods , currently producing many interesting astrophysical applications , are all based on this tensorial property of the induced shear .
such basic property breaks down when the source galaxies happen to be observed through two clusters at different redshifts , partially aligned along the line of sight , because an asymmetric part in the jacobian matrix associated with the ray tracing transformation is expected , now that the incoming light rays are bent twice . in this paper
we address the study of double lenses and obtain five main results .
( i ) first we generalize the procedure to extract the available information , contained in the observed shear field , from the case of a single lens to that of a double lens .
( ii ) then we evaluate the possibility of detecting the signature of double lensing given the known properties of the distribution of clusters of galaxies .
in particular , we show that a few configurations are likely to be present in the sky , for which the small effects characteristic of double lensing may already be within detection limits ( i.e. , we show that the signal involved is expected to be larger than what could be produced by statistical noise , which includes effects associated with the distribution of the source ellipticities and with the spread in redshift of the lensed galaxies ) .
( iii ) as a different astrophysical application , we demonstrate how the method can be used to detect the presence of a dark cluster that might happen to be partially aligned with a bright cluster studied in terms of statistical lensing ; if the properties of the bright cluster are well constrained by independent diagnostics , the location and the structure of the dark cluster can be....
And you have already written the first three sentences of the full article: the study of statistical gravitational lensing effects on large numbers of source galaxies due to intervening matter has been a subject of major and rapid progress both from the methodological and from the observational point of view ( e.g. , see kaiser & squires 1993 ; luppino & kaiser 1997 ; taylor et al .
1998 ; lombardi & bertin 1998a , b , hereafter paper i , ii ) .
this indeed offers a very promising approach to study the overall mass distribution , especially on the scale of clusters of galaxies ..
Please generate the next two sentences of the article | in fact , the most appealing aspect of this line of research is its diagnostic potential , with the possibility to measure mass distributions independently of the traditional tools that have to rely on the use of dynamical models .
the interest in this method has gained further momentum from the most recent developments of telescopes and instrumentation . |
5,207 | Suppose that you have an abstract for a scientific paper: a theoretical model of a single molecule coupled to many vibronic modes is presented . at low energies ,
transport is dominated by electron - vibron processes where transfer of an electron through the dot is accompanied by the excitation or emission of quanta ( vibrons ) .
because the frequency of the @xmath0th mode is taken as an @xmath0th multiple of the frequency of the fundamental mode , several energetically degenerate or quasidegenerate vibronic configurations can contribute to transport .
we investigate the consequences of strong electron - vibron coupling in a fully _ symmetric _ setup .
several striking features are predicted . in particular , a gate - asymmetry and pronounced negative differential conductance features are observed .
we attribute these features to the presence of slow channels originating from the interplay of franck - condon suppression of transport channels with spin and/or orbital degeneracies . .
And you have already written the first three sentences of the full article: the coupling of electronic and mechanical degrees of freedom is at the core of the physics of nanoelectromechanical systems ( nems)@xcite .
pronounced vibrational effects in electronic transport have been observed in several recent experiments on molecules @xcite and single wall carbon nanotube quantum dots @xcite .
stimulated by the experimental works , several groups @xcite have attempted to theoretically explain some features of the measured stability diagrams ( i.e. , of the differential conductance in a bias voltage - gate voltage colour map ) which appear to be ubiquitous . specifically , one observes the following : ( i ) equidistant lines run parallel to the edges of the coulomb diamonds ..
Please generate the next two sentences of the article | ( ii ) the probed diamonds show often negative differential conductance ( ndc ) features appearing between excited vibronic states .
( iii ) this corresponds to a sequence of peaks in the current as a function of the bias voltage . |
5,208 | Suppose that you have an abstract for a scientific paper: a two - component bose - einstein condensate confined in an axially - symmetric potential with two local minima , resembling two concentric annular traps , is investigated .
the system shows a number of phase transitions that result from the competition between phase coexistence , and radial / azimuthal phase separation .
the ground - state phase diagram , as well as the rotational properties , including the ( meta)stability of currents in this system , are analysed . .
And you have already written the first three sentences of the full article: the field of cold atoms has expanded dramatically over the last 15 years .
it has now reached a stage where experimentalists are capable of designing the form of the confining potential .
going to extreme aspect ratios , conditions of quasi - one- and quasi - two - dimensional behavior have been achieved . in other experiments ,.
Please generate the next two sentences of the article | it has also become possible to design toroidal trapping potentials @xcite , in which persistent currents have been observed @xcite .
recent theoretical studies have examined bose - einstein condensates in one - dimensional annular traps . |
5,209 | Suppose that you have an abstract for a scientific paper: we prove an isomorphism of floer cohomologies under geometric composition of lagrangian correspondences in exact and monotone settings . .
And you have already written the first three sentences of the full article: lagrangian correspondences were described by weinstein @xcite as generalizations of symplectomorphisms , in an attempt to build a symplectic category with composable morphisms between non - symplectomorphic manifolds . by definition a lagrangian correspondence from @xmath0 to @xmath1
is a lagrangian submanifold in the product , @xmath2 , with respect to the symplectic structure @xmath3 .
the basic examples are graphs of symplectomorphisms ..
Please generate the next two sentences of the article | composition of symplectomorphisms generalizes to _ geometric composition _ of lagrangian correspondences @xmath4 , @xmath5 , defined by @xmath6 in general this will be a singular subset of @xmath7 which is isotropic at smooth points . however , if we assume transversality of the intersection @xmath8 , then the restriction of the projection @xmath9 to @xmath10 is an immersion @xcite , and hence @xmath11 is an immersed lagrangian correspondence
. we will study the class of _ embedded _ geometric compositions , for which in addition @xmath12 is injective , and hence @xmath13 is a smooth lagrangian correspondence . |
5,210 | Suppose that you have an abstract for a scientific paper: adaptive networks rely on in - network and collaborative processing among distributed agents to deliver enhanced performance in estimation and inference tasks .
information is exchanged among the nodes , usually over noisy links .
the combination weights that are used by the nodes to fuse information from their neighbors play a critical role in influencing the adaptation and tracking abilities of the network .
this paper first investigates the mean - square performance of general adaptive diffusion algorithms in the presence of various sources of imperfect information exchanges , quantization errors , and model non - stationarities . among other results
, the analysis reveals that link noise over the regression data modifies the dynamics of the network evolution in a distinct way , and leads to biased estimates in steady - state .
the analysis also reveals how the network mean - square performance is dependent on the combination weights .
we use these observations to show how the combination weights can be optimized and adapted .
simulation results illustrate the theoretical findings and match well with theory .
diffusion adaptation , adaptive networks , imperfect information exchange , tracking behavior , diffusion lms , combination weights , energy conservation . .
And you have already written the first three sentences of the full article: adaptive network consists of a collection of agents that are interconnected to each other and solve distributed estimation and inference problems in a collaborative manner .
two useful strategies that enable adaptation and learning over such networks in real - time are the incremental strategy @xcite and the diffusion strategy @xcite .
incremental strategies rely on the use of a hamiltonian cycle , i.e. , a cyclic path that covers all nodes in the network , which is generally difficult to enforce since determining a hamiltonian cycle is an np - hard problem ..
Please generate the next two sentences of the article | in addition , cyclic trajectories are not robust to node or link failure . in comparison ,
diffusion strategies are scalable , robust , and able to match well the performance of incremental networks . in adaptive diffusion implementations |
5,211 | Suppose that you have an abstract for a scientific paper: this paper aims to present explicit photon - like ( 3 + 1 ) spatially finite soliton solutions of screw type to the vacuum field equations of extended electrodynamics ( eed ) in relativistic formulation .
we begin with emphasizing the need for spatially finite soliton modelling of microobjects .
then we briefly comment the properties of solitons and photons and recall some facts from eed . making use of the localizing functions from differential topology ( used in the partition of unity ) we explicitly construct spatially finite screw solutions .
further a new description of the spin momentum inside eed , based on the notion for energy - momentum exchange between @xmath0 and @xmath1 , is introduced and used to compute the integral spin momentum of a screw soliton .
the consistency between the spatial and time periodicity naturally leads to a particular relation between the longitudinal and transverse sizes of the screw solution , namely , it is equal to @xmath2 .
planck s
formula @xmath3 in the form of @xmath4 arizes as a measure of the integral spin momentum . .
And you have already written the first three sentences of the full article: the very notion of _ really existing objects _ , i.e. _ physical objects carrying energy - momentum _ , necessarily implies that all such objects must have definite stability properties , as well as propertiies that do not change with time ; otherwise everything would constantly change and we could not talk about objects and structure at all , moreover no memory and no knowledge would be possible . through definite procedures of _ measurement _ we determine , where and when this is possible , quantitative characteristics of the physical objects .
the characteristics obtained differ in : their nature and qualities ; in their significance to understand the structure of the objects they characterize ; in their abilities to characterize interaction among objects ; and in their universality .
natural objects may be classified according to various principles ..
Please generate the next two sentences of the article | the classical point - like objects ( called usually particles ) are allowed to interact continuously with each other just through exchanging ( through some mediator usually called field ) universal conserved quantities : energy , momentum , angular momentum , so that , the set of objects `` before '' interaction is the same as the set of objects `` after '' interaction , no objects have disapeared and no new objects have appeared , only the conserved quantities have been redistributed .
this is in accordance with the assumption of point - likeness , i.e. particles are assumed to have no internal structure , so they are undestroyable . hence |
5,212 | Suppose that you have an abstract for a scientific paper: in this work , we look for possible new physics effects on the electromagnetic charge and anapole form factors , @xmath0 and @xmath1 , for a massless dirac neutrino , when these quantities are calculated in the context of an effective electroweak yang - mills theory , which induces the most general @xmath2invariant lorentz tensor structure of nonrenormalizable type for the @xmath3 vertex . it is found that in this context , besides the standard model contribution , the additional contribution to @xmath4 and @xmath5 ( @xmath6 and @xmath7 , respectively ) are gauge independent and finite functions of @xmath8 after adopting a renormalization scheme .
these form factors , @xmath6 and @xmath7 , get contribution at the one loop level only from the proper neutrino electromagnetic vertex .
besides , the relation @xmath9 ( @xmath10 , @xmath11 ) is still fulfilled and hence the relation @xmath12 ( @xmath13 , @xmath14)is gotten , just as in the sm . using the experimental constraint on the anomalous @xmath3 vertex ,
a value for the additional contribution to the charge radius of @xmath15 is obtained , which is one order of magnitude lower than the sm value .
= = # 1tempboxa= tempdima=0.5tempdima 0.5tempboxa -tempdima tempboxa # 1tempboxa= tempdima=0.5tempdima 0.5tempboxa -tempdima tempboxa # 1 .
And you have already written the first three sentences of the full article: many authors have studied the neutrino charge radius ( ncr ) @xcite . in 1972 ,
bardeen , gastmans and lautrup @xcite showed in the frame of the sm and using the unitary gauge that the ncr is infinite and therefore it is not a physical quantity .
later , in the same year , s.y ..
Please generate the next two sentences of the article | lee @xcite working in the unitary gauge considered the @xmath16 scattering and defined the ncr including besides the usual terms , diagrams in which the photon is replaced by a neutral gauge boson @xmath17 . in this way he obtained a finite , although gauge dependent quantity @xcite .
one of the earliest analyses of the neutrino charge radius , in the context of the general one - loop electromagnetic form factor of a fermion in electroweak theories , was carried out in 1977 by lee and shrock @xcite . |
5,213 | Suppose that you have an abstract for a scientific paper: giantly enhanced cross - phase modulation with suppressed spectral broadening is predicted between optically - induced dark - state polaritons whose propagation is strongly affected by photonic bandgaps of spatially periodic media with multilevel dopants .
this mechanism is shown to be capable of fully entangling two single - photon pulses with high fidelity . .
And you have already written the first three sentences of the full article: the main impediment towards the use of single photons in schemes for deterministic quantum logic and teleportation @xcite as very robust and versatile carriers of quantum information @xcite is the weakness of optical nonlinearities in conventional media . a major trend aimed at the enhancement of optical nonlinearities exploits one - dimensional ( 1d- ) periodic distributed bragg reflectors and 2d- or 3d - periodic photonic crystals ( pcs ) , where light can be slowed down or trapped via multiple reflections in the vicinity of photonic bandgaps ( pbgs ) @xcite .
giantly enhanced nonlinearity has been predicted when dopants with transition frequencies within the pbg are implanted in the structure , so that light near such frequencies resonantly interacts with the dopants and is concurrently affected by the pbg dispersion @xcite .
the resulting soliton - like transmission of very weak pulses within the pbg while filtering out spurious noise is highly advantageous for classical communication @xcite ..
Please generate the next two sentences of the article | however , this mechanism is incompatible with the goals of quantum logic and communications , particularly with photon - photon entanglement , because of the quantum noise associated with resonant field - atom interactions .
another pathway to enhance the nonlinearities is based on electromagnetically induced transparency ( eit ) in atomic media , which comes about when classical driving fields induce coherence between atomic levels and transform the weak fields into atom - dressed dark - state polaritons @xcite . |
5,214 | Suppose that you have an abstract for a scientific paper: we present here the extragalactic background light ( ebl ) predicted by semi - analytic models of galaxy formation , and show how measurements of the absorption of gamma rays of @xmath0 tev energies via pair production on the ebl can probe cosmology and the formation of galaxies . semi - analytic models permit a physical treatment of the key processes of galaxy formation including gravitational collapse and merging of dark matter halos , gas cooling and dissipation , star formation , supernova feedback and metal production and have been shown to reproduce key observations at low and high redshift . using this approach
, we investigate the consequences of variations in input assumptions such as the stellar initial mass function and the underlying cosmology .
we conclude that observational studies of the absorption of @xmath1 tev gamma rays will help to constrain the star formation history of the universe , and the nature and extent of the extinction of starlight due to dust and reradiation of the absorbed energy at infrared wavelengths .
cosmology : observations , diffuse radiation infrared : galaxies galaxies : evolution gamma rays : theory .
And you have already written the first three sentences of the full article: it has long been appreciated that high energy @xmath2-rays from sources at cosmological distances will be absorbed via electron - positron pair production @xcite on the diffuse background of long wavelength photons produced over the history of the universe .
now that several extragalactic tev sources have been discovered , it is beginning to become possible to use this process to probe the extragalactic background light ( ebl ) .
this technique will become increasingly powerful as many more sources will presumably be discovered at greater distances with the new generation of @xmath2-ray telescopes ( glast , celeste , stacee , magic , hess , veritas , and milagro ) ..
Please generate the next two sentences of the article | broadly speaking , there are three approaches to studying the ebl/@xmath2-absorption connection , represented by the three speakers on this topic here at the veritas workshop : * limits on the ebl , and on models for its production , from @xmath2-absorption data @xcite ; * semi - empirical estimates of the ebl @xcite ; and * prediction of the ebl and @xmath2-absorption from physical theories of galaxy formation and evolution in a cosmological framework .
the advantage of the last of these approaches , which we will follow in this talk , is that it permits one to deduce from @xmath2-ray absorption data a great deal about galaxy formation and evolution , including the effects of the stellar initial mass distribution and of dust extinction and reradiation . |
5,215 | Suppose that you have an abstract for a scientific paper: recent results have shown that a substantial fraction of high - redshift lyman alpha galaxies contain considerable amounts of dust .
this implies that lyman alpha galaxies are not primordial , as has been thought in the past .
however , this dust has not been directly detected in emission ; rather it has been inferred based on extinction estimates from rest - frame ultraviolet ( uv ) and optical observations .
this can be tricky , as both dust and old stars redden galactic spectra at the wavelengths used to infer dust .
measuring dust emission directly from these galaxies is thus a more accurate way to estimate the total dust mass , giving us real physical information on the stellar populations and interstellar medium ( ism ) enrichment .
new generation instruments such as the atacama large millimeter array ( alma ) and sub - millimeter array ( sma ) , should be able to detect dust emission from some of these galaxies in the sub - mm . using measurements of the uv spectral slopes , we derive far - infrared flux predictions for of a sample of 23 z @xmath0 4 lyman alpha galaxies .
we find that in only a few hours , we can detect dust emission from 39 @xmath1 22% of our lyman alpha galaxies . comparing these results to those found from a sample of 21 lyman break galaxies ( lbgs )
, we find that lbgs are on average 60% more likely to be detected than ly@xmath2 galaxies , implying that they are more dusty , and thus indicating an evolutionary difference between these objects .
these observations will provide better constraints on dust in these galaxies than those derived from their uv and optical fluxes alone .
undeniable proof of dust in these galaxies could explain the larger than expected ly@xmath2 equivalent widths seen in many ly@xmath2 galaxies today .
[ firstpage ] galaxies : ism galaxies : high - redshift galaxies : evolution .
And you have already written the first three sentences of the full article: lyman alpha ( ly@xmath2 ) galaxies have been studied in detail for nearly a decade now , and we are only just beginning to learn about the properties of individual objects .
most initial narrow - band studies ( e.g. , hu et al . 1998 ; rhoads et al . 2000 ) observed blank fields with two filters : a narrow - band filter ( to capture the ly@xmath2 emission line ) , and a broad - band filter encompassing this narrow - band ( used to measure a narrow - band excess ) .
learning the detailed properties of individual ly@xmath2 galaxies would be difficult with these data.
Please generate the next two sentences of the article | . however , these early studies were able to measure the equivalent widths ( ews ) of their objects , calculated from the ratio of narrow - band flux to broad - band flux ( malhotra & rhoads 2002 ) .
some of these initial results were surprising , as in many cases the ly@xmath2 ew distribution was higher than one might have expected from stellar population models , as many objects exhibited rest - frame ly@xmath2 ews over 200 ( e.g. , kudritzki et al . |
5,216 | Suppose that you have an abstract for a scientific paper: it recently has been demonstrated that signals conveyed by evanescent modes can travel faster than light . in this report
some special features of signals are introduced and investigated , for instance the fundamental property that signals are frequency band limited .
evanescent modes are characterized by extraordinary properties : their energy is _ negative _ , they are not directly measurable , and the evanescent region is not causal since the modes traverse this region instantaneously .
the study demonstrates the necessity of quantum mechanical principles in order to interprete the superluminal signal velocity of classical evanescent modes . .
And you have already written the first three sentences of the full article: tunneling represents the wave mechanical analogy to the propagation of evanescent modes @xcite .
evanescent modes are observed , e.g. in the case of total reflection , in undersized waveguides , and in periodic dielectric heterostructures @xcite .
compared with the wave solutions an evanescent mode is characterized by a purely @xmath0 wave number , so that i.e. the wave equation yields for the electric field @xmath1 @xmath2 where @xmath3 is the angular frequency , t the time , x the distance , k the wave number , and @xmath4 the @xmath5 wave number of the evanescent mode ..
Please generate the next two sentences of the article | thus evanescent modes are characterized by an exponential attenuation and a lack of phase shift .
the latter means that the mode has not spent time in the evanescent region , which in turn results in an infinite velocity in the phase time approximation neglecting the phase shift at the boundary @xcite . |
5,217 | Suppose that you have an abstract for a scientific paper: recently , zhong et al . [ phys . rev . a 87 , 022337(2013 ) ] investigated the dynamics of quantum fisher information ( qfi ) in the presence of decoherence .
we here reform their results and propose two schemes to enhance and preserve the qfis for a qubit system subjected to a decoherence noisy environment by applying @xmath0 operator process .
the proposed schemes are related to the @xmath1 ( or the @xmath2 ) non - hermitian operator process corresponding to before ( or after ) the interest system suffers from decoherence , respectively . resorting to the bloch sphere representation , we derive the exact analytical expressions of the qfis with respect to the amplitude parameter @xmath3 and the phase parameter @xmath4 , and in detail investigate the influence of @xmath0 operator parameters on the qfis . compared with pure decoherence process ( without non - hermitian operator process ) , we find that the @xmath5 operator process can potentially enhance and preserve the qfis by choosing appropriate @xmath0 operator parameters , while with the help of the @xmath6 operator process one could completely eliminate the effect of decoherence to improve the parameters estimation . finally , a generalized non - hermitian operator parameters effect on the parameters estimation is also considered . .
And you have already written the first three sentences of the full article: quantum fisher information ( qfi)@xcite which is one of the most important ingredients in parameter estimation fields has been extensively investigated in both the classical and quantum worlds .
qfi characterizing the sensitivity of a state with respect to perturbation of the parameters is employed as a measure to quantify the precision of parameter estimation .
the parameter estimation is the purpose of the information in a finite number of observation value to obtain highest precision of the parameter and design schemes to attain that precision which is bounded by the quantum cramr - rao inequality,@xcite i.e. , @xmath7 , where @xmath8 is the number of experiments and @xmath9 denotes the qfi of the parameter @xmath4 ..
Please generate the next two sentences of the article | this inequality indicates that the inverse of the qfi provides the lower bound of the error of the estimation . on the other hand
, qfi is formally generalized from the classical one , and there are several variants of quantum versions of fisher information@xcite , among which the one based on the symmetric logarithmic derivative operator has been used most widely . |
5,218 | Suppose that you have an abstract for a scientific paper: the thurston - bennequin invariant provides one notion of self - linking for any homologically - trivial legendrian curve in a contact three - manifold . here
we discuss related analytic notions of self - linking for legendrian knots in @xmath0 .
our definition is based upon a reformulation of the elementary gauss linking integral and is motivated by ideas from supersymmetric gauge theory .
we recover the thurston - bennequin invariant as a special case . .
And you have already written the first three sentences of the full article: the linking number @xmath1 of disjoint , oriented curves @xmath2 is among the most basic invariants in knot theory , and as such it admits many different descriptions .
we begin with three .
let @xmath3 be euclidean coordinates on @xmath0 and consider the global angular form @xcite @xmath4^{3/2}}\,\in\,\omega^2\big(\br^3-\{0\}\big)\,.\ ] ] with the given normalization , @xmath5 is the pullback of an , unit - volume form @xmath6 on @xmath7 under the retraction @xmath8^{1/2}}\ , ..
Please generate the next two sentences of the article | \end{aligned}\ ] ] without loss , we take the embedded curves @xmath9 to be parametrized by smooth maps @xmath10 in terms of which we write the difference @xmath11 the gauss formula for the linking number of @xmath12 and @xmath13 is then given by an integral over the torus @xmath14 , @xmath15 essential here , since @xmath12 and @xmath13 are disjoint space curves , the singularity of @xmath16 at the origin is avoided , and the gauss integrand is everywhere smooth and bounded on @xmath17 . alternatively , because @xmath6 represents a generator for the cohomology @xmath18 , the gauss linking integral computes the topological degree @xmath19 where @xmath20 is the composition @xmath21 in its second description as the degree of @xmath20 , the linking number is clearly an integer and invariant under smooth isotopies of the curves @xmath22 .
the overall sign of the linking number depends upon the orientations for @xmath17 and @xmath23 . throughout , if @xmath24 are angular coordinates on @xmath17 , we orient the torus by @xmath25 . |
5,219 | Suppose that you have an abstract for a scientific paper: we report that the ionic - liquid gating of bulk single crystals of a topological insulator can control the type of the surface carriers and even results in ambipolar transport .
this was made possible by the use of a highly bulk - insulating bisbtese@xmath0 system where the chemical potential is located close to both the surface dirac point and the middle of the bulk band gap .
thanks to the use of ionic liquid , the control of the surface chemical potential by gating was possible on the whole surface of a bulk three - dimensional sample , opening new experimental opportunities for topological insulators .
in addition , our data suggest the existence of a nearly reversible electrochemical reaction that causes bulk carrier doping into the crystal during the ionic - liquid gating process . .
And you have already written the first three sentences of the full article: three - dimensional ( 3d ) topological insulators ( tis ) are characterized by a novel topological order @xcite which dictates the appearance of spin - filtered massless dirac fermions on the surface.@xcite to experimentally address the peculiar physics of 3d tis , it is desirable to access the dirac point of the surface state ( ss).@xcite this is relatively easy with the surface - sensitive spectroscopies such as the angle - resolved photoemission @xcite and the scanning tunneling microscope,@xcite but it is more challenging for the bulk - sensitive transport experiments because the chemical potential is always pinned to the bulk bands ( including the impurity band ) in real materials . to tune the chemical potential to a desirable position for transport experiments ,
two approaches have been employed : one is the tuning of the chemical compositions upon synthesizing crystals,@xcite and the other is the gating to control the surface carriers.@xcite among the latter approach , the electric - double - layer gating ( edlg ) method is a promising new technique @xcite to allow application of a large electric field.@xcite in the edlg configuration , either cations or anions in a liquid electrolyte are accumulated near the surface of a sample by application of an electric field , and they form an electric double layer which generates a very strong electric field locally on the surface .
this leads to the induced surface carrier density of as high as @xmath110@xmath2 @xmath3.@xcite such a large tunability of the surface carrier density is the merit of the edlg method . in the context of tis , yuan _ et al ..
Please generate the next two sentences of the article | _ showed @xcite that the edlg method allows an ambipolar doping control in ultrathin films of bi@xmath0te@xmath4 ; however , the surface state was obviously gapped in the ultrathin films used in ref . , and consequently the transport properties were likely to be dominated by the bulk state .
in the present paper , we show that the edlg method can achieve ambipolar transport even in bulk single crystals , if one uses the highly bulk - insulating bi@xmath5sb@xmath6te@xmath7se@xmath8 ( bsts ) system.@xcite in our experiment , the control of the chemical potential was possible on the _ whole surface of a bulk 3d sample _ , opening new experimental opportunities for tis . |
5,220 | Suppose that you have an abstract for a scientific paper: for many years various asymmetrical profiles of different spectral lines emitted from solar flares have been frequently observed . these asymmetries or line shifts
are caused predominantly by vertical mass motions in flaring layers and they provide a good diagnostics for plasma flows during solar flares .
there are many controversial results of observations and theoretical analysis of plasma flows in solar chromospheric flares .
the main difficulty is the interpretation of line shifts or asymmetries . for many years
, methods based on bisector techniques were used but they give a reliable results only for some specific conditions and in most cases can not be applied .
the most promising approach is to use the non - lte techniques applied for flaring atmosphere .
the calculation of synthetic line profiles is performed with the radiative transfer techniques and the assumed physical conditions correspond to flaring atmosphere .
i will present an overview of different observations and interpretations of line asymmetries in chromospheric flares .
i will explain what we have learnt about the chromospheric evaporation in the frame of hydrodynamical models as well as reconnection models .
a critical review will be done on the classical methods used to derive doppler - shifts for optically thick chomospheric lines . in particular , details on the new approach for interpreting chromospheric line asymmetries based on the non - lte techniques will be presented . .
And you have already written the first three sentences of the full article: spectroscopic observations of solar chromospheric flares show that the line profiles emitted by the flaring plasma almost always exhibit asymmetries or shifts .
these features are surely due to the chromospheric plasma motion and the resulting doppler - shifts effects .
interpretation of the shape of line profiles allows us to understand the nature of plasma flows during solar flares ..
Please generate the next two sentences of the article | plasma flows in the chromosphere are important in the analysis of dynamics and energetics of solar flares as well as these phenomena supply matter to the coronal parts of flares in the process of chromospheric evaporation .
understanding of the mechanisms which generate flows is necessary for complete description of solar flares . |
5,221 | Suppose that you have an abstract for a scientific paper: we analyze the dynamical processes behind delayed double ionization of atoms subjected to strong laser pulses . using reduced models ,
we show that these processes are a signature of hamiltonian chaos which results from the competition between the laser field and the coulomb attraction to the nucleus .
in particular , we exhibit the paramount role of the unstable manifold of selected periodic orbits which lead to a delay in these double ionizations . among delayed double ionizations , we consider the case of `` recollision excitation with subsequent ionization '' ( resi ) and , as a hallmark of this mechanism
, we predict oscillations in the ratio of resi to double ionization yields versus laser intensity .
we discuss the significance of the dimensionality of the reduced models for the analysis of the dynamical processes behind delayed double ionization . .
And you have already written the first three sentences of the full article: the dynamical processes by which atoms lose their electrons when subjected to strong laser pulses usually fall into two main categories @xcite : sequential double ionization ( sdi ) in which electrons are removed one after the other , and a less trivial class of processes coined nonsequential double ionization ( nsdi ) . in nsdi processes , the coulomb interaction between two electrons plays an essential role .
a particularly relevant example is afforded by the recollision scenario in nsdi @xcite in which a preionized electron returns to the ion core to excite a bound electron .
this excitation may lead to a double ionization if the energy transfer from the preionized electron to the bound electron is sufficient to overcome the coulomb attraction to the nucleus , while the preionized electron keeps enough kinetic energy to remain ionized ..
Please generate the next two sentences of the article | this so - called `` direct impact ionization '' @xcite is often invoked to explain the additional amount of double ionization at intermediate values of laser intensities .
however the dynamics exhibits a much richer variety of double ionization processes . |
5,222 | Suppose that you have an abstract for a scientific paper: strong electron correlation effects in the photophysics of quasi - one - dimensional @xmath0-conjugated organic systems such as polyenes , polyacetylenes , polydiacetylenes , etc . , have been extensively studied .
far less is known on correlation effects in two - dimensional @xmath0-conjugated systems . here
we present theoretical and experimental evidence for moderate repulsive electron@xmath1electron interactions in a number of finite polycyclic aromatic hydrocarbon molecules with @xmath2 symmetry .
we show that the excited state orderings in these molecules are reversed relative to that expected within one - electron and mean - field theories .
our results reflect similarities as well as differences in the role and magnitude of electron correlation effects in these two - dimensional molecules compared to those in polyenes . .
And you have already written the first three sentences of the full article: + [ toc ] strong electron correlation effects remain a highly relevant topic in the physics and chemistry of carbon - based materials .
extensive experimentation has confirmed strong electron correlation effects in quasi - one - dimensional ( quasi-1d ) carbon - based systems such as linear @xmath0-conjugated polymers , single - walled carbon nanotubes , graphene nanoribbons , etc .
historically , the study of the excited state ordering in finite polyenes @xcite provided the most convincing evidence for strong electron correlation effects in quasi-1d @xmath0-conjugated systems , and formed the basis of correlated - electron theories in the long chain polyacetylenes and polydiacetylenes . @xcite the early calculations @xcite were within the semiempirical pariser@xmath1parr@xmath1pople ( ppp ) @xmath0-electron model hamiltonian,@xcite within which eigenstates of even polyenes with c@xmath4 point group symmetry have even and odd spatial as well as charge - conjugation symmetries ( ccss ) , and allowed one - photon ( two - photon ) transitions from the @xmath5a@xmath6 ground state are to @xmath7b@xmath8 ( @xmath7a@xmath6 ) states with opposite ( same ) symmetries ( the superscript @xmath9 indicates singlet spin state and the `` plus '' and `` minus '' superscripts refer to ccs ) ..
Please generate the next two sentences of the article | the occurrence of the lowest two - photon state , the 2@xmath7a@xmath6 , _ below _ the one - photon 1@xmath7b@xmath8 in polyenes @xcite is opposite to that expected within the one - electron hckel and mean - field hartree@xmath1fock ( hf ) theories and is a consequence of strong short - range electron@xmath1electron ( e@xmath1e ) interactions within the ppp model.@xcite subsequent to these early model calculations , considerable effort has gone into developing more sophisticated quantum chemical correlated _ ab initio _ approaches to polyene spectra .
quantum chemical approaches that are now able to reproduce the correct one - photon versus two - photon state ordering for short linear polyenes ( usually up to octatetraene ) include the complete active space second order perturbation theory ( caspt2 ) and third - order coupled cluster theory , @xcite and the extended algebraic diagrammatic construction ( adc(2)-x ) method . |
5,223 | Suppose that you have an abstract for a scientific paper: we present the results of a systematic exploration of an alternative evolutionary scenario to form double neutron - star binaries , first proposed by brown ( 1995 ) , which does not involve a neutron star passing through a common envelope . in this scenario ,
the initial binary components have very similar masses , and both components have left the main sequence before they evolve into contact ; preferably the primary has already developed a co core .
we have performed population synthesis simulations to study the formation of double neutron star binaries via this channel and to predict the orbital properties and system velocities of such systems .
we obtain a merger rate for dnss in this channel in the range of 0.1 12 @xmath0 .
these rates are still subject to substantial uncertainties such as the modelling of the contact phase .
[ firstpage ] stars : evolution binaries : general stars : neutron .
And you have already written the first three sentences of the full article: double neutron star ( dns ) systems , i.e. binaries consisting of a radio pulsar and a usually undetected second neutron star , have provided an excellent test bed for general relativity theory .
the orbital decay observed in dnss is the first indirect evidence for gravitational - wave radiation .
the merger of the two neutron stars in dnss is expected to be a major source for gravitational - wave detection by the laser interferometer gravitational wave observatory ( ligo ) , virgo , or the laser interferometer space antenna ( lisa ) ..
Please generate the next two sentences of the article | such mergers are also thought to be potential progenitors of the short - duration gamma - ray bursts ( grbs ) .
the most commonly discussed formation channel of dnss , which we refer to as the standard scenario ( e.g. bhattacharya & van den heuvel 1991 ) , involves a high - mass x - ray binary ( hmxb ) phase at an intermediate stage . |
5,224 | Suppose that you have an abstract for a scientific paper: we establish a min - max estimate on the volume width of a closed riemannian manifold with nonnegative ricci curvature .
more precisely , we show that every closed riemannian manifold with nonnegative ricci curvature admits a pl morse function whose level set volume is bounded in terms of the volume of the manifold . as a consequence of this sweep - out estimate , there exists an embedded , closed ( possibly singular ) minimal hypersurface whose volume is bounded in terms of the volume of the manifold . .
And you have already written the first three sentences of the full article: in this article , we show the following result .
[ theo:0 ] let @xmath0 be a closed riemannian @xmath1-manifold with nonnegative ricci curvature .
there exists an embedded closed minimal hypersurface @xmath2 in @xmath0 with a singular set of hausdorff dimension at most @xmath3 such that @xmath4 where @xmath5 is an explicit positive constant depending only on @xmath1 . observe that both the ricci curvature condition and the inequality are scale invariant in this theorem ..
Please generate the next two sentences of the article | we do not know whether the curvature condition can be dropped in dimension greater than two . in dimension two ,
it is the case according to ( * ? ? ? |
5,225 | Suppose that you have an abstract for a scientific paper: contrary to the common lore based on naive dimensional analysis , the seesaw scale for neutrino masses can be _ naturally _ in the tev range , with small parameters coming from radiative corrections .
we present one such class of type - i seesaw models , based on the left - right gauge group @xmath0 realized at the tev scale , which fits the observed neutrino oscillation parameters as well as other low energy constraints .
we discuss how the small parameters of this scenario can arise naturally from one loop effects .
the neutrino fits in this model use quasi - degenerate heavy majorana neutrinos , as also required to explain the matter - antimatter asymmetry in our universe via resonant leptogenesis mechanism .
we discuss the constraints implied by the dynamics of this mechanism on the mass of the right - handed gauge boson in this class of models with enhanced neutrino yukawa couplings compared to the canonical seesaw model and find a lower bound of @xmath1 tev for successful leptogenesis assuming maximal @xmath2 asymmetry for each flavor .
we also present a model with explicit neutrino mass fit , where the lower bound goes up to 13.1 tev due to less than maximal primordial @xmath2 asymmetry predicted by the model . .
And you have already written the first three sentences of the full article: the seesaw mechanism @xcite seems to provide a simple way to understand the smallness of neutrino masses .
the simplest among the various seesaw mechanisms is the type - i seesaw , which requires the introduction of standard model ( sm ) gauge - singlet right - handed ( rh ) neutrinos ( @xmath3 s ) .
the majorana mass @xmath4 of these rh neutrinos explicitly breaks the global @xmath5 symmetry of the sm by two units and gives rise to a light neutrino mass matrix of the form @xmath6 where @xmath7 is the dirac mass generated due to the neutrino yukawa couplings @xmath8 after the electroweak symmetry breaking ..
Please generate the next two sentences of the article | if one assumes maximal allowed values for the third - generation dirac mass @xmath9 , as is implied by certain grand unified theories such as @xmath10 , then the seesaw scale is pushed up to @xmath11 gev making it virtually inaccessible to both collider experiments at the energy frontier and other low energy searches at the intensity frontier .
such naive ( dimensional counting " ) considerations however can be misleading in the context of specific ultraviolet ( uv ) complete seesaw models where there may be dynamical suppressions of neutrino dirac masses . |
5,226 | Suppose that you have an abstract for a scientific paper: in a quasi - one - dimensional system the particles remain ordered from left to right allowing the association of a volume element to the particle which on average resides there .
thus the properties of that single particle can give the local densities in the volume element . with reservoirs of different temperatures connected to each end of the system a steady heat current with an anomalous thermal conductivity results . a local configurational entropy density
is calculated from two - particle correlation functions which varies locally within the nonequilibrium steady state .
this local configurational entropy is proposed as the configurational component of the local entropy of the nonequilibrium steady state .
@xmath0 e - mail : ( [email protected] ) . .
And you have already written the first three sentences of the full article: for a system of @xmath1 particles in volume @xmath2 at temperature @xmath3 in thermal and mechanical equilibrium the true entropy is the gibbs entropy @xcite @xmath4 where @xmath5 is the probability that an @xmath1 particle system has a particular set of particle positions and velocities @xmath6 .
@xmath7 is the internal energy and @xmath8 is boltzmann s constant .
if the distribution @xmath5 factors into the product of a velocity distribution @xmath9 ( which is gaussian at equilibrium ) and a configurational @xmath1-particle distribution @xmath10 , where the @xmath11 superscript signifies that the system contains @xmath1 particles , then at equilibrium it is usual to define a new configurational correlation function @xcite for a sub - set of @xmath12 particles @xmath13 as @xmath14 ( where @xmath15 is the local number density at the position @xmath16 ) ..
Please generate the next two sentences of the article | the correlation function @xmath13 has the property that it approaches one as both the separation between particles , and the system size , becomes infinite .
the first attempt to calculate the configurational entropy of a dense fluid at equilibrium was by green @xcite . considering a canonical ensemble of @xmath1 particles |
5,227 | Suppose that you have an abstract for a scientific paper: heavy ion reactions and other collective dynamical processes are frequently described by different theoretical approaches for the different stages of the process , like initial equilibration stage , intermediate locally equilibrated fluid dynamical stage and final freeze - out stage . for the last stage the best known is the cooper - frye description
used to generate the phase space distribution of emitted , non - interacting , particles from a fluid dynamical expansion / explosion , assuming a final ideal gas distribution , or ( less frequently ) an out of equilibrium distribution . in this work
we do not want to replace the cooper - frye description , rather clarify the ways how to use it and how to choose the parameters of the distribution , eventually how to choose the form of the phase space distribution used in the cooper - frye formula .
moreover , the cooper - frye formula is used in connection with the freeze - out problem , while the discussion of transition between different stages of the collision is applicable to other transitions also .
more recently hadronization and molecular dynamics models are matched to the end of a fluid dynamical stage to describe hadronization and freeze - out .
the stages of the model description can be matched to each other on spacetime hypersurfaces ( just like through the frequently used freeze - out hypersurface ) .
this work presents a generalized description of how to match the stages of the description of a reaction to each other , extending the methodology used at freeze - out , in simple covariant form which is easily applicable in its simplest version for most applications . .
And you have already written the first three sentences of the full article: relativistic heavy ion reactions exhibit dominant collective flow behaviour , especially at higher energies where the number of involved particles , including quarks and gluons , increases dramatically . at intermediate stages
approximate local equilibrium is reached , while the initial and final stages may be far out of local equilibrium .
also , different stages may have different forms or phases of matter , especially when quark gluon plasma ( qgp ) is formed ..
Please generate the next two sentences of the article | the need to describe and match different stages of a reaction was realized by the development of the final freeze - out ( fo ) description in landau s fluid dynamical ( fd ) model @xcite .
then it was improved by milekhin @xcite , and a covariant simple model was given by cooper and frye @xcite . |
5,228 | Suppose that you have an abstract for a scientific paper: we work out the thermodynamic equations for the decays and scatterings of heavy majorana neutrinos including the constraints from unitarity .
the boltzmann equations depend on the cp asymmetry parameter which contains both , a self - energy and a vertex correction . at thermal equilibrium
there is no net lepton asymmetry due to the cpt theorem and the unitarity constraint .
we show explicitly that deviations from thermal equilibrium create the lepton asymmetry .
further considerations on the cp asymmetry in + heavy majorana neutrino decays .75 in marion flanz , emmanuel a. paschos _ institut fr physik _ , + _ universitt dortmund _ , + _ 44221 dortmund , germany _
+ .75 in .
And you have already written the first three sentences of the full article: over the past few years it has been shown that a lepton asymmetry can be generated by the mixing of heavy majorana neutrinos .
majorana neutrinos have the remarkable property of being mixed states of particles and antiparticles . by definition
they induce @xmath0 and consequently @xmath1 transitions . in addition.
Please generate the next two sentences of the article | they could have couplings to scalar particles , which allow them to decay into higgs particles and leptons , i.e. @xmath2 @xcite . in these models
@xmath3violation is introduced through complex couplings and appears in the self - energy @xcite or vertex corrections @xcite . |
5,229 | Suppose that you have an abstract for a scientific paper: we construct 4-dimensional cosmological frw models by compactifying a black 5-brane solution of type iib supergravity , which carries both magnetic ns - ns - charge and rr - charge .
the influence of nontrivial rr - fields on the dynamics of the cosmological models is investigated .
= -1 cm -0.3 cm .2 cm lmu - tpw 96 - 27 + tum - hep-258/96 + sfb-375/122 + hep - th/9610166 + october 1996 + r. poppe@xmath0 , s. schwager@xmath1 .5 cm _ @xmath0 physik department , technische universitt mnchen + 85748 garching , germany _ .2 cm _
@xmath1 sektion physik , universitt mnchen + theresienstr .
37 , 80333 mnchen , germany _ .
And you have already written the first three sentences of the full article: cosmological models obtained by dimensional reduction of 10-dimensional supergravity theories are an active field of research @xcite@xcite .
since supergravity is the low energy limit of string theory , these models should provide a way towards understanding the quantum effects in cosmology .
so far , there has been much activity in investigating models including fields of the ns - ns - sector ..
Please generate the next two sentences of the article | the discovery , that the conformal field theory of p - brane - like superstring backgrounds charged under rr - gauge fields is that of open strings with dirichlet boundary conditions @xcite , has made the rr - field contents of type ii string theories a very interesting subject for string cosmological models .
recently , in a first study of cosmological models including rr - fields , it was found that inflating phases can occur in a certain range of parameters which label the solutions to the equations of motion @xcite . |
5,230 | Suppose that you have an abstract for a scientific paper: a diffusion process on complex networks is introduced in order to uncover their large scale topological structures .
this is achieved by focusing on the slowest decaying diffusive modes of the network .
the proposed procedure is applied to real - world networks like a friendship network of known modular structure , and an internet routing network . for the friendship network ,
its known structure is well reproduced . in case of the internet , where the structure is far less well - known
, one indeed finds a modular structure , and modules can roughly be associated with individual countries .
quantitatively the modular structure of the internet manifests itself in an approximately @xmath0 times larger participation ratio of its slowest decaying modes as compared to the null model a random scale - free network .
the extreme edges of the internet are found to correspond to russian and us military sites .
complex random networks , network modules , statistical physics 89.75.-k , 89.20.hh , 89.75.hc , 05.40.fb .
And you have already written the first three sentences of the full article: complex networks are natural structures for representing many real - world systems .
their flexible and adaptive features make them ideal for interrelating various types of information and to update them as time goes by .
recently , there has been tremendous interest , from various fields of science , in the study of the statistical properties of such networks @xcite . by now , many interesting features of complex networks have been established ..
Please generate the next two sentences of the article | so far , the main attention in the study of complex networks has been on the properties of individual nodes and how they connect ( link ) to their nearest neighbors .
however , exploring the _ local _ properties of the network outside the nearest neighbor level , has not been well studied . |
5,231 | Suppose that you have an abstract for a scientific paper: the fiber bundle model describes a collection of elastic fibers under load .
the fibers fail sucessively and for each failure , the load distribution among the surviving fibers changes .
even though very simple , this model captures the essentials of failure processes in a large number of materials and settings .
we present here a review of the fiber bundle model with different load redistribution mechanisms from the point of view of statistics and statistical physics rather than materials science , with a focus on concepts such as criticality , universality and fluctuations .
we discuss the fiber bundle model as a tool for understanding phenomena such as creep , and fatigue , how it is used to describe the behavior of fiber reinforced composites as well as modelling e.g. network failure , traffic jams and earthquake dynamics . .
And you have already written the first three sentences of the full article: in materials science and engineering , a class of simple models , known as fiber bundle models ( fbm ) , has proven to be very effective in practical applications such as fiber reinforced composites . in this context ,
such models have a history that goes back to the twenties @xcite , and they constitute today an elaborate toolbox for studying such materials , rendering computer studies orders of magnitudes more efficient than brute force methods . since the late eighties @xcite , these models have received increasing attention in the physics community due to their deceivingly simple appearance coupled with an extraordinary richness of behaviors .
as these models are just at the edge of what is possible analytically and typically not being very challenging from a numerical point of view so that extremely good statistics on large systems are available , they are perfect as model systems for studying failure phenomena as a part of theoretical physics ..
Please generate the next two sentences of the article | fracture and material stability has for practical reasons interested humanity ever since we started using tools : our pottery should be able to withstand handling , our huts should be able to withstand normal weather . as science took on the form
we know today during the renaissance , leonardo da vinci studied five hundred years ago experimentally the strength of wires fiber bundles as a function of their length @xcite . |
5,232 | Suppose that you have an abstract for a scientific paper: in supersymmetric models with radiatively - driven naturalness and light higgsinos , the top squarks may lie in the 0.53 tev range and thus only a fraction of natural parameter space is accessible to lhc searches .
we outline the range of top squark and lightest susy particle masses preferred by electroweak naturalness in the standard parameter space plane .
we note that the branching fraction for @xmath0 decay favors top squarks much heavier than 500 gev .
such a range of top - squark mass values is in contrast to previous expectations where @xmath1 gev had been considered natural . in radiative natural susy ,
top squarks decay roughly equally via @xmath2 and @xmath3 where @xmath4 and @xmath5 are higgsino - like electroweak - inos .
thus , top squark pair production should yield all of @xmath6 , @xmath7 , @xmath8 and @xmath9 signatures at comparable rates .
we propose that future lhc top squark searches take place within a semi - simplified model which corresponds more closely to expectations from theory .
ou - hep-161104 + ut-16 - 32 + * a top - squark hunter s guide * + howard baer@xmath10 , vernon barger@xmath11 , natsumi nagata@xmath12 and michael savoy@xmath13 + _ @xmath13department of physics and astronomy , + university of oklahoma , norman , ok 73019 , usa + _ _ @xmath14department of physics and astronomy , + university of wisconsin , madison , wi 53706 , usa + _ _ @xmath15department of physics , university of tokyo , bunkyo - ku , tokyo 113 - 0033 , japan + _ .
And you have already written the first three sentences of the full article: the supersymmetrized ( susy ) standard model ( sm ) , _ e.g. _ , the minimal supersymmetric standard model ( mssm ) , has for a long time intrigued particle theorists in that it is free of the scalar field quadratic divergences that plague non - supersymmetric theories @xcite .
in addition , the mssm has made three predictions which have since been verified by experiment : 1 .
the value of @xmath16 which arises from unified gauge couplings at @xmath17 gev that evolve via renormalization group ( rg ) evolution down to the weak scale within the context of the mssm @xcite , 2 ..
Please generate the next two sentences of the article | the large top quark mass @xmath18 gev @xcite is exactly what is needed to initiate a radiative breakdown of electroweak symmetry in the mssm @xcite , and 3 .
the measured value of the higgs boson mass @xmath19 gev @xcite which falls squarely within the narrow window required by the mssm @xcite . |
5,233 | Suppose that you have an abstract for a scientific paper: an algorithm to compute polynomial conserved densities of polynomial nonlinear lattices is presented .
the algorithm is implemented in _
mathematica _ and can be used as an automated integrability test . with the code * diffdens.m * , conserved densities are obtained for several well - known lattice equations . for systems with parameters ,
the code allows one to determine the conditions on these parameters so that a sequence of conservation laws exist . , conservation law ; integrability ; semi - discrete ; lattice .
And you have already written the first three sentences of the full article: there are several motives to find the explicit form of conserved densities of differential - difference equations ( ddes ) .
the first few conservation laws have a physical meaning , such as conservation of momentum and energy .
additional ones facilitate the study of both quantitative and qualitative properties of solutions @xcite ..
Please generate the next two sentences of the article | furthermore , the existence of a sequence of conserved densities predicts integrability .
yet , the nonexistence of polynomial conserved quantities does not preclude integrability . |
5,234 | Suppose that you have an abstract for a scientific paper: we analyze the sequence of polynomials defined by the differential - difference equation @xmath0 asymptotically as @xmath1 .
the polynomials @xmath2 arise in the computation of higher derivatives of the inverse error function @xmath3 .
we use singularity analysis and discrete versions of the wkb and ray methods and give numerical results showing the accuracy of our formulas .
msc - class : 33b20 ( primary ) 34e20 , 33e30 ( secondary ) .
keywords : inverse error function , differential - difference equations , singularity analysis , discrete wkb method . .
And you have already written the first three sentences of the full article: the error function @xmath4 is defined by @xcite @xmath5 and its inverse @xmath6 , which we will denote by @xmath7 satisfies @xmath8 = \operatorname{erf}\left [ \mathfrak{i}(x)\right ] = x.$ ] the function @xmath9 appears in several problems of heat conduction @xcite . in @xcite
we considered the function @xmath10 and its inverse @xmath11 satisfying @xmath12 = n\left [ s(x)\right ] = x.\ ] ] it is clear from ( [ erf ] ) and ( [ n ] ) that@xmath13\ ] ] and therefore@xmath14 in @xcite we showed that@xmath15 \label{ds}\ ] ] and @xmath16 where @xmath2 is a polynomial of degree @xmath17 satisfying the recurrence @xmath18 the same approach was employed by carlitz in @xcite . from ( [ 2.3 ] ) , it follows easily that for a fixed value of @xmath17 @xmath19 from ( [ sj ] ) and ( [ sn ] ) , we conclude that@xmath20 since@xmath21 we have@xmath22 it follows from ( [ ider ] ) that estimating @xmath23 for large values of @xmath17 is equivalent to finding an asymptotic approximation of the polynomials @xmath2 when @xmath24 .
the objective of this work is to study @xmath2 asymptotically as @xmath1 for various ranges of @xmath25 we shall obtain different asymptotic expansions for @xmath1 and ( i ) @xmath26 ( ii ) @xmath27 and ( iii ) @xmath28 the paper is organized as follows : in section [ section2 ] we approach the problem using a singularity analysis of the generating function @xcite of the polynomials @xmath29 in section [ section3 ] we apply the wkb method to the differential - difference equation ( [ 2.3 ] ) . in @xcite.
Please generate the next two sentences of the article | , we used this approach in the asymptotic analysis of computer science problems and in @xcite to study the krawtchouk polynomials .
finally , in section [ section4 ] we analyze ( [ 2.3 ] ) again using the ray method @xcite and obtain an asymptotic approximation valid in various regions of the @xmath30 domain . in @xcite , @xcite , @xcite , we employed the same technique to analyze asymptotically other families of polynomials and in @xcite , @xcite to study some queueing problems . |
5,235 | Suppose that you have an abstract for a scientific paper: we present results of _ hubble space telescope _ ( hst ) observations of the radio galaxy 3c 244.1 .
the broadband f702w ( _ r _ ) and f555w ( _ v _ ) images ( wfpc2/pc ) show an elliptical galaxy and gaseous filaments and blobs surrounding it . in the narrow - band ramp filter , dominated by [ o iii]@xmath0 , these filaments are bright and have the same morphology as the broad band images . to the south , the filaments have a cone - shaped structure and the radio jet is located at the center of this cone . to the north of the galaxy
, the structure is found near the nucleus of the galaxy within its elliptical profile . from the photometry ,
the two brighter structures seem to be extended narrow line emission regions ( enlrs ) .
the comparison with diagnostic line ratios shows that the observed emission is consistent with interactions between the expanding radio - jet and the local denser medium . .
And you have already written the first three sentences of the full article: the _ hubble space telescope _ ( hst ) has been used to undertake a systematic survey of extragalactic radio sources , the 3cr snapshot survey ( de koff et al .
1996 ; martel et al . 1998,1999
; mccarthy et al . 1997 , de vries et al . 1997 ) selected from the _ revised third cambridge catalogue of radio sources _ ( 3cr ) ( bennett 1962a , b ; spinrad et al ..
Please generate the next two sentences of the article | 1985 ) . these data , taken with the wide field planetary camera ( wfpc2 ) using the f702w , f555w and ramp narrow - band filters ,
allow us to investigate the relationships between the radio and optical morphologies in a large sample of powerful radio galaxies over redhshifts of @xmath1 . |
5,236 | Suppose that you have an abstract for a scientific paper: we have incorporated the oblate distortion of the shape of the star due to the stellar rotation , which modifies the finite disk correction factor ( @xmath0 ) in the m - cak hydrodynamical model .
we implement a simplified version for the @xmath0 allowing us to solve numerically the non linear m - cak momentum equation .
we solve this model for a classical be star in the polar and equatorial directions .
the star s oblateness modifies the polar wind , which is now much faster than the spherical one , mainly because the wind receives radiation from a larger ( than the spherical ) stellar surface . in the equatorial direction we obtain slow solutions , which are even slower and denser than the spherical ones . for the case
when the stellar rotational velocity is about the critical velocity , the most remarkable result of our calculations is that the density contrast between the equatorial density and the polar one , is about 100 .
this result could explain a long - standing problem on be stars . .
And you have already written the first three sentences of the full article: pelupessy et al . ( 2000 ) formulated the wind momentum equation for sectorial line driven winds including the finite disk correction factor for an oblate rotating star with gravity darkening for both the continuum and the lines .
they calculated models with line force parameters around the bi stability jump at 25000 k. in this case , from the pole to the equator , the mass flux increases and the terminal velocity decreases .
their results showed a wind density contrast @xmath1 ( hereafter @xmath2 ) of about a factor 10 independent of the rotation rate of the star . in this work.
Please generate the next two sentences of the article | , we implement an approximative version for the oblate finite disk correction factor , @xmath3 , allowing us to solve numerically the non linear m cak momentum .
we solve then this equation for a _ classical be _ star , for polar and equatorial directions . in this study |
5,237 | Suppose that you have an abstract for a scientific paper: i review recent results from numerical simulations on the structure and dynamics of the ism , and attempt to put together a coherent dynamical scenario . in particular , i discuss results on 1 ) the spatial distribution of the gas components , showing that reasonable agreement between simulations and observations exists , but noting that in most models the components are simply defined as temperature intervals , because distinct thermodynamic `` phases '' do not arise ; 2 ) some statistical issues of the physical fields , like the dependence of the one - point statistics of the density field on the effective equation of state of the gas , the poor correlation of magnetic strength with density , the energy spectrum in weakly and highly compressible cases , and the one point statistics of the velocity field ; 3 ) the effects of spectroscopic observation on distorting the physical structures and results from synthetic observations of the simulations , and 4 ) several dynamical and thermodynamical issues , such as the ( apparently minor ) role of the thermal instability in forming and confining clouds , the continuous , rather than abrupt , transition between `` phases '' , which in turn may be consequences of the dynamics rather than the agents controlling it , the possibility of short time scales ( @xmath0 a few myr ) for molecular cloud formation , and the star - gas connection , mentioning that the models generally exhibit self - propagating star and cluster formation , while the stars may drive the medium- and small - scale gas motions , and that a `` star formation instability '' may induce chaotic behavior of the star formation rate locally .
i conclude with a round - up view , and a discussion of the work needed ahead .
# 1_#1 _ # 1_#1 _ = # 1 ' # 1#1i"13i 1.25 in .125 in .25 in .
And you have already written the first three sentences of the full article: two of the most influential models of the interstellar medium ( ism ) to date are the two- and three - phase models of field , goldsmith & habing ( 1969 ) and of mckee & ostriker ( 1977 , hereafter , mo ) .
these models relied on the then known atomic and radiative heating and cooling processes to provide a self - consistent picture of the ism in which the concepts of thermal and pressure equilibria played a fundamental role .
another important model was the time - dependent model of the ism by gerola , kafatos & mccray ( 1974 ) , which was presented as an alternative to the pressure equilibrium two - phase model of field et al.(1969 ) but assumed radically different conditions : a constant - density medium under the influence of stochastic , local heating events that should cause strong local fluctuations of pressure and temperature , because the cooling and recombination times are comparable or shorter than the time between exposure of a given gas parcel to one of those heating events ..
Please generate the next two sentences of the article | note that the mo model also recognized the existence of local fluctuations in the pressure , although it was still based on the premise of `` rough pressure balance '' .
nevertheless , both the equilibrium and the time dependent models left out a number of important aspects in the ism physics . |
5,238 | Suppose that you have an abstract for a scientific paper: we prove trace inequalities for a self - adjoint operator on an abstract hilbert space .
these inequalities lead to universal bounds on spectral gaps and on moments of eigenvalues @xmath0 that are analogous to those known for schrdinger operators and the dirichlet laplacian , on which the operators of interest are modeled . in addition
we produce inequalities that are new even in the model case .
these include a family of differential inequalities for generalized riesz means and theorems stating that arithmetic means of @xmath1 for @xmath2 are universally bounded from above by multiples of the geometric means , @xmath3 . for schrdinger operators and the dirichlet laplacian these bounds are weyl - sharp , i.e. , saturated by the standard semiclassical estimates as @xmath4 . .
And you have already written the first three sentences of the full article: universal spectral bounds for laplace and schrdinger operators , i.e. , bounds that control eigenvalues with expressions that do not depend on the specific geometry of the domain or on details of the potential ( cf .
@xcite ) , can be derived from fundamental identities involving traces of operators and their commutators @xcite .
this insight has proved useful both for unifying numerous previously known inequalities of this kind and for discovering new ones @xcite ..
Please generate the next two sentences of the article | related methods have also been used to obtain control on the spectrum of laplace and schrdinger operators in terms of curvature @xcite .
many of the universal inequalities related to trace identities are sharp in the sense that they are saturated for particular examples : for the schrdinger operators treated in @xcite the upper bounds on eigenvalue gaps @xmath5 become identities for all @xmath6 in the case of the harmonic oscillator , while for laplacians on embedded manifolds discussed in @xcite all of the gap bounds become identities for embedded spheres . |
5,239 | Suppose that you have an abstract for a scientific paper: an hallmark of present - day dyson - schwinger equation applications in hadron physics is the existence of a systematic and symmetry preserving truncation scheme .
this enables the proof of exact results ; e.g. , the leptonic decay constant of every pseudoscalar meson except the pion vanishes in the chiral limit .
calculations using the scheme s leading - order truncation are reliable in the vector and flavour nonsinglet pseudoscalar channels . in this rainbow - ladder truncation
, an impulse approximation provides the consistent current for all six - point quark schwinger functions .
that is well illustrated via the anomalous process @xmath0 .
using two- , three- and four - point schwinger functions calculated in rainbow - ladder truncation , the textbook value of the width is obtained algebraically and independent of model details if , and only if , the impulse approximation is used to describe the associated matrix element . .
And you have already written the first three sentences of the full article: a number of brief accounts of the modern application of dyson - schwinger equations ( dses ) to hadron physics and qcd have recently appeared @xcite .
they have recapitulated on aspects of dynamical chiral symmetry breaking and confinement , and the expression of these phenomena in the hadron spectrum ; and contain original contributions regarding : comparisons between dse results and lattice simulations , and the mutual benefits of such comparisons @xcite ; the pion and its excited states @xcite ; and states with vacuum quantum numbers @xcite .
we have a modicum to add ..
Please generate the next two sentences of the article | we begin with qcd s renormalised gap equation @xmath1 wherein : @xmath2 is the dressed - gluon propagator ; @xmath3 is the dressed - quark - gluon vertex ; @xmath4 is the @xmath5-dependent current - quark bare mass ; and @xmath6 represents a translationally - invariant regularisation of the integral , with @xmath5 the regularisation mass - scale .
we employ a pauli - villars scheme , which is implemented in eq.([gendse ] ) by considering the quarks as minimally anticoupled ( @xmath7 ) to additional massive gluons ( @xmath8 ) . |
5,240 | Suppose that you have an abstract for a scientific paper: pure thermodynamical considerations to describe the entropic evolution of the universe seem to violate the second law of thermodynamics .
this suggests that the gravitational field itself has entropy . in this paper
we expand recent work done by rudjord , gr@xmath0n and sigbj@xmath0rn where they suggested a method to calculate the gravitational entropy in black holes based on the so - called ` weyl curvature conjecture ' .
we study the formulation of an estimator for the gravitational entropy of reissner - nordstrm , kerr , kerr - newman black holes , and a simple case of wormhole .
we calculate in each case the entropy for both horizons and the interior entropy density .
then , we analyse whether the functions obtained have the expected behaviour for an appropriate description of the gravitational entropy density .
example.eps gsave newpath 20 20 moveto 20 220 lineto 220 220 lineto 220 20 lineto closepath 2 setlinewidth gsave .4 setgray fill grestore stroke grestore .
And you have already written the first three sentences of the full article: the world changes .
this basic fact is expressed in the second law of thermodynamics : _ the entropy of a closed system never decreases _ : @xmath1 where the entropy is denoted by @xmath2 . in the 1870s ,
ludwig boltzmann @xcite@xcite provided a description of the entropy relating the states of macro and micro - systems ..
Please generate the next two sentences of the article | he argued that any system would evolve toward the macrostate that is consistent with the largest possible number of microstates .
the number of microstates and the entropy of the system are related by the fundamental formula : @xmath3 where @xmath4 jk@xmath5 is boltzmann s constant and @xmath6 is the volume of the phase - space that corresponds to the macrostate of entropy @xmath2 . |
5,241 | Suppose that you have an abstract for a scientific paper: we describe how the effect of charge noise on a pair of spins coupled via the exchange interaction can be calculated by modelling charge fluctuations as a random telegraph noise process using probability density functions .
we develop analytic expressions for the time dependent superoperator of a pair of spins as a function of fluctuation amplitude and rate .
we show that the theory can be extended to include multiple fluctuators , in particular , spectral distributions of fluctuators .
these superoperators can be included in time dependent analyses of the state of spin systems designed for spintronics or quantum information processing to determine the decohering effects of exchange fluctuations . .
And you have already written the first three sentences of the full article: the exchange interaction is of increasing importance in the study of controllable quantum mechanics using solid - state systems .
as well as being fundamentally important in manybody physics , it is this interaction which is often used to mediate spin flips or entanglement in spintronics and quantum information processing ( qip ) @xcite . for these reasons
there has been considerable study recently on the origin and control of the exchange interaction @xcite . for applications involving the time varying control of the exchange interaction , such as qip , the stability in time of this interaction is of crucial importance ..
Please generate the next two sentences of the article | as the origin of the exchange interaction is essentially the overlap of electron wave functions , the interaction strength is sensitive to the local charge environment .
recent work @xcite has shown that the dependence of the exchange interaction is approximately linearly dependent on fluctuations in the local electric field . in this paper |
5,242 | Suppose that you have an abstract for a scientific paper: the critical behaviour of a bond - disordered ashkin - teller model on a square lattice is investigated by intensive monte - carlo simulations .
a duality transformation is used to locate a critical plane of the disordered model .
this critical plane corresponds to the line of critical points of the pure model , along which critical exponents vary continuously . along this line
the scaling exponent corresponding to randomness @xmath0 varies continuously and is positive so that randomness is relevant and different critical behaviour is expected for the disordered model .
we use a cluster algorithm for the monte carlo simulations based on the wolff embedding idea , and perform a finite size scaling study of several critical models , extrapolating between the critical bond - disordered ising and bond - disordered four state potts models .
the critical behaviour of the disordered model is compared with the critical behaviour of an anisotropic ashkin - teller model which is used as a refference pure model .
we find no essential change in the order parameters critical exponents with respect to those of the pure model .
the divergence of the specific heat @xmath1 is changed dramatically .
our results favor a logarithmic type divergence at @xmath2 , @xmath3 for the random bond ashkin - teller and four state potts models and @xmath4 for the random bond ising model . .
And you have already written the first three sentences of the full article: how is the critical behaviour affected by the introduction of disorder ( usualy dilution or bond - randomness ) into a model ?
the harris criterion @xcite states that @xmath5 , the scaling index of the operator corresponding to randomness at the pure system fixed point ( also called the crossover exponent ) is equal to @xmath6 ( @xmath7 and @xmath8 are the specific - heat and correlation length exponents of the pure model ) .
thus the critical behaviour of the pure system is unaltered by disorder if @xmath9 , and altered when @xmath10 ..
Please generate the next two sentences of the article | if @xmath11 the situation is marginal .
renormalization - group methods ( namely expansion in the parameter @xmath12 , where @xmath13 is the dimensionality ) , applied to n - component continuous spin models with weak quenched bond disorder@xcite , confirmed the harris criterion @xmath14 . |
5,243 | Suppose that you have an abstract for a scientific paper: using a lattice string model , a number of peculiar excitation situations related to non - propagating excitations and non - radiating sources are demonstrated .
external fields can be used to trap excitations locally but also lead to the ability to steer such excitations dynamically as long as the steering is slower than the field s wave propagation .
i present explicit constructions of a number of examples , including temporally limited non - propagating excitations , directional excitation and virtually slowed propagation . using these dynamical lattice constructions
i demonstrate that neither persistent temporal oscillation nor static localization are necessary for non - propagating excitations to occur . .
And you have already written the first three sentences of the full article: can a local excitation ( source ) in classical field theories be invisible to observers outside the region of excitation ?
this question has recently received renewed interest .
berry _ et al . _.
Please generate the next two sentences of the article | @xcite described a peculiar excitation case for the one - dimensional wave - equation of a perfectly elastic string under tension .
they show that the response of the string can be made to be confined to a bounded region by carefully choosing a forced excitation of oscillatory type . |
5,244 | Suppose that you have an abstract for a scientific paper: we investigate the harmonically trapped interacting bose gas in a quasi-2d geometry using the classical field method .
the system exhibits quasi - long - range order and non - classical rotational inertia at temperatures below the berezinskii - kosterlitz - thouless cross - over to the superfluid state .
in particular , we compute the scissors - mode oscillation frequencies and find that the irrotational mode changes its frequency as the temperature is sweeped across the cross - over thus providing microscopic evidence for the emergence of superfluidity . .
And you have already written the first three sentences of the full article: superfluids are peculiar states of matter in which , at the cost of losing part of their individuality , particles gain the ability of cooperative lossless motion @xcite .
the occurrence of superfluidity can be attributed to the formation of certain non - local correlations within the system . for two - dimensional ( 2d ) systems , mermin and
wagner showed that heisenberg models can be neither ferromagnetic or anti - ferromagnetic at finite temperatures @xcite ..
Please generate the next two sentences of the article | hohenberg further ruled out the existence of long - range ordering in 2d bose and fermi systems @xcite .
these rigorous results imply that bose - einstein condensation ( bec ) does not exist at any finite temperature in uniform , interacting 2d systems in the thermodynamic limit , since spontaneous long - range ordering is prevented by long - wavelength fluctuations . |
5,245 | Suppose that you have an abstract for a scientific paper: to solve numerically boundary value problems for parabolic equations with mixed derivatives , the construction of difference schemes with prescribed quality faces essential difficulties . in parabolic problems ,
some possibilities are associated with the transition to a new formulation of the problem , where the fluxes ( derivatives with respect to a spatial direction ) are treated as unknown quantities . in this case , the original problem is rewritten in the form of a boundary value problem for the system of equations in the fluxes .
this work deals with studying schemes with weights for parabolic equations written in the flux coordinates .
unconditionally stable flux locally one - dimensional schemes of the first and second order of approximation in time are constructed for parabolic equations without mixed derivatives .
a peculiarity of the system of equations written in flux variables for equations with mixed derivatives is that there do exist coupled terms with time derivatives . .
And you have already written the first three sentences of the full article: investigating many applied problems , we can consider a second - order parabolic equation with mixed derivatives as the basic equation .
an example is diffusion processes in anisotropic media . in desining various approximations for the corresponding boundary - value problems , we focus on the inheritance of the primary properties of the differential problem during the construction of the discrete problem .
locally one - dimensional difference schemes are obtained in a simple enough way for second - order parabolic equations without mixed derivatives @xcite ..
Please generate the next two sentences of the article | mixed derivatives complicate essentially the construction of unconditionally stable schemes of splitting with respect to the spatial variables for parabolic equations with variable derivatives , even for two - dimensional problems . in some problems
, it is convenient to use the fluxes ( derivatives with respect to a spatial direction ) as unknow quantities . |
5,246 | Suppose that you have an abstract for a scientific paper: we use recent results from the wilkinson microwave anisotropy probe ( wmap ) for the locations of peaks and troughs of the cosmic microwave background ( cmb ) power spectrum , together with constraints from large - scale structure , to study a quintessence model in which the pure exponential potential is modified by a polynomial factor .
we find that the model is compatible with all the recent data for a wide range of cosmological and potential parameters .
moreover , quintessence is favoured compared to @xmath0cdm for @xmath1 and relatively high values of the average fraction of dark energy before last scattering ( `` early quintessence '' ) ; for @xmath2 , quintessence and @xmath0cdm give similar results , except for high values of early quintessence , in which case @xmath0cdm is favoured .
0.5 cm 0.5 cm .
And you have already written the first three sentences of the full article: recent cosmological observations suggest that there is a dark energy component to the energy density of the universe , which should be added to the matter component so as to reach the critical density .
theorists have considered various possibilities for the nature of this dark energy , notably a cosmological constant and quintessence , a dynamical scalar field leading to a time - varying equation of state parameter , @xmath3 .
these models most often involve a single field @xcite or , in some cases , two coupled scalar fields @xcite ..
Please generate the next two sentences of the article | other possibilities for the origin of dark energy include the generalized chaplygin gas proposal @xcite and cardassian models @xcite . in order to unravel the nature of dark energy ,
it is crucial to use observations so as to be able to discriminate among different models . in particular |
5,247 | Suppose that you have an abstract for a scientific paper: a macronova ( or kilonova ) was observed as an infrared excess several days after short gamma - ray burst , grb 130603b .
although the @xmath0-process radioactivity is widely discussed as an energy source , it requires huge mass of ejecta from a neutron star ( ns ) binary merger .
we propose a new model that the x - ray excess gives rise to the simultaneously observed infrared excess via thermal re - emission and explore what constraints this would place on the mass and velocity of the ejecta .
this x - ray - powered model explains both the x - ray and infrared excesses with a single energy source by the central engine like a black hole , and allows for broader parameter region , in particular smaller ejecta mass @xmath1 with iron mixed as suggested by general relativistic simulations for typical ns - ns mergers , than the previous models .
we also discuss the other macronova candidates in grb 060614 and grb 080503 , and implications for the search of electromagnetic counterparts to gravitational waves . .
And you have already written the first three sentences of the full article: what is the energy source of a macronova ( or kilonova ) ?
macronovae are considered as the emission from the ejecta with mass @xmath2 and the velocity @xmath3 , which are accompanied by the mergers of a ns binary ( e.g. , * ? ? ?
* ; * ? ? ?.
Please generate the next two sentences of the article | * ; * ? ? ?
* ; * ? ? ? |
5,248 | Suppose that you have an abstract for a scientific paper: motivated by damage due to heating in sensor operation , we consider the throughput optimal offline data scheduling problem in an energy harvesting transmitter such that the resulting temperature increase remains below a critical level .
we model the temperature dynamics of the transmitter as a linear system and determine the optimal transmit power policy under such temperature constraints as well as energy harvesting constraints over an awgn channel .
we first derive the structural properties of the solution for the general case with multiple energy arrivals .
we show that the optimal power policy is piecewise monotone decreasing with possible jumps at the energy harvesting instants .
we derive analytical expressions for the optimal solution in the single energy arrival case .
we show that , in the single energy arrival case , the optimal power is monotone decreasing , the resulting temperature is monotone increasing , and both remain constant after the temperature hits the critical level .
we then generalize the solution for the multiple energy arrival case . .
And you have already written the first three sentences of the full article: in many wireless sensor applications , temperature increase caused by sensor operation has to be carefully managed .
for example , wireless sensors implanted in the human body have to be designed such that the temperature due to their operation does not cause any threat for the metabolism .
a line of medical research started by pennes in 1948 @xcite explores the temperature dynamics due to electromagnetic radiation in conjunction with heat losses to the environment and dissipation of heat in the tissue . in the context of sensors that communicate data ,.
Please generate the next two sentences of the article | temperature sensitivity varies depending on the type of tissue . for a given specific tissue
, it is recommended that the temperature does not exceed a critical level , in order to prevent damage to the tissue . |
5,249 | Suppose that you have an abstract for a scientific paper: several new effects have been investigated in recent analyses of supersymmetric dark matter .
these include the effects of the uncertainties of wimp velocity distributions , of the uncertainties of quark densities , of large cp violating phases , of nonuniversalities of the soft susy breaking parameters at the unification scale and of coannihilation on supersymmetric dark matter .
we review here some of these with emphasis on the effects of nonuniversalities of the gaugino masses at the unification scale on the neutralino - proton cross - section from scalar interactions .
the review encompasses several models where gaugino mass nonuniversalities occur including sugra models and d brane models .
one finds that gaugino mass nonuniversalities can increase the scalar cross - sections by as much as a factor of 10 and also significantly extend the allowed range of the neutralino mass consistent with constraints up to about 500 gev .
these results have important implications for the search for supersymmetric dark matter .
= 14.5pt .
And you have already written the first three sentences of the full article: over the recent past there has been considerable experimental activity in the direct detection of dark matter@xcite and further progress is expected in the ongoing experiments@xcite and new experiments that may come online in the future@xcite . at the same time
there have been several theoretical developments which have shed light on the ambiguities and possible corrections that might be associated with the predictions on supersymmetric dark matter .
these consist of the effects on the dark matter analyses of wimp velocity@xcite and of the rotation of the galaxy@xcite , the effects of the uncertainties of quark densities@xcite and the uncertainties of the susy parameters@xcite , effects of large cp violating phases@xcite , effects of scalar nonuniversalities@xcite , effects of nonuniversalities of gaugino masses@xcite and effects of coannihilation@xcite . in this paper.
Please generate the next two sentences of the article | we will discuss some of these briefly but mainly focus on the effects of nonuniversalities of the gaugino masses on dark matter . in the minimal supersymmetric standard model ( mssm )
there are 32 supersymmetric particles and with r parity conservation the lowest mass supersymmetric particle ( lsp ) is absolutely stable . in many unified models , such as in the sugra models@xcite |
5,250 | Suppose that you have an abstract for a scientific paper: we derive an equation determining the small-@xmath0 evolution of the @xmath1 structure function of a large nucleus which includes all multiple pomeron exchanges in the leading logarithmic approximation using mueller s dipole model @xcite .
we show that in the double leading logarithmic limit this evolution equation reduces to the glr equation @xcite .
16.5 cm -1 cm 22.4 cm nuc - mn-99/1-t + tpi - minn-99/05 * small@xmath0 @xmath1 structure function of a nucleus including multiple pomeron exchanges * + yuri v. kovchegov + + _ school of physics and astronomy , university of minnesota , + minneapolis , mn 55455 _ + + + .
And you have already written the first three sentences of the full article: the problem of understanding the large gluon density regime in high energy scattering has always been one of the challenges of perturbative qcd ( pqcd ) .
unitarity of the total cross section and saturation of the gluon distribution are among the most important issues related to the problem .
the bfkl equation @xcite is the only well established tool of pqcd which allows us to explore this high density region by resumming the leading longitudinal logarithmic contribution to the scattering process . in bfkl evolution.
Please generate the next two sentences of the article | the small@xmath0 partons are produced overlapping each other in the transverse coordinate space @xcite , therefore creating high density regions in the hadron s wave function ( hot spots ) .
the next to leading order correction to bfkl equation has been calculated recently @xcite . |
5,251 | Suppose that you have an abstract for a scientific paper: we suggest a theory of internal coherent tunnelling in the pseudogap region where the applied voltage is below the free electron gap . we consider quasi 1d systems where the gap is originated by a lattice dimerization ( peierls or ssh effect ) like in polyacethylene , as well as low symmetry 1d semiconductors .
results may be applied to several types of conjugated polymers , to semiconducting nanotubes and to quantum wires of semiconductors .
the approach may be generalized to tunnelling in strongly correlated systems showing the pseudogap effect , like the family of high tc materials in the undoped limit .
we demonstrate the evolution of tunnelling current - voltage characteristics from smearing the free electron gap down to threshold for tunnelling of polarons and further down to the region of bi - electronic tunnelling via bipolarons or kink pairs . the interchain tunnelling is described in a parallel comparison with the on chain optical absorption , also within the subgap region . .
And you have already written the first three sentences of the full article: the interchain , interplane transport of electrons in low dimensional ( quasi 1d , 2d ) materials attracts much attention @xcite in view of striking differences between longitudinal and transverse transport mechanisms revealing a general problematics of strongly correlated electronic systems . beyond the low field ( linear ) conduction , the tunnelling current - voltage j - u characteristics @xmath0 , @xmath1 are of particular importance .
the interest has been renewed thanks to recently developed @xcite design of intrinsic tunnelling devices where electronic transitions between weakly coupled chains or planes take place in the bulk of the unperturbed material .
the first feature one expects to see at any tunnelling experiment in gapful conductors is the regime of free electrons when the current onset corresponds to the voltage @xmath2 of the gap in the spectrum of electrons ..
Please generate the next two sentences of the article | but contrarily to usual systems , like semi- or even superconductors , there is also a possibility for tunnelling within the subgap region @xmath3 .
it is related to the pseudogap ( pg ) phenomenon known for strongly correlated electrons in general , well pronounces in quasi 1d systems and particularly in cases where the gap is opened by a spontaneous symmetry breaking ( see @xcite and refs . therein ) . |
5,252 | Suppose that you have an abstract for a scientific paper: by applying a magnetic field whose zeeman energy exceeds the kondo energy by an order of magnitude the ground state of the friedel - anderson impurity is a magnetic state . in recent years the author introduced
the friedel artificially inserted resonance ( fair ) method to investigate impurity properties . within this fair approach
the magnetic ground state is derived .
its full excitation spectrum and the composition of the excitations is calculated and numerically evaluated . from the excitation spectrum the electron density of states
is calculated .
majority and minority d - resonances are obtained .
the width of the resonances is about twice as wide as the mean field theory predicts
. this broadening is due to the fact that any change of the occupation of the d - state in one spin band changes the eigenstates in the opposite spin band and causes transitions in both spin bands .
this broadening reduces the height of the resonance curve and therefore the density of states by a factor of two .
this yields an intuitive understanding for a previous result of the fair approach that the critical value of the coulomb interaction for the formation of a magnetic moment is twice as large as the mean field theory predicts .
pacs : 75.20.hr , 71.23.an , 71.27.+a .
And you have already written the first three sentences of the full article: the properties of magnetic impurities in a metal is one of the most intensively studied problems in solid state physics .
the work of friedel @xcite and anderson @xcite laid the foundation to understand why some transition - metal impurities form a local magnetic moment while others do nt .
kondo @xcite showed that multiple scattering of conduction electrons by a magnetic impurity yields a divergent contribution to the resistance in perturbation theory ..
Please generate the next two sentences of the article | yoshida @xcite introduced the concept that the ( spin 1/2 ) magnetic impurity forms a singlet state with the conduction electrons and is non - magnetic at zero temperature .
these new insights stimulated a large body of theoretical and experimental work ( see for example @xcite , @xcite , @xcite , @xcite , @xcite , @xcite , @xcite , @xcite , @xcite , @xcite ) . |
5,253 | Suppose that you have an abstract for a scientific paper: we propose an experimental setup to efficiently measure the dynamic structure factor of ultracold quantum gases .
our method uses the interaction of the trapped atomic system with two different cavity modes , which are driven by external laser fields . by measuring the output fields of the cavity the dynamic structure factor of the atomic system
can be determined .
contrary to previous approaches the atomic system is not destroyed during the measurement process . .
And you have already written the first three sentences of the full article: the rapid experimental progress in the manipulation of ultracold quantum gases has enabled the creation of strongly correlated many - body systems , which are challenging to describe theoretically @xcite . the unambiguous identification of these phases requires precise measurements to characterize its properties .
a powerful tool represents the response function , which provides static properties of the system as well as reveals information about the excitations of the examined state . here ,
we propose a method for an _ in situ _ measurement of the response function to a external and weak probing field for a trapped gas of ultracold atoms . in seminal experimental measurements.
Please generate the next two sentences of the article | the bogoliubov excitation spectrum in a bose - einstein condensate has been measured by probing the dynamic structure factor @xcite .
nowadays , this method has been applied to access the excitation spectrum within the bec - bcs crossover @xcite , as well as the smooth transition of the excitation gap from the superfluid to the mott insulating phase @xcite . |
5,254 | Suppose that you have an abstract for a scientific paper: we present measurements of the critical velocity for vortex shedding in a highly oblate bose - einstein condensate with a moving repulsive gaussian laser beam . as a function of the barrier height @xmath0
, the critical velocity @xmath1 shows a dip structure having a minimum at @xmath2 , where @xmath3 is the chemical potential of the condensate . at fixed @xmath4 , we observe that the ratio of @xmath1 to the speed of sound @xmath5 monotonically increases for decreasing @xmath6 , where @xmath7 is the beam width and @xmath8 is the condensate healing length .
we explain our results with the density reduction effect of the soft boundary of the gaussian obstacle , based on the local landau criterion for superfluidity .
the measured value of @xmath9 with our stiffest obstacle is about 0.4 , which is in good agreement with theoretical predictions for a two - dimensional superflow past a circular cylinder . .
And you have already written the first three sentences of the full article: a superfluid flows without friction but becomes dissipative above a certain critical velocity @xmath1 via generating its elementary excitations such as phonons and vortices .
the landau criterion provides a conventional energetic consideration to determine the critical velocity , stating @xmath10 $ ] @xcite , where @xmath11 is the energy of an elementary excitation of momentum @xmath12 . for a homogeneous system ,
the landau critical velocity is equal to the speed of sound @xmath5 ..
Please generate the next two sentences of the article | however , the dynamic response of a superfluid flow is significantly sensitive to the boundary condition of the system and hence a quantitative understanding of the critical velocity has been a challenging task in the study of superfluidity .
one of the paradigmatic situations considered in fluid mechanics is a two - dimensional ( 2d ) flow past a circular cylinder . for an incompressible flow , |
5,255 | Suppose that you have an abstract for a scientific paper: in these proceedings we present the results for lepton flavour violating tau and muon decays within the susy seesaw scenario .
specifically , we consider the constrained minimal supersymmetric standard model extended by three right handed neutrinos , @xmath0 and their corresponding susy partners , @xmath1 , ( @xmath2 ) , and use the seesaw mechanism for neutrino mass generation .
we include the predictions for the branching ratios of two types of lepton flavour violating channels , @xmath3 and @xmath4 , and compare them with the present bounds and future experimental sensitivities .
we first analyse the dependence of the branching ratios with the most relevant susy seesaw parameters , and we then focus on the particular sensitivity to @xmath5 , which we find specially interesting on the light of its potential future measurement .
we further study the constraints from the requirement of successfully producing the baryon asymmetry of the universe via thermal leptogenesis , which is another appealing feature of the susy seesaw scenario .
we conclude with the impact that a potential measurement of @xmath5 can have on lepton flavour violating physics .
this is a very short summary of the works in refs .
@xcite and @xcite to which we refer the reader for more details . .
And you have already written the first three sentences of the full article: the seesaw mechanism is implemented by the inclusion of a majorana mass @xmath6 for the right handed neutrinos ( allowed due to their singlet character under all the symmetries of the standard model ( sm ) ) and by considering a large separation between this mass and the electroweak ( ew ) scale @xcite .
after ew symmetry breaking , the full @xmath7 neutrino mass matrix is given in terms of the @xmath8 dirac mass matrix , @xmath9 , and the @xmath8 majorana mass matrix @xmath6 . here
@xmath10 is the @xmath8 neutrino yukawa coupling and @xmath11 with @xmath12 gev ..
Please generate the next two sentences of the article | the ratio of the two higgs doublets vacuum expectations values is @xmath13 .
the assumption of @xmath14 leads to the usual seesaw equation , @xmath15 , which guaranties the smallness of the light neutrino masses . |
5,256 | Suppose that you have an abstract for a scientific paper: cells generally convert external nutrient resources to support metabolism and growth . understanding the thermodynamic efficiency of this conversion is essential to determine the general characteristics of cellular growth . using a simple protocell model with catalytic reaction dynamics to synthesize the necessary enzyme and membrane components from nutrients , the entropy production per unit cell - volume growth is calculated analytically and numerically based on the rate equation for chemical kinetics and linear non - equilibrium thermodynamics .
the minimal entropy production per unit cell growth is found to be achieved at a non - zero nutrient uptake rate , rather than at a quasi - static limit as in the standard carnot engine .
this difference appears because the equilibration mediated by the enzyme exists only within cells that grow through enzyme and membrane synthesis .
optimal nutrient uptake is also confirmed by protocell models with many chemical components synthesized through a catalytic reaction network .
the possible relevance of the identified optimal uptake to optimal yield for cellular growth is also discussed . .
And you have already written the first three sentences of the full article: a cell is a system that transforms nutrients into substrates for growth and division . by assuming that the nutrient flow from the outside of a cell is an energy and material source
, the cell can be regarded as a system to transform energy and matter into cellular reproduction .
it is important to thermodynamically study the efficiency of this transformation@xcite . regarding material transformation ,.
Please generate the next two sentences of the article | the yield is defined as the molar concentration of nutrients ( carbon sources ) needed to synthesize a molar unit of biomass ( cell content ) and has been measured in several microbes @xcite . as the conversion of nutrients to cell content
is not perfect and material loss to the outside of a cell occurs as waste , the yield is generally lower than unity . |
5,257 | Suppose that you have an abstract for a scientific paper: employing instanton technique we evaluate equilibrium persistent current ( pc ) produced by a quantum particle moving in a periodic potential on a ring and interacting with a dissipative environment formed by diffusive electron gas .
the model allows for detailed non - perturbative analysis of interaction effects and depending on the system parameters yields a rich structure of different regimes .
we demonstrate that at low temperatures pc is exponentially suppressed at sufficiently large ring perimeters @xmath0 where the dephasing length @xmath1 is set by interactions and does not depend on temperature .
this behavior represents a clear example of quantum decoherence by electron - electron interactions at @xmath2 . .
And you have already written the first three sentences of the full article: electron decoherence is one of the key ingredients of the many - body ground state in the presence of disorder and electron - electron interactions .
the existing non - perturbative theory of this phenomenon at low temperatures in realistic disordered conductors @xcite is rather complicated , to a large extent because of the necessity to properly account for fermi statistics for interacting electrons . at the same time
the main physical reason for electron dephasing appears obvious already without unnecessary technical details : it is the electron interaction with the fluctuating quantum electromagnetic field produced by other electrons moving in a disordered potential . in order to be able to quantitatively.
Please generate the next two sentences of the article | describe and understand the latter effect guinea @xcite suggested a model which mimics all essential features of the `` real '' problem of interacting electrons in a disordered conductor except for the pauli exclusion principle .
this model describes a quantum particle moving on a ring with radius @xmath3 and interacting with quantum dissipative environment . for a system in thermodynamic equilibrium quantum decoherence manifests itself as effective suppression of off - diagonal density matrix elements beyond a certain length @xmath1 . |
5,258 | Suppose that you have an abstract for a scientific paper: ngc 6782 is an early - type barred spiral galaxy exhibiting a rich and complex morphology with multiple ring patterns . to provide a physical understanding of its structure and kinematical properties ,
two - dimensional hydrodynamical simulations have been carried out .
numerical calculations reveal that the striking features in ngc 6782 can be reproduced provided that the gas flow is governed by the gravitational potential associated with a slowly rotating strong bar .
in particular , the response of the gaseous disk to the bar potential leads to the excitation of spiral density waves at the inner lindblad resonance giving rise to the appearance of a nearly circular nuclear ring with a pair of dust lanes . for a sufficiently strong bar potential ,
the inner 4:1 spiral density waves are also excited .
the interaction of the higher harmonic waves with the waves excited at the inner lindblad resonance and confined by the outer lindblad resonance results in the observed diamond - shaped ( or pointy oval ) inner ring structure . the overall gas morphology and kinematical features
are both well reproduced by the model provided that the pattern speed of the bar is @xmath0 km s@xmath1 kpc@xmath1 . .
And you have already written the first three sentences of the full article: it has long been recognized that a periodic potential , such as a rotating bar , can drive density waves in a differentially rotating disk .
a linear inviscid theory of the excitation and propagation of these waves in such disks was described in the seminal work of goldreich & tremaine ( 1979 , 1980 ) .
subsequently , yuan ( 1984 ) showed that the gravitational potential associated with a rotating bar can effectively excite nonlinear density waves with high radial streaming velocities at the outer lindblad resonance ( olr ) in the limit that self - gravity in the gas disk could be neglected ..
Please generate the next two sentences of the article | the excitation and wave propagation with self - gravity was later considered in the linear and nonlinear approximation by yuan & cheng ( 1989 , 1991 ) .
further progress was achieved by the development of a nonlinear asymptotic theory by yuan & kuo ( 1997 ) , who explicitly included the effects of gas pressure , viscosity , and self - gravitation in the formulation . however , the theory s applicability was somewhat limited as it was derived only in the vicinity of the resonances . building upon this study , |
5,259 | Suppose that you have an abstract for a scientific paper: the fundamental rovibrational band of co near 4.7@xmath0 m is a sensitive tracer of the presence and location of molecular gas in the planet - forming region of protoplanetary disks at 0.0110au .
we present a new analysis of a high - resolution spectral survey ( r@xmath196,000 , or @xmath2 ) of co rovibrational lines from protoplanetary disks spanning a wide range of stellar masses and of evolutionary properties .
we find that the co emission originates in two distinct velocity components .
line widths of both components correlate strongly with disk inclination , as expected for gas in keplerian rotation . by measuring the line flux ratios between vibrational transitions
@xmath3 , we find that the two velocity components are clearly distinct in excitation .
the broad component ( @xmath4 ) probes the disk region near the magnetospheric accretion radius at @xmath5au , where the gas is hot ( @xmath6k ) .
the narrow component ( @xmath7 ) probes the disk at larger radii of 0.110au , where the gas is typically colder ( 200700k ) .
co excitation temperatures and orbital radii define an empirical temperature - radius relation as a power law with index @xmath8 between 0.053au . the broad co component , co - spatial with the observed orbital distribution of hot jupiters , is rarely detected in transitional and herbig ae disks , providing evidence for an early dissipation of the innermost disk .
an inversion in the temperature profile beyond 3au is interpreted as a tracer of a regime dominated by uv pumping in largely devoid inner disks , and may be a signature of the last stage before the disk enters the gas - poor debris phase .
_ accepted by the astrophysical journal _ .
And you have already written the first three sentences of the full article: the inner @xmath9au of protoplanetary disks is thought to be the region in which most exoplanets form @xcite .
initially , the inner disk likely has a smooth radial distribution of gas and dust that is truncated by the stellar magnetic field at the co - rotation radius , within 0.1au .
from this point , disk material accretes onto the central star through magnetospheric accretion ( e.g. * ? ? ?.
Please generate the next two sentences of the article | however , over time , inner disks evolve , and gaps and inner holes frequently develop within a few myr @xcite . some of these gaps may be carved by photo - evaporation @xcite , and others by dynamical clearing by planets coupled with pressure - driven dust migration @xcite .
the evolutionary window available for planet formation is therefore limited by , and linked to , the time scale of inner disk dispersal of a few myr @xcite . |
5,260 | Suppose that you have an abstract for a scientific paper: we present results of new , deep _
suzaku _ x - ray observations ( @xmath0ks ) of the intracluster medium ( icm ) in abell 1689 out to its virial radius , combined with complementary data sets of the projected galaxy distribution obtained from the _ sdss _ catalog and the projected mass distribution from our recent comprehensive weak and strong lensing analysis of _ subaru / suprime - cam _ and _ hst / acs _ observations .
faint x - ray emission from the icm around the virial radius ( @xmath1 ) is detected at @xmath2 significance , thanks to low and stable x - ray background of _ suzaku_. the _ suzaku _ observations reveal anisotropic gas temperature and entropy distributions in cluster outskirts of @xmath3 correlated with large - scale structure of galaxies in a photometric redshift slice around the cluster .
the high temperature ( @xmath4kev ) and entropy region in the northeastern ( ne ) outskirts is apparently connected to an overdense filamentary structure of galaxies outside the cluster .
the gas temperature and entropy profiles in the ne direction are in good agreement , out to the virial radius , with that expected from a recent _ xmm - newton _ statistical study and with an accretion shock heating model of the icm , respectively . to the contrary , the other outskirt regions in contact with low density void environments have low gas temperatures ( @xmath5kev ) and entropies , deviating from hydrostatic equilibrium .
these anisotropic icm features associated with large - scale structure environments suggest that the thermalization of the icm occurs faster along overdense filamentary structures than along low - density void regions .
we find that the icm density distribution is fairly isotropic , with a three - dimentional density slope of @xmath6 in the radial range of @xmath7 , and with @xmath8 in @xmath3 , which however is significantly shallower than the navarro , frenk , & white universal matter density profile in the outskirts , @xmath9 .
a joint x - ray and lensing analysis shows....
And you have already written the first three sentences of the full article: clusters of galaxies are the largest self - gravitating systems in the universe , and x - ray observations have revealed characteristics of intracluster medium ( icm ) which carries @xmath19% mass of known baryons , such as temperature , icm mass , and metals therein
. however , the icm emission has been detectable only to @xmath20 times the virial radius @xmath21 ( e.g. * ? ? ?
* ) due to limited sensitivities of detectors ..
Please generate the next two sentences of the article | this means @xmath22% of an entire cluster volume has been unexplored in x - rays .
according to the hierarchical structure formation scenario based on cold dark matter ( cdm ) paradigm , mass accretion flows onto clusters , in particular , along filamentary structures , are still on - going . |
5,261 | Suppose that you have an abstract for a scientific paper: we analyze fluctuations of quark number and electric charge , in 2-flavour qcd at finite temperature and vanishing net baryon number density . in the hadronic phase we find that an enhancement of charge fluctuations arises from contributions of doubly charged hadrons to the thermodynamics .
the rapid suppression of fluctuations seen in the high temperature phase suggests that in the qgp quark number and electric charge are predominantly carried by quasi - particles with the quantum numbers of quarks . .
And you have already written the first three sentences of the full article: lattice calculations of bulk thermodynamic observables , e.g. the energy density and pressure , clearly show that the transition to the high temperature phase of qcd is accompanied by the liberation of partonic degrees of freedom .
asymptotically , at infinite temperature , energy density and pressure approach the limit of an ideal gas of quarks and gluons . at @xmath0
the deviations from this asymptotic behaviour are still about 15% which is too large to be accounted for by ordinary high temperature perturbation theory ..
Please generate the next two sentences of the article | this shows the relevance of non - perturbative effects leading , for instance , to thermal quark and gluon masses . for temperatures close to @xmath1 , _
i.e. _ @xmath2 , these non - perturbative features dominate bulk thermodynamic behaviour , leading to large deviations from the ideal gas relation @xmath3 , a strong reduction of the velocity of sound and large screening lengths @xcite . |
5,262 | Suppose that you have an abstract for a scientific paper: in this work we study an so(10 ) gut model with minimum higgs representations belonging only to the * 210 * and * 16 * dimensional representations of so(10 ) .
we add a singlet fermion @xmath0 in addition to the usual * 16 * dimensional representation containing quarks and leptons
. there are no higgs bi - doublets and so charged fermion masses come from one - loop corrections .
consequently all the fermion masses , dirac and majorana , are of the see - saw type .
we minimize the higgs potential and show how the left - right symmetry is broken in our model where it is assumed that a @xmath1-parity odd higgs field gets a vacuum expectation value at the grand unification scale . from the renormalization group equations we infer that in our model unification happens at @xmath2 gev and left - right symmetry can be extended up to some values just above @xmath3 gev .
the yukawa sector of our model is completely different from most of the standard grand unified theories and we explicitly show how the yukawa sector will look like in the different phases and briefly comment on the running of the top quark mass .
we end with a brief analysis of lepton number asymmetry generated from the interactions in our model . .
And you have already written the first three sentences of the full article: the so(10 ) grand unified theory has several interesting features @xcite . it can accommodate left - right symmetry as one of the intermediate symmetry and hence provides an explanation of parity violation @xcite .
@xmath4 is a generator of the group so(10 ) and hence lepton number violation takes place spontaneously .
this explains the origin of lepton number violation and neutrino majorana mass naturally ..
Please generate the next two sentences of the article | the smallness of neutrino masses is assured by the see - saw mechanism , so that by keeping the scale of @xmath4 violation high the smallness of the neutrino mass is guaranteed .
quarks and leptons are treated equally in so(10 ) gut . |
5,263 | Suppose that you have an abstract for a scientific paper: a brief review of the @xmath0 dependence of the dihadron correlations from rhic is presented .
we attempt to construct a consistent picture that can describe the data as a whole , focusing on the following important aspects , 1 ) the relation between jet fragmentation of survived jet and medium response to quenched jets , 2 ) the possible origin of the medium response and its relation to intermediate @xmath0 physics for single hadron production , 3 ) the connection between the near - side ridge and away - side cone , 4 ) and their relations to low energy results . .
And you have already written the first three sentences of the full article: dihadron azimuthal correlation has been a successful tool in understanding the interactions between jet and medium , and in extracting the properties of the sqgp . over the years
, the correlation analyses have been carried out in various regions of transverse momentum ( @xmath0 ) for the triggers and partners .
many interesting features have been discovered . in the high @xmath0 region ,.
Please generate the next two sentences of the article | the correlation distributions show narrow peaks around @xmath1 ( near - side ) and @xmath2 ( away - side ) @xcite , consistent with fragmentation of jets escaping the dense medium with small energy loss . in the low @xmath0 region ,
the correlation distributions are dominated by a double hump structure around @xmath3 at the away - side ( the cone ) @xcite and a structure elongated along the @xmath4 but centered around @xmath1 ( the ridge ) @xcite , characteristic of a complicated response of the medium to energy deposited by the quenched jets . in the meanwhile , many theoretical models @xcite have been proposed to interpret the data . |
5,264 | Suppose that you have an abstract for a scientific paper: the alice detector at the lhc recorded first pb pb collisions at @xmath0 tev in november and december of 2010 .
we report on the measurements of anisotropic flow for charged and identified particles . from the comparison with measurements at lower energies and with model predictions we find that the system created at these collision energies is described well by hydrodynamical model calculations and behaves like an almost perfect fluid . .
And you have already written the first three sentences of the full article: anisotropic flow is an important observable in ultra - relativistic heavy - ion collisions as it signals the presence of multiple interactions between the constituents of the created matter .
anisotropic flow has been observed in nucleus
nucleus collisions from low energies up to @xmath0 tev at the large hadron collider ( lhc ) @xcite ..
Please generate the next two sentences of the article | the azimuthal anisotropic flow is usually characterized by the fourier coefficients @xcite : @xmath1\rangle , \label{eq : harmonics}\ ] ] where @xmath2 is the azimuthal angle of the particle , @xmath3 is the azimuthal angle of the initial state spatial plane of symmetry , and @xmath4 is the order of the harmonic .
the second fourier coefficient @xmath5 is called elliptic flow @xcite . because the magnitude of the anisotropic flow depends strongly on the friction in the created matter , characterized by the shear viscosity over entropy density ratio @xmath6 , the large elliptic flow observed at rhic provided compelling evidence for strongly interacting matter which , in addition , appears to behave like an almost perfect fluid @xcite . |
5,265 | Suppose that you have an abstract for a scientific paper: since the discovery of the first exoplanet , those most adequate for life to begin and evolve have been sought . due to observational bias , however , most of the discovered planets so far are gas giants , precluding their habitability .
if these hot jupiters are located in the habitable zone of their host stars , and if rocky moons orbit them , these moons may be habitable . in this work
we present a model for planetary transit simulation considering the presence of moons and planetary rings around the planet .
the moon s orbit is considered to be circular and coplanar with the planetary orbit .
the other physical and orbital parameters of the star , planet , moon and rings can be adjusted in each simulation .
it is possible to simulate as many successive transits as desired .
since the presence of spots on the surface of the star may produce a signal similar to that of the presence of a moon , our model also allows for the inclusion of starspots .
the result of the simulation is the light curve with the planetary transit .
white noise may also be added to the light curves , to produce curves similar to those obtained by the corot and kepler space telescopes .
the goal is to determine the criteria for detectability of moons and/or ring systems using photometry .
the results show that it is possible to detect moons with radii as little as 1.3 r@xmath0 with corot and 0.3 r@xmath0 with kepler . .
And you have already written the first three sentences of the full article: since the detection of the first extra - solar planet orbiting a solar - like star in 1995 , 51 peg b @xcite , several new discoveries have been made .
the most used planetary detection methods are radial velocity and transit .
together , both techniques led to the discovery of the vast majority of the over 570 planets observed so far ( according to the extra - solar planets encyclopaedia , http://exoplanet.eu ) . when the same planet is detected by both methods ,.
Please generate the next two sentences of the article | the complete set of planetary and orbital parameters is determined .
two space missions designed to detect planetary transits are operational right now : corot , from the cnes with a consortium of many countries , and kepler , from nasa . |
5,266 | Suppose that you have an abstract for a scientific paper: results of the analysis of the miniboone experiment data for the neutral current elastic neutrino scattering off the @xmath0 target with the nuwro monte carlo generator are presented .
inclusion in the nuwro the two body current contribution leads to the axial mass value @xmath1 gev consistent with the older evaluations based on the neutrino - deuteron scattering data . the strange quark contribution to the nucleon spin
is estimated with the value @xmath2 . .
And you have already written the first three sentences of the full article: there has been a lot of interest in neutrino interactions in the few gev energy region , coming from the oscillation experiments and the demand to better constrain the systematic errors . for the neutrino energies around @xmath3 gev the most abundant reaction
is charged current quasi - elastic ( ccqe ) scattering : @xmath4 and it is also the most important process in the investigation of the oscillation phenomenon , e.g. in the t2k experiment @xcite . due to the standard
conserved vector current ( cvc ) and partially conserved axial current ( pcac ) hypotheses , using the electron scattering data and assuming a dipole form of the axial form factor , the weak transition matrix element contains only one unknown parameter , the axial mass @xmath5 ..
Please generate the next two sentences of the article | recent neutrino ccqe cross section measurements , notably the high statistics muon double differential cross section results from the miniboone ( mb ) experiment @xcite , suggest @xmath5 values significantly larger than estimations from the older deuteron target neutrino measurements and from the pion electro - production data @xcite .
it is becoming clear that in order to understand correctly the mb data , a two body current contribution to the cross section must be considered @xcite . in the experimental event identification |
5,267 | Suppose that you have an abstract for a scientific paper: we have mapped two molecular clouds at ( @xmath0 ) = ( @xmath1 ) and ( @xmath0 ) = ( @xmath2 ) in 21-cm line and continuum emission .
these clouds show unusually large velocity dispersions of more than 100 ( fwhm ) which has also been seen in @xmath3co , @xmath4 , and cs emissions .
this dispersion is roughly an order of magnitude larger compared to giant molecular clouds . from our hi observation
we estimate that the atomic mass of the cloud at @xmath5 is about @xmath6 and the mass of the cloud at @xmath7 is @xmath8 .
the ratio of total molecular mass to atomic mass for these clouds appears to be normal for clouds near the galactic center .
the main peculiar feature of these clouds is their abnormally large velocity dispersion ; the extent in velocity is from about 0 km s@xmath9 ( lsr ) to 200 km s@xmath9 .
these clouds are connected , in the @xmath10v plane , to high velocity ridges that extend over several degrees of the longitude . these properties , we believe ,
provide important clues to the physical process responsible for their large velocity dispersion . .
And you have already written the first three sentences of the full article: there are more than 100 giant molecular clouds in the galaxy with mass of 10@xmath11m@xmath12 or greater .
the internal velocity dispersion of these clouds , measured using @xmath3co emission , is in most cases approximately equal to their virial velocity of about 15 ( dame 1986 ) .
however , there are at least two very unusual molecular clouds , located at @xmath13(@xmath14 ) and ( @xmath15 ) , which have extremely large velocity dispersions of about 100 ( fwhm ) as seen in several molecular lines including @xmath3co.
Please generate the next two sentences of the article | . hereafter we shall refer to these objects as wide line clouds ( wlcs ) .
oort drew attention to the large velocity dispersion of the wlc at @xmath16 longitude in his influential review article almost two decades ago ( 1977 ) . |
5,268 | Suppose that you have an abstract for a scientific paper: the accretion of hot , dense matter which consists of heavy nuclei , free nucleons , degenerated electrons , photons and neutrinos is studied .
the composition of free nucleons and their chemical potentials are provided through the equation of state for hot , dense matter proposed by @xcite .
the numbers of leptons are calculated through the reactions of neutrinos and through the simplified transfers of neutrinos in the accreting matter .
the thermally equilibrium fluid structure of the accretion is solved .
the angular momentum transfer in the disk is analyzed with the shear stress which is driven in the frame of the general relativity .
when the mass of a central black hole and the accretion rate are selected as @xmath0 and @xmath1sec@xmath2 , which provide the typical luminosity of gamma ray bursts(grbs ) , the fraction of free protons in the accreting matter becomes very small , @xmath3 , while that of free neutrons is closer to unity , @xmath4 .
then the antielectron neutrinos @xmath5 can freely escape through the disk but the electron neutrinos @xmath6 are almost absorbed in the disk . thus the frequent collisions of @xmath5 with @xmath6 over the disk could nt be occurred .
the accretion disk is cooled mainly by @xmath5 , which suppresses the increase of temperature and increases the density in the accreting matter such as @xmath7k and @xmath8g/@xmath9 at the inner side of the disk .
the scattering optical depths of @xmath5 and @xmath6 then reach to be very large , @xmath10 .
thus the accretion disk could be thermally unstable within the duration of diffusion time of neutrinos , @xmath11(ms ) . the ram pressure produced by many scattering of @xmath5
are very strong , which might produce the neutrino driven wind or jets .
the luminosity and mean energy of neutrinos , @xmath12 , @xmath13 , ejected from the disk increases with the specific angular momentum of a black hole .
the mean energy is inversely proportional to the central mass , @xmath14 , while the luminosity @xmath12 is....
And you have already written the first three sentences of the full article: an intense gamma - ray burst , grb030329 , allowed us to carry out the very detailed observations of optical , x - ray , and radio counterparts to the burst .
its photometry and spectroscopy led to the separation between the afterglow and sn contributions @xcite .
the sn component is similar to sn 1998bw ; an unusual type ic sn @xcite ..
Please generate the next two sentences of the article | it makes clear that at least some grbs arise from core - collapse sne .
grb030329 was seen as a double - pulsed burst with the total duration time of @xmath1630 sec @xcite . |
5,269 | Suppose that you have an abstract for a scientific paper: an overview is provided for 200 years of galactic studies at the tartu observatory .
galactic studies have been one of the main topics of studies in tartu over the whole period of the history of the observatory , starting from f.g.w .
struve and j.h .
mdler , followed by ernst pik and grigori kuzmin , and continuing with the present generation of astronomers .
our goal was to understand better the structure , origin and evolution of stars , galaxies and the universe . .
And you have already written the first three sentences of the full article: galactic studies have been one of the main topics of the tartu observatory over the whole period of its existence .
these studies began with the work by f.g.w .
struve on double stars and measurements of stellar parallaxes in early 19th century , when tartu observatory was founded in the kaiserliche universitt zu dorpat ..
Please generate the next two sentences of the article | modern era of galactic studies began about 95 years ago when ernst pik determined the dynamical density of matter in the disk of the galaxy in 1915 , the distance to the andromeda nebula in 1922 , and found main principles of stellar structure and evolution in 1938 .
his student grigori kuzmin developed principles of galactic modeling and calculated the local density of matter near the sun , suggesting the absence of local dark matter in large quantities . |
5,270 | Suppose that you have an abstract for a scientific paper: we present results for the optical absorption spectra of small - diameter single - wall carbon and boron nitride nanotubes obtained by _ ab initio _ calculations in the framework of time - dependent density functional theory .
we compare the results with those obtained for the corresponding layered structures , i.e. the graphene and hexagonal bn sheets .
in particular , we focus on the role of depolarization effects , anisotropies and interactions in the excited states .
we show that already the random phase approximation reproduces well the main features of the spectra when crystal local field effects are correctly included , and discuss to which extent the calculations can be further simplified by extrapolating results obtained for the layered systems to results expected for the tubes .
the present results are relevant for the interpretation of data obtained by recent experimental tools for nanotube characterization such as optical and fluorescence spectroscopies as well as polarized resonant raman scattering spectroscopy .
we also address electron energy loss spectra in the small - q momentum transfer limit . in this case , the interlayer and intertube interactions play an enhanced role with respect to optical spectroscopy . .
And you have already written the first three sentences of the full article: the science of nanostructures is one of the fields of growing interest in materials science .
nanotubes , in particular , are of both fundamental and technological importance ; being quasi - one - dimensional ( 1d ) structures , they possess a number of exceptional properties .
while the peculiar electronic structure metallic versus semiconducting behavior of carbon nanotubes depends sensitively on the diameter and the chirality , i.e. , on the way the graphene sheet is wrapped up into a tube @xcite , boron nitride ( bn ) tubes display a more uniform behavior with a wide band - gap ( larger than 4 ev ) , almost independent of diameter and chirality @xcite ..
Please generate the next two sentences of the article | the potential applications of nanotubes in nanodevices are numerous @xcite : super - tough nanotube fibres @xcite , gas sensors @xcite , field effect displays @xcite , and electromechanical devices @xcite , to name only a few .
one of the most spectacular examples is the realization of field effect transistors both with carbon nanotubes @xcite and with bn - nanotubes @xcite . |
5,271 | Suppose that you have an abstract for a scientific paper: distribution and kinematics of molecular gas in the central region of the barred spiral galaxy maffei 2 were investigated using a data set of @xmath0co(10 ) , @xmath0co(21 ) , cs(21 ) lines and 103 ghz continuum .
we found that the offset ridges along the kpc - scale bar continue to the central spiral structure embedded in the weak oval structure which is regarded as @xmath12 orbit in the bar potential .
the spiral structure continues toward the center diverging from the oval structure .
the size of these structures is less than @xmath2 pc . the mass concentration within @xmath3 35 pc is estimated to be @xmath4 .
the high mass concentration is consistent with theoretical predictions concerning the creation of such a nuclear spiral structure . a comparison with the tracers of dense gas and star - forming region suggests that the dense molecular gas traced by cs(21 ) line is formed at the crossing points of @xmath11 and @xmath12 orbits and the star - forming region appears after @xmath5 yr which is comparable with the free - fall time of the dense gas traced by the cs line ( @xmath6 @xmath7 ) . .
And you have already written the first three sentences of the full article: to maintain activities of central starbursts or active galactic nuclei in galaxies , fueling of molecular gas toward the center is necessary .
bar is one of the possible mechanisms , for the gas fueling .
many numerical simulations of gas motion in the bar potential show that bars can accumulate gas toward the central region ( e.g. , athanassoula 1992 ) ..
Please generate the next two sentences of the article | observational evidence of gas accumulation toward the central kilo - parsec region has also been shown .
for example , sakamato et al . ( 1999 ) and sheth et al . |
5,272 | Suppose that you have an abstract for a scientific paper: recently a new method for determining the neutrino mass hierarchy by comparing the effective values of the atmospheric @xmath0 measured in the electron neutrino disappearance channel , @xmath1 , with the one measured in the muon neutrino disappearance channel , @xmath2 , was proposed .
if @xmath3 is larger ( smaller ) than @xmath4 the hierarchy is of the normal ( inverted ) type .
we re - examine this proposition in the light of two very high precision measurements : @xmath2 that may be accomplished by the phase ii of the tokai - to - kamioka ( t2k ) experiment , for example , and @xmath3 that can be envisaged using the novel mssbauer enhanced resonant @xmath5 absorption technique . under optimistic assumptions for the systematic uncertainties of both measurements , we estimate the parameter region of @xmath6 in which the mass hierarchy can be determined . if @xmath7 is relatively large , @xmath8 , and both of @xmath1 and @xmath2 can be measured with the precision of @xmath9 % it is possible to determine the neutrino mass hierarchy at @xmath10 95% cl for @xmath11 for the current best fit values of all the other oscillation parameters .
1.6 cm in spite of the great progress that has been made in recent years there still remains a number of important questions regarding the nature of neutrinos .
one such unknown is whether the neutrinos have a normal or inverted mass hierarchy .
this unresolved ambiguity in the neutrino mass pattern is usually phrased as follows : if the neutrino masses are labeled as @xmath12 ( @xmath13 ) for the mass of the neutrino state with the greatest ( least ) @xmath14 component then for the normal hierarchy @xmath15 and for the inverted hierarchy @xmath16 .
the determination of this pattern must shed light on the secret of how the lepton sector is organized and may testify to the underlying symmetries by which the structure of neutrino masses and lepton flavor mixing are prescribed @xcite .
it is widely recognized that it is difficult to determine the neutrino....
And you have already written the first three sentences of the full article: let us first explain the unconventional way of determining neutrino mass hierarchy , the `` @xmath0 disappearance '' method @xcite , to be explored in this paper .
suppose that we measure the atmospheric @xmath0 by doing disappearance measurements of @xmath21 and @xmath22 in vacuum . for clarity ,
we start with a simplified setting where the solar mixing angle @xmath23 vanishes . in this case.
Please generate the next two sentences of the article | , it is obvious that @xmath24 and @xmath25 channels are governed by @xmath26 and approximately @xmath27 , respectively , since the two oscillations scales approximately decouple from each other .
notice that because @xmath28 , @xmath29 for the normal hierarchy and @xmath30 for the inverted hierarchy . |
5,273 | Suppose that you have an abstract for a scientific paper: nowadays , to facilitate the communication and cooperation among employees , a new family of online social networks has been adopted in many companies , which are called the `` enterprise social networks '' ( esns ) .
esns can provide employees with various professional services to help them deal with daily work issues .
meanwhile , employees in companies are usually organized into different hierarchies according to the relative ranks of their positions .
the company internal management structure can be outlined with the organizational chart visually , which is normally confidential to the public out of the privacy and security concerns . in this paper
, we want to study the ioc ( nference of rganizational hart ) problem to identify company internal organizational chart based on the heterogeneous online esn launched in it .
ioc is very challenging to address as , to guarantee smooth operations , the internal organizational charts of companies need to meet certain structural requirements ( about its depth and width ) . to solve the ioc problem , a novel unsupervised method create ( hr covr )
is proposed in this paper , which consists of @xmath0 steps : ( 1 ) social stratification of esn users into different social classes , ( 2 ) supervision link inference from managers to subordinates , and ( 3 ) consecutive social classes matching to prune the redundant supervision links .
extensive experiments conducted on real - world online esn dataset demonstrate that create can perform very well in addressing the ioc problem . .
And you have already written the first three sentences of the full article: in social sciences , people in social organizations ( e.g. , a country or a company ) can be categorized into different rankings of socioeconomic tiers based on factors like wealth , income , social status , occupation , power , etc . in this paper
, we will take `` company '' as an example and the internal hierarchical structure of employees in a company can be outlined with _ company organizational chart _ formally .
most company organizational charts are usually tree - structure diagrams with ceo at the root , executive vice presidents ( evps ) at the second level and so forth ..
Please generate the next two sentences of the article | company organizational chart shows the company internal management structure as well as the relationships and relative ranks of employees with different positions / jobs , which is a common visual depiction of how a company is organized . nowadays , to facilitate the collaboration and communication among employees , a new type of online social networks named _ enterprise social networks _
( esns ) has been adopted inside the firewalls of many corporations . |
5,274 | Suppose that you have an abstract for a scientific paper: we describe the bottomonium spectrum obtained on the milc configurations which incorporate 2 + 1 flavors of dynamical quarks .
we compare to quenched and 2 flavor results also on milc configurations .
we show that the lattice spacing determination using different quantities shows clear signs of convergence with 2 + 1 flavors and give results for the leptonic width and hyperfine splitting , in the form of the ratio of the 1st excited state of the @xmath0 to that of the ground state . .
And you have already written the first three sentences of the full article: measurement of the @xmath0 spectrum gives an excellent test for studying the dynamical content of the configurations being used .
nrqcd can be used to give precise results which indicate how the light dynamical quarks feed in to the heavy meson properties .
the program at cleo - c will enable lattice results on @xmath0 spectroscopy to be experimentally verified @xcite . here.
Please generate the next two sentences of the article | we present new results using dynamical configurations from the milc collaboration @xcite .
we have used the coarser set of available ensembles . |
5,275 | Suppose that you have an abstract for a scientific paper: the aim of this paper is to give a description of the poisson furstenberg boundary of random walks on non - amenable baumslag solitar groups . after a short introduction to baumslag
solitar groups and their geometry , we change our focus to random walks on these groups .
the poisson furstenberg boundary is a probabilistic model for the long - time behaviour of random walks . for random walks on non - amenable baumslag
solitar groups we identify the poisson furstenberg boundary in terms of the boundary of the hyperbolic plane and the space of ends of the associated bass serre tree using kaimanovich s strip criterion .
the precise statement can be found in theorem [ thm : identification ] on page .
* keywords : * random walk , poisson furstenberg boundary , strip criterion , baumslag solitar group , compactification .
* msc 2010 classes : * 60j50 ( primary ) , 60g50 , 20f65 , 50c63 . .
And you have already written the first three sentences of the full article: for any two non - zero integers @xmath0 and @xmath1 the baumslag
solitar group @xmath2 is given by the presentation @xmath3 .
these groups were introduced by baumslag and solitar in @xcite , who identified @xmath4 as the first example of a two - generator one - relator non - hopfian group and thus answered a question by b. h. neumann , see @xcite . later on , it was shown that @xmath2 is hopfian if and only if @xmath5 or @xmath6 or @xmath7 , where @xmath8 denotes the set of prime divisors of @xmath9 , see @xcite and @xcite ..
Please generate the next two sentences of the article | after reviewing some fundamental properties of baumslag
solitar groups , we shall consider random walks on these groups . |
5,276 | Suppose that you have an abstract for a scientific paper: we describe the data reduction algorithms for the multiband imaging photometer for spitzer ( mips ) instrument .
these algorithms were based on extensive preflight testing and modeling of the si : as ( 24 ) and ge : ga ( 70 and 160 ) arrays in mips and have been refined based on initial flight data .
the behaviors we describe are typical of state - of - the - art infrared focal planes operated in the low backgrounds of space .
the ge arrays are bulk photoconductors and therefore show a variety of artifacts that must be removed to calibrate the data . the si array , while better behaved than the ge arrays , does show a handful of artifacts that also must be removed to calibrate the data .
the data reduction to remove these effects is divided into three parts .
the first part converts the non - destructively read data ramps into slopes while removing artifacts with time constants of the order of the exposure time .
the second part calibrates the slope measurements while removing artifacts with time constants longer than the exposure time .
the third part uses the redundancy inherit in the mips observing modes to improve the artifact removal iteratively . for each of these steps
, we illustrate the relevant laboratory experiments or theoretical arguments along with the mathematical approaches taken to calibrate the data .
finally , we describe how these preflight algorithms have performed on actual flight data . .
And you have already written the first three sentences of the full article: most of our knowledge of the universe at far infrared wavelengths has been obtained with photoconductive detectors , particularly as used in the infrared astronomy satellite ( iras ) and the infrared space observatory ( iso ) .
these detectors have been selected because they provide excellent performance at relatively elevated operating temperatures ( compared with those needed to suppress thermal noise in bolometers ) .
similar considerations led to development of high performance photoconductor arrays for the multiband imaging photometer for spitzer ( mips ) , namely a ge : ga array and a stressed ge : ga array operating at 70 and 160 respectively which were built at the university of arizona ..
Please generate the next two sentences of the article | to provide complementary measurements at 24 , the instrument also includes a si : as blocked impurity band ( bib ) array , built at boeing north america ( bna ) under contract to the infrared spectrograph ( irs ) team . in the bib or impurity band conduction ( ibc ) architecture ,
the high impedance required to minimize johnson noise is provided by a thin , high - purity layer of silicon . |
5,277 | Suppose that you have an abstract for a scientific paper: we consider the 2d quasi - periodic scattering problem in optics , which has been modelled by a boundary value problem governed by helmholtz equation with transparent boundary conditions . a spectral collocation method and a tensor product spectral method
are proposed to numerically solve the problem on rectangles .
the discretization parameters can be adaptively chosen so that the numerical solution approximates the exact solution to a high accuracy .
our methods also apply to solve general partial differential equations in two space dimensions , one of which is periodic .
numerical examples are presented to illustrate the accuracy and efficiency of our methods .
helmholtz equation , transparent boundary condition , spectral method , chebfun 65m70 , 65t40 , 65t50 , 78a45 .
And you have already written the first three sentences of the full article: with the development of electromagnetic and optics technology and the increasing demands in industrial and military applications , scattering from periodic structures @xcite have attracted much interest in recent years . a variety of numerical methods including finite difference methods @xcite , finite element methods @xcite , spectral and spectral element methods @xcite , integral equation methods @xcite , dirichlet - to - neumann map methods @xcite , and mode expansion method @xcite have been developed by the engineering community and the applied mathematical community for solving linear diffraction problems from periodic structures .
finite difference and finite element methods are easy to implement and result in sparse linear systems , which enable the use of sparse direct solvers .
however , these methods typically have significant dispersion errors for high - frequency problems and thus fail to provide accurate solutions ..
Please generate the next two sentences of the article | if the medium is piecewise constant , boundary integral equations formulated on the interfaces of multilayer structures @xcite or the boundaries of the obstacles @xcite are natural and mathematically rigorous . by exploiting high - order quadratures , one obtains much higher efficiency and accuracy than finite difference and finite element methods . for problems with general medium , spectral methods @xcite can be employed .
they are simple to implement and typically require relatively small number of unknowns to attain a fixed accuracy . |
5,278 | Suppose that you have an abstract for a scientific paper: a fundamental goal of quantum technologies concerns the exploitation of quantum coherent dynamics for the realisation of novel quantum applications such as quantum computing , quantum simulation , and quantum metrology .
a key challenge on the way towards these goals remains the protection of quantum coherent dynamics from environmental noise .
here , we propose a concept of hybrid dressed state from a pair of continuously driven systems .
it allows sufficiently strong driving fields to suppress the effect of environmental noise , while at the same time being insusceptible to both the amplitude and phase noise in the continuous driving fields .
this combination of robust features significantly enhances coherence times under realistic conditions , and at the same time provides new flexibility in hamiltonian engineering that otherwise is not achievable .
we demonstrate theoretically applications of our scheme for noise resistant analog quantum simulation in the well studied physical systems of nitrogen - vacancy centers in diamond and of trapped ions .
the scheme may also be exploited for quantum computation and quantum metrology . _
introduction. _ quantum technologies hold the promise for the realisation of a wide variety of applications including quantum computing @xcite , quantum simulation @xcite , quantum metrology @xcite and precision measurements @xcite as well as quantum sensing @xcite to name just a few .
this motivates the considerable effort that is being invested in the creation of the technological basis for these devices with the ultimate goal of constructing quantum devices that can outperform their classical counterparts .
one of the main obstacles on this path is the effect of noise and decoherence due to interaction with an uncontrolled environment , the effect of which becomes increasingly severe as the number of system components grows .
this poses a considerable challenge for achieving the quantum control of such systems while maintaining the quantum coherence of....
And you have already written the first three sentences of the full article: we consider two - level systems as described by the following hamiltonian @xmath114 where @xmath1 ( @xmath2 ) represent pauli operators , noise can occur along all three axes @xmath115}\sigma_{\alpha}^k$ ] .
given the usual case of @xmath116 , the effect of transverse noise is suppressed by the energy gap @xmath8 .
thus the main decoherence comes from the longitudinal noise @xmath117 } \sigma_{z}^k,\ ] ] in the form of dephasing . and relative fluctuation @xmath118 ..
Please generate the next two sentences of the article | ( b ) the decay of coherence as a function of time for hybrid dressed spin ( hybrid ds ) .
the driving amplitude is @xmath30 . |
5,279 | Suppose that you have an abstract for a scientific paper: the synchrotron self - compton ( ssc ) emission from gamma - ray burst ( grb ) forward shock can extend to the very - high - energy ( vhe ; @xmath0100 gev ) range .
such high energy photons are rare and are attenuated by the cosmic infrared background before reaching us . in this work ,
we discuss the prospect to detect these vhe photons using the current ground - based cherenkov detectors .
our calculated results are consistent with the upper limits obtained with several cherenkov detectors for grb 030329 , grb 050509b , and grb 060505 during the afterglow phase . for 5 bursts in our nearby grb sample
( except for grb 030329 ) , current ground - based cherenkov detectors would not be expected to detect the modeled vhe signal . only for those very bright and nearby bursts like grb 030329 , detection of vhe photons is possible under favorable observing conditions and a delayed observation time of @xmath110 hours . .
And you have already written the first three sentences of the full article: on february 28 , 1997 , the first x - ray afterglow of a gamma - ray burst ( grb ) was detected , leading to the identification of its progenitor at cosmological distances @xcite . in a few days ,
the afterglow faded away with time as a power law .
this behavior is satisfactorily explained in the spherical ( isotropic ) fireball model involving relativistic ejecta decelerated by circumburst medium @xcite ..
Please generate the next two sentences of the article | the introduction of collimated jets relaxes the energy requirement of grbs by a factor of several hundred , as well as explains the steeper temporal decay of afterglows @xcite .
grbs are extra - galactic sources of gev and probably higher energy photons . |
5,280 | Suppose that you have an abstract for a scientific paper: we investigate the effect of a finite temperature on the behavior of logic circuits based on the principle of quantum cellular automata ( qca ) and of ground state computation .
in particular , we focus on the error probability for a wire of qca cells that propagates a logic state . a numerical model and an analytical , more approximate , model are presented for the evaluation of the partition function of such a system and , consequently , of the desired probabilities .
we compare the results of the two models , assessing the limits of validity of the analytical approach , and provide estimates for the maximum operating temperature . .
And you have already written the first three sentences of the full article: in recent years a new paradigm for computation has been proposed by craig lent and coworkers@xcite , based on the concept of quantum cellular automata ( qca ) .
such a concept , although extremely difficult to implement from a technological point of view@xcite , has several interesting features that make it worth pursuing .
the basic building block is made up of a single cell , containing two electrons that can be localized in four different areas or `` dots , '' located at the vertices of a square , as shown in each of the cells represented in fig ..
Please generate the next two sentences of the article | [ eins](a ) .
coulomb repulsion forces the two electrons to occupy dots that are aligned along one of the diagonals , and each of the two possible alignments is associated with a logic state . by placing cells next to each other , a wire can be formed ( binary wire ) , along which polarization enforced at one end will propagate@xcite , as a consequence of the system of charges relaxing down to the ground state . |
5,281 | Suppose that you have an abstract for a scientific paper: we study the evolution of scalar curvature perturbations in a brane - world inflation model in a 5d anti - de sitter spacetime .
the inflaton perturbations are confined to a 4d brane but they are coupled to the 5d bulk metric perturbations .
we numerically solve full coupled equations for the inflaton perturbations and the 5d metric perturbations using hawkins - lidsey inflationary model . at an initial time , we assume that the bulk is unperturbed .
we find that the inflaton perturbations at high energies are strongly coupled to the bulk metric perturbations even on subhorizon scales , leading to the suppression of the amplitude of the comoving curvature perturbations at a horizon crossing .
this indicates that the linear perturbations of the inflaton field does not obey the usual 4d klein - gordon equation due to the coupling to 5d gravitational field on small scales and it is required to quantise the coupled brane - bulk system in a consistent way in order to calculate the spectrum of the scalar perturbations in a brane - world inflation . .
And you have already written the first three sentences of the full article: our view of how our universe may be described within a higher - dimensional spacetime has been revolutionised via brane - world models @xcite ( see , c.g .
, @xcite for review ) . a simple way to study the effects of the higher - dimensional gravity on inflation models is to consider a 4d inflaton field confined to the brane in the context of the randall - sundrum model @xcite .
work to date has concentrated mainly on deriving corrections to the standard 4d result by assuming that 5d metric perturbations generated by the inflaton perturbations can be neglected ..
Please generate the next two sentences of the article | then the modification of spectrum is coming from the modified friedmann equation .
although a lot of interesting results have been obtained in this direction @xcite , it remains to see the consistency of neglecting the bulk metric perturbations . |
5,282 | Suppose that you have an abstract for a scientific paper: the evolution of electromagnetic and massless dirac perturbations in the space - time geometry of kehagias - sfetsos(ks ) black hole in the deformed hoava - lifshitz(hl ) gravity is investigated and the associated quasinormal modes(qnms ) are evaluated from time domain integration data .
we find a considerable deviation in the nature of field evolution in hl theory from that in the schwarzschild space - time and qnm region extends over a longer time in hl theory before the power - law tail decay begins .
the dependence of the field evolution on the hl parameter @xmath0 is also studied . in the time domain picture
we find that the length of qnm region increases with @xmath0 .
but the late time decay of field follows the same power - law tail behavior as in the case of schwarzschild black hole . .
And you have already written the first three sentences of the full article: recently a renormalizable theory of gravity in 3 + 1 dimensions was proposed by hoava , inspired from the lifshitz theory in solid state physics , now known as hoava - lifshitz(hl ) theory@xcite .
the theory is a potential candidate of quantum field theory of gravity .
it assumes a lifshitz - like anisotropic scaling between space and time at short distances , characterized by a dynamical critical exponent z = 3 and thus breaking the lorentz invariance ..
Please generate the next two sentences of the article | while in the ir limit it flows to z = 1 , retrieving the einstein s general relativity(gr ) .
the discussions on the consequences of theory are going on@xcite . as a new theory , it is interesting to investigate its various aspects in parallel . since the theory has the same newtonian and post newtonian corrections as those of gr , |
5,283 | Suppose that you have an abstract for a scientific paper: based on the exact numerical simulation and physical analysis , we have demonstrated all - angle single - beam left - handed behavior and superlens for both te and tm modes in a two - dimensional coated photonic crystals .
the imaging behaviors by two - dimensional photonic - crystal - based superlens have been investigated systematically .
good - quality images and focusing , with relative refractive index of -1 , have been observed in these systems for both polarized waves .
in contrast to the images in near - field region for the lowest valence band , non - near - field images , explicitly following the well - known wave - beam negative refraction law , have been demonstrated .
the absorption and compensation for the losses by introducing optical gain in these systems have also been discussed . thus , extensive applications of such a phenomenon to optical devices are anticipated . .
And you have already written the first three sentences of the full article: recently there has been a great deal of interest in studying a novel class of media that has become known as the left - handed materials ( lhms)[1 - 20 ] .
these materials are characterized by simultaneous negative permittivity @xmath0 and negative permeability @xmath1 .
properties of such materials were analyzed theoretically by veselago over 30 years ago[1 ] . as was shown by veselago.
Please generate the next two sentences of the article | , the lhms possess some peculiar electromagnetic properties such as inverse snell s law , reversed doppler shift , and reversed cherenkov radiation .
it had also been suggested that slab of the lhm could be employed as an unconventional flat lens . due to the absence of naturally occurring materials having both negative @xmath0 and negative @xmath1 , |
5,284 | Suppose that you have an abstract for a scientific paper: the magnetic responses of a spin-@xmath0 ladder doped with non - magnetic impurities are studied combining both analytical and numerical methods .
the regime where frustration induces incommensurability is taken into account .
several improvements are made on the results of the seminal work by sigrist and furusaki [ sigrist and a. furusaki , j. phys .
soc .
jpn .
, * 65 * , 2385 ( 1996 ) ] , and deviations from the brillouin magnetization curve due to interactions are also analyzed .
we first discuss the magnetic profile around a single impurity and the effective interactions between impurities within the bond - operator mean - field theory .
the results are compared to density - matrix renormalization group calculations . in particular ,
these quantities are shown to be sensitive to the transition to the incommensurate regime .
we then focus on the behavior of the zero - field susceptibility through an effective curie constant . at zero - temperature ,
we give doping - dependent corrections to the results of sigrist and furusaki on general bipartite lattices , and compute exactly the distribution of ladder clusters due to chain breaking effects .
solving the effective model with exact diagonalization and quantum monte - carlo gives the temperature dependence of the curie constant .
its high - temperature limit is understood within a random dimer model , while the low - temperature tail is compatible with a real - space renormalization group scenario .
interestingly , solving the full microscopic model does not show a plateau corresponding to the saturation of the impurities _ in isotropic ladders_. the second magnetic response which is analyzed is the magnetic curve .
below fields of the order of the spin gap , the magnetization process is controlled by the physics of interacting impurity spins .
the random dimer model is shown to capture the bulk of the curve , accounting for the deviation from a brillouin behavior due to interactions .
the effective model calculations....
And you have already written the first three sentences of the full article: the presence of disorder and impurities in strongly correlated systems offers a good opportunity to better understand the role played by quantum fluctuations in such materials @xcite .
either intrinsically present or explicitly added by doping , impurities in condensed matter systems can rarely be ignored , in particular when they induce new physics as compared to the disorder - free situation .
prominent examples are the kondo effect @xcite , anderson localization @xcite , dirty bosons physics in disordered superconductors @xcite , impurities in magnetic semiconductors @xcite , spin glasses @xcite ... in the context of antiferromagnetic ( af ) mott insulators , parent compounds of high temperature superconducting cuprates for instance , spin ladder materials @xcite have been shown to display very interesting features , in particular when the number of legs is an even number ..
Please generate the next two sentences of the article | for example , a finite energy gap @xmath3 appears in the excitation spectrum of two - leg af spin-1/2 ladders @xcite , as seen for instance in srcu@xmath1o@xmath4 @xcite .
furthermore , defects in gapped ladders induce very interesting effects @xcite , in particular the apparition of effective gapless modes below the bare spin gap @xmath3 . having in mind that the ground - state of a two - leg ladder displays short - range resonating valence bond like physics @xcite |
5,285 | Suppose that you have an abstract for a scientific paper: = 0.6 cm * abstract * we extend firstly the regular phantom black hole solution to a slowly rotating black hole case and find that the phantom field depresses the angular velocity of the event horizon and suppresses the super - radiation of black hole .
we also probe the dependence of quasi - periodic oscillations frequencies in relativistic precession model on the phantom parameter . with the observation data of gro j1655 - 40
, we make a constraint on the parameters of the regular and slowly rotating phantom black hole .
our results show that although the best - fit value of the phantom parameter @xmath0 is small , the allowed value of @xmath0 in the @xmath1 region is @xmath2 , which means that the phantom theoretical model can not be excluded by the constraint from quasi - periodic oscillations with the observation data of gro j1655 - 40 .
= 0.8 cm .
And you have already written the first three sentences of the full article: phantom dark energy is a special kind of theoretical models with the negative kinetic energy@xcite , which has been investigated extensively in cosmology because it can provide a mechanism to interpret the accelerating expansion of the current universe @xcite . due to its negative kinetic energy ,
the phantom dark energy owns the super negative equation of state @xmath3 , which leads to that the null energy condition is violated for phantom field .
the universe dominated by phantom dark energy will blow up incessantly and arrive at a future singularity named big rip at where anything in the universe including the large galaxies will be torn up ..
Please generate the next two sentences of the article | although the phantom dark energy owns such exotic properties , it is still supported by recent precise observational data @xcite .
however , all of these observational examinations and constraints on phantom dark energy are taken in the scope of cosmology . in black hole physics , the behaviors and properties of phantom field |
5,286 | Suppose that you have an abstract for a scientific paper: quantum phases provide us with important information for understanding the fundamental properties of a system .
however , the observation of quantum phases , such as berry s phase and the sign of the matrix element of the hamiltonian between two non - equivalent localized orbitals in a tight - binding formalism , has been challenged by the presence of other factors , e.g. , dynamic phases and spin / valley degeneracy , and the absence of methodology . here ,
we report a new way to directly access these quantum phases , through polarization - dependent angle - resolved photoemission spectroscopy ( arpes ) , using graphene as a prototypical two - dimensional material .
we show that the momentum- and polarization - dependent spectral intensity provides direct measurements of ( i ) the phase of the band wavefunction and ( ii ) the sign of matrix elements for non - equivalent orbitals . upon rotating light polarization by @xmath0
, we found that graphene with a berry s phase of @xmath1 ( @xmath2 1 for single- and @xmath2 2 for double - layer graphene for bloch wavefunction in the commonly used form ) exhibits the rotation of arpes intensity by @xmath3 , and that arpes signals reveal the signs of the matrix elements in both single- and double - layer graphene .
the method provides a new technique to directly extract fundamental quantum electronic information on a variety of materials . .
And you have already written the first three sentences of the full article: quantum phases are the most beautiful example of quantum physics and essential to understand physics in any material . for example ,
berry s phase , the accumulated phase in the eigenfunction acquired by evolving the quantum system adiabatically around a closed loop in the parameter space of the hamiltonian @xcite , has been shown to be responsible for the aharonov - bohm effect @xcite , the half - integer quantum hall effect @xcite , etc .
another important example is the sign of the hopping matrix element ( or hopping integral ) @xmath4 of the hamiltonian between two non - equivalent localized orbitals @xmath5 and @xmath6 in a tight - binding formalism ..
Please generate the next two sentences of the article | this phase , a fundamental quantity in determining the electronic structure of a system , is dictated by the characteristics of the atomistic interaction , e.g. , whether it is attractive or repulsive .
both of these are important to directly extract fundamental quantum electronic information on a variety of materials @xcite . in graphene |
5,287 | Suppose that you have an abstract for a scientific paper: based on fors2-vlt long - slit spectroscopy , the analysis of the central absorption line indices of 9 s0 galaxies in the fornax cluster is presented .
central indices correlate with central velocity dispersions ( @xmath0 ) as observed in ellipticals ( e ) .
however , the stellar population properties of these s0s indicates that the observed trends are produced by relative differences in age and @xmath1-element abundances and not in metallicity ( [ fe / h ] ) as previous studies have found in e galaxies .
the observed scatter in the line indices versus @xmath0 relations can be partially explained by the rotationally - supported nature of many of these systems .
the presence of tighter line indices vs. maximum ( circular ) rotational velocity ( @xmath2 ) relations confirms this statement .
it was also confirmed that the dynamical mass is the driving physical property of all these correlations and in our fornax s0s it has to be estimated assuming rotational support . .
And you have already written the first three sentences of the full article: in figure 1 ( left ) , different central line indices are plotted against @xmath0 for our sample ( bedregal et al .
bright and faint s0s lay in two separate clumps , each one in opposite extremes of the @xmath0 range .
when models from @xcite are used to estimate stellar population parameters , the observed trends seem to be driven by age and @xmath1-element relative abundances ..
Please generate the next two sentences of the article | this is opposite to what is usually found in e , where [ fe / h ] is an important driver of the correlations . by parametrising line indices using @xcite models we found that age can explain the observed slopes of h@xmath5-log(@xmath0 ) and fe - log(@xmath0 ) relations , while additional differences in @xmath1-element relative abundances would be required to explain the mg - log(@xmath0 ) trends . on the other hand
, [ fe / h ] by itself can not explain any of the observed index@xmath3-log(@xmath0 ) relations . |
5,288 | Suppose that you have an abstract for a scientific paper: domain wall - type solution with oscillating thickness in a real , scalar field model is investigated with the help of a polynomial approximation . we propose a simple extension of the polynomial approximation method . in this approach
we calculate higher order corrections to the planar domain wall solution , find that the domain wall with oscillating thickness radiates , and compute dumping of oscillations of the domain wall .
dynamics of a planar domain wall with oscillating thickness in @xmath0 model + by + maciej lusarczyk@xmath1 + jagiellonian university , institute of physics + reymonta 4 , 30 - 059 cracow , poland + @xmath1 e - mail : [email protected] .
And you have already written the first three sentences of the full article: topological defects constitues an important class of solutions in field - theoretical models with degenerate vacua .
they play very important role in several branches of physics .
let us mention here field - theoretical cosmology and the cosmic strings hypothesis ( see @xcite , @xcite , @xcite ) , dynamics of superconductors , superfluids and liquid crystals in condensed matter physics ( see @xcite - @xcite ) as well as a flux tube in qcd ..
Please generate the next two sentences of the article | + this short and incomplete list shows the necessity of having effective computing methods to study the dynamics of topological defects . in spite of the increasing development of mathematical techniques to solve nonlinear equations , exact solutions
seem not to be the rule and numerical methods have been the most common approach to study properties of topological defects |
5,289 | Suppose that you have an abstract for a scientific paper: we consider the population of black widow pulsars ( bwps ) .
the large majority of these are members of globular clusters . for minimum companion masses
@xmath00.1m@xmath1 , adiabatic evolution and consequent mass loss under gravitational radiation appear to provide a coherent explanation of all observable properties .
we suggest that the group of bwps with minimum companion masses @xmath2 are systems relaxing to equilibrium after a relatively recent capture event .
we point out that all binary millisecond pulsars ( msps ) with orbital periods @xmath3hr are bwps ( our line of sight allows us to see the eclipses in 10 out of 16 cases ) .
this implies that recycled msps emit either in a wide fan beam or a pencil beam close to the spin plane .
simple evolutionary ideas favour a fan beam .
[ firstpage ] binaries : close .
And you have already written the first three sentences of the full article: it is widely believed that most millisecond pulsars ( msps ) are spun up by accretion from a close binary companion .
this recycling ( radhakrishnan & srinivasan , 1981 ) can only take place when the neutron star magnetic field has decayed to a value @xmath4 g. if accretion subsequently stops for some reason , the neutron star appears as a millisecond pulsar with a very low spindown rate , as its low magnetic field makes dipole radiation very weak . in line with these ideas a large proportion of millisecond pulsars
are members of binary systems ..
Please generate the next two sentences of the article | often these pulsars undergo very wide eclipses , with an obscuring object much larger than the companion star s roche lobe .
this must be an intense wind from the companion star , driven in some way by the pulsar emission ( fruchter et al . , 1988 ) . |
5,290 | Suppose that you have an abstract for a scientific paper: in this work i summarize a model of binary stellar evolution involving case c mass transfer followed by a common envelope that strips away the hydrogen from the core of the primary star at the cost of shrinking the orbital separation and then , through tidal interaction , spins it up .
this model is then used to produce the possible progenitors of long gamma - ray burst / hypernova ( grb / hn ) explosions . as the core collapses with the newly supplied angular momentum it produces a kerr black hole surrounded by an accretion disk .
energy is extracted from the rotation of the black hole ( bh ) through the blandford - znajek ( bz ) mechanism to power both , the long gamma - ray burst and the accompanying hypernova ( supernova type ic broad line ) . if the binary survives the asymmetric mass loss its remnant is a black - hole binary that may eventually be observed as a soft x - ray transient ( sxt ) when the companion evolves and starts to transfer mass back to the black hole . a comparison with a sample of black - hole binaries where the masses and orbital periods are well constrained is performed . .
And you have already written the first three sentences of the full article: the collapsar model @xcite predicts that long - duration , soft spectrum , gamma - ray bursts ( grbs ) would be accompanied by a supernova ( sn ) explosion .
this was first confirmed by the spectroscopic association of grb 980425 with sn 1998bw and later followed by another four events ( grb 030329/sn 2003dh , grb 031203/sn 2003lw , grb 060218/sn 2006aj and grb
100316d / sn 2010bh ; see ref ..
Please generate the next two sentences of the article | * for a recent review ) .
there is less conclusive , but substantial evidence of grb / sn association in another two - dozen events . nonetheless , most gamma - ray bursts have no observed supernova counterpart , most likely because the greater fraction of them occur at large red shifts and thus make a supernova detection unlikely . |
5,291 | Suppose that you have an abstract for a scientific paper: it is well known that a triangulation of a closed 2-manifold is tight with respect to a field of characteristic two if and only if it is neighbourly ; and it is tight with respect to a field of odd characteristic if and only if it is neighbourly and orientable .
no such characterization of tightness was previously known for higher dimensional manifolds . in this paper , we prove that a triangulation of a closed 3-manifold is tight with respect to a field of odd characteristic if and only if it is neighbourly , orientable and stacked . in consequence ,
the khnel - lutz conjecture is valid in dimension three for fields of odd characteristic .
next let @xmath0 be a field of characteristic two .
it is known that , in this case , any neighbourly and stacked triangulation of a closed 3-manifold is @xmath0-tight . for triangulated closed 3-manifolds with at most 71 vertices or with first betti number at most 188
, we show that the converse is true .
but the possibility of an @xmath0-tight non - stacked triangulation on a larger number of vertices remains open .
we prove the following upper bound theorem on such triangulations . if an @xmath0-tight triangulation of a closed 3-manifold has @xmath1 vertices and first betti number @xmath2 , then @xmath3 .
equality holds here if and only if all the vertex links of the triangulation are connected sums of boundary complexes of icosahedra . 57q15 , 57r20 , 05c15 .
_ keywords : _ stacked spheres ; stacked manifolds ; triangulations of 3-manifolds ; tight triangulations ; icosahedron . .
And you have already written the first three sentences of the full article: all simplicial complexes considered in this paper are finite and abstract .
all homologies are simplicial homologies with coefficients in a field @xmath0 .
the vertex set of a simplicial complex @xmath4 will be denoted by @xmath5 . for @xmath6 ,.
Please generate the next two sentences of the article | the induced subcomplex @xmath7 $ ] of @xmath4 on the vertex set @xmath8 is defined by @xmath7 : = \{\alpha\in x \ , : \ , \alpha\subseteq a\}$ ] .
a simplicial complex @xmath4 is said to be a _ triangulated manifold _ |
5,292 | Suppose that you have an abstract for a scientific paper: we show how one may define baryon constituent quarks in a rigorous manner , given physical assumptions that hold in the large-@xmath0 limit of qcd .
this constituent picture gives rise to an operator expansion that has been used to study large-@xmath0 baryon observables ; here we apply it to the case of charge radii of the @xmath1 and @xmath2 states , using minimal dynamical assumptions .
for example , one finds the relation @xmath3 to be broken only by three - body , @xmath4 effects for any @xmath0 .
epsf 255=255 by 60 255 by-60255 by 0.1 in .1 in .1 in .
And you have already written the first three sentences of the full article: the only known path to rendering qcd - like theories perturbative at all energy scales is to increase the number @xmath0 of color charges@xcite , so that @xmath5 itself becomes the small expansion parameter .
while mesons in large @xmath0 continue to exhibit the quantum numbers of a single quark - antiquark pair , the large-@xmath0 baryon requires @xmath0 valence quarks , since su(@xmath0 ) group theory requires a minimum of @xmath0 fundamental representation indices to form a color singlet .. ] however , physical baryons consist also of myriad gluons and sea quark - antiquark pairs ; does this then imply that large @xmath0 baryons have a meaning only within the context of the valence quark model ?
in this paper we claim that this is not the case , and indeed argue that it is possible to use the very existence of baryons boasting well - defined quantum numbers and large-@xmath0 arguments to derive a _ rigorous _ constituent quark picture ..
Please generate the next two sentences of the article | these assumptions are clearly independent of the momentum transfer scale , and therefore this constituent picture holds from the low - energy to deep - inelastic scattering regimes .
, the individual coefficients of the terms in the @xmath5 expansion might grow large for high momentum transfers , spoiling the utility of the expansion . |
5,293 | Suppose that you have an abstract for a scientific paper: recently some experimental evidences have been obtained in favour of the existence of the inhomogeneous fulde - ferrell - larkin - ovchinnikov ( fflo ) superconducting state in heavy - fermion superconductor cecoin@xmath0 and organic superconductor @xmath1-(bets)@xmath2fecl@xmath3 .
however the unambiguous identification of fflo state remains very difficult .
we present the theoretical studies of the gaussian fluctuations near the tricritical point ( where the fflo modulation appears ) and demonstrate that the behavior of the fluctuational specific heat , paraconductivity and diamagnetism is qualitatively different from the usual superconducting transition .
special values of the critical exponent and the crossovers between different fluctuational regimes may provide a unique test for the fflo state appearance . .
And you have already written the first three sentences of the full article: the long - standing hunt for the inhomogenous superconducting state predicted by fulde and ferrell @xcite and by larkin and ovchinnikov @xcite ( the so - called fflo state ) has recently known a revival in the study of fermionic cold atoms @xcite , quantum chromodynamics color superconductivity @xcite and heavy fermion superconductor cecoin@xmath0 @xcite .
the fflo phase consists in a condensate of finite momentum cooper pairs in contrast to the zero momenta pairs of the usual bcs state .
hence the fflo superconducting order parameter acquires a spatial variation ..
Please generate the next two sentences of the article | such a state may be induced when a chemical potential difference is applied between two species of fermions with mutual pairing attraction . in superconductors
the different chemical potentials are obtained by a zeeman splitting @xmath4 between spin up and down states , @xmath5 and @xmath6 being respectively the bohr magneton and an external magnetic field ( in magnetic superconductors @xmath7 is the internal exchange field ) . |
5,294 | Suppose that you have an abstract for a scientific paper: we investigate a pseudo - hermitian lattice system , which consists of a set of isomorphic pseudo - hermitian clusters coupled together in a hermitian manner .
we show that such non - hermitian systems can act as hermitian systems .
this is made possible by considering the dynamics of a state involving an identical eigenmode of each isomorphic cluster .
it still holds when multiple eigenmodes are involved when additional restriction on the state is imposed .
this hermitian dynamics is demonstrated for the case of an exactly solvable @xmath0-symmetric ladder system . .
And you have already written the first three sentences of the full article: the hermitian quantum mechanics is a well - developed framework because a hermitian hamiltonian leads to a real spectrum and unitary time evolution , which preserves the probability normalization .
however , a decade ago it was observed that a large class of non - hermitian hamiltonians possess real spectra @xcite and a pseudo - hermitian hamiltonian connects with its equivalent hermitian hamiltonian via a similarity transformation am43,am37 , quantum theory based on non - hermitian hamiltonian was established @xcite . in additional , such
a framework also indicates the preservation of probability normalization if a positive - definite inner product is employed to replace the dirac inner product ..
Please generate the next two sentences of the article | nevertheless , to date the interpretation and the measurement in experiment of such an inner product are not clear . while the dirac probability ( dirac inner product ) can be measured in a universal manner . therefore being an acceptable theory of quantum mechanics , the dirac probability is of central importance to most practical physical problems .
parity and time - reversal symmetric ( @xmath0-symmetric ) system has attracted much attention due to recent progresses on experimental investigations in @xmath0-symmetric optical systems , observation of passive @xmath0-symmetric breaking in passive optical double - well structure @xcite and observation of spontaneous symmetry breaking together with power oscillations in optical coupled system @xcite were carried out . |
5,295 | Suppose that you have an abstract for a scientific paper: an euclidean greedy embedding of a graph is a straight - line embedding in the plane , such that for every pair of vertices @xmath0 and @xmath1 , the vertex @xmath0 has a neighbor @xmath2 with smaller distance to @xmath1 than @xmath0 .
this drawing style is motivated by greedy geometric routing in wireless sensor networks .
a christmas cactus is a connected graph in which every two simple cycles have at most one vertex in common and in which every cutvertex is part of at most two biconnected blocks .
it has been proved that christmas cactus graphs have an euclidean greedy embedding .
this fact has played a crucial role in proving that every 3-connected planar graph has an euclidean greedy embedding .
the proofs construct greedy embeddings of christmas cactuses of exponential size , and it has been an open question whether exponential area is necessary in the worst case for greedy embeddings of christmas cactuses .
we prove that this is indeed the case . .
And you have already written the first three sentences of the full article: consider a graph @xmath3 and a straight - line embedding of @xmath4 in the euclidean plane . for simplicity
, we identify each vertex with the corresponding point in @xmath5 .
an embedding of @xmath4 is _ greedy _ if for every pair @xmath6 , vertex @xmath0 has a neighbor @xmath2 in @xmath4 , for which it is @xmath7 , where @xmath8 denotes the euclidean distance between points @xmath9 and @xmath10 ..
Please generate the next two sentences of the article | equivalently , every pair @xmath6 is joined by a distance - decreasing , or _ greedy _ , path .
greedy embeddings are motivated by geometric routing in wireless sensor networks . |
5,296 | Suppose that you have an abstract for a scientific paper: it is shown that coherent spin motion of electron hole pairs localized in band gap states of silicon can influence charge carrier recombination .
based on this effect , a readout concept for silicon based solid
state spin quantum computers as proposed by kane is suggested .
the @xmath0p quantum bit ( qbit ) is connected via hyperfine coupling to the spin of the localized donor electron .
when a second localized and singly occupied electronic state with an energy level deep within the band gap or close to the valence edge is in proximity , a gate controlled exchange between the @xmath0p nucleus and the two electronic states can be activated that leaves the donor deep level pair either unchanged in a @xmath1-state or shifts it into a singlet state @xmath2 . since the donor deep level transition is spin
dependent , the deep level becomes charged or not , depending on the nuclear spin orientation of the donor nucleus .
thus , the state of the qbit can be read with a sequence of light pulses and photo conductivity measurements . .
And you have already written the first three sentences of the full article: the state of the art of classical computer concepts is rapidly approaching the physical limits as fabrication technology of metal oxide semiconductor logic is minimized to scales where quantum effects determine device properties . while these natural limitations of classical electronics are the dead end for the development of conventional electronics , they open up possibilities for new alternative concepts such as spintronics and quantum computing ( qc ) @xcite . a concept for a silicon based solid state spin quantum computer as outlined by kane @xcite , combines the advantages of conventional semiconductor technology with regard to the high degree to which this technology has been developed and the fundamental concepts of qc , the massive parallel processing of information by coherent quantum states .
kane s concept takes advantage of the two nuclear spin energy eigenstates of @xmath0p - donor nuclei which can be used as well isolated ( long relaxation times ) quantum bits ( qbits ) if they are embedded in a nuclear spin
free crystalline @xmath3si matrix ..
Please generate the next two sentences of the article | interaction between these nuclear spin qbits can be controlled by electric fields from charged metal gates above and between the donor atoms which can selectively increase the hyperfine interaction between the localized electron donor states as well as the exchange interaction between electron donor states of different @xmath0p - atoms @xcite . before an implementation of the silicon based spin
qc is possible , many technological challenges have to be overcome among which the problem of a single spin readout is particularly difficult . in the original proposal |
5,297 | Suppose that you have an abstract for a scientific paper: we use an exact transfer - matrix approach to compute the equilibrium properties of a system of hard disks of diameter @xmath0 confined to a two - dimensional channel of width @xmath1 at constant longitudinal applied force . at this channel width , which is sufficient for next - nearest - neighbor disks to interact ,
the system is known to have a great many jammed states .
our calculations show that the longitudinal force ( pressure ) extrapolates to infinity at a well - defined packing fraction @xmath2 that is less than the maximum possible @xmath3 , the latter corresponding to a buckled crystal . in this quasi - one - dimensional problem
there is no question of there being any _ real _ divergence of the pressure at @xmath2 .
we give arguments that this avoided phase transition is a structural feature
the remnant in our narrow channel system of the hexatic to crystal transition but that it has the phenomenology of the ( avoided ) ideal glass transition .
we identify a length scale @xmath4 as our equivalent of the penetration length for amorphous order : in the channel system , it reaches a maximum value of around @xmath5 at @xmath2 , which is larger than the penetration lengths that have been reported for three dimensional systems .
it is argued that the @xmath6-relaxation time would appear on extrapolation to diverge in a vogel fulcher manner as the packing fraction approaches @xmath2 . .
And you have already written the first three sentences of the full article: there is a long history of studying exactly soluble one - dimensional models in statistical physics .
while sometimes these models are interesting in their own right , the main motive for their study is usually to cast some light upon behavior in higher , more physical dimensions @xmath7 , such as @xmath8 and @xmath9 , where exact solutions can not usually be found . in this paper
we study a quasi - one - dimensional system of @xmath10 hard disks of diameter @xmath0 confined by impenetrable walls separated by distance @xmath11 , where @xmath12 is the width of the region containing the centers of the disks ( see fig ..
Please generate the next two sentences of the article | [ fig : notation ] ) . for @xmath13 , a disk may make contact with its nearest- and next - nearest - neighbor ( nnn ) disks , but neighboring disks can not pass each other .
the ordering of the disks is still preserved : @xmath14 , where @xmath15 is the position of the center of disk @xmath16 , measured along the channel , and @xmath17 is the total length available to the disk centers . |
5,298 | Suppose that you have an abstract for a scientific paper: we study scaling relations of compressible isothermal strongly magnetized turbulence using numerical simulations with resolution 512@xmath0 .
we find a good correspondence of our results with the fleck ( 1996 ) model of compressible hydrodynamic turbulence .
in particular , we find that the density - weighted velocity , i.e. @xmath1 , proposed in kritsuk et al .
( 2007 ) obeys the kolmogorov scaling , i.e. @xmath2 for the high mach number turbulence .
similarly , we find that the exponents of the third order structure functions for @xmath3 stay equal to unity for all mach numbers studied .
the scaling of higher order correlations obeys the she - lvque ( 1994 ) scalings corresponding to the two - dimensional dissipative structures , and this result does not change with the mach number either .
in contrast to velocity @xmath4 which exhibits different scaling parallel and perpendicular to the local magnetic field , the scaling of @xmath3 is similar in both directions .
in addition , we find that the peaks of density create a hierarchy in which both physical and column densities decrease with the scale in accordance to the fleck ( 1996 ) predictions .
this hierarchy can be related ubiquitous small ionized and neutral structures ( sins ) in the interstellar gas .
we believe that studies of statistics of the column density peaks can provide both consistency check for the turbulence velocity studies and insight into supersonic turbulence , when the velocity information is not available .
address = department of astronomy , university of wisconsin , madison , wi , [email protected] address = department of astronomy , university of wisconsin , madison , wi , [email protected] .
And you have already written the first three sentences of the full article: the interstellar medium ( ism ) is a highly compressible turbulent , magnetized fluid , exhibiting density fluctuations on all observable scales .
it has been long realized by many researchers that incompressible hydrodynamic , i.e. kolmogorov , description is inadequate for such a medium ( see * ? ? ?
* for review ) ..
Please generate the next two sentences of the article | scaling relations , if they were obtained for the interstellar gas , would be very helpful for addressing many problems , including the evolution of molecular clouds and star formation .
attempts to include effects of compressibility into the interstellar turbulence description can be dated as far back as the work by @xcite . |
5,299 | Suppose that you have an abstract for a scientific paper: in this paper we study a simple gravity model dual to a @xmath0-dimensional system with a boundary at finite charge density and temperature . in our naive @xmath1 extension of a well known ads / cft system a non - zero charge density must be supported by a magnetic field . as a result ,
the hall conductivity is a constant inversely proportional to the coefficients of pertinent topological terms .
since the direct conductivity vanishes , such behaviors resemble that of a quantum hall system with fermi energy in the gap between the landau levels .
we further analyze the properties stemming from our holographic approach to a quantum hall system .
we find that at low temperatures the thermal and electric conductivities are related through the wiedemann - franz law , so that every charge conductance mode carries precisely one quantum of the heat conductance . from the computation of the edge currents we learn that the naive holographic model is dual to a gapless system if tensionless rs
branes are used in the ads / bcft construction . to reconcile this result with the expected quantum hall behavior
we conclude that gravity solutions with tensionless rs branes must be unstable , calling for a search of more general solutions . we briefly discuss the expected features of more realistic holographic setups .
itep - th-41/12 + iip - th-16/12 * on the ads / bcft approach to quantum hall systems * + _ @xmath2 international institute of physics , federal university of rio grande do norte , + av .
odilon gomes de lima 1722 , capim macio , natal - rn 59078 - 400 , brazil _ + _ @xmath3 institute for theoretical and experimental physics , + b. cheremushkinskaya 25 , moscow 117218 , russia _ + _ @xmath4 infn - laboratori nazionali di frascati , + via enrico fermi 40 , i-00044 frascati , italy _ + _ @xmath5 infn - sezione di perugia , + via a. pascoli , i-06123 perugia , italy _ + .
And you have already written the first three sentences of the full article: in an elegant paper @xcite takayanagi has recently proposed an extension of the ads / cft conjecture @xcite to deal with the situation , when the cft is defined on a space with a boundary .
these so called boundary cft s , or bcft s , naturally appear in various applications to condensed matter phenomena .
the main idea behind the takayanagi s construction is to appropriately extend the boundary of the cft inside the bulk of the @xmath6 space in order to cut out a physically relevant piece ..
Please generate the next two sentences of the article | the ads / bcft conjecture finds its natural roots in the holographic derivation of entanglement entropy @xcite and in the randall - sundrum model @xcite .
indeed , the extension of the cft s boundary inside the bulk of the @xmath6-space may be regarded as a modification of a `` thin '' randall - sundrum brane , intersecting the @xmath6 boundary . |
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