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3,300 | Suppose that you have an abstract for a scientific paper: cuprous oxide ( cu@xmath0o ) films from 25 nm to 1500 nm were electrodeposited on n - si(100 ) and ni / n - si(100 ) substrates from aqueous solution at room temperature .
x - ray diffraction and transmission electron microscopy imaging show that the cu@xmath0o structure and morphology is strongly affected by the substrate choice , with v shape and u shape columnar growth on n - si(100 ) and ni / n - si(100 ) , respectively . atomic force microscopy reveals the presence of rounded grains at the surface in both cases .
anomalous and normal roughening are observed in films grown on n - si and ni , respectively , but estimates of scaling exponents are not conclusive . on the other hand ,
the distributions of local heights , roughness , and extremal heights show good agreement with those of the fourth order linear stochastic equation of mullins and herring ( mh ) .
thus , surface dynamics in both systems is dominated by diffusion of adsorbed molecules , with no large scale effect of possible inhomogeneities in mass flux from the solution or in reaction and adsorption rates . in growth on n - si substrates ,
the noise amplitude of the mh equation increases in time as @xmath1 , while the coefficient of the curvature - related term is time - independent .
step edge energy barriers restrict the mass flux across grain boundaries , thus a broad size distribution of initial grains leads to coarsening of the larger ones .
this explains their v shape in the thickest films and establishes a connection with the anomalous roughening .
these effects are reduced in films grown on ni / n - si , which initially have much larger grains with narrower size distributions and , consequently , smaller fluctuations in coarse grained growth rates .
thus , despite the relevance of electrochemical conditions for cu@xmath0o films to grow and their influence on crystallographic orientation , large scale surface features are determined by physical properties of the material and its interactions with the substrate , with a....
And you have already written the first three sentences of the full article: cu@xmath0o ( cuprous oxide ) is a p - type semiconductor that has recently attracted the attention of experimental and theoretical groups due to its potential for application in metal base transistors @xcite , spintronic @xcite , photocathode for water splitting @xcite , electrochemical supercapacitors @xcite and catalysts @xcite , and for light harvesting @xcite .
the deposition of cu@xmath0o layers has been achieved by different techniques , such as pulsed laser deposition @xcite , magnetron sputtering @xcite , copper oxidation @xcite , radical oxidation @xcite , and electrodeposition @xcite .
electrodeposition is a very versatile technique , allowing to modify many structural , optical , and electrical properties by the control of the deposition parameters @xcite ..
Please generate the next two sentences of the article | moreover , electrodeposition appears as a cost effective method to the preparation of metal and semiconductor thin films for device applications . when compared with physical deposition processes , such as sputtering , electrodeposition has the particular feature of diffusive mass transport of species from the electrolyte to the growing surface @xcite .
a comprehensive understanding of the electrochemical growth mechanisms , taking into account the mass transport at the electrode surface , plays a vital role to the production of films with the desired properties . |
3,301 | Suppose that you have an abstract for a scientific paper: for any orbifold @xmath0 , we explicitly construct a simplicial complex @xmath1 from a given triangulation of the ` coarse ' underlying space together with the local isotropy groups of @xmath0 .
we prove that , for any local system on @xmath0 , this complex @xmath1 has the same cohomology as @xmath0 .
the use of @xmath1 in explicit calculations is illustrated in the example of the ` teardrop ' orbifold . .
And you have already written the first three sentences of the full article: orbifolds or v - manifolds were first introduced by satake @xcite , and arise naturally in many ways .
for example , the orbit space of any proper action by a ( discrete ) group on a manifold has the structure of an orbifold ; this applies in particular to moduli spaces .
furthermore , the orbit space of any almost free action by a compact lie group has the structure of an orbifold , as does the leaf space of any foliation with compact leaves and finite holonomy ..
Please generate the next two sentences of the article | examples of orbifolds are discussed in @xcite and many others . for an orbifold @xmath0
, one can define in a natural way a cohomology theory with coefficients in any local system on @xmath0 . |
3,302 | Suppose that you have an abstract for a scientific paper: the phase diagram of the two - leg t-@xmath0 ladder is explored , using the density matrix renormalization group method .
results are obtained for energy gaps , electron density profiles and correlation functions for the half - filled and quarter - filled cases .
the effective lagrangian velocity parameter @xmath1 is shown to vanish at half - filling .
the behaviour of the one - hole gap in the nagaoka limit is investigated , and found to disagree with theoretical predictions .
a tentative phase diagram is presented , which is quite similar to the full t - j ladder , but scaled up by a factor of about two in coupling .
near half - filling a luther - emery phase is found , which may be expected to show superconducting correlations , while near quarter - filling the system appears to be in a tomonaga - luttinger phase . .
And you have already written the first three sentences of the full article: the discovery of high - temperature superconductivity in the cuprate materials has sparked huge interest in models of strongly correlated electrons in low - dimensional systems , such as the hubbard , @xmath2-@xmath3 and @xmath2-@xmath0 models .
these models are exactly solvable in one dimension , at least in some special cases ; but the two - dimensional models pose a formidable numerical challenge .
the ` minus sign ' problem is a major stumbling block for monte carlo calculations in these fermionic systems ; and the convergence of density matrix renormalization group ( dmrg ) calculations is slow in two dimensions ..
Please generate the next two sentences of the article | exact finite - lattice calculations are limited to small lattice sizes ; while series expansions have typically only been useful for special cases such as the half - filled limit . in these circumstances ,
a considerable effort has been invested in the study of ` ladder ' systems consisting of two or more coupled chains of sites . |
3,303 | Suppose that you have an abstract for a scientific paper: coal@xmath0o@xmath1 spinel with magnetic co@xmath2 ions on the diamond a - lattice is known to be magnetically frustrated .
we compare neutron single crystal diffraction patterns measured in zero and applied magnetic fields with the ones obtained from classical monte - carlo models . in simulations we test the influence of various parameters on diffraction patterns : the ratio of nearest- , @xmath3 , and next - nearest , @xmath4 , neighbor interactions , magnetic field applied along the principal crystallographic directions , and random disorder on the a(co@xmath2)- and b(al@xmath5)- sites .
we conclude that the models considered so far explain the broadening of magnetic bragg peaks in zero magnetic field and their anisotropic response to applied magnetic field only partly . as bulk properties of our single crystal
are isotropic , we suggest that its microstructure , specifically @xmath6111@xmath7-twin boundaries , could be a reason of the nonconventional magnetic order in coal@xmath0o@xmath1 . .
And you have already written the first three sentences of the full article: theoretical studies@xcite predict that the magnetic geometrically nonfrustrated diamond lattice can host a highly degenerate frustrated state consisting of coplanar spirals , the so - called spiral spin liquid ( ssl ) .
this counterintuitive finding is comprehended when taking into account that the diamond lattice is composed of two interpenetrated face - centered cubic ( fcc ) sublattices which on their own are highly frustrated@xcite .
the magnetic frustration of the overall diamond lattice is caused by a significant j@xmath0 interaction which couples nearest - neighbor sites within each fcc sublattice ..
Please generate the next two sentences of the article | the ssl should evolve@xcite when the ratio @xmath4/@xmath3 exceeds @xmath8 , while for lower @xmath4/@xmath3 a collinear antiferromagnet ( af ) should be the ground state .
the labeling of j s reflects the fact that j@xmath9 is the nearest - neighbor coupling of the diamond lattice and j@xmath0 is the next - nearest - neighbor one . |
3,304 | Suppose that you have an abstract for a scientific paper: the irs 13e complex is an unusual concentration of massive , early - type stars at a projected distance of @xmath00.13pc from the milky way s central supermassive black hole sagittarius a * ( sgr a * ) . because of their similar proper motion and their common nature as massive , young stars it has recently been suggested that irs 13e may be the remnant of a massive stellar cluster containing an intermediate - mass black hole ( imbh ) that binds its members gravitationally in the tidal field of sgr a*. here , we present an analysis of the proper motions in the irs 13e environment that combines the currently best available data with a time line of 10 years .
we find that an imbh in irs 13e must have a minimum mass of @xmath010@xmath1m@xmath2 in order to bind the source complex gravitationally .
this high mass limit in combination with the absence so far of compelling evidence for a non - thermal radio and x - ray source in irs 13e make it appear unlikely that an imbh exists in irs 13e that is sufficiently massive to bind the system gravitationally . .
And you have already written the first three sentences of the full article: in spite of factors such as a strong tidal field due to the central supermassive black hole sgr a * ( e.g. , * ? ? ? * ; * ? ? ?
* ) , or strong stellar winds , which pose serious obstacles for star formation , surprisingly , numerous young ( a few times @xmath3yrs ) , massive stars can be found in the central parsec , e.g. , the one to two dozen bright so - called he - stars .
the young , massive stars are mainly concentrated in the region @xmath010@xmath4 in projection around sgr a * and appear to rotate around sgr a * in two counter - rotating disks that contain an apparently coeval population of wolf - rayet ( wr ) , luminous blue variables ( lbv ) , and o / b - stars ( * ? ? ?.
Please generate the next two sentences of the article | * ; * ? ? ?
* also paumard et al . |
3,305 | Suppose that you have an abstract for a scientific paper: a hybrid method is developed based on the spectral and finite - difference methods for solving the inhomogeneous zerilli equation in time - domain .
the developed hybrid method decomposes the domain into the spectral and finite - difference domains .
the singular source term is located in the spectral domain while the solution in the region without the singular term is approximated by the higher - order finite - difference method .
the spectral domain is also split into multi - domains and the finite - difference domain is placed as the boundary domain . due to the global nature of the spectral method , a multi - domain method composed of the spectral domains
only does not yield the proper power - law decay unless the range of the computational domain is large .
the finite - difference domain helps reduce boundary effects due to the truncation of the computational domain .
the multi - domain approach with the finite - difference boundary domain method reduces the computational costs significantly and also yields the proper power - law decay .
stable and accurate interface conditions between the finite - difference and spectral domains and the spectral and spectral domains are derived . for the singular source term
, we use both the gaussian model with various values of full width at half maximum and a localized discrete @xmath0-function . the discrete @xmath0-function was generalized to adopt the gauss - lobatto collocation points of the spectral domain .
the gravitational waveforms are measured .
numerical results show that the developed hybrid method accurately yields the quasi - normal modes and the power - law decay profile .
the numerical results also show that the power - law decay profile is less sensitive to the shape of the regularized @xmath0-function for the gaussian model than expected .
the gaussian model also yields better results than the localized discrete @xmath0-function . .
And you have already written the first three sentences of the full article: since the classic works @xcite by frank zerilli in early @xmath1 s on the particle falling in a schwarzschild geometry , a lot of research and study has been performed on this fundamental problem @xcite .
one of the earliest computational calculations was made by press and his co - workers , which is now known as drpp calculation @xcite on the radiation emitted when a particle starting from rest at infinity falls into a non - spinning black hole .
the collision of two black holes is , in principle , one of the most efficient mechanisms for the generation of the gravitational waves . in recent years.
Please generate the next two sentences of the article | the extreme mass ratio limit of the binary system has been a special focus of research in gravitational physics .
extreme - mass - ratio inspirals ( emris ) are one of the main sources of the gravitational waves for the gravitational wave detectors , such as laser interferometer space antenna ( lisa ) @xcite . |
3,306 | Suppose that you have an abstract for a scientific paper: active prominences exhibit plasma motions , resulting in difficulties with the interpretation of spectroscopic observations .
these solar features being strongly influenced by the radiation coming from the solar disk , doppler dimming or brightening effects may arise , depending on which lines are observed and on the velocity of the plasma . interlocking between the different atomic energy levels and non local thermodynamic equilibrium lead to non - trivial spectral line profiles , and this calls for complex numerical modeling of the radiative transfer in order to understand the observations .
we present such a tool , which solves the radiative transfer and statistical equilibrium for h , , , and in moving prominences where radial plasma motions are taking place .
it is found that for isothermal , isobaric prominence models , the resonance lines are very sensitive to the doppler effect and thus show a strong doppler dimming .
the lines doppler effect for the prominence models considered here .
we illustrate how the code makes it possible to retrieve the plasma thermodynamic parameters by comparing computed and observed line profiles of hydrogen and helium resonance lines in a quiescent prominence .
this new non - lte radiative transfer code including velocities allows us to better understand the formation of several lines of importance in prominences , and in conjunction with observations , infer the prominence plasma thermodynamic properties and full velocity vector . .
And you have already written the first three sentences of the full article: the main motivation of our modeling work is to contribute to building realistic prominence models . for this
, we need an accurate knowledge of thermodynamic quantities ( temperature , densities , ) , level populations ( useful , e.g. , to infer the magnetic field properties from spectro - polarimetric observations ) , velocity fields , energy budget .
however these quantities still have large uncertainties associated with them ..
Please generate the next two sentences of the article | observations of several different lines from different atoms / ions allow us in theory to measure these parameters . among these lines ,
the h and he lines are important as they are strong and largely contribute to the radiative losses . |
3,307 | Suppose that you have an abstract for a scientific paper: the expression for the spin susceptibility @xmath0 of degenerate quark matter is derived with corrections upto @xmath1 .
it is shown that at low density , @xmath2 changes sign and turns negative indicating a ferromagnetic phase transition . to this order , we also calculate sound velocity @xmath3 and incompressibility @xmath4 with arbitrary spin polarization .
the estimated values of @xmath3 and @xmath4 show that the equation of state of the polarized matter is stiffer than the unpolarized one .
finally we determine the finite temperature corrections to the exchange energy and derive corresponding results for the spin susceptibility . .
And you have already written the first three sentences of the full article: one of the active areas of high energy physics research has been exploration of the so called quantum chromodynamics ( qcd ) phase diagram . in particular , with the advent of ultrarelativistic heavy ion beams at rhic and cern and with the upcoming facilities of gsi where compressed baryonic matter is expected to be produced , such studies have assumed special importance . beside the laboratory experiments , various astrophysical objects like neutron stars , quark stars ,
provide natural sites where many of the theoretical conjectures about the various phases of quark matter can be tested .
the latter , in the present context , is more relevant here , as we study the possibility of para - ferro phase transition in dense quark system interacting via one gluon exchange ..
Please generate the next two sentences of the article | the original idea about para - ferro phase transition in quark matter was proposed recently in @xcite where the possibility of bloch like phase transition @xcite was studied and it was shown that spin polarized quark matter might exist at low density @xcite .
the underlying mechanism of such a phase transition is analogous to what was originally proposed for the degenerate electron gas @xcite . |
3,308 | Suppose that you have an abstract for a scientific paper: we show that simple 2 and 3-layer flux - transport dynamos , when forced at the top by a poloidal source term , can produce a widely varying amplitude of toroidal field at the bottom , depending on how close the meridional flow speed of the bottom layer is to the propagation speed of the forcing applied above the top layer , and how close the amplitude of the @xmath0-effect is to two values that give rise to a resonant response .
this effect should be present in this class of dynamo model no matter how many layers are included .
this result could have implications for the prediction of future solar cycles from the surface magnetic fields of prior cycles .
it could be looked for in flux - transport dynamos that are more realistic for the sun , done in spherical geometry with differential rotation , meridional flow and @xmath0-effect that vary with latitude and time as well as radius .
because of these variations , if resonance occurs , it should be more localized in time , latitude and radius . .
And you have already written the first three sentences of the full article: dikpati et al ( 2006 ) first used a flux transport dynamo calibrated to the sun ( dikpati et al 2004 ) to simulate and predict solar cycle peaks from the record of past surface magnetic field patterns .
this was done mathematically by forcing the dynamo equations at the top boundary , with a forcing function derived from past surface magnetic fields .
flux transport dynamos , and indeed all dynamos , have their own unforced , usually complex frequencies of excitation that are commonly found by treating the dynamo equations as an eigenvalue problem ..
Please generate the next two sentences of the article | many naturally occurring and man - made systems have such properties .
when a physical system that has natural freqencies is excited by external forcing whose own frequency is close to one of the natural ones , there can be resonance produced that is , the system will be excited strongly by the forcing compared to the case where the forcing frequency is not close to a natural one . |
3,309 | Suppose that you have an abstract for a scientific paper: weak value amplification ( wva ) is a concept that has been extensively used in a myriad of applications with the aim of rendering measurable tiny changes of a variable of interest . in spite of this
, there is still an on - going debate about its _ true _ nature and whether is really needed for achieving high sensitivity .
here we aim at solving the puzzle , using some basic concepts from quantum estimation theory , highlighting what the use of the wva concept can offer and what it can not .
while wva can not be used to go beyond some fundamental sensitivity limits that arise from considering the full nature of the quantum states , wva can notwithstanding enhance the sensitivity of _ real _ detection schemes that are limited by many other things apart from the quantum nature of the states involved , i.e. _ technical noise_. importantly , it can do that in a straightforward and easily accessible manner . .
And you have already written the first three sentences of the full article: weak value amplification ( wva ) @xcite is a concept that has been used under a great variety of experimental conditions @xcite to reveal tiny changes of a variable of interest . in all those cases ,
a priori sensitivity limits were not due to the quantum nature of the light used ( _ photon statistics _ ) , but instead to the insufficient resolution of the detection system , what might be termed generally as _
technical noise_. wva was a feasible choice to go beyond this limitation . in spite of this extensive evidence , .
Please generate the next two sentences of the article | its interpretation has historically been a subject of confusion " @xcite .
for instance , while some authors @xcite show that weak - value - amplification techniques ( which only use a small fraction of the photons ) compare favorably with standard techniques ( which use all of them ) " , others @xcite claim that wva does not offer any fundamental metrological advantage " , or that wva @xcite `` does not perform better than standard statistical techniques for the tasks of single parameter estimation and signal detection '' . however , these conclusions are criticized by others based on the idea that `` the assumptions in their statistical analysis are irrelevant for realistic experimental situations '' @xcite . |
3,310 | Suppose that you have an abstract for a scientific paper: atom interferometry is a rapidly advancing field and this letter proposes an experiment based on existing technology that can search for new short distance forces . with current technology
it is possible to improve the sensitivity by up to a factor of @xmath0 and near - future advances will be able to rewrite the limits for forces with ranges from 100 @xmath1 m to 1 km .
new short distance forces are a frequent prediction of theories beyond the standard model and the search for these new forces is a promising channel for discovering new physics . over the past 15 years
there has been rapid advances in light pulse atom interferometry ( ai ) and in a wide variety of settings , ai is the most sensitive measurement .
this letter will explore the sensitivity of ai to new forces .
ai holds great promise in improving currently sensitivity over a wide range of distances from roughly to .
new forces can couple to matter in many different ways ; however , there is a benchmark parameterization that is frequently applicable to new forces where the potential between two particles is proportional to the mass of the particles @xmath2 where @xmath3 is a dimensionless number that characterizes the new force s strength relative to gravity and @xmath4 is the compton wavelength of the particle being exchanged . the coupling , @xmath3 , could be composition , spin or velocity dependent or have a power - law fall off rather than an exponential / yukawa behavior ; however , this parameterization is a standard benchmark and will be used in this letter .
theories predict a wide range of @xmath4 and @xmath3 .
some theories give @xmath5 such as gauge mediated supersymmetry theories that have moduli mediated forces @xcite , large extra dimensions @xcite or theories that have gravity shut off at the scale of the cosmological constant @xcite .
alternatively , many theories also predict @xmath6@xcite .
the most reknowned of these theories are peccei - quinn axions can mediate forces with @xmath7 @xcite .
thus ,....
And you have already written the first three sentences of the full article: the atom interferometry used in this proposal is similar to @xcite and uses many of the techniques in @xcite .
light pulse atom interferometry uses two counter - propagating lasers that couple hyperfine degenerate ground states of alkali ( or alkali - like ) atoms through a near - resonance raman transition . while the lasers are on , the system undergoes rabi oscillations between two states having a relative momentum @xmath12 . by performing a @xmath13 series of raman pulses ,
the atom s wave packet is split into a slow and fast component , then after an interrogation time , @xmath14 , the states are reversed and the wave packet is brought back together for the final beam splitter that interferes the two halves of the wave packet . the maximal spatial separation of the wave packets in the interferometer is @xmath15 ..
Please generate the next two sentences of the article | there often is an initial velocity , @xmath16 , to the atom s wave packets that is used to doppler - select the desired atomic transitions .
an initial velocity can also arise from the thermal velocities . |
3,311 | Suppose that you have an abstract for a scientific paper: the identity of dark matter is one of the key outstanding problems in both particle and astrophysics . in this thesis ,
i review some candidates of dark matter , especially wimps ( weakly interacting massive particles ) which is one of the best candidate so it is called that wimps miracle .
in addition of this , there are also some theories of modification of gravity , by changing the law of gravity , it could be possible that the dark matter observations are explained . until the dark matter particle is detected , there is some room for uncertainty .
so we should consider every part of the problem and solve it .
dark matter problem is covering a large area so every possibility is important .
so @xmath0 gravity is also reviewed in this thesis and some theories are considered as a possible solution of dark matter problem .
finally we highlight that , even in the case of wimps or another particles solution , @xmath0 gravity is also can be used for this problem .
however , last words will be said by experiments .
* keywords * : dark matter , weakly interacting particles(wimps ) , @xmath0 gravity , cosmology .
karanlik maddenin gizemi hem astrofizik hem de paracik fizii aisindan ok nemli bir problemdir .
bu tezde , karanlik madde adaylarini , zellikle wimps mucizesi olarak bilinen ve en gl aday olan wimps(zayif etkileen ktleli paracik)i inceledim .
karanlik maddenin gizemini zmeye alian bundan baka teoriler de vardir , rnein gravitasyonun modifiye edilmesi gibi .
karanlik madde paraciklari deneylerde bulunana kadar , bu gizem srecektir . biz
bu gizemi her aidan inceleyip zm retmemiz gerekir nk ok geni bir alani kapsayan bu alan iin her bir ihtimal bile ok nemlidir .
karanlik maddeyi aiklamaya aday olan @xmath0 gravitasyon teorisini de bu tezde inceledik ve zm retmeye alitik .
sonu olarak , gerek wimps olsun gerekse baka paraciklar olsun , @xmath0 gravistasyon teorisi de gzel bir alternatiftir ve kullanilabilir .
tabii hangisinin doru olduunu deneyler onaylaycak .
+ + +....
And you have already written the first three sentences of the full article: dark matter is a very strange form of matter . it does not interact with known objects because of the lack of electromagnetic interaction .
however , it has a mass and we know that it exists.the main reason for this view is from gravitational interactions on the visible matter which holds galaxies and galaxies of clusters together .
the idea of the existence of a new form of matter escaping electromagnetic detections , traces back at least to 1915 ..
Please generate the next two sentences of the article | the name `` dark matter '' was firstly used by the jacobus kapteyn in 1922 in his studies of the motions of stars in our galaxy @xcite .
he found that there is no need of dark matter within and around the solar system . in 1923 , jan oort arrived to an opposite conclusion that there should be twice as much dark matter as visible matter in the solar vicinity . |
3,312 | Suppose that you have an abstract for a scientific paper: we have produced a catalog of line identifications and equivalent width measurements for all absorption features in eight ultraviolet echelle quasar spectra .
these spectra were selected as having the highest signal - to - noise among the _
hst_/stis spectra obtained with the e230 m grating .
we identify 56 metal - line systems toward the eight quasars , and present plots of detected transitions , aligned in velocity - space .
we found that about 1/4 - 1/3 of the features in the forest region , redward of the incidence of the forest , are metal lines .
high ionization transitions are common .
we see both and in 88 90% of the metal - line systems for which the spectra cover the expected wavelength .
is seen in 58% , while low ionization absorption in , , and/or is detected in 50% of the systems for which they are covered .
this catalog will facilitate future studies of the forest and of metal - line systems of various types .
[ firstpage ] intergalactic medium quasars : absorption lines . .
And you have already written the first three sentences of the full article: the most important chemical transitions for quasar absorption line systems at low redshift ( e.g. , @xmath0@xmath11 ) still lay in the ultra - violet spectral range .
a limited number of the most uv - bright quasars have been observed with the hubble space telescope ( _ hst_)/ space telescope imaging spectrograph ( stis ) , which has provided a detailed view of absorption systems along the lines of sight .
these data are available from the multimission archive at space telescope ( mast ) . however , in order to compile statistics of absorbers or to study particular systems , it is necessary to identify the spectral features ..
Please generate the next two sentences of the article | this can be complicated , particularly in the forest region , and when the available spectral coverage is limited .
in the course of our studies of the forest and metal - line systems we have studied in detail eight of the highest quality _ |
3,313 | Suppose that you have an abstract for a scientific paper: based on the assumption of a safe velocity @xmath0 depending on the vehicle density @xmath1 a macroscopic model for traffic flow is presented that extends the model of the khne - kerner - konhuser by an interaction term containing the second derivative of @xmath2 .
we explore two qualitatively different forms of @xmath3 : a conventional , fermi - type function and , motivated by recent experimental findings , a function that exhibits a plateau at intermediate densities , i.e. in this density regime the exact distance to the car ahead is only of minor importance . to solve the fluid - like equations a lagrangian particle scheme is developed .
+ the suggested model shows a much richer dynamical behaviour than the usual fluid - like models .
a large variety of encountered effects is known from traffic observations many of which are usually assigned to the elusive state of `` synchronized flow '' .
furthermore , the model displays alternating regimes of stability and instability at intermediate densities , it can explain data scatter in the fundamental diagram and complicated jam patterns . within this model , a consistent interpretation of the emergence of very different traffic phenomena
is offered : they are determined by the velocity relaxation time , i.e. the time needed to relax towards @xmath2 .
this relaxation time is a measure of the average acceleration capability and can be attributed to the composition ( e.g. the percentage of trucks ) of the traffic flow . .
And you have already written the first three sentences of the full article: traffic is a realization of an open one - dimensional many - body system . recently ,
popkov and schtz @xcite found that the fundamental diagram determines the phase diagram of such a system , at least for a very simple , yet exactly solvable toy model , the so called asymmetric exclusion process ( asep ) .
in particular , the most important feature that influences the phase diagram is the number of extrema in the fundamental diagram ..
Please generate the next two sentences of the article | this is exactly the theme of this report .
we present an extension of classical , macroscopic ( `` fluid - like '' ) traffic flow models . |
3,314 | Suppose that you have an abstract for a scientific paper: this paper corrects an earlier work suggesting that the quantum expectation value of the proper length is bounded from below by the planck length .
the original calculation examined fluctuations of the conformal factor of einstein - hilbert gravity . however , in einstein - hilbert gravity , the conformal factor is not a dynamical field subject to fluctuations .
this paper performs the same calculation using the trace anomaly - induced effective action for the conformal factor and finds that , while conformal fluctuations modify the short - distance behavior of the interval , the interval still approaches zero in the coincidence limit . .
And you have already written the first three sentences of the full article: nearly 30 years ago , padamanabhan @xcite performed a simple calculation suggesting that quantum gravitational fluctuations place a lower bound on distance measurements .
he considered fluctuations of the conformal factor @xmath0 in metrics of the form @xmath1 while keeping the background metric @xmath2 classical . crudely speaking
, padmanabhan argued that the conformal factor @xmath0 has a green s function that diverges as @xmath3 , in such a way that @xmath4 remains finite in the coincidence limit ..
Please generate the next two sentences of the article | this calculation was part of a larger approach to quantum gravity and quantum cosmology in which the conformal factor was treated as a dynamical field to be quantized , while the rest of the metric was treated as a classical field as in standard qft .
this approach sidesteps some of the thornier conceptual problems associated with quantizing the metric , since conformal fluctuations preserve the causal structure of spacetime . |
3,315 | Suppose that you have an abstract for a scientific paper: when massless excitations are limited or modified by the presence of material bodies one observes a force acting between them generally called casimir force .
such excitations are present in any fluid system close to its true bulk critical point .
we derive exact analytical results for both the temperature and external ordering field behavior of the thermodynamic casimir force within the mean - field ginzburg - landau ising type model of a simple fluid or binary liquid mixture .
we investigate the case when under a film geometry the boundaries of the system exhibit strong adsorption onto one of the phases ( components ) of the system .
we present analytical and numerical results for the ( temperature - field ) relief map of the force in both the critical region of the film close to its finite - size or bulk critical points as well as in the capillary condensation regime below but close to the finite - size critical point .
_ keywords _ : rigorous results in statistical mechanics , classical phase transitions ( theory ) , finite - size scaling .
And you have already written the first three sentences of the full article: in a recent article @xcite , we have derived exact results for both the temperature @xmath0 and external ordering field @xmath1 behavior of the order parameter profile and the corresponding response functions local and total susceptibilities within the three - dimensional continuum mean - field ginzburg - landau ising type model of a simple fluid or binary liquid mixture for a system with a film geometry @xmath2 . in the current article
we extend them to derive exact results for the thermodynamic casimir force within the same model .
we concentrate in the region of the parametric space in @xmath3 plane close to the critical point of the fluid or close to the demixing point of the binary liquid mixture ..
Please generate the next two sentences of the article | we recall that for classical fluids in the case of a simple fluid or for binary liquid mixtures the wall generically prefers one of the fluid phases or one of the components . because of that in the current article we study the case when the bounding surfaces of the system strongly prefer one of the phases of the system . since in such systems
one observes also the phenomena of the capillary condensation close below the critical point for small negative values of the ordering field @xmath4 , we also study the behavior of the force between the confining surfaces of the system in that parametric region . here |
3,316 | Suppose that you have an abstract for a scientific paper: coherent control of a system involves steering an interaction to a final coherent state by controlling the phase of an applied field .
plasmas support coherent wave structures that can be generated by intense laser fields . here
, we demonstrate the coherent control of plasma dynamics in a laser wakefield electron acceleration experiment .
a genetic algorithm is implemented using a deformable mirror with the electron beam signal as feedback , which allows a heuristic search for the optimal wavefront under laser - plasma conditions that is not known _ a priori_. we are able to improve both the electron beam charge and angular distribution by an order of magnitude .
these improvements do not simply correlate with having the ` best ' focal spot , since the highest quality vacuum focal spot produces a greatly inferior electron beam , but instead correspond to the particular laser phase front that steers the plasma wave to a final state with optimal accelerating fields .
center for ultrafast optical science , university of michigan , ann arbor , mi 48109 - 2099 usa polytech paris - sud - universit paris - sud , 91405 orsay , france .
And you have already written the first three sentences of the full article: the concept of coherent control precise measurement or determination of a process through control of the phase of an applied oscillating field has been applied to many different systems , including quantum dynamics@xcite , trapped atomic ions@xcite , chemical reactions@xcite , cooper pairs@xcite , quantum dots@xcite and thz generation@xcite to name but a few .
a plasma wave is a coherent and deterministically evolving structure that can be generated by the interaction of laser light with plasma .
it is therefore natural to assume that coherent control techniques may also be applied to plasma waves ..
Please generate the next two sentences of the article | plasma waves produced by high power lasers have been studied intensively for their numerous applications , such as the production of ultrashort pulses by plasma wave compression@xcite , generation of extremely high power pulses by raman amplification@xcite , for inertial confinement fusion ignition schemes@xcite , as well as for fundamental scientific investigations . in particular ,
laser wakefield acceleration of ultra - relativistic electron beams@xcite , has been a successful method for accelerating electrons to relativistic energies over a very short distance . in laser wakefield acceleration , an electron bunch ` surfs ' on the electron plasma wave generated by an intense laser and gains a large amount of energy . |
3,317 | Suppose that you have an abstract for a scientific paper: we have measured an extensive set of @xmath0 colors for m31 globular clusters @xcite .
we compare the predicted simple stellar population colors of three population synthesis models to the intrinsic colors of galactic and m31 globular clusters .
the best - fitting models fit the cluster colors very well the weighted mean color offsets are all @xmath1 mag .
the most significant offsets between model and data are in the @xmath2 and @xmath3 passbands ; these are not unexpected and are likely due to problems with the spectral libraries used by the models .
the metal - rich clusters ( @xmath4}\gtrsim-0.8 $ ] ) are best fit by young ( 8 gyr ) models , while the metal - poor clusters are best fit by older ( 1216 gyr ) models .
if this range of globular cluster ages is correct , it implies that conditions for cluster formation must have existed for a substantial fraction of the galaxies lifetimes . .
And you have already written the first three sentences of the full article: predicting the integrated spectral energy distributions of stellar populations is important in the solution of many problems in astronomy , from determining the ages of globular clusters to modeling counts of faint galaxies at high redshift . beginning with the early work of @xcite , successive generations of modelers
have combined the best available data on stellar structure and evolution to predict the appearance of the combined light of generations of stars .
although the subject of population synthesis has a long history , it is an active area of research : synthesis techniques and many of the input data ( isochrones , opacities , spectral libraries ) continue to be improved.
Please generate the next two sentences of the article | . there is good evidence that globular clusters ( gcs ) are internally homogeneous in age and metallicity @xcite .
gcs are the best observational analogs of modelers ` simple stellar populations ' , i.e. populations of stars formed over a short time out of gas with homogeneous chemical composition . |
3,318 | Suppose that you have an abstract for a scientific paper: hypervelocity stars ( hvss ) ejected by the massive black hole at the galactic center have unique kinematic properties compared to other halo stars .
their trajectories will deviate from being exactly radial because of the asymmetry of the milky way potential produced by the flattened disk and the triaxial dark matter halo , causing a change of angular momentum that can be much larger than the initial small value at injection .
we study the kinematics of hvss and propose an estimator of dark halo triaxiality that is determined only by instantaneous position and velocity vectors of hvss at large galactocentric distances ( @xmath0 ) .
we show that , in the case of a substantially triaxial halo , the distribution of deflection angles ( the angle between the stellar position and velocity vector ) for hvss on bound orbits is spread uniformly over the range 10@xmath1180@xmath1 .
future astrometric and deep wide - field surveys should measure the positions and velocities of a significant number of hvss , and provide useful constraints on the shape of the galactic dark matter halo .
[ firstpage ] black hole physics galaxy : center galaxy : halo stellar dynamics .
And you have already written the first three sentences of the full article: recent observations have revealed the existence of a population of hypervelocity stars ( hvss ) traveling in the halo of the milky way ( mw ) with galactic rest - frame velocities @xmath2 in the range between @xmath3 and @xmath4 @xcite .
hvss are probably b - type main sequence stars with lifetimes @xmath5 , galactocentric distances @xmath6 kpc , and move with speeds large enough to escape from the galaxy .
the significant excess of b - type stars with velocities @xmath7 and distances @xmath8 kpc observed by @xcite may also be an indication that many hvss are ejected into the halo on _ bound _ orbits ..
Please generate the next two sentences of the article | hvss were first recognized by @xcite as an unavoidable byproduct of the presence a massive black hole ( bh ) in the galactic center .
only a close encounter with a relativistic potential well can accelerate a 3 - 4 @xmath9 star to such extreme velocities , and at least three different ejection mechanisms have been proposed : the interaction between background stars and an intermediate - mass black hole ( imbh ) inspiralling towards sgr a@xmath10 @xcite , the disruption of stellar binaries in the tidal field of sgr a@xmath10 @xcite , and the scattering of stars off a cluster of stellar - mass bhs orbiting sgr a@xmath10 @xcite in all these models , hvss have unique kinematics compared to other halo stars : 1 ) they have almost zero initial specific angular momentum at ejection , @xmath11 , where @xmath12 the mass of sgr @xmath13 and @xmath14 the pericenter distance of the star ; 2 ) their high speeds diminish the impact of two - body relaxation or dynamical friction effects on their motion ; and 3 ) their trajectories will deviate from being exactly radial because of the asymmetry of the milky way potential produced by the flattened disk and the triaxial dark matter ( dm ) halo , causing a change of angular momentum that can be much larger than the initial small value . |
3,319 | Suppose that you have an abstract for a scientific paper: we present systematic calculations on the spectroscopy and transition properties of even - even te isotopes by using the large - scale configuration interaction shell model approach with a realistic interaction .
these nuclei are of particular interest since their yrast spectra show a vibrational - like equally - spaced pattern but the few known e2 transitions show anomalous rotational - like behavior , which can not be reproduced by collective models .
our calculations reproduce well the equally - spaced spectra of those isotopes as well as the constant behavior of the @xmath0 values in @xmath1te .
the calculated @xmath0 values for neutron - deficient and heavier te isotopes show contrasting different behaviors along the yrast line .
the @xmath0 of light isotopes can exhibit a nearly constant bevavior upto high spins .
we show that this is related to the enhanced neutron - proton correlation when approaching @xmath2 .
the advent of large - scale radioactive beam facilities and new detection technologies have enabled the study of the spectroscopy and transition properties of @xmath3 nuclei just above the presumed doubly magic nucleus @xmath4sn @xcite .
several unexpected phenomena have recently been observed : large @xmath5 values of neutron deficient semi - magic @xmath6 isotopes have triggered extensive experimental @xcite and theoretical @xcite activities , in particular regarding the fundamental roles played by core excitations and the nuclear pairing correlation ( or seniority coupling ) .
the study of transition rates in isotopic chains just above @xmath7 may provide further information on the role of core excitations @xcite .
the limited number of valence protons and neutrons are not expected to induce any significant quadrupole correlation in this region @xcite .
the low - lying collective excitations of those nuclei were discussed in terms of quadrupole vibrations @xcite in relation to the fact that the even - even te isotopes between @xmath8 and 70 show regular equally -....
And you have already written the first three sentences of the full article: this work is supported by the swedish research council ( vr ) under grant nos . 621 - 2012 - 3805 , and 621 - 2013 - 4323 and the gran gustafsson foundation .
we also thank d.s .
delion for discussions and for his efforts studying above - mentioned nuclei within the coherent state model and p. maris for his effort calculating those nuclei with the code mfdn ..
Please generate the next two sentences of the article | the computations were performed on resources provided by the swedish national infrastructure for computing ( snic ) at pdc , kth , stockholm .
62ifxundefined [ 1 ] ifx#1 ifnum [ 1 ] # 1firstoftwo secondoftwo ifx [ 1 ] # 1firstoftwo secondoftwo `` `` # 1''''@noop [ 0]secondoftwosanitize@url [ 0 ] |
3,320 | Suppose that you have an abstract for a scientific paper: we have measured the weak lensing signal as a function of restframe @xmath0 , @xmath1 , and @xmath2-band luminosity for a sample of ` isolated ' galaxies .
these results are based on four - band photometry from the red - sequence cluster survey , enabling us to determine photometric redshifts for a large number of galaxies .
we select a secure sample of lenses with photometric redshifts @xmath3 and study the relation between the virial mass and baryonic contents .
in addition , we discuss the implications of the derived photometric redshift distribution for published cosmic shear studies . the virial masses are derived from a fit to the observed lensing signal . for a galaxy with a fiducial luminosity of @xmath4l@xmath5
we obtain a mass @xmath6m@xmath7 .
the virial mass as a function of luminosity is consistent with a power - law @xmath8 , with similar slopes for the three filters considered here .
these findings are in excellent agreement with results from the sloan digital sky survey and semi - analytic models of galaxy formation .
we measure the fraction of mass in stars and the baryon fraction in galaxies by comparing the virial mass - to - light ratio to predicted stellar mass - to - light ratios .
we find that star formation is inefficient in converting baryons into stars , with late - type galaxies converting @xmath9% and early - type galaxies converting only @xmath10% of baryons into stars .
our results imply that the progenitors of early - type galaxies must have low stellar mass fractions , suggestive of a high formation redshift . .
And you have already written the first three sentences of the full article: observations of rotation curves of spiral galaxies and measurements of the velocity dispersions of stars in early - type galaxies have provided important evidence for the existence of massive dark matter halos around galaxies ( e.g. , van albada & sancisi 1986 ) .
in addition , these studies have presented evidence of tight relations between the baryonic and dark matter components ( e.g. , tully & fisher 1977 ; faber & jackson 1976 ) .
results based on strong lensing by galaxies support these findings ( e.g. , keeton , kochanek & falco 1998 ) ..
Please generate the next two sentences of the article | the origin of these scaling relations must be closely related to the process of galaxy formation , but the details are still not well understood , mainly because of the complex behaviour of the baryons .
furthermore , on the small scales where baryons play such an important role , the accuracy of cosmological numerical simulations is limited . |
3,321 | Suppose that you have an abstract for a scientific paper: _ hubble space telescope _ wide field planetary camera 2 images of hickson compact group 79 , seyfert s sextet , are presented .
both point sources and extended sources detected on the three wf chips were photometered in four filters : f336w , f439w , f555w , and f814w .
unlike other hcgs that have been imaged with _ hst _ , there do not appear to be any candidate young star clusters among the detected point sources .
the majority of the point sources that may be star clusters associated with the sextet have red colors consistent with stellar populations older than 1 gyr .
a similar conclusion is drawn with regard to the extended sources .
the majority of these appear to be background galaxies , but a few candidate dwarf galaxies are identified as potentially associated with seyfert s sextet .
however , no blue , star forming objects similar to the tidal dwarf galaxy candidates identified in other hcgs are found among the extended objects identified in this study .
a redshift for one dwarf galaxy candidate was measured from a spectrum obtained with the hobby - eberly telescope , and this object was found to have a redshift similar to ngc6027e , the discordant spiral formerly identified as a member of this compact group .
the _ hst _
observations presented here and previous radio observations of the neutral gas content of this group suggest that the interactions that have taken place in the sextet only redistributed the stars from the member galaxies within the group .
we speculate that future interactions may be strong enough to strip the gas from ngc6027d and trigger star cluster formation . .
And you have already written the first three sentences of the full article: compact groups of galaxies are found at the extreme end of the distribution of galaxy surface densities ; by definition , compact groups consist of four or more isolated galaxies found within a small area on the sky . using the @xcite compact group selection criteria , the surface densities of galaxies in compact groups are similar to or larger than those found in the centers of massive galaxy clusters . a radial velocity survey of the 100 hickson compact groups ( hcgs ; * ?
* ) has verified that the majority of these hcgs are physical associations of 3 or more galaxies with a median velocity dispersion of 200 km sec@xmath0 .
one expects that in such dense groups with small velocity dispersions that interactions and mergers among the members are inevitable ..
Please generate the next two sentences of the article | as expected , the morphologies of the galaxies in compact groups often show evidence of tidal interaction .
galaxy mergers are complicated phenomena , and it is difficult to disentangle the past histories of the merging galaxies , even in isolated , merging pairs . in compact groups |
3,322 | Suppose that you have an abstract for a scientific paper: in this paper , we consider polynomials orthogonal with respect to a varying perturbed laguerre weight @xmath0 for @xmath1 and @xmath2 on certain contours in the complex plane . when the parameters @xmath3 , @xmath4 and the degree @xmath5 are fixed , the hankel determinant for the singular complex weight is shown to be the isomonodromy @xmath6-function of the painlev iii equation .
when the degree @xmath7 , @xmath3 is large and @xmath4 is close to a critical value , inspired by the study of the wigner time delay in quantum transport , we show that the double scaling asymptotic behaviors of the recurrence coefficients and the hankel determinant are described in terms of a boutroux tronque solution to the painlev i equation .
our approach is based on the deift - zhou nonlinear steepest descent method for riemann - hilbert problems .
2010 _ mathematics subject classification _ : primary 33e17 , 34m55 , 41a60 . _ keywords and phrases _ : asymptotics ; hankel determinants ; painlev i equation ; painlev iii equation ; riemann - hilbert approach . .
And you have already written the first three sentences of the full article: let @xmath8 be the following singularly perturbed laguerre weight @xmath9 with @xmath10 the hankel determinant is defined as @xmath11=\det(\mu_{i+j})_{i , j=0}^{k-1},\ ] ] where @xmath12 is the @xmath13-th moment of @xmath8 , namely , @xmath14 note that when @xmath15 , the integral in the above formula is convergent so that the hankel determinant @xmath16=d_k[w(x;t)]$ ] in is well - defined .
moreover , it is well - known that the hankel determinant can be expressed as @xmath17 = \prod_{j=0}^{k-1 } \gamma_{j , n}^{-2}(t);\]]see @xcite , where @xmath18 is the leading coefficient of the @xmath5-th order polynomial orthonormal with respect to the weight function in . or
, let @xmath19 be the @xmath5-th order monic orthogonal polynomial , then @xmath18 appears in the following orthogonal relation @xmath20 for fixed @xmath3 ..
Please generate the next two sentences of the article | moreover , the monic orthogonal polynomials @xmath19 satisfy a three - term recurrence relation as follows : @xmath21with @xmath22 and @xmath23 , where the appearance of @xmath3 and @xmath4 in the coefficients indicates their dependence on @xmath3 and the parameter @xmath4 in the varying weight . in this paper , however ,
we will focus on the case when @xmath1 . since all the above integrals on @xmath24 become divergent for negative @xmath4 , we need to deform the integration path from the positive real axis to certain curves in the complex plane . |
3,323 | Suppose that you have an abstract for a scientific paper: correlation effects on the electronic structure of half - metallic cras in zinc - blende structure are studied for different substrate lattice constants . depending on the substrate the spectral weight of the non - quasiparticle states
might be tuned from a well developed value in the case of inas substrate to an almost negligible contribution for the gaas one . a piezoelectric material that would allow the change in the substrate lattice parameters opens the possibility for practical investigations of the switchable ( tunable ) non - quasiparticle states . since the latter are important for the tunneling magnetoresistance and related phenomena it creates new opportunities in spintronics .
15.6 cm .
And you have already written the first three sentences of the full article: one of the strongest motivations to investigate magnetic semiconductors and half - metallic ferromagnets ( hmf ) is the possibility to design and produce novel stable structures on semiconducting substrates with new interesting properties . adopting this point of view first - principle studies
are an excellent starting point to predict new systems having the desired properties .
recently akinaga _ et al ..
Please generate the next two sentences of the article | _ @xcite found the possibility to fabricate zinc - blende ( zb ) type cras half - metallic ferromagnetic material .
experimental data confirmed that this material is ferromagnetic with the magnetic moment of @xmath0 , in agreement with theoretical predictions @xcite . |
3,324 | Suppose that you have an abstract for a scientific paper: we consider a self - consistent system of bianchi type - i ( bi ) gravitational field and a binary mixture of perfect fluid and dark energy given by a cosmological constant .
the perfect fluid is chosen to be the one obeying either the usual equation of state , i.e. , @xmath0 , with @xmath1 $ ] or a van der waals equation of state .
role of the @xmath2 term in the evolution of the bi universe has been studied . .
And you have already written the first three sentences of the full article: in view of its importance in explaining the observational cosmology many authors have considered cosmological models with dark energy . in a recent paper kremer @xcite has modelled the universe as a binary mixture whose constitutes are described by a van der waals fluid and by a dark energy density .
@xcite showed that `` tracker field '' , a form of qiuntessence , may explain the coincidence , adding new motivation for the quintessence scenario .
the fate of density perturbations in a universe dominated by the chaplygin gas , which exhibit negative pressure was studied by fabris _.
Please generate the next two sentences of the article | _ @xcite . model with chaplygin gas was also studied in the refs .
@xcite . in doing |
3,325 | Suppose that you have an abstract for a scientific paper: recently , the extremely sensitive torsion - rotation transitions in methanol have been used to set a tight constraint on a possible variation of the proton - to - electron mass ratio over cosmological time scales . in order to improve this constraint ,
laboratory data of increased accuracy will be required . here
, we explore the possibility for performing high - resolution spectroscopy on methanol in a stark - deflected molecular beam .
we have calculated the stark shift of the lower rotational levels in the ground torsion - vibrational state of and molecules , and have used this to simulate trajectories through a typical molecular beam resonance setup .
furthermore , we have determined the efficiency of non - resonant multi - photon ionization of methanol molecules using a femtosecond laser pulse .
the described setup is in principle suited to measure microwave transitions in at an accuracy below 10@xmath0 . .
And you have already written the first three sentences of the full article: theories that extend the standard model of particle physics have presented scenarios that allow for , or even predict , spatial - temporal variations of the constants of nature @xcite .
possible variations of the fine structure constant , @xmath1 , representing the strength of the electromagnetic force , or the proton - to - electron mass ratio , @xmath2 , a measure of the strength of the strong force , lead to shifts in the spectra of atoms and molecules .
many studies have been devoted to observe these shifts . by comparing metal absorptions in the spectra from distant quasars with the corresponding transitions measured in the laboratory , webb _ et al . _.
Please generate the next two sentences of the article | @xcite found evidence that suggests that the fine structure constant , @xmath1 , has a smaller value at high redshift .
in later work , this variation was interpreted as a spatial variation of @xmath1 @xcite . in parallel , laboratory experiments on earth |
3,326 | Suppose that you have an abstract for a scientific paper: the surprise discovery of superconductivity below 5k in sodium cobalt oxides when hydrated with water has caught the attention of experimentalists and theorists alike .
most explanations for its occurence have focused heavily on the properties of some small elliptically shaped pockets predicted to be the electronically dominant fermi surface sheet , but direct attempts to look for them have instead cast serious doubts over their existence .
here we present evidence that these pockets do indeed exist , based on bulk measurements of the electron momentum distribution in unhydrated and hydrated sodium cobalt oxides using the technique of x - ray compton scattering .
hydrated sodium cobalt oxides ( na@[email protected]@xmath2o ) , for a certain range of na concentrations , exhibit superconductivity at a temperature of 5k @xcite .
although many analogies have been drawn with the high-@xmath3 cuprates ( for instance , as being possibly the only other example of a mott insulator becoming superconducting under doping @xcite ) , the sodium cobaltate system exhibits its own unique set of anomalous behaviour such as unusually high thermopower @xcite and @xmath4-linear resistivity @xcite ) , distinctly indicative of strongly correlated electron behaviour . in a conventional superconductor ,
electrons at the fermi surface form cooper pairs under an attractive interaction mediated by lattice vibrations .
the manner in which electrons form these pairs can be strongly influenced by the shape of the fermi surface .
questions regarding the origin of the pairing interaction and the nature of the superconductivity in the cobaltates has stimulated significant theoretical speculation , most of which has focused heavily on the properties of some small elliptically shaped pockets predicted to be the electronically dominant fermi surface sheet @xcite , but the outcome of direct attempts to look for them has instead cast serious doubt over their existence @xcite . here
we present evidence that these pockets do....
And you have already written the first three sentences of the full article: we acknowledge the financial support of the royal society ( s.b.d . ) and the uk epsrc , and invaluable discussions with igor mazin , michelle johannes and zahid hasan .
this experiment was performed with the approval of the japan synchrotron radiation research institute ( jasri , proposal nos .
2005a0092-nd3a - np and 2005b0182-nd3a - np ) ..
Please generate the next two sentences of the article | this work was partially supported by a grant - in - aid for scientific research ( no.18340111 ) from the ministry of education , culture , sports , science and technology , japan .
k. takada , h. sakurai , e. takayama - muromachi , f. izumi , r. a. dilanian , t. sasaki , nature ( london ) * 422 * , 53 ( 2003 ) . |
3,327 | Suppose that you have an abstract for a scientific paper: it is widely believed that anisotropy in the expansion of the universe will decay exponentially fast during inflation .
this is often referred to as the cosmic no - hair conjecture . however , we find a counter example to the cosmic no - hair conjecture in the context of supergravity . as a demonstration , we present an exact anisotropic power - law inflationary solution which is an attractor in the phase space .
we emphasize that anisotropic inflation is quite generic in the presence of anisotropic sources which couple with an inflaton .
kobe - th-14 - 10 .
And you have already written the first three sentences of the full article: as is well known , the event horizon of black holes hides the initial conditions of the collapsed matter other than mass , charge , and angular momenta , which is named the black hole no - hair theorem @xcite .
the similar thing should happen for inflation because of the cosmological event horizon , namely , any initial conditions should go away beyond the cosmological event horizon .
in fact , in the presence of the cosmological constant , there is a cosmic no - hair theorem proved by wald @xcite . even for a general accelerating universe driven by a scalar field ,.
Please generate the next two sentences of the article | it is legitimate to expect that the anisotropy decays exponentially first in the presence of the cosmological event horizon .
this prejudice is often referred to as the cosmic no - hair conjecture . |
3,328 | Suppose that you have an abstract for a scientific paper: low - energy dynamics in the unit - charge sector of the @xmath0 model on spherical space ( space - time @xmath1 ) is treated in the approximation of geodesic motion on the moduli space of static solutions , a six - dimensional manifold with non - trivial topology and metric .
the structure of the induced metric is restricted by consideration of the isometry group inherited from global symmetries of the full field theory .
evaluation of the metric is then reduced to finding five functions of one coordinate , which may be done explicitly .
some totally geodesic submanifolds are found and the qualitative features of motion on these described .
epsf = -0.4 in = -0.2 in = 6.6 in .
And you have already written the first three sentences of the full article: the @xmath0 model in flat space is a scalar field theory whose configuration space @xmath2 consists of finite energy maps from euclidean @xmath3to the complex projective space @xmath0 , the energy functional being constructed naturally from the riemannian structures of the base and target spaces ( that is , the model is a pure sigma model in the broad sense ) .
the requirement of finite energy imposes a boundary condition at spatial infinity , that the field approaches the same constant value , independent of direction in @xmath3 , so that the field may be regarded as a map from the one point compactification @xmath4 to @xmath0 .
since @xmath5 also , finite energy configurations are effectively maps @xmath6 , the homotopy theory of which is well understood , and the configuration space is seen to consist of disconnnected sectors @xmath7 labelled by an integer @xmath8 , the `` topological charge '' ( degree ) , @xmath9 each configuration is trapped within its own sector because time evolution is continuous ..
Please generate the next two sentences of the article | the lorentz invariant , time - dependent model is not integrable but complete solution of the static problem has been achieved by means of a bogomolnyi argument and the general charge @xmath8 moduli space , the space of charge-@xmath8 static solutions @xmath10 , is known ( that _ all _ static , finite energy solutions of the @xmath0 model saturate the bogomolnyi bound is a non - trivial result @xcite ) .
each static solution within the charge-@xmath8 sector has the same energy ( minimum within that sector and proportional to @xmath8 ) , and @xmath11 is parametrized by @xmath12 parameters ( the moduli ) , so such a moduli space may be thought of as the @xmath13-dimensional level bottom of a potential valley defined on the infinite dimensional charge-@xmath8 sector , @xmath7 . low energy _ |
3,329 | Suppose that you have an abstract for a scientific paper: we classify , up to automorphisms , the elliptic fibrations on the singular k3 surface @xmath0 whose transcendental lattice is isometric to @xmath1 . .
And you have already written the first three sentences of the full article: we classify elliptic fibrations on the singular k3 surface @xmath0 associated to the laurent polynomial @xmath2 in order to compute the nron - severi lattice , the picard number , and other basic properties of an algebraic surface , it is useful to identify an elliptic fibration on the surface .
moreover , in view of different applications , one may be interested in finding all the elliptic fibrations of a certain type .
the fibrations of rank @xmath3 and maximal torsion lead more easily to the determination of the @xmath4series of the variety @xcite ..
Please generate the next two sentences of the article | those of positive rank lead to symplectic automorphisms of infinite order of the variety .
lenstra s elliptic curve method ( ecm ) for finding small factors of large numbers originally used elliptic curves on @xmath5 with a torsion - group of order 12 or 16 and rank @xmath6 on @xmath5 @xcite , @xcite . |
3,330 | Suppose that you have an abstract for a scientific paper: polymerization of rna from a template dna is carried out by a molecular machine called rna polymerase ( rnap ) .
it also uses the template as a track on which it moves as a motor utilizing chemical energy input .
the time it spends at each successive monomer of dna is random ; we derive the exact distribution of these `` dwell times '' in our model .
the inverse of the mean dwell time satisfies a michaelis - menten - like equation and is also consistent with a general formula derived earlier by fisher and kolomeisky for molecular motors with unbranched mechano - chemical cycles .
often many rnap motors move simultaneously on the same track . incorporating the steric interactions among the rnaps in our model
, we also plot the three - dimensional phase diagram of our model for rnap traffic using an extremum current hypothesis . .
And you have already written the first three sentences of the full article: rna polymerase ( rnap ) is a molecular motor @xcite .
it moves on a stretch of dna , utilizing chemical energy input , while polymerizing a messenger rna ( mrna ) @xcite .
the sequence of monomeric subunits of the mrna is dictated by the corresponding sequence on the template dna ..
Please generate the next two sentences of the article | this process of template - dictated polymerization of rna is usually referred to as _ transcription _
it comprises three stages , namely , initiation , elongation of the mrna and termination . |
3,331 | Suppose that you have an abstract for a scientific paper: we develop a model to describe the properties of random assemblies of polydisperse hard spheres .
we show that the key features to describe the system are _ ( i ) _ the dependence between the free volume of a sphere and the various coordination numbers between the species , and _
( ii ) _ the dependence of the coordination numbers with the concentration of species ; quantities that are calculated analytically .
the model predicts the density of random close packing and random loose packing of polydisperse systems for a given distribution of ball size and describes packings for any interparticle friction coefficient .
the formalism allows to determine the optimal packing over different distributions and may help to treat packing problems of non - spherical particles which are notoriously difficult to solve .
understanding the basic properties of spheres packings is a major challenge since this problem may provide valuable knowledge regarding low temperature phases in condensed matter physics @xcite .
the canonical example is perhaps the monodisperse sphere packing problem .
it has been mathematically proven that the optimum way to arrange monodisperse spheres is the face - centered cubic lattice ; a problem that has been solved recently by hales , @xmath0 400 years after the famous kepler conjecture on the issue . on the other hand , it is commonly observed that packings arrange in a random fashion at a lower density state called random close packing or rcp @xcite .
furthermore , packings are mechanically stable up to an even lower limit called random loose packing , rlp . in parallel with the large literature dealing with monodisperse sphere packings , a large body of experimental
, theoretical and numerical work has been devoted to the analysis of polydisperse systems ; the interest arising due to the simple fact that polydispersivity is omnipresent in most realistic systems and industrial applications @xcite . while previous approaches have focused on frictionless packings , an....
And you have already written the first three sentences of the full article: .volume fraction for @xmath98 , rlp . [ cols="^,^,^,^,^,^,^,^,^,^,^",options="header " , ]
according to the theory , the average voronoi volume for a packing with a distribution of radius @xmath109 , is given by the following self - consistent equation : where the different quantities are calculated as follow : @xmath111 @xmath112 to simplify we denoted @xmath113 , @xmath114 and @xmath80 the step - function .
@xmath115 @xmath116 @xmath117 @xmath118 @xmath119 @xmath120.
Please generate the next two sentences of the article | |
3,332 | Suppose that you have an abstract for a scientific paper: we consider an interpretation of the recent lattice data on the current - current correlators in the @xmath0-space .
the data indicate rather striking difference between ( axial)vector and ( pseudo)scalar channels which goes beyond the predictions of the standard non - perturbative models .
we argue that if the difference is to be explained by power corrections , there is a unique choice of the form of the correction .
we discuss the emerging picture of the power corrections . .
And you have already written the first three sentences of the full article: we shall be concerned here with the current - current correlators in the coordinate space : [ twopoint ] ( x)= 0|j(x)j^(0)|0 , in case of the @xmath1 and ( pseudo)scalar currents : j_^(va)&=&|q_i_(1_5)q_j , + j^sp&=&[(m_i- m_j)(m_i+m_j)]|q_i(1_5)q_j , where @xmath2 and @xmath3 are the quark fields and masses .
the two - point functions ( [ twopoint ] ) obey a dispersion representation : ( x)=_0^dt k_1(x ) im(t ) , where im@xmath4 is related to the current induced cross section and @xmath5 is the modified bessel function , which behaves for small @xmath6 as : k(z0)+z . in the limit @xmath7
, @xmath8 coincides with the free - field correlator and the main theoretical issue is how the asymptotic freedom gets violated at intermediate @xmath0 ..
Please generate the next two sentences of the article | + from pure theoretical point of view , the use of the @xmath0-space is no better than the use of the momentum space , which is the traditional tool of the qcd sum rules @xcite .
each representation has its own advantages and inconveniences ( for a recent discussion see @xcite ) . |
3,333 | Suppose that you have an abstract for a scientific paper: we discuss the suitability of holographically generated optical potentials for the investigation of superfluidity in ultracold atoms . by using a spatial light modulator and
a feedback enabled algorithm we generate a smooth ring with variable bright regions that can be dynamically rotated to stir ultracold atoms and induce superflow .
we also comment on its future integration into a cold atoms experiment . .
And you have already written the first three sentences of the full article: in 1938 , kaptiza @xcite and allen / misener @xcite independently discovered that , below 2.17 k , liquid helium-4 can flow without friction .
this superfluidity is also a property of dilute ultracold atomic gases , and has been demonstrated through the presence of a critical velocity @xcite , the formation of arrays of vortices under rotation @xcite and the observation of persistent flow @xcite .
the high degree of control over both the gas interactions and the trapping potential allows detailed studies of superfluidity in these systems , whilst their accurate modelling is also possible using the mean - field gross - pitaevskii equation ..
Please generate the next two sentences of the article | there have been numerous alternative proposals for toroidal atom traps using magnetic fields with @xcite or without rf - dressing @xcite , electrostatic fields @xcite , time - averaged optical fields @xcite or laguerre - gauss beams @xcite .
an advantage of using optical rather than magnetic potentials is that they are suitable for trapping atoms in any state . in order for any of these to be used to study superflow of ultracold atoms , a stirring mechanism needs to be introduced , such as the transfer of orbital angular momentum from an additional light source @xcite or a stirring laser beam @xcite . |
3,334 | Suppose that you have an abstract for a scientific paper: we derive the degrees of freedom of the lasso fit , placing no assumptions on the predictor matrix @xmath0 .
like the well - known result of zou , hastie and tibshirani [ _ ann .
statist . _
* 35 * ( 2007 ) 21732192 ] , which gives the degrees of freedom of the lasso fit when @xmath0 has full column rank , we express our result in terms of the active set of a lasso solution .
we extend this result to cover the degrees of freedom of the generalized lasso fit for an arbitrary predictor matrix @xmath0 ( and an arbitrary penalty matrix @xmath1 ) . though our focus is degrees of freedom , we establish some intermediate results on the lasso and generalized lasso that may be interesting on their own . . .
And you have already written the first three sentences of the full article: we study degrees of freedom , or the `` effective number of parameters , '' in @xmath2-penalized linear regression problems .
in particular , for a response vector @xmath3 , predictor matrix @xmath4 and tuning parameter @xmath5 , we consider the lasso problem [ @xcite , @xcite ] @xmath6 the above notation emphasizes the fact that the solution @xmath7 may not be unique [ such nonuniqueness can occur if @xmath8 . throughout the paper , when a function @xmath9 may have a nonunique minimizer over its domain @xmath1
, we write @xmath10 to denote the set of minimizing @xmath11 values , that is , @xmath12 ..
Please generate the next two sentences of the article | a fundamental result on the degrees of freedom of the lasso fit was shown by @xcite .
the authors show that if @xmath13 follows a normal distribution with spherical covariance , @xmath14 , and @xmath15 are considered fixed with @xmath16 , then @xmath17 where @xmath18 denotes the active set of the unique lasso solution at @xmath13 , and @xmath19 is its cardinality . |
3,335 | Suppose that you have an abstract for a scientific paper: in view of important implications in the @xmath0 decay , the @xmath1 decay modes of @xmath2 are analyzed with broken flavor su(3 ) symmetry in search for long - distance final - state interactions .
if we impose one mild theoretical constraint on the electromagnetic form factors , we find that a large phase difference of final - state interactions is strongly favored between the one - photon and the gluon decay amplitudes .
measurement of @xmath3 and @xmath4 off the @xmath2 peak can settle the issue without recourse to theory . .
And you have already written the first three sentences of the full article: the final state interaction ( fsi ) in the nonleptonic @xmath0 decay has been an important unsolved issue in connection with the search of direct cp violations . unlike the short - distance fsi
, the long - distance fsi has not been understood well enough even qualitatively .
the experimental data of the @xmath5 decay clearly show that the fsi phases are large in the @xmath6 decay modes@xcite ..
Please generate the next two sentences of the article | opinions divide as to how strong the fsi is in the @xmath0 decay .
some theorists have suggested that the long - distance fsi should be small at the mass scale of the @xmath0 meson . |
3,336 | Suppose that you have an abstract for a scientific paper: temperature - dependent in - plane , @xmath0 , and inter - plane , @xmath1 , resistivities were measured for the iron - arsenide superconductor ( ba@xmath2k@xmath3)fe @xmath4as@xmath4 over a broad doping range from parent compound to optimal doping @xmath5 , @xmath6 .
the coupled magnetic / structural transition at @xmath7 is clearly observed for samples with @xmath826 k ( @xmath9 ) , however its effect on resistivity is much weaker than in the electron - doped ba(fe@xmath2co@xmath3)fe @xmath4as@xmath4 , and the transition leads only to a decrease of resistivity .
in addition to the feature at @xmath7 , the inter - plane resistivity shows a maximum at @xmath10200 k , which moves slightly to higher temperature with doping , revealing a trend opposite to the electron - doped materials .
a smeared feature at about the same temperature is seen in @xmath0 . for @xmath11 ,
the temperature dependence of resistivity shows systematic evolution and is close to linear at optimal doping .
this feature , being most pronounced for @xmath12 , suggests the existence of a quantum critical point close to optimal doping . .
And you have already written the first three sentences of the full article: superconductivity in hole - doped ( ba@xmath2k@xmath3)fe@xmath4as@xmath4 @xcite ( bak122 , in the following ) was found soon after the discovery of superconductivity with high critical temperatures in oxypnictide feas - based materials @xcite .
several studies reported anisotropic properties of single crystals , representative of various parts of the phase diagram @xcite , however , no systematic evolution of the resistivity and its anisotropy was undertaken so far , due to a difficulty in preparation of single crystals with well controlled potassium content .
high quality single crystals of k - doped materials can be grown from feas flux @xcite , however , the high melting temperature of the flux , leading to high potassium vapor pressure , limits this technique to growth of only the underdoped compositions ..
Please generate the next two sentences of the article | the compositions on the overdoped side can be grown from kas flux @xcite .
initial success in growing single crystals through the use of sn flux , and finding their low anisotropy through measurements of the upper critical field @xcite , was stopped by finding of the macroscopic phase separation in sn - flux @xcite or polycrystalline @xcite samples and gross effect of small sn incorporation on the phase diagram @xcite . |
3,337 | Suppose that you have an abstract for a scientific paper: the dynamics of fabry - perot cavity with suspended mirrors is described .
the suspended mirrors are nonlinear oscillators interacting with each other through the laser circulating in the cavity .
the degrees of freedom decouple in normal coordinates , which are the position of the center of mass and the length of the cavity .
we introduce two parameters and study how the dynamics changes with respect to these parameters .
the first parameter specifies how strong the radiation pressure is .
it determines whether the cavity is multistable or not .
the second parameter is the control parameter , which determines location of the cavity equilibrium states .
the equilibrium state shows hysteresis if the control parameter varies within a wide range .
we analyze stability of the equilibrium states and identify the instability region .
the instability is explained in terms of the effective potential : the stable states correspond to local minima of the effective potential and unstable states correspond to local maxima .
the minima of the effective potential defines the resonant frequencies for the oscillations of the cavity length .
we find the frequencies , and analyze how to tune them .
multistability of the cavity with a feedback control system is analyzed in terms of the servo potential .
the results obtained in this paper are general and apply to all fabry - perot cavities with suspended mirrors . .
And you have already written the first three sentences of the full article: very long fabry - perot cavities serve as measuring devices for interferometric gravitational wave detectors .
several such detectors are currently under construction @xcite .
the cavities are planned to have high circulating power and large storage time ..
Please generate the next two sentences of the article | for example , ligo ( laser interferometer gravitational wave observatory ) fabry - perot cavities will accumulate 10 kw of power and will have roughly 1 ms of storage time . the suspended mirrors are designed to move freely along the direction of the beam propagation .
due to multi - beam interference in the fabry - perot cavity the motion of the mirrors strongly affects the light inside the cavity . |
3,338 | Suppose that you have an abstract for a scientific paper: 15.pt we consider photon radiation in @xmath0 events at the upgraded fermilab tevatron and the cern large hadron collider ( lhc ) as a tool to measure the electric charge of the top quark .
we analyze the contributions of @xmath1 production and radiative top quark decays to @xmath2 , assuming that both @xmath3-quarks are tagged . with 20 fb@xmath4 at the tevatron , the possibility that the `` top quark '' discovered in run i is actually an exotic charge @xmath5 quark can be ruled out at the @xmath6 confidence level . at the lhc
, it will be possible to determine the charge of the top quark with an accuracy of about 10% . .
And you have already written the first three sentences of the full article: it is widely believed that the new particle discovered at fermilab in 1995 @xcite is the long sought top quark .
its behavior is certainly consistent with standard model ( sm ) expectations for top , but many of its properties are still only poorly known . in particular , the top quark s electric charge one of the most fundamental quantities characterizing a particle has not been measured yet .
it still remains not only to confirm that the discovered quark has charge @xmath7 ( and hence the expected sm quantum numbers ) , but also to measure the strength of its electromagnetic ( em ) coupling to rule out anomalous contributions to its em interactions ..
Please generate the next two sentences of the article | indeed , one alternative interpretation has not yet been ruled out : that the new particle is a charge @xmath5 quark . in
the published top quark analyses of the cdf and d collaborations ( see ref . |
3,339 | Suppose that you have an abstract for a scientific paper: recent observations by mauerhan et al .
have shown the unprecedented transition of the previously identified luminous blue variable ( lbv ) and supernova impostor sn 2009ip to a real type iin supernova ( sn ) explosion .
we present high - cadence optical imaging of sn 2009ip obtained between 2012 ut sep . 23.6 and oct . 9.6 , using @xmath0 meter aperture telescopes from the coral towers observatory in cairns , australia .
the light curves show well - defined phases , including very rapid brightening early on ( 0.5 mag in 6 hr observed during the night of sep .
24 ) , a transition to a much slower rise between sep . 25 and sep . 28 , and a plateau / peak around oct . 7 .
these changes are coincident with the reported spectroscopic changes that , most likely , mark the start of a strong interaction between the fast sn ejecta and a dense circumstellar medium formed during the lbv eruptions observed in recent years . in the 16-day observing period sn 2009ip brightened by 3.7 mag from @xmath1 mag on sep .
23.6 ( @xmath2 ) to @xmath3 mag ( @xmath4 ) on oct . 9.6 , radiating @xmath5 erg in the optical wavelength range .
currently , sn 2009ip is more luminous than most type iip sne and comparable to other type iin sne . .
And you have already written the first three sentences of the full article: establishing an observational mapping between the properties of core - collapse supernovae ( ccsne ) explosions ( and related luminous outbursts ) and local populations of massive stars is key for constraining stellar evolution theory ( e.g. , langer 2012 ) .
arguably , the best link so far comes from the direct detections of red - supergiants with main - sequence masses @xmath6 m@xmath7 as progenitors of type iip supernovae ( e.g. , smartt 2009 , and references therein ) , the most common kind of ccsne .
however , direct detections of sn progenitors with higher masses ( @xmath8 m@xmath7 ) has been elusive ( e.g. , kochanek et al . 2008 ; smartt 2009 ) ..
Please generate the next two sentences of the article | the detection of a very luminous star ( @xmath9 mag ) identified in pre - explosion images at the location of the type iin sn 2005gl provided the first direct evidence for a very massive h - rich star ( @xmath10 m@xmath7 ) that exploded as a luminous ccsn ( gal - yam et al .
2007 ; gal - yam & leonard 2009 ) . |
3,340 | Suppose that you have an abstract for a scientific paper: we construct in this article a new realization of quantum geometry , which is obtained by quantizing the recently - introduced flux formulation of loop quantum gravity . in this framework ,
the vacuum is peaked on flat connections , and states are built upon it by creating local curvature excitations .
the inner product induces a discrete topology on the gauge group , which turns out to be an essential ingredient for the construction of a continuum limit hilbert space .
this leads to a representation of the full holonomy - flux algebra of loop quantum gravity which is unitarily - inequivalent to the one based on the ashtekar
isham lewandowski vacuum .
it therefore provides a new notion of quantum geometry .
we discuss how the spectra of geometric operators , including holonomy and area operators , are affected by this new quantization .
in particular , we find that the area operator is bounded , and that there are two different ways in which the barbero immirzi parameter can be taken into account .
the methods introduced in this work open up new possibilities for investigating further realizations of quantum geometry based on different vacua . .
And you have already written the first three sentences of the full article: following einstein s insight that gravity is encoded into the geometry of spacetime , quantum gravity aims at providing realizations of quantum geometry . in this task ,
one key technical and conceptual challenge is to reconcile the regularizations required in quantum field theory with the diffeomorphism symmetry which underlies general relativity . indeed ,
a number of approaches employ discretizations as regulators , which is the case for instance of regge calculus @xcite , and in this class of theories , where one attempts to represent geometrical data on a triangulation , diffeomorphism symmetry is generically broken @xcite . in light of this ,.
Please generate the next two sentences of the article | a very important result is therefore the construction of a continuum notion of quantum geometry , which was achieved in the context of loop quantum gravity @xcite ( lqg hereafter ) by ashtekar , isham , and lewandowski @xcite .
the so - called ashtekar lewandowski ( al ) representation provides a hilbert space representation of the kinematical algebra of observable of the full _ continuum _ theory . |
3,341 | Suppose that you have an abstract for a scientific paper: data on @xmath0 show a large increase in branching fractions near @xmath1 .
a suggestion of ali et al .
@xcite is to interpret this as evidence for a tetraquark , @xmath2 .
however , it may also be interpreted in terms of @xmath3 , @xmath4 and @xmath5 above the open-@xmath6 threshold , followed by de - excitation processes such as @xmath7 . in the charm sector
, a hypothesis open to experimental test is that @xmath8 and @xmath9 peaks in the mass range 3872 to 3945 mev may all be due to regular @xmath10 and @xmath11 @xmath12 states ( and perhaps @xmath13 and @xmath14 ) mixed with meson - meson . *
meson spectroscopy without tetraquarks * .
And you have already written the first three sentences of the full article: there is much speculation about the existence of tetraquarks .
most papers unfortunately do not distinguish between tetraquarks and simple meson - meson .
it is prudent , but less exciting , to examine conventional interpretations in terms of non - exotic @xmath15 , @xmath16 , @xmath12 or @xmath17 states with admixtures of meson - meson ..
Please generate the next two sentences of the article | nuclei may be viewed as six quark combinations .
however , nucleon - nucleon phase shifts may be fitted in terms of meson exchanges . |
3,342 | Suppose that you have an abstract for a scientific paper: we present a preliminary measurement of the angular clustering of faint ( @xmath0 ) field galaxies in which we concentrate on the behavior of @xmath1 on small angular scales ( @xmath2 ) .
the galaxies are strongly clustered and @xmath1 is well - characterized by a power law of the form @xmath3 .
the best - fitting value of the power law index , @xmath4 , is , however , steeper than the fiducial value of @xmath5 , indicating that there are more pairs of galaxies separated by @xmath2 in our sample than would be otherwise expected . using the best - fitting form of @xmath1 , we estimate that @xmath6 of the galaxies are in physically close pairs ( separations @xmath7 kpc ) .
this is a factor of order 2 larger than local galaxy samples but comparable to galaxy samples with @xmath8 .
the mean redshift of our galaxies is of order 0.95 , and , therefore , our result suggests that there was little or no evolution in the merger rate of galaxies between @xmath9 and @xmath10 . .
And you have already written the first three sentences of the full article: the angular clustering of faint @xmath11-selected field galaxies has been studied extensively ( e.g. , efstathiou et al . 1991 ; roche et al . 1993 , 1996 ;
brainerd , smail & mould 1995 ; hudon & lilly 1996 ; lidman & peterson 1996 ; villumsen , freudling & da costa 1996 ; woods & fahlman 1997 ) , and a prime motivation of these studies has been to investigate the nature of the faint field population .
in particular , it is possible to infer the effective correlation length of the sample and the rate at which clustering evolves from a combination of the amplitude of the angular autocorrelation function , @xmath1 , and the redshift distribution of the faint galaxies , @xmath12 ..
Please generate the next two sentences of the article | these observations can then be used to link properties of the faint field population with samples of local galaxies .
while the exact interpretation remains controversial , it is generally accepted that overall @xmath1 is fitted well by a power law of the form @xmath13 ( although see infante & pritchet ( 1995 ) for evidence of a flattening in the power - law coefficient at faint limits ) . |
3,343 | Suppose that you have an abstract for a scientific paper: we report on optical and rxte observations of a new high - latitude bursting x - ray transient , xte j2123058 .
we identified the optical counterpart and discovered a @xmath0 hr periodic optical modulation , which was subsequently shown to be the same as the spectroscopic orbital period . from the absence of orbital x - ray modulation and the presence of partial
optical eclipses the binary inclination is between @xmath1 and @xmath2 . from the optical magnitude in quiescence and from the x - ray flux of type i x - ray bursts ,
the source distance is between 4.5 and 15 kpc , which implies that the source is unusually far from the galactic plane since @xmath3 .
optical bursts with properties consistent with being reprocessed x - ray bursts occurred .
we detect a pair of high frequency qpos at @xmath4 hz and @xmath5 hz simultaneously . according to the beat frequency model
, this qpo separation implies a neutron star spin period of @xmath6 ms . a change in the energy spectrum occurred during the decay of the outburst , which may have been due to the onset of the propeller mechanism .
if so , then the neutron star magnetic field strength is between 2 and 8 @xmath7 g for an assumed distance of 10 kpc .
however , the changes in the timing and spectral properties observed during the decay are typical of atoll sources , which may indicate that the changes are due solely to the dynamics of the accretion disk .
as the phase averaged v - band magnitude declined from 17.26 at the peak of the outburst to 19.24 , and the x - ray flux decreased from @xmath8 erg @xmath9 s@xmath10 to @xmath11 erg @xmath9 s@xmath10 , the peak - to - peak amplitude of the v - band modulation increased from 0.75 to 1.49 magnitudes .
this behavior can be explained if the size of the accretion disk decreases during the decay of the outburst . .
And you have already written the first three sentences of the full article: the x - ray transient xte j2123058 was discovered by the _ rossi x - ray timing explorer all - sky monitor ( rxte / asm ) on june 27 , 1998 ( @xcite ) .
x - ray bursts were detected in pointed rxte observations made on june 27 and june 29 ( @xcite ) , indicating that the system contains a neutron star .
based on the burst profiles and time intervals between bursts , we classify the bursts as type i ( @xcite ) ..
Please generate the next two sentences of the article | if this system is a neutron star low mass x - ray binary ( lmxb ) , as the data suggest , it is unusual because of its high galactic latitude ( @xmath3 ) . _ in this paper , we report on optical and rxte observations of xte j2123058 .
our results include the optical identification of xte j2123058 ( @xcite ) , the measurement of a 5.9573 hr optical photometric modulation during its outburst ( @xcite ) , which proved to be the binary orbital period ( @xcite ) , and constraints on the binary inclination . |
3,344 | Suppose that you have an abstract for a scientific paper: in bosonic formulation of the negative energy sea , so called dirac sea presented in the preceding paper [ arxiv : hep - th/0603242 ] , one of the crucial points is how to construct a positive definite inner product in the negative energy states , since naive attempts would lead to non - positive definite ones . in the preceding paper
the non - local method is used to define the positive definite inner product . in the present article
we make use of a kind of @xmath0-regularization and renormalization method which may clarify transparently the analytical properties of our formulation .
yitp-06 - 35 + kuns-2032 + oiqp-06 - 09 + hep - th/0607182 * dirac sea and hole theory for bosons ii * + _ renormalization approach _ + yoshinobu habara@xmath1 , yukinori nagatani@xmath2 , + holger b. nielsen@xmath3 and masao ninomiya@xmath4 + _ @xmath5department of physics , graduate school of science , + kyoto university , kyoto 606 - 8502 , japan + @xmath6okayama institute for quantum physics , + kyoyama - cho 1 - 9 , okayama - city 700 - 0015 , japan + @xmath7niels bohr institute , university of copenhagen , + 17 blegdamsvej copenhagen , denmark + @xmath8yukawa institute for theoretical physics , + kyoto university , kyoto 606 - 8502 , japan _ .
And you have already written the first three sentences of the full article: recently , a long - standing problem or puzzle @xcite in any relativistic quantum field theories has been investigated by the present authors @xcite .
the problem is how to construct the negative energy sea , or dirac sea for bosons , since as is well known the fermion fields was historically second quantized firstly by dirac in terms of dirac sea and hole theory @xcite . in the fermion case there
exists pauli s exclusion principle and easily negative energy sea , namely , the dirac sea is constructed . in the bosonic cases contrary to fermions , one might think at first that it would be impossible to construct such a sea due to lack of the pauli principle , so that infinite number of bosons at each energy state could exist and thus the negative energy states could never be filled ..
Please generate the next two sentences of the article | however , we succeeded in constructing the dirac sea for bosons , so called _ boson sea_. in fact , there we solved one of the serious problems : how to construct the positive definite norm of the negative energy states .
there we have used a non - local definition ( the detail of the methods see @xcite ) . |
3,345 | Suppose that you have an abstract for a scientific paper: silicene consists of a monolayer of silicon atoms in a buckled honeycomb structure .
it was recently discovered that the symmetry of such a system allows for interesting rashba spin - orbit effects .
a perpendicular electric field is able to couple to the sublattice pseudospin , making it possible to electrically tune and close the band gap .
therefore , external electric fields may generate a topological phase transition from a topological insulator to a normal insulator ( or semimetal ) and vice versa .
the contribution of the present article to the study of silicene is twofold : first , we perform a group theoretical analysis to systematically construct the hamiltonian in the vicinity of the @xmath0 points of the brillouin zone and find an additional , electric field induced spin - orbit term , that is allowed by symmetry .
subsequently , we identify a tight binding model that corresponds to the group theoretically derived hamiltonian near the @xmath0 points .
second , we start from this tight binding model to analyze the topological phase diagram of silicene by an explicit calculation of the @xmath1 topological invariant of the band structure . to this end , we calculate the @xmath1 topological invariant of the honeycomb lattice in a manifestly gauge invariant way which allows us to include @xmath2 symmetry breaking terms like rashba spin orbit interaction into the topological analysis .
interestingly , we find that the interplay of a rashba and an intrinsic spin - orbit term can generate a non - trivial quantum spin hall phase in silicene .
this is in sharp contrast to the more extensively studied honeycomb system graphene where rashba spin orbit interaction is known to compete with the quantum spin hall effect in a detrimental way . .
And you have already written the first three sentences of the full article: one of the main subjects of current interest in condensed matter physics is the search for materials that host topological insulator ( ti ) phases @xcite .
two dimensional tis exhibit the quantum spin hall effect ( qshe ) with gapless edge states and a finite energy gap in the bulk @xcite .
the first proposal of this state of matter was made by kane and mele @xcite on the basis of graphene in the presence of spin - orbit interaction ( soi ) ..
Please generate the next two sentences of the article | however , the relevant soi in graphene turns out to be rather small @xcite such that the effect seems to be inaccessible in experiments .
this situation is different in hgte / cdte quantum wells where the qshe was also predicted theoretically @xcite and experimentally seen soon after @xcite . |
3,346 | Suppose that you have an abstract for a scientific paper: four - wave mixing near resonance in an atomic vapor can produce relative intensity squeezed light suitable for precision measurements beyond the shot - noise limit .
we develop an analytic distributed gain / loss model to describe the competition of mixing and absorption through the non - linear medium . using a novel matrix calculus , we present closed - form expressions for the degree of relative intensity squeezing produced by this system .
we use these theoretical results to analyze experimentally measured squeezing from a @xmath0rb vapor and demonstrate the analytic model s utility as an experimental diagnostic . 10 c. f. mccormick , v. boyer , e. arimondo , and p. d. lett , `` strong relative intensity squeezing by four - wave mixing in rubidium vapor , '' * 32 * , 178180 ( 2007 ) .
q. glorieux , l. guidoni , s. guibal , j .-
p .
likforman , and t. coudreau , `` strong quantum correlations in four wave mixing in @xmath0rb vapor , '' ( spie , 2010 ) , vol .
7727 of _ proc .
spie _ , p. 772703 . c. f. mccormick , a. m. marino , v. boyer , and p. d. lett , `` strong low - frequency quantum correlations from a four - wave - mixing amplifier , '' * 78 * , 043816 ( 2008 ) .
v. boyer , a. m. marino , and p. d. lett , `` generation of spatially broadband twin beams for quantum imaging , '' * 100 * , 143601 ( 2008 ) .
v. boyer , a. m. marino , r. c. pooser , and p. d. lett , `` entangled images from four - wave mixing , '' science * 321 * , 544547 ( 2008 ) .
v. boyer , c. f. mccormick , e. arimondo , and p. d. lett , `` ultraslow propagation of matched pulses by four - wave mixing in an atomic vapor , '' * 99 * , 143601 ( 2007 ) .
r. c. pooser , a. m. marino , v. boyer , k. m. jones , and p. d. lett , `` low - noise amplification of a continuous - variable quantum state , '' * 103 * , 010501 ( 2009 ) .
q. glorieux , r. dubessy , s. guibal , l. guidoni , j .-
p .
likforman , t. coudreau , and e. arimondo , `` double-@xmath1....
And you have already written the first three sentences of the full article: relative intensity squeezing by four - wave mixing in an atomic vapor is emerging as a promising technique for performing high - precision measurements beyond the shot - noise limit .
first demonstrated by mccormick et al .
@xcite , the technique uses atomic coherences to produce quantum correlated `` twin beams '' , enabling the shot - noise of one beam to be measured and subtracted from the other to obtain a low - noise differential measurement ; for example of a weakly absorbing sample ..
Please generate the next two sentences of the article | this scheme was recently shown to reduce the relative intensity noise by @xmath2db below the shot - noise limit @xcite , and noise reduction has been observed in both the low fourier frequency @xcite and multi - mode imaging @xcite domains .
furthermore , as one of the twin beams is near - resonant with the atoms , this squeezing technique has promising applications in quantum information processing @xcite . however , absorption near resonance degrades the quantum correlations . both mixing gain and absorption losses |
3,347 | Suppose that you have an abstract for a scientific paper: we have examined long term changes in signal amplitude gain , energy resolution and detection efficiency for the active components of the pibeta detector system .
beam defining plastic scintillation counters were operated in a @xmath01mhz stopped @xmath1 beam for a period of 297 days , accumulating radiation doses of up to @xmath2rad .
detectors in the charged particle tracking system a pair of cylindrical multi - wire proportional chambers and a thin plastic scintillation barrel - shaped hodoscope array were irradiated during the same running period with an average dose of @xmath3rad . individual csi(undoped crystal )
calorimeter detectors received an average dose of @xmath0120rad , mainly from photons , positrons and protons originating from @xmath1 hadronic interactions as well as from @xmath1 and @xmath4 weak decays at rest in the active target .
* keywords : * long term temporal stability of detector gain , energy resolution and detection efficiency , radiation hardness , radiation resistance , radiation damage . .
And you have already written the first three sentences of the full article: the pibeta collaboration has proposed a program of precise measurements of rare @xmath5 and @xmath6 decays at the paul scherrer institute ( psi ) @xcite , with particular emphasis on the pion beta decay branching ratio , @xmath7 .
the pibeta apparatus is a large solid angle non - magnetic detector optimized for detection of photons and electrons in the energy range of 5150@xmath8mev with high efficiency , energy resolution and solid angle .
the main sensitive components of the apparatus , shown and labeled in fig ..
Please generate the next two sentences of the article | [ fig1 ] , are : * bc , a thin forward beam counter placed approximately 4@xmath8 m upstream of the detector center , ac@xmath9 and ac@xmath10 , two cylindrical active collimators , ad , an active degrader , all made of plastic scintillator and used for beam definition ; * at , a 9-element segmented active plastic scintillator target , used to stop the beam particles while simultaneously sampling the lateral beam profile ; * mwpc@xmath9 and mwpc@xmath10 , two concentric low - mass cylindrical multi - wire proportional chambers for charged particle tracking , surrounding the active target ; * pv , a fast 20-bar segmented thin plastic scintillator hodoscope , surrounding the mwpcs , used for particle identification ; * a 240-element fast high - resolution segmented spherical pure - csi shower calorimeter surrounding the target region and tracking detectors , subtending a solid angle of @xmath11% of @xmath12 ; * cv , a set of cosmic muon plastic scintillator veto counters around the entire apparatus , not shown in fig .
[ fig1 ] . to [ fig1 ] |
3,348 | Suppose that you have an abstract for a scientific paper: we investigate the dynamics of a double quantum dot charge qubit which is coupled to piezoelectric acoustic phonons , appropriate for gaas heterostructures . at low temperatures ,
the phonon bath induces a non - markovian dynamical behavior of the oscillations between the two charge states of the double quantum dot . upon applying the numerically exact quasiadiabatic propagator path - integral scheme ,
the reduced density matrix of the charge qubit is calculated , thereby avoiding the born - markov approximation .
this allows a systematic study of the dependence of the @xmath0-factor on the lattice temperature , on the size of the quantum dots , as well as on the interdot coupling .
we calculate the @xmath0-factor for a recently realized experimental setup and find that it is two orders of magnitudes larger than the measured value , indicating that the decoherence due to phonons is a subordinate mechanism . .
And you have already written the first three sentences of the full article: various candidates for realizing building blocks of quantum information processors with nanoscale solid state structures have been proposed and also partially realized in ground - breaking experiments .
an important class of proposals consists of using the charge degree of freedom in semiconducting double quantum dots ( dqds ) @xcite to realize a quantum mechanical two - state system or quantum bit ( qubit).@xcite thereby , the logical states @xmath1 and @xmath2 are given by the low - energy charge states of the dqd with one excess electron either on the left or the right dot .
the transition between these states occurs via tunneling between the two dots ..
Please generate the next two sentences of the article | a significant advantage of the charge qubit is its direct controllability via external voltage sources . in recent experiments ,
the coherent manipulation of charge states of dqds has been achieved.@xcite thereby , the control over the bias and the gate voltages permits to reliably tune the dqd in the coulomb blockade regime to the required transition line @xmath3 . |
3,349 | Suppose that you have an abstract for a scientific paper: an inhomogeneous anisotropic medium with specific structure geometry can apply the tunable spin - dependent geometrical phase to the light passing through the medium , and thus can be used to steer the spin - dependent splitting ( sds ) of light . in this paper
, we exemplify this inference by the @xmath0 plate , an inhomogeneous anisotropic medium .
it is demonstrated that when a linearly polarized light beam normally passes through a @xmath0 plate , @xmath1-space sds first occurs , and then the real - space sds in the far - field focal plane of a converging lens is distinguishable .
interestingly , the sds , described by the normalized stokes parameter @xmath2 , shows a multi - lobe and rotatable splitting pattern with rotational symmetry .
further , by tailoring the structure geometry of the @xmath0 plate and/or the incident polarization angle of light , the lobe number and the rotation angle both are tunable .
our result suggests that the @xmath0 plate can serve as a potential device for manipulating the photon spin states and enable applications such as in nano - optics and quantum information . .
And you have already written the first three sentences of the full article: in recent years , some fundamental effects in optics have attracted much attention , such as the spin hall effect of light @xcite , optical coriolis effect @xcite , and optical magnus effect @xcite .
they manifest themselves as the splitting of photon spin states , that is , when a linearly polarized light beam passes through a refractive index gradient ( e.g. , interfaces of different media ) or an inhomogeneous medium , its left and right circular polarization components separate from each other .
this spin - dependent splitting ( sds ) effect is directly attributed to different geometrical phases that the two spin components respectively experienced , corresponding to the spin - orbital interaction @xcite ..
Please generate the next two sentences of the article | the light beam can acquire a spin - dependent geometrical phase upon the reflection or refraction of a refractive index gradient created by the interface of different media .
when a linearly polarized paraxial light beam impinges obliquely upon this interface , the sds in real space ( coordinate space ) generates , that is , the two spin components separate from each other and reside on both sides of the incident plane @xcite . |
3,350 | Suppose that you have an abstract for a scientific paper: constrained willmore surfaces are conformal immersions of riemann surfaces that are critical points of the willmore energy @xmath0 under compactly supported infinitesimal conformal variations .
examples include all constant mean curvature surfaces in space forms . in this paper
we investigate more generally the critical points of arbitrary geometric functionals on the space of immersions under the constraint that the admissible variations infinitesimally preserve the conformal structure . besides constrained willmore surfaces we discuss in some detail examples of constrained minimal and volume critical surfaces , the critical points of the area and enclosed volume functional under the conformal constraint . in calc .
var .
partial differential equations * 32 * ( 2008 ) , 263 - 277 . ] .
And you have already written the first three sentences of the full article: in 1882 felix klein posed the question whether every abstract riemann surface @xmath1 can be realized in euclidean 3space .
a positive answer to this question was given by a. garsia @xcite and r. redy @xcite , who proved that every riemann surface can be conformally embedded into @xmath2 .
this immediately raises the question for the optimal geometric realizations in @xmath2 of a given abstract riemann surface , or , slightly more general , for the optimal ( especially beautiful , symmetric ... ) conformal immersions of a riemann surface into space ..
Please generate the next two sentences of the article | the same question may be raised about optimal realizations of topological types of surfaces , without the conformal constraint . in this context
, there is a general agreement that an excellent way to make the notion of `` optimal '' precise is to look for surfaces that are critical points of the willmore functional @xmath3 . |
3,351 | Suppose that you have an abstract for a scientific paper: in this paper we revisit the problem of a nematic liquid crystal in contact with patterned substrates .
the substrate is modelled as a periodic array of parallel infinite grooves of well - defined cross section sculpted on a chemically homogeneous substrate which favors local homeotropic anchoring of the nematic .
we consider three cases : a sawtooth , a crenellated and a sinusoidal substrate .
we analyse this problem within the modified frank - oseen formalism .
we argue that , for substrate periodicities much larger than the extrapolation length , the existence of different nematic textures with distinct far - field orientations , as well as the anchoring transitions between them , are associated with the presence of topological defects either on or close to the substrate . for the sawtooth and sinusoidal case , we observe a homeotropic to planar anchoring transition as the substrate roughness is increased . on the other hand , a homeotropic to oblique anchoring transition is observed for crenellated substrates . in this case , the anchoring phase diagram shows a complex dependence on the substrate roughness and substrate anchoring strength . .
And you have already written the first three sentences of the full article: in the last decades the study of nematic liquid crystals in the presence of microstructured substrates has been the subject of intense research @xcite .
this problem is interesting not only from a fundamental point of view , but also due to its practical applications , such as the design of zenithally bistable devices @xcite , or the trapping of colloidal particles on specified sites @xcite .
the presence of the structured substrate typically distorts the nematic orientational order , leading to elastic distortions and the formation of topological defects . on the other hand.
Please generate the next two sentences of the article | , the substrate topography can determine the director orientation far away from the substrate .
since the seminal work of berreman @xcite , this problem has been extensively studied and generalized in the literature @xcite . wetting and filling transitions by nematics on these surfaces have also been studied @xcite . when the substrate has cusps , disclination - like singularities generally appear at or very close to them @xcite . however , even when the substrate is smooth disclination lines may appear , in the nematic , close to the substrate @xcite . in both cases , these orientation - field singularities play an important role to understand the different textures of the nematic in contact with a patterned substrate under strong anchoring conditions . in this paper |
3,352 | Suppose that you have an abstract for a scientific paper: we present preliminary results of vla hi imaging of selected virgo cluster galaxies .
the goal is to study environmental effects on galaxy evolution .
our sample of 41 galaxies is spread throughout the cluster and spans a wide range in star formation properties . here
we present the total hi maps of 13 galaxies .
we find a number of galaxies with extended hi tails , almost all pointing away from the cluster center .
truncated hi disks are found close to the center but also in the outer region .
some galaxies near the cluster center show compression of the gas on one side .
multiwavelength data of ngc 4569 and kinematics on ngc 4396 indicate that some of the hi is extra - planar .
these preliminary results on the hi morphology already suggest that a variety of environmental effects such as icm - ism interactions , harassment , tidal interactions or mergers may be at work to affect the evolution of galaxies . .
And you have already written the first three sentences of the full article: it has long been known that galaxies in the dense cluster environments systematically differ from those in the field in their morphology , stellar populations , gas fractions and gas distributions .
more interestingly , observations of galaxy clusters at intermediate redshift show that these properties change with redshift .
this could indicate that the dense cluster environment speeds up the evolution of galaxies ..
Please generate the next two sentences of the article | various mechanisms affecting the evolution of galaxies have been suggested such as ram - pressure stripping , merging , tidal interaction , harassment or starvation . in spite of the abundance of statistical studies on clusters at intermediate redshifts ( e.g. * ? ? ?
* ; * ? ? ? |
3,353 | Suppose that you have an abstract for a scientific paper: we discuss bayesian analysis of multivariate time series with dynamic factor models that exploit time - adaptive sparsity in model parametrizations via the latent threshold approach .
one central focus is on the transfer responses of multiple interrelated series to underlying , dynamic latent factor processes .
structured priors on model hyper - parameters are key to the efficacy of dynamic latent thresholding , and mcmc - based computation enables model fitting and analysis . a detailed case study of electroencephalographic ( eeg ) data from experimental psychiatry highlights the use of latent threshold extensions of time - varying vector autoregressive and factor models .
this study explores a class of dynamic transfer response factor models , extending prior bayesian modeling of multiple eeg series and highlighting the practical utility of the latent thresholding concept in multivariate , non - stationary time series analysis .
_ msc 2010 subject classifications : _
62f15 , 62m10 , 62p10 _ key words & phrases : _ dynamic factor models ; dynamic sparsity ; eeg time series ; factor - augmented vector autoregression ; impulse response ; multivariate time series ; sparse time - varying loadings ; time - series decomposition ; transfer response factor models . .
And you have already written the first three sentences of the full article: in high - dimensional time series analysis , the need to define time - varying patterns of sparsity in model parameters has proven challenging .
dynamic latent thresholding , introduced in @xcite , provides a general approach that induces parsimony into time series model structures with potential to reduce effective parameter dimension and improve model interpretations as well as forecasting performance .
the utility of various classes of latent threshold models ( ltms ) has been demonstrated in recent applied studies in macroeconomics @xcite and financial forecasting and portfolio decisions @xcite ..
Please generate the next two sentences of the article | the scope of the approach includes dynamic regressions , dynamic latent factor models , time - varying vector autoregressions , and dynamic graphical models of multivariate stochastic volatility , and also opens a path to new approaches to dynamic network modeling @xcite .
this paper adapts the latent thresholding approach to different classes of multivariate factor models with a one main interest in dynamic transfer response analysis . |
3,354 | Suppose that you have an abstract for a scientific paper: we introduce a graphical representation of stabilizer states and translate the action of clifford operators on stabilizer states into graph operations on the corresponding stabilizer - state graphs .
our stabilizer graphs are constructed of solid and hollow nodes , with ( undirected ) edges between nodes and with loops and signs attached to individual nodes .
we find that local clifford transformations are completely described in terms of local complementation on nodes and along edges , loop complementation , and change of node type or sign .
additionally , we show that a small set of equivalence rules generates all graphs corresponding to a given stabilizer state ; we do this by constructing an efficient procedure for testing the equality of any two stabilizer graphs . .
And you have already written the first three sentences of the full article: stabilizer states are ubiquitous elements of quantum information theory , as a consequence both of their power and of their relative simplicity .
the fields of quantum error correction , measurement - based quantum computation , and entanglement classification all make substantial use of stabilizer states and their transformations under clifford operations @xcite .
stabilizer states are distinctly quantum mechanical in that they can possess arbitrary amounts of entanglement , but the existence of a compact description that can be updated efficiently sets them apart from other highly entangled states ..
Please generate the next two sentences of the article | their prominence , as well as their name , derives from this description , a formalism in which a state is identified by a set of pauli operators generating the subgroup of the pauli group that stabilizes it , i.e. , the subgroup of which the state is the @xmath0 eigenvector . in this paper
we seek to augment the stabilizer formalism by developing a graphical representation both of the states themselves and of the transformations induced on them by clifford operations . |
3,355 | Suppose that you have an abstract for a scientific paper: we present an in - depth weak lensing analysis of the cluster ms1008@xmath01@xmath11224 based on deep multicolor imaging obtained during the science verification of fors1 at the vlt .
the image quality ( half arcsec seeing ) and depth of the vlt images allow the shear signal to be mapped with high signal - to - noise and to be traced out to @xmath2 , near the edge of the @xmath3 field of view . using bvri color information , as well as 81 redshifts in the field from the cnoc survey
, background galaxies can be effectively separated from cluster and foreground objects .
psf distorsions are found to be moderate across the fors images and thus easily removed . due to the small statistical errors in the mass reconstruction
, this dataset provides a testing ground where several systematic effects ( e.g. mass - sheet degeneracy , redshift distribution of the background sources , cluster galaxy contamination ) , which are involved in the weak lensing analysis , can be quantified .
several methods are used to remove the mass - sheet degeneracy which is found to dominate the systematic error budget .
we measure a lower limit to the mass of @xmath4 within @xmath5 and a `` total '' mass of @xmath6 by fitting a softened isothermal sphere .
we find the mass distribution fairly uniform , with no significant substructures , in agreement with the virial analysis .
the availability of the cnoc redshift data and x - ray observations on this cluster allow a comparison of different determinations of the mass radial profile .
we find the lensing and x - ray measurements in excellent agreement , while the mass derived from the virial analysis is marginally ( @xmath7@xmath8 ) in agreement at radii where both methods are reliable .
this analysis underscores the importance of systematics in the mass determination of clusters , particularly when such a high quality dataset is not available or in similar studies at higher redshifts . .
And you have already written the first three sentences of the full article: the study of the weak lensing distortion of background galaxies is a powerful tool for measuring the mass distribution of galaxy clusters .
it has long been recognized ( tyson et al .
1984 ) that the tidal field of a cluster acts by slightly modifying the images of distant , background galaxies . by measuring these small distortions the projected mass distribution of the lensing cluster can be derived in a model independent fashion ( kaiser & squires 1993 ) , in contrast with other mass estimators ( x - ray measurements of intra - cluster gas density and temperature , galaxy dynamics ) . to date.
Please generate the next two sentences of the article | , there are approximately 20 clusters which have been well studied with lensing techniques ( see , e.g. , mellier 1999 for a review ) . in several cases the resulting masses
are claimed to be larger ( by a factor of two ) than those obtained using different methods . at present , it is not known if this discrepancy is due to biases and inaccuracies in the x - ray and dynamical estimates , or to the lensing data reduction method . as a matter of fact , it is not even clear whether there is a real discrepancy ( see wu et al . |
3,356 | Suppose that you have an abstract for a scientific paper: we study the isotope effects arising from the coupling of correlated electrons with dispersionless phonons by considering the hubbard - holstein model at half - filling within the dynamical mean - field theory .
in particular we calculate the isotope effects on the quasi - particle spectral weight @xmath0 , the renormalized phonon frequency , and the static charge and spin susceptibilities . in the weakly correlated regime @xmath1 , where @xmath2 is the hubbard repulsion and @xmath3 is the bare electron half - bandwidth , the physical properties are qualitatively similar to those characterizing the holstein model in the absence of coulomb repulsion , where the bipolaronic binding takes place at large electron - phonon coupling , and it reflects in divergent isotope responses . on the contrary in the strongly correlated regime @xmath4 , where the bipolaronic metal - insulator transition becomes of first order , the isotope effects are bounded , suggesting that the first order transition is likely driven by an electronic mechanism , rather then by a lattice instability .
these results point out how the isotope responses are extremely sensitive to phase boundaries and they may be used to characterize the competition between the electron - phonon coupling and the hubbard repulsion . .
And you have already written the first three sentences of the full article: one of the most direct methods to establish the coupling of an electronic property with the dynamics of the underlying lattice is the isotope effect ( ie ) , @xmath5 , which probes the dependence of the electronic quantity @xmath6 on the ion mass @xmath7 .
for example , the observation of a large ie on the superconducting transition temperature @xmath8 has been an important evidence for a phonon - mediated pairing mechanism in conventional low - temperature superconductors . in the weak - coupling bcs model ,
the superconducting critical temperature is proportional to the debye phonon frequency which scales as @xmath9 ..
Please generate the next two sentences of the article | the resulting ie on @xmath8 , @xmath10 , has been considered as one of the most important confirmation of the bcs theory .
the vanishingly small values of @xmath11 in optimally doped high-@xmath8 copper oxides superconductors has initially induced a large part of the scientific community to believe that the pairing mechanism in these compounds was mainly of electronic origin , and oriented the theoretical research towards purely electronic models , relegating the lattice to a secondary role . |
3,357 | Suppose that you have an abstract for a scientific paper: the study of eclipsing binaries is our primary source of measured properties of normal stars , achieved through analysis of light and radial velocity curves of eclipsing systems .
the study of oscillations and pulsations is increasingly vital for determining the properties of single stars , and investigating the physical phenomena active in their interiors . combining the two methods
holds the promise of establishing stringent tests of stellar evolutionary theory , and of calibrating model - dependent asteroseismology with empirically measured stellar properties .
i review recent advances and outline future work . .
And you have already written the first three sentences of the full article: the study of eclipsing binary star systems ( hereafter ebs ) has a long history .
the eclipse hypothesis was proposed as an explanation of the periodic dimmings of the ` demon star ' algol ( @xmath0persei ) by john @xcite .
the first empirical measurement of the masses and radii of two stars in an eb was that by @xcite for @xmath0aurigae ; the numbers are close to modern values @xcite . shortly afterwards , @xcite established a quantitative method for analysing light curves of eclipses ..
Please generate the next two sentences of the article | the era of high - quality space photometry began in 2006 , with a light curve of @xmath1centauri from the wire satellite @xcite .
this star shows deep total eclipses on a 38.8d period ( fig.[fig : pcen ] ) , and prior to the serendipitous observations from wire was not known as either an eclipsing or spectroscopic binary despite its brightness ( @xmath2 ) . |
3,358 | Suppose that you have an abstract for a scientific paper: neutral - current and charged - current deep - inelastic scattering at very high four - momentum transfer squared ( @xmath0 ) have been studied in positron - proton collisions at center - of - mass energy 300 gev using the zeus detector at hera .
an integrated luminosity of 47.7 pb@xmath1 was collected in the years 1994 - 1997 .
differential cross sections are presented for @xmath2 gev@xmath3 and compared to standard model predictions . .
And you have already written the first three sentences of the full article: deep - inelastic scattering ( dis ) provides a wealth of information about nucleon structure . recently ,
very high momentum transfers in dis have been achieved at the hera collider , where 820 gev protons have been collided with 27.5 gev positrons for a center - of - mass energy @xmath4=300 gev . in the highest momentum transfer region , @xmath5 dis cross sections depend on proton parton densities and properties of the electroweak interaction .
the @xmath6 dis process is illustrated in fig ..
Please generate the next two sentences of the article | [ fig : dis ] . the variables used to describe the process are @xmath7 , the struck parton momentum fraction , @xmath8 , the fractional energy transfer in the proton rest frame ( inelasticity ) and @xmath0 , the four - momentum transfer squared , where @xmath9 .
neutral - current dis events are characterized by the exchange of a photon or @xmath10-boson , and have a positron and a jet ( or jets ) in the final state . |
3,359 | Suppose that you have an abstract for a scientific paper: in contemporary particle physics , the masses of fundamental particles are incalculable constants , being supplied by experimental values . inspired by observation of the empirical particle mass spectrum , and their corresponding physical interaction couplings , we propose that the masses of elementary particles arise solely due to the self - interaction of the fields associated with the charges of a particle . a first application of this idea is seen to yield correct order of magnitude predictions for neutrinos , charged leptons and quarks .
we then discuss more ambitious models , where also different generations may arise from _
e.g. _ self - organizing bifurcations due to the underlying non - linear dynamics , with the coupling strength acting as non - linearity " parameter .
if the model is extended to include gauge bosons , the photon is automatically the only fundamental particle to remain massless as it has no charges .
it results that gluons have an effective range @xmath0fm , physically explaining why qcd has finite reach . .
And you have already written the first three sentences of the full article: the biggest , and oldest , unresolved enigma in fundamental particle physics is : _ where do the observed masses of elementary particles come from ? _ , the concept of mass is not really understood , and their numerical values remain a mystery . there is the widespread , but erroneous , belief that when the higgs boson is confirmed , the origin of mass has been found .
this is not the case .
it merely replaces one set of unknown parameters ( particle masses ) with an equally unknown set of parameters ( coupling constants to the higgs field(s ) ) , so nothing is gained in the _ fundamental understanding _ of masses . despite what can be imagined about the triviality regarding masses from frequent statements like.
Please generate the next two sentences of the article | the supersymmetric partners differ _ only _ in their masses ( and spin ) compared to the normal particles " , ... the planck scale , @xmath1 gev " , and the mass of the top quark is 175 gev " , etc , the concept of mass has never been defined in an unambiguous way , not even in classical physics .
in fact , jammer @xcite has been able to write two whole monographs on this thorny subject , concluding that nobody knows what mass really is . |
3,360 | Suppose that you have an abstract for a scientific paper: we study the system that two atoms simultaneously interact with a single - mode thermal field via different couplings and different spontaneous emission rates when two - photon process is involved .
it is found that we indeed can employ the different couplings to produce the atom - atom thermal entanglement in two - photon process .
the different atomic spontaneous emission rates are also utilizable in generating thermal entanglement .
we also investigate the effect of the cavity leakage . to the initial atomic state @xmath0a slight leakage can relieve the restriction of interaction time and we can obtain a large and steady entanglement .
pacs number : 03.67.-a , 03.67.-hz , 42.50.-p .
And you have already written the first three sentences of the full article: entanglement plays an important role in respect that it is a valuable resource in quantum information processing such as quantum teleportation1 , quantum computation@xcite and quantum cryptography@xcite , _
etc_. several schemes have been proposed to prepare purified and distilled entangled state both theoretically and experimentally@xcite .
although the interaction between a quantum system and its surroundings can result in inevitable decoherence of the quantum system , people have recognized that we can employ the interaction to generate entanglement@xcite ..
Please generate the next two sentences of the article | the two - atom entangled states are widely studied in cavity qed6,7,8,9,10 . in cavity qed ,
the dissipation in the model of atoms interacting with magnetic field generally includes two aspects : the cavity leakage through which the intra - cavity magnetic field can exchange information with its environmental noise , the atomic spontaneous emission that is induced by vacuum fluctuation effect . in the sense of using the impact of environmental noise , |
3,361 | Suppose that you have an abstract for a scientific paper: we report a study of the axialisation and laser cooling of single ions and small clouds of ions in a penning trap .
a weak radiofrequency signal applied to a segmented ring electrode couples the magnetron motion to the cyclotron motion , which results in improved laser cooling of the magnetron motion .
this allows us to approach the trapping conditions of a paul trap , but without any micromotion . using an iccd camera
we show that the motion of a single ion can be confined to dimensions of the order of 20 @xmath0 m or less .
we have measured increased magnetron cooling rates for clouds of a few ions , using an rf - photon correlation technique . for certain laser cooling conditions ,
the magnetron motion of the center of mass of the cloud grows and stabilises at a large value .
this results in the ions orbiting the center of the trap together in a small cloud , as confirmed by photon - photon correlation measurements . .
And you have already written the first three sentences of the full article: trapped ions are currently being studied extensively with regard to their possible use in the realisation of a prototype quantum computer @xcite .
laser - cooled trapped ions offer distinct advantages over many other proposed quantum technologies for this purpose . as a result , much work in the area of quantum information science has focused on the use of miniature radiofrequency ( paul ) traps ( for single ions ) or linear radiofrequency traps ( which allow the preparation of stationary strings of ions ) . in both cases , strong confinement to the lamb - dicke regime may be obtained ( e.g. @xcite ) .
unfortunately , the low - temperature limit of the paul trap can be affected by the micromotion of the trapped ions ..
Please generate the next two sentences of the article | this arises as a result of the applied radiofrequency trapping field and can not be completely avoided , although the micromotion is generally minimised by the application of potentials to compensation electrodes .
decoherence rates may be limited by the presence of the micromotion or by the small size of the trap electrodes , which allow image charge and patch potential effects to become significant @xcite . |
3,362 | Suppose that you have an abstract for a scientific paper: we propose a simple scheme to establish entanglement among stationary qubits based on the mechanism of resonance scattering between them and a single - spin - flip wave packet in designed spin network .
it is found that through the natural dynamical evolution of an incident single - spin - flip wave packet in a spin network and the subsequent measurement of the output single - spin - flip wave packet , multipartite entangled states among @xmath0 stationary qubits , greenberger - horne - zeilinger ( ghz ) and w states can be generated with success probabilities @xmath1 and @xmath2 respectively , where @xmath3 is the transmission amplitude of the near - resonance scattering . .
And you have already written the first three sentences of the full article: in quantum information science it is a crucial problem to develop techniques for generating entanglement among stationary qubits .
entanglement as unique feature of quantum mechanics can be used not only to test fundamental quantum - mechanical principles @xcite , but to play a central role in applications @xcite .
especially , multipartite entanglement has been recognized as a powerful resource in quantum information processing and communication ..
Please generate the next two sentences of the article | there are two typical multipartite entangled states , greenberger - horne - zeilinger ( ghz ) and w states , which are usually referred to as maximal entanglement .
numerous protocols for the preparation of such states have been proposed @xcite . |
3,363 | Suppose that you have an abstract for a scientific paper: the work studies a number of approaches to solving motion planning problem for a mobile robot with a trailer
. different control models of car - like robots are considered from the differential - geometric point of view .
the same models can be also used for controlling a mobile robot with a trailer . however , in cases where the position of the trailer is of importance , i.e. , when it is moving backward , a more complex approach should be applied . at the end of the article , such an approach , based on recent works in sub - riemannian geometry ,
is described .
it is applied to the problem of reparking a trailer and implemented in the algorithm for parking a mobile robot with a trailer .
* keywords : * mobile robot , trailer , motion planning , sub - riemannian geometry , nilpotent approximation .
* msc 2010 : * 22e25 , 53a17 , 58e25 , 70q05 . .
And you have already written the first three sentences of the full article: control problems for wheeled robots are usually described by nonholonomic systems .
a nonholonomic system arises when the dimension of configuration space is greater than the dimension of control . here and below
, the configuration space represents possible positions of a wheeled robot , i.e. , for a car - like robot it can be expressed in the following way : @xmath0 where @xmath1 corresponds to the reference point of the robot on a plane and @xmath2 corresponds to the orientation of the robot . for nonholonomic systems , motion in some directions is infinitesimally prohibited , but it is locally and globally possible ( through complex maneuvers of the system ) ..
Please generate the next two sentences of the article | there is a well - known problem about parking of a car which can not move in a direction perpendicular to the direction of motion of the wheels .
in fact , every driver has faced this problem . |
3,364 | Suppose that you have an abstract for a scientific paper: many studies of the loop i magnetic superbubble place the sun at the edges of the bubble .
one recent study models the polarized radio continuum of loop i as two magnetic shells with the sun embedded in the rim of the s1 shell .
if the sun is in such a shell , it should be apparent in both the local interstellar magnetic field and the distribution of nearby interstellar material .
the properties of these subshells are compared to the interstellar magnetic field ( ismf ) and the distribution of interstellar and within @xmath0 pc of the sun .
although the results are not conclusive , the ismf direction obtained from polarized stars within @xmath1 pc is consistent with the ismf direction of the s1 shell .
the distribution of nearby interstellar with log @xmath2 is described equally well by a uniform distribution or an origin in spherical shell - like features .
higher column densities of ( log @xmath3 ) tend to be better described by the pathlength of the sightline through the s1 and s2 subshells .
column densities of the recombinant ion are found to increase with the strength of the interstellar radiation field , rather than with star distance or total pathlength through the two magnetic subshells .
the ion can not be used to trace the distribution of local interstellar gas unless the spatial variations in the radiation field are included in the calculation of the ionization balance , in addition to possible abundance variations .
the result is that a model of loop i as composed of two spherical magnetic subshells remains a viable description of the distribution of nearby low density ism , but is not yet proven . .
And you have already written the first three sentences of the full article: the location of the sun in the rim of the loop i superbubble has been inferred from radio continuum data , kinematical data on the flow of local ism away from the center of loop i , data on gas - phase abundances in local ism , and the coincidence of the velocity of ism inside and outside of the heliosphere .
loop i is an evolved superbubble shell formed from stellar evolution in a subgroup of the sco - cen association , @xmath4 myrs ago ( e.g. * ? ? ? * ; * ? ? ?
* ; * ? ? ?.
Please generate the next two sentences of the article | * ; * ? ? ?
both the original dimensions found for the loop i bubble observed in 820 mhz @xcite , and more recent studies of ( * ? ? ? |
3,365 | Suppose that you have an abstract for a scientific paper: previous work on soft - gluon resummation for direct photon production is extended to include additional subleading logarithmic terms through @xmath0 and some representative comparisons are made to experimental results from the e-706 and ua-6 collaborations .
the additional terms are small in magnitude , indicating good convergence properties to the level of accuracy calculated .
the scale dependence remains much smaller than that of the next - to - leading - order calculation . .
And you have already written the first three sentences of the full article: direct photon production is widely recognized as a process that is potentially important in determinations of the gluon distribution function . the next - to - leading - order ( nlo )
cross section for direct photon production has been given in refs .
the role of higher - order soft - gluon corrections has also been addressed more recently ..
Please generate the next two sentences of the article | threshold resummation studies for direct photon production have appeared in refs .
@xcite while a joint threshold and transverse momentum resummation formalism has been given in ref . |
3,366 | Suppose that you have an abstract for a scientific paper: we present our methods for generating a catalog of 7,000 synthetic images and 40,000 integrated spectra of redshift @xmath0 galaxies from the illustris simulation .
the mock data products are produced by using stellar population synthesis models to assign spectral energy distributions ( sed ) to each star particle in the galaxies .
the resulting synthetic images and integrated seds therefore properly reflect the spatial distribution , stellar metallicity distribution , and star formation history of the galaxies . from the synthetic data products it is possible to produce monochromatic or color - composite images , perform sed fitting , classify morphology , determine galaxy structural properties , and evaluate the impacts of galaxy viewing angle .
the main contribution of this paper is to describe the production , format , and composition of the image catalog that makes up the illustris simulation obsevatory . as a demonstration of this resource ,
we derive galactic stellar mass estimates by applying the sed fitting code fast to the synthetic galaxy products , and compare the derived stellar masses against the true stellar masses from the simulation .
we find from this idealized experiment that systematic biases exist in the photometrically derived stellar mass values that can be reduced by using a fixed metallicity in conjunction with a minimum galaxy age restriction .
methods : numerical cosmology : theory cosmology : galaxy formation .
And you have already written the first three sentences of the full article: the formation of dark matter haloes has been studied extensively using numerical dark matter only simulations ( e.g. , * ? ? ? * ; * ? ? ?
* ; * ? ? ?
* ; * ? ? ?.
Please generate the next two sentences of the article | * ; * ? ? ?
extending the insight from dark matter only simulations to include a theory of galaxy formation requires a method to link the formation of dark matter haloes to observable galaxy properties . |
3,367 | Suppose that you have an abstract for a scientific paper: we present the failure of the standard coupled - channels method in explaining the inelastic scattering together with other observables such as elastic scattering , excitation function and fusion data .
we use both microscopic double - folding and phenomenological deep potentials with shallow imaginary components .
we argue that the solution of the problems for the inelastic scattering data is not related to the central nuclear potential , but to the coupling potential between excited states .
we present that these problems can be addressed in a systematic way by using a different shape for the coupling potential instead of the usual one based on taylor expansion . .
And you have already written the first three sentences of the full article: in this paper , we consider the @xmath0c+@xmath0c reaction as a case study to point out the problems for the inelastic scattering states which have so far remained unsolved , and to address particularly the magnitude problem for the inelastic scattering data .
theoretical calculations using the coupled - channels ( cc ) method fail to correctly predict the magnitude of the single-2@xmath1 and mutual-2@xmath1 states data together with the elastic scattering data . in order to get the magnitude right
, many futile theoretical attempts have been made for these states ..
Please generate the next two sentences of the article | previous theoretical works show that the shapes of the central real potentials are actually correct , since they explain the elastic scattering data and predict the resonances at the correct energies with reasonable widths .
it appears that the failure of the standard methods is mostly related to the inelastic scattering data : the magnitude of the theoretical cross - sections is much smaller than the measured experimental data . in this paper |
3,368 | Suppose that you have an abstract for a scientific paper: a formalism is presented to evaluate the sivers function in constituent quark models .
a non - relativistic reduction of the scheme is performed and applied to the isgur - karl model .
the results obtained are consistent with a sizable sivers effect and the signs for the @xmath0 and @xmath1 flavor contributions turn out to be opposite .
the burkardt sum rule is fulfilled to a large extent . after the estimate of the qcd evolution of the results from the momentum scale of the model to the experimental one , a reasonable agreement with the available data
is obtained .
a calculation of nuclear effects in the extraction of neutron single spin asymmetries in semi - inclusive deep inelastic scattering off @xmath2he is also described . in the kinematics of forth - coming experiments at jlab
, it is found that the nuclear effects arising within an impulse approximation approach are under control .
address= dipartimento di fisica , universit degli studi di perugia , via a. pascoli , 06100 perugia , italy , altaddress= infn , sezione di perugia , via a. pascoli , 06100 perugia , italy address= departament de fisica terica , universitat de valncia + and institut de fisica corpuscular , consejo superior de investigaciones cientficas + 46100 burjassot ( valncia ) , spain address= dipartimento di fisica , universit degli studi di perugia , via a. pascoli , 06100 perugia , italy , address= departament de fisica terica , universitat de valncia + and institut de fisica corpuscular , consejo superior de investigaciones cientficas + 46100 burjassot ( valncia ) , spain , altaddress= th - division , ph department , cern , ch-1211 genve 23 , switzerland .
And you have already written the first three sentences of the full article: the partonic structure of transversely polarized nucleons is one of their less known features ( for a review , see , e.g. , ref .
@xcite ) . the work presented here aims to contribute to the effort of shedding some light on it .
semi - inclusive deep inelastic scattering ( sidis ) is one of the proposed processes to access the parton distributions ( pds ) of transversely polarized hadrons ..
Please generate the next two sentences of the article | sidis of unpolarized electrons off a transversely polarized target shows azimuthal asymmetries , the so called `` single spin asymmetries '' ( ssas ) @xcite .
the ssas are due to two physical mechanisms , whose contributions can be distinguished @xcite . |
3,369 | Suppose that you have an abstract for a scientific paper: we show that , due to the weak ferromagnetism of la@xmath0sr@xmath1cuo@xmath2 , an external magnetic field leads to a dimensional crossover 2d @xmath3 3d for the in - plane transport .
the crossover results in an increase of the hole s localization length and hence in a dramatic negative magnetoresistance in the variable range hopping regime .
this mechanism quantitatively explains puzzling experimental data on the negative magnetoresistance in the nel phase of la@xmath0sr@xmath1cuo@xmath2 . .
And you have already written the first three sentences of the full article: the physics of the high - temperature superconducting oxides is determined by the interplay between the charge and spin degrees of freedom , ultimately responsible for the superconductivity itself .
a variety of interesting phenomena exists already at low doping when the oxide layers are insulating . in la@xmath0sr@xmath1cuo@xmath2 ( lsco ) , the insulating ( spin - glass ) region corresponds to doping @xmath4 , with incommensurate magnetism which exists down to the boundary with the antiferromagnetic phase ( at @xmath5 ) , and even inside the nel region ( @xmath6 ) .
@xcite a popular point of view favors an explanation of the incommensurate magnetism based on the tendency of the holes to form stripes . " @xcite however , experimental data on variable range hopping ( vrh ) ( see the review ref . ) , unambiguously indicate localization of holes for @xmath4 and therefore support an approach based on a purely magnetic scenario , where a spiral distortion of the spin background is generated by localized holes.
Please generate the next two sentences of the article | . the corresponding theory explains quantitatively the variety of magnetic and transport data in lsco .
@xcite magnetic phenomena in the low - doping region reflect , in addition to the heisenberg exchange , the presence of anisotropies in the spin - spin interactions , such as dzyaloshinsky - moriya ( dm ) and xy terms . in the present paper |
3,370 | Suppose that you have an abstract for a scientific paper: we present the historical light curve of t tau derived from photographic plates in the harvard college observatory archives .
we find that the optical light of t tau varied by 2 - 3 ( or more ) magnitudes on time scales as short as a month prior to @xmath0 1917 , consistent with the results of lozinskii ( 1949 ) .
extreme light fluctuations of greater than 2 magnitudes abruptly ceased in the late 1910 s and , to the best of our knowledge , have not repeated since this time .
we compare the observed light variations of t tau to the t tauri stars ry tau and rw aur , whose light curves we also constructed from inspection of the archival plates .
we find that variable extinction along the line of sight to the star is the most likely explanation for the observed light fluctuation of t tau during the early part of the 20th century . .
And you have already written the first three sentences of the full article: joy ( 1945 ) identified t tauri stars as a distinct class of variable stars and ambartsumian ( 1947 ; 1949 ) first suggested that they represent solar - like stars in the early stages of formation .
they have since that time become understood as such and have been studied vigorously ( e.g. menard & bertout 1999 and references therein ) .
the prototype and one of the brightest members of the class , t tau , was discovered in the mid 1800 s to vary significantly in visual magnitude . however , t tau is a complicated system and is not a typical member of the t tauri class ..
Please generate the next two sentences of the article | three optical nebulosities are associated with it .
hind s variable nebula ( ngc 1555 ) and a small nebulosity ( ngc 1554 ) lie @xmath0 45@xmath1 and @xmath0 4@xmath2 to the west , respectively ( herbig 1950 ) . |
3,371 | Suppose that you have an abstract for a scientific paper: is there a mathematical theory underlying intelligence ?
control theory addresses the output side , motor control , but the work of the last 30 years has made clear that perception is a matter of bayesian statistical inference , based on stochastic models of the signals delivered by our senses and the structures in the world producing them
. we will start by sketching the simplest such model , the hidden markov model for speech , and then go on illustrate the complications , mathematical issues and challenges that this has led to .
4.5 mm * keywords and phrases : * perception , speech , vision , bayesian , statistics , inference , markov . .
And you have already written the first three sentences of the full article: -5 mm how can we understand intelligent behavior ?
how can we design intelligent computers ?
these are questions that have been discussed by scientists and the public at large for over 50 years . as mathematicians ,.
Please generate the next two sentences of the article | however , the question we want to ask is `` is there a _ mathematical _ theory underlying intelligence ? ''
i believe the first mathematical attack on these issues was control theory , led by wiener and pontryagin . |
3,372 | Suppose that you have an abstract for a scientific paper: in this work , we study the luminosity - metallicity relation ( lmr ) and the stellar mass - metallicity relation ( mmr ) of galactic systems in a hierarhical clustering scenario .
we performed numerical hydrodynamical simulations with the chemical gadget-2 of scannapieco et al.(2005 ) in a @xmath0cdm universe .
we found that our simulated galactic systems reproduce the observed local lmr and its evolution in zero point and slope .
the simulated mmr is also in agreement with recent observational results . from the analysis of the evolution of the mmr
, we found a characteristic mass at @xmath1 which separates two galactic populations with different astrophysical properties .
more massive systems tend to have their stars formed at @xmath2 and show less evolution than smaller systems .
hence , this characteristic mass is determined by the formation of the structure in a hierarchical scenario .
our results also suggest the need for efficient supernova feedback .
1.0 cm 0.3 cm en este trabajo , estudiamos la relacin luminosidad - metalicidad ( lmr ) y la relacin masa estelar - metalicidad ( mmr ) de los sistemas galcticos en un modelo de agregacin jerrquica .
realizamos simulaciones numricas hidrodinmicas con el cdigo qumico gadget-2 de scannapieco et al .
( 2005 ) en un universo @xmath0cdm .
encontramos que nuestros sistemas galcticos simulados reproducen la lmr local y su evolucin en el punto cero y la pendiente .
la mmr simulada est tambin en acuerdo con resultados observacionales recientes . a partir del anlisis de la evolucin de la mmr , hallamos una masa caracterstica en @xmath1 , la cual separa dos poblaciones galcticas con diferentes propiedades astrofsicas .
los sistemas ms masivos tienden a formar sus estrellas a @xmath3 y muestran menor evolucin que los sistemas pequeos .
entonces , esta masa caracterstica es determinada por la formacin de la estructura en un universo jerrquico .
nuestros resultados sugieren tambin la necesidad de un importante _ feedback _ por....
And you have already written the first three sentences of the full article: determining the chemical composition of galaxies is of fundamental importance for tracing back the history of evolution of galaxies .
in particular , the lmr has been widely studied in the local universe .
metallicities are tightly related with the luminosities of galaxies in such a way , that brighter systems have higher abundances ( lamareille et al ..
Please generate the next two sentences of the article | furthermore , recent studies have also suggested that this relation extends to intermediate redshifts but displaced towards lower metallicities and higher luminosities ( kobulnicky et al .
2003 ) . |
3,373 | Suppose that you have an abstract for a scientific paper: in this paper , we prove a necessary and sufficient condition for the edge universality of covariance matrices , which is conjectured by pillai and yin in @xcite .
consider the sample covariance matrices of the form @xmath0 , where @xmath1 is an @xmath2 rectangular matrix with i.i.d entries @xmath3 satisfying @xmath4 and @xmath5 . under the assumption @xmath6 , we prove that the tracy - widom law holds at the soft edge ( i.e. , for the largest eigenvalues ) if and only if @xmath7 .
this condition was first proposed for wigner matrices by lee and yin @xcite . .
And you have already written the first three sentences of the full article: sample covariance matrices are fundamental objects in modern multivariate statistics . in the classical setting @xcite , for an @xmath8 matrix @xmath1 , people focus on the asymptotic properties of @xmath9 when @xmath10 is fixed and @xmath11 goes to infinity . in this case
the central limit theorems and laws of large number can be applied to the statistical inference procedure .
however , the advance of technology has led to high dimensional data where @xmath10 is comparable to or even larger than @xmath11 @xcite ..
Please generate the next two sentences of the article | this high dimensionality can not be handled with the classical multivariate statistical theory . in modern statistical study of sample covariance matrices
@xcite , the largest eigenvalues have been playing important roles in analyzing the covariance matrices . |
3,374 | Suppose that you have an abstract for a scientific paper: we briefly review some of the recent developments in qcd spin physics .
bnl - nt-03/28 + rbrc-338 + .
And you have already written the first three sentences of the full article: for many years now , spin physics has played a very prominent role in qcd .
the field has been carried by the hugely successful experimental program of polarized deeply - inelastic lepton - nucleon scattering ( dis ) , and by a simultaneous tremendous progress in theory .
this talk summarizes some of the interesting new developments in spin physics in the past roughly two years ..
Please generate the next two sentences of the article | as we will see , there have yet again been exciting new data from polarized lepton - nucleon scattering , but also from the world s first polarized @xmath0 collider , rhic .
there have been very significant advances in theory as well . |
3,375 | Suppose that you have an abstract for a scientific paper: we calculate photons from jet - plasma interaction considering collisional and radiative energy loss of jet parton .
the phase space distribution of the participating jet is dynamically evolved by solving fokker - planck equation .
we treat the strong coupling constant ( @xmath0 ) as function of momentum and temperature while calculating the drag and diffusion coefficients .
it is observed that the quenching factor is substantially modified as compared to the case when @xmath0 is taken as constant .
it is shown that the phenix data is reasonably well reproduced when contributions from all the relevant sources are taken into account .
energy loss , running coupling , qgp .
And you have already written the first three sentences of the full article: heavy ion collisions have received significant attention in recent years . electromagnetic probes ( photons , dileptons etc )
have been proposed to be one of the most promising tools to characterize the initial state of the collisions @xcite . because of the very nature of their interactions with the constituents of the system they tend to leave the system almost unscattered .
photons are produced at various stages of the evolution process ..
Please generate the next two sentences of the article | the initial hard scatterings ( compton and annihilation ) of partons lead to photon production which we call hard photons .
if quark gluon plasma ( qgp ) is produced initially , there are qgp - photons from thermal compton plus annihilation processes . |
3,376 | Suppose that you have an abstract for a scientific paper: some six years ago , we ( erlykin and wolfendale , 1997 ) proposed the ` single source model ' in which a local , recent supernova remnant ( snr ) was responsible for the ` knee ' in the cosmic ray ( cr ) energy spectrum at @xmath0 pev . stimulated by the paper by bhadra ( 2002 ) , which drew attention to a possible gamma ray signature of this local remnant , we now study the situation for the local source and we conclude that , in contrast to bhadra s conclusion , the non - observation of this remnant is understandable - at least using our snr model .
it is due to the fact that this snr , being local , develops in the local hot interstellar medium ( hism ) with its low density of gas and also being nearby it will be an extended source occupying up to 40@xmath1 of the sky and thus indistinguishable from the background . plus 2 mm minus 2 mm 23.0 cm 17.0 cm -1.0 in -42pt * high - energy cosmic gamma rays + from the ` single source ' * ' '' '' a.d . erlykin@xmath2 and a.w .
wolfendale@xmath3 @xmath4 lebedev physical institute , leninsky prospekt , moscow , russia + @xmath5 department of physics , university of durham , dh1 3le , uk + .
And you have already written the first three sentences of the full article: the ` knee ' , a rather sharp steepening in the primary cosmic ray ( cr ) energy spectrum at about 3 pev , was inferred from the observation of a similar feature in the measured size spectrum of extensive air showers by kulikov and khristiansen ( 1958 ) .
the knee is commonly asserted to be due to an increasing failure of ` galactic containment ' of the cr generated by sources within the galaxy , the containment being caused by the magnetic fields in the interstellar medium ( ism ) , however , it is the firmly - held view of the present authors that the knee is too sharp for this explanation and we have advanced what we claim to be a more realistic model .
this is our ` single source ( ss ) model ' ( see erlykin and wolfendale , 1997 , 2001b for recent details ) which comprises cosmic ray acceleration up to the knee energy by supernova remnants , the knee itself being due to the truncation that occurs at 3 pev for oxygen nuclei from a single , recent , nearby snr ..
Please generate the next two sentences of the article | the other main accelerated nucleus at these energies is iron and its termination occurs at about 12 pev where , it is claimed by us that there is a small second knee ( when the spectrum is plotted as @xmath6 vs. @xmath7 , the knees appear as small peaks ) . the remainder of the cr spectrum ( at least to some 10@xmath8 gev , or so ) is presumed due to ` super'-snr and other sources and their spatial distribution is such as to give a comparatively smooth spectrum in the pev region .
erlykin and wolfendale ( to be referred to henceforth as ew ) have examined a variety of other cosmic ray data and concluded that there is either support for the model or that the data are neutral . |
3,377 | Suppose that you have an abstract for a scientific paper: the flavor composition of high - energy astrophysical neutrinos is a rich observable .
however , present analyses can not effectively distinguish particle showers induced by @xmath0 versus @xmath1 .
we show that this can be accomplished by measuring the intensities of the delayed , collective light emission from muon decays and neutron captures , which are , on average , greater for @xmath1 than for @xmath0 .
this new technique would significantly improve tests of the nature of astrophysical sources and of neutrino properties .
we discuss the promising prospects for implementing it in icecube and other detectors .
* introduction. * high - energy astrophysical neutrinos , long sought , were recently discovered by the icecube collaboration @xcite .
their energy spectrum provides important clues about extreme astrophysical sources as well as neutrino properties at unexplored energies .
however , pressing mysteries remain . exploiting the flavor composition
the ratios of the fluxes of @xmath2 , @xmath3 , and @xmath4 to the total flux offers crucial additional clues . in the nominal scenario , a composition of @xmath5 at the source
is transformed by neutrino vacuum mixing to @xmath6 at earth @xcite . even for arbitrary flavor composition at the source , the maximal range of flavor composition at earth with only standard
mixing is surprisingly narrow @xcite , making deviations sensitive indicators of new physics @xcite .
so far , icecube measurements of the flavor composition mostly separate muon tracks made primarily by charged - current ( cc ) @xmath7 interactions from particle showers made by all other interactions .
a significant limitation is their poor ability to distinguish between cc interactions of @xmath0 and @xmath1 ( unless noted , @xmath8 refers to @xmath9 ) . *
synopsis of the paper. * we propose a new technique to break this @xmath0-@xmath1 degeneracy , one that could work for a wider range of energies than existing ideas ( glashow resonance @xcite ,....
And you have already written the first three sentences of the full article: we calculate the probability that an observed shower , containing @xmath70 muon decays , was initiated by a neutrino @xmath8 , of definite flavor @xmath71 , or @xmath72 .
the main observable of a shower is its energy @xmath68 , which is proportional to the total collected light . because the detector energy resolution is narrow ,
we simply take it to be flat in the range @xmath73 e_\text{sh}$ ] ..
Please generate the next two sentences of the article | using bayes theorem , the probability that a shower with energy @xmath68 and @xmath70 muon decays was initiated by a @xmath8 is @xmath74 } \;.\ ] ] here , @xmath75 is the probability that a shower with energy @xmath68 is produced by the cc interaction of a @xmath8 , which we detail below , while @xmath76 is the probability that said shower yields @xmath70 muon decays , which is calculated via ` fluka ` simulations and shown in figs .
[ fig : muon_decay_distribution ] and [ fig : muon_decay_energies ] for different shower energies . |
3,378 | Suppose that you have an abstract for a scientific paper: the average ( thermal ) gyroradius of charged particles is re - examined from a quantum - mechanical point of view .
the straight quantum - mechanical calculation clearly reproduces its conventionally used random - mean - square ( rms ) expectation value .
the quasi - classical approach reproduces its mean expectation value as well thus confirming the purely classical calculation .
it shows that the fluctuations in the gyroradius amount to 21.5% of its rms value .
this fluctuation is , however , within the usual @xmath0-``freedom '' range of choice in the definition of the rms gyroradius respectively the mean thermal speed on which the rms value is based , its correct ( nonrelativistic ) value @xmath1 and its simplified version @xmath2 .
the gyroradius @xmath3 of a particle of charge @xmath4 and mass @xmath5 in a magnetic field of strength @xmath6 is one of the fundamental parameters used in plasma physics .
its exact classical definition for a single particle of perpendicular velocity @xmath7 is @xmath8 written here for an electron with cyclotron frequency @xmath9 ( see any textbook on plasma physics , e.g. , * ? ? ?
* ) .
its ion equivalent is obvious .
single electrons have undefined temperature , usually assumed to be zero , hence the exactness of the given expression . in quantum mechanics electrons obey landau levels possessing a well defined magnetic length @xmath10 which corresponds to the gyroradius of an electron in the lowest landau energy level , @xmath11 .
in high temperature plasmas one defines the gyroradius through the thermal velocity , respectively the perpendicular temperature @xmath12 .
a more precise definition makes use of the velocity distribution function of the electrons to calculate the average gyroradius @xmath13 as the moment of the classical distribution with respect to the perpendicular particle velocity . in the random - mean - square ( rms ) limit this yields the above expression for @xmath14 with replacement @xmath15 , which is nothing but the well....
And you have already written the first three sentences of the full article: knowing the spectrum of quantum mechanical states of an electron in magnetic field there are two ways of calculating the thermal gyroradius at given temperature @xmath24 .
either the gyroradius is calculated by averaging it over the distribution which is its expectation value @xmath13 , would be the exact way to do it , or one calculates the energy expectation value @xmath32 which provides the expectation value of the squared gyroradius @xmath33 whose root can also be taken to represent the thermal gyroradius .
this latter value will be calculated first ..
Please generate the next two sentences of the article | the energy levels of an electron in a homogeneous magnetic field ( the case of interest here as a magnetic inhomogeneity provides only higher order corrections ) has been calculated long ago @xcite .
since the parallel dynamics of an electron is not of interest here , it can be taken classically . |
3,379 | Suppose that you have an abstract for a scientific paper: we present a series of monitoring observations of the crab nebula with the _ chandra x - ray observatory _ , focusing on the temporal evolution of the structure .
this series of 8 observations , spanning a period of approximately six months , shows the dynamic nature of the inner x - ray structures .
we detected outward moving `` wisps '' from the recently discovered inner ring seen in optical observations .
we also find that the inner ring itself shows temporal variations in structure .
the torus also appears to be expanding .
such temporal variations generally match the canonical scenario that an expanding synchrotron nebula injected from the pulsar is confined by the supernova ejecta .
# 1_#1 _ # 1_#1 _ = # 1 1.25 in .125 in .25 in .
And you have already written the first three sentences of the full article: the crab nebula has been the best laboratory for investigating the mechanism linking the pulsar wind nebula ( pwn ) with the pulsar .
the energetics confirms that the pwn is powered by the spin - down energy of the pulsar , and it is generally believed that this energy is transported by a relativistic wind ( e.g. kennel & coroniti 1984 ) .
hester ( 1998 ) and tanvir , thomson , & tsikarishvili ( 1997 ) showed that the `` wisps '' , which are elliptical ripples around the pulsar ( scargle 1969 ) , are moving outwards with a speed of about 0.5_c_. such high energy phenomena must be associated with x - ray emission ..
Please generate the next two sentences of the article | here , we present the results of a series of monitoring x - ray observations of the crab nebula with _
chandra _ , whose spatial resolution of @xmath0 is comparable to that of ground - based optical telescopes . |
3,380 | Suppose that you have an abstract for a scientific paper: we present optical and near - infrared ( nir ) photometry of a classical nova , v2362 cyg (= nova cygni 2006 ) .
v2362 cyg experienced a peculiar rebrightening with a long duration from @xmath0 to @xmath1 d after the maximum of the nova .
our multicolor observation indicates an emergence of a pseudophotosphere with an effective temperature of @xmath2 k at the rebrightening maximum . after the rebrightening maximum , the object showed a slow fading homogeneously in all of the used bands for one week .
this implies that the fading just after the rebrightening maximum ( @xmath3 week ) was caused by a slowly shrinking pseudophotosphere .
then , the nir flux drastically increased , while the optical flux steeply declined .
the optical and nir flux was consistent with blackbody radiation with a temperature of @xmath4 during this nir rising phase .
these facts are likely to be explained by dust formation in the nova ejecta . assuming an optically thin case
, we estimate the dust mass of @xmath5 m@xmath6 , which is less than those in typical dust - forming novae .
these results support the senario that a second , long - lasting outflow , which caused the rebrightening , interacted with a fraction of the initial outflow and formed dust grains . .
And you have already written the first three sentences of the full article: classical novae are cataclysmic variable stars which are semidetached binary systems containing a late - type star and a white dwarf ( wd ) .
the nova outburst is induced by a thermonuclear runaway in the matter transferred from the late - type star onto the surface of the wd .
a large amount of gas accumulated on the wd is ejected due to nova outbursts ..
Please generate the next two sentences of the article | the ejected mass is typically @xmath7 m@xmath8 in an outburst .
the expansion velocity of the ejecta reaches @xmath9@xmath10 . |
3,381 | Suppose that you have an abstract for a scientific paper: the radical pair ( rp ) mechanism , which describes the quantum dynamics of a spatially separated electron pair , is considered as one of the principal models of avian magnetoreception .
different from the conventional phenomenological approach where the sensitivity of avian magnetoreception is characterized by the singlet yield @xmath0 , we introduce the quantum fisher information ( qfi ) , which represents the maximum information about the magnetic field s direction extracted from the rp state , to give a precise measure of sensitivity of avian compass essentially .
the consistency between our results and experimental observations suggests that qfi plays a decisive role in avian magnetoreception .
besides , within the framework of quantum metrology , we can judge the feasibility of any possible measurement scheme for avian magnetoreception , and shed light on an intrinsic relevance between the singlet yield and a concrete measurement scheme of our approach .
the present work allows us to understand many things about avian magnetoreception from a fully new perspective of quantum metrology , and provide a new route to establish a direct connection between quantum information and many other biological functions . _
introduction_. recent evidence suggests that some unique features of quantum mechanics can be harnessed to enhance biological functions in a large variety of living organisms , e.g. , in natural selection @xcite , olfaction sense @xcite , enzymatic reactions @xcite , photosynthetic light harvesting @xcite , avian magnetoreception @xcite , etc .
, which indicates that quantum biology has been entering a new stage @xcite .
as one of the principal models of avian magnetoreception , the radical pair ( rp ) mechanism @xcite , based on singlet - triplet transitions due to the anisotropic hyperfine ( hf ) interaction , suggests that migratory birds depend on the photoinduced rps for navigation , which has been supported by intensive evidences and behavioral experiments with birds @xcite .....
And you have already written the first three sentences of the full article: a standard scenario in quantum parameter estimation can be described as follows : firstly , a probe system would be prepared in an appropriate initial state @xmath116 , and then it undergoes an evolution which would imprint the parameter information onto the evolved state , say @xmath40 , and finally it would subject to a povm measurement . the overall process is repeated @xmath117 times , and we infer the parameter @xmath38 from the statistics of the measurement outcomes by choosing an unbiased estimator .
the variance of this estimator , i.e. , @xmath118 , quantifies the error on estimation of @xmath38 , and is lower bounded by : @xmath119 where @xmath120 is the classical fisher information optimized over all the possible estimators , and qfi is the quantum fisher information , which is further optimized over all the allowable measurements and is given by @xcite @xmath121,\ ] ] where the symmetric logarithmic derivative @xmath122 in the above equation is defined as : @xmath123 writing @xmath40 in its spectral decomposition as @xmath124 , one can obtain @xcite : @xmath125
in this section , we would derive the approximate expressions of qfi for an arbitrary initial state of rp with and without the oscillating field , i.e. , eq ..
Please generate the next two sentences of the article | ( 7 ) and eq .
( 9 ) in the main text , respectively . |
3,382 | Suppose that you have an abstract for a scientific paper: the properties of @xmath0 star clusters in the large and small magellanic clouds were determined from ground - based ccd images in ubvr passbands .
the areal coverage was extensive , corresponding to 11.0 kpc@xmath1 in the lmc and 8.3 kpc@xmath1 in the smc .
after corrections for reddening , the colors and magnitudes of the clusters were converted to ages and masses , and the resulting mass distributions were searched for the effects of fading , evaporation , and size - of - sample bias .
the data show a clear signature of cluster fading below the detection threshold .
the initial cluster mass function ( icmf ) was determined by fitting the mass and age distributions with cluster population models .
these models suggest a new method to determine the icmf that is nearly independent of fading or disruption and is based on the slope of a correlation between age and the maximum cluster mass in equally spaced intervals of log - age . for a nearly uniform star formation rate , this correlation has a slope equal to @xmath2 for an icmf of @xmath3 .
we determine that @xmath4 is between @xmath5 and @xmath6 for the lmc and smc using this method plus another method in which models are fit to the mass distribution integrated over age and to the age distribution integrated over mass .
the maximum mass method also suggests that the cluster formation rate in the lmc age gap between 3 and 13 gy is about a factor of ten below that in the period from 0.1 gy to 1 gy .
the oldest clusters correspond in age and mass to halo globular clusters in the milky way .
they do not fit the trends for lower - mass clusters but appear to be a separate population that either had a very high star formation rate and became depleted by evaporation or formed with only high masses . .
And you have already written the first three sentences of the full article: super - star clusters are extreme among clusters of stars .
they are compact and very luminous , and many are young versions of the massive globular clusters found in giant galaxies like the milky way . the milky way , however , has not been able to form a cluster as compact and massive as a globular cluster for about 10 gy ( although there is a controversial claim that one is forming now
kndlseder 2000 ) . in spite of this ,.
Please generate the next two sentences of the article | six super - star clusters are known in five nearby dwarf irregular ( dim ) galaxies and are inferred to be present , though still embedded , in 4 others . this led billett , hunter , & elmegreen ( 2002 ) to question what conditions allowed these tiny i m galaxies to form such massive clusters .
billett et al . |
3,383 | Suppose that you have an abstract for a scientific paper: this paper reports on three - dimensional numerical simulations of dynamics and thermodynamics in the diffuse interstellar medium ( ism ) .
our models are local , account for sheared galactic rotation , magnetic fields , and realistic cooling , and resolve scales @xmath0 pc .
this combination permits the study of quasi - steady - state turbulence in a cloudy medium representing the warm / cold atomic ism .
turbulence is driven by the magnetorotational instability ( mri ) ; our models are the first to study the saturated state of mri under strongly inhomogeneous conditions , with cloud / intercloud density and temperature contrasts @xmath1 . for volume - averaged densities @xmath2 , the mean saturated - state velocity dispersion ranges from @xmath3 , with a scaling @xmath4 .
the mri is therefore likely quite important in driving turbulence in low - density regions of the ism , both away from the midplane in the inner galaxy ( as observed at high latitudes ) , and throughout the far outer galaxy ( where the mean density drops and the disk flares ) .
the mri may even be key to suppressing star formation at large radii in spiral galaxies , where the pressure can be high enough that without mri - driven turbulence , a gravitationally - unstable cold layer would form .
as expected , we find that turbulence affects the thermal structure of the ism . in all our simulations , the fraction of thermally - unstable gas increases as the mri develops , and in the saturated state is largest in high-@xmath5 models .
the mass fractions of warm - stable and unstable gas are typically comparable , in agreement with observations .
while inclusion of resistive dissipation of magnetic fields could enhance the amount of thermally - unstable gas compared to current models , our present results indicate that even high levels of turbulence can not wipe out the signature of thermal instability , and that a shift to a `` phase continuum '' description is probably unwarranted . instead
, we find that temperature and....
And you have already written the first three sentences of the full article: far from the energizing regions of star formation in the milky way and other galaxies , the interstellar medium ( ism ) is still roiling with activity , and rife with structure . both the microphysical properties and turbulent activity have been increasingly well characterized by galactic and extragalactic radio observations . in particular , recent high - resolution galactic emission surveys in the 21 cm hydrogen line ( e.g. @xcite ) , combined with galactic absorption surveys ( e.g. @xcite ) , and mapping of face - on external galaxies ( e.g. @xcite ) , have begun to provide a wealth of thermal and kinematic information about the atomic ism component , which comprises the majority of the total ism mass in most spiral galaxies .
analysis of this data promises to yield a detailed empirical description of the atomic gas , which is known to consist of both warm and cold components , and to be strongly turbulent ( e.g. @xcite ) . as observations of the ism advance ,
there is a need on the theoretical side for increasingly sophisticated ism modeling . with modern computational tools.
Please generate the next two sentences of the article | , it is possible to pursue time - dependent hydrodynamic models which incorporate many physical processes .
this numerical modeling can extend established `` classical '' results for simplified systems into more realistic regimes , and test conceptual proposals for the behavior of complex systems in a rigorous fashion . |
3,384 | Suppose that you have an abstract for a scientific paper: licensed but unutilized television ( tv ) band spectrum is called as tv white space in the literature .
ultra high frequency ( uhf ) tv band spectrum has very good wireless radio propagation characteristics .
the amount of tv white space in the uhf tv band in india is of interest .
comprehensive quantitative assessment and estimates for the tv white space in the @xmath0-@xmath1mhz band for four zones of india ( all except north ) are presented in this work .
this is the first effort in india to estimate tv white spaces in a comprehensive manner .
the average available tv white space per unit area in these four zones is calculated using two methods : ( i ) the primary ( licensed ) user and secondary ( unlicensed ) user point of view ; and , ( ii ) the regulations of federal communications commission in the united states . by both methods ,
the average available tv white space in the uhf tv band is shown to be more than @xmath2mhz ! a tv transmitter frequency - reassignment algorithm is also described .
based on spatial - reuse ideas , a tv channel allocation scheme is presented which results in insignicant interference to the tv receivers while using the least number of tv channels for transmission across the four zones . based on this reassignment , it is found that four tv band channels ( or @xmath3mhz ) are sufficient to provide the existing uhf tv band coverage in india . .
And you have already written the first three sentences of the full article: with rising demand for bandwidth , several researchers around the world have measured and studied the occupancy of spectrum in different countries .
these measurements suggest that except for the spectrum allocated to services like cellular technologies , and the industrial , scientific and medical ( ism ) bands , most of the allocated spectrum is heavily underutilized .
the overall usage of the analyzed spectrum is as low as 4.54% in singapore @xcite , 6.2% in auckland @xcite , 17.4% in chicago @xcite and 22.57% in barcelona @xcite . among all the unutilized portions of the frequency spectrum , white spaces in the ultra high frequency ( uhf ) television ( tv ) bands have been of particular interest owing to the superior propagation characteristics as compared to the higher frequency bands ..
Please generate the next two sentences of the article | loosely speaking , the unutilized ( or underutilized ) tv channels collectively form the tv white spaces .
the amount of available tv white space varies with location and time . |
3,385 | Suppose that you have an abstract for a scientific paper: recently experiments showed that some adhesive receptor - ligand complexes increase their lifetimes when they are stretched by mechanical force , while the force increase beyond some thresholds their lifetimes decrease .
several specific chemical kinetic models have been developed to explain the intriguing transitions from the catch - bonds " to the slip - bonds " . in this work
we suggest that the counterintuitive forced dissociation of the complexes is a typical rate process with dynamic disorder . an uniform one - dimension force modulating agmon - hopfield model is used to quantitatively describe the transitions observed in the single bond p - selctin glycoprotein ligand 1(psgl-1)@xmath0p - selectin forced dissociation experiments , which were respectively carried out on the constant force [ marshall , _
et al . _ , ( 2003 ) nature * 423 * , 190 - 193 ] and the force steady- or jump - ramp [ evans _ et al . _ , ( 2004 ) proc .
natl .
acad .
sci .
usa * 98 * , 11281 - 11286 ] modes .
our calculation shows that the novel catch - slip bond transition arises from a competition of the two components of external applied force along the dissociation reaction coordinate and the complex conformational coordinate : the former accelerates the dissociation by lowering the height of the energy barrier between the bound and free states ( slip ) , while the later stabilizes the complex by dragging the system to the higher barrier height ( catch ) .
adhesive receptor - ligand complexes with unique kinetic and mechanical properties paly key roles in cell aggregation , adhesion and other life s functions in cells .
a well studied example is the receptors in selectin family which comprises e- , l- and p - selectin interacting and forming bonds " with their glycoprotein ligands .
these bonds are primarily responsible for the tethering and rolling of leukocytes on inflamed endothelium under shear stress @xcite . in particular , in the past two years great experimental efforts @xcite have been....
And you have already written the first three sentences of the full article: the physical picture of our theory for the forced dissociation of receptor - ligand bonds is very similar with the small ligand binding to heme proteins @xcite : there is a energy surface for dissociation which dependents on both the reaction coordinate for the dissociation and the conformational coordinate @xmath7 of the complex , while the later is perpendicular to the former ; for each conformation @xmath7 there is a different dissociation rate constant which obeys the bell rate model , while the distribution of @xmath7 could be modulated by the force component along x - direction ; higher temperature or larger diffusivity ( low viscosities ) allows @xmath7 variation within the complex to take place , which results in a variation of the energy barrier of the bond with time .
there are two types of experimental setups to measure forced dissociation of receptor - ligand complexes .
first we consider constant force mode @xcite ..
Please generate the next two sentences of the article | a diffusion equation in the presence of a coordinate dependent reaction is given by @xcite @xmath8 where @xmath9 is probability density for finding a value @xmath7 at time @xmath10 , and @xmath11 is the diffusion constant .
the motion is under influence of a force modulating potential @xmath12 , where @xmath13 is intrinsic potential in the absence of any force , and a coordinate - dependent bell rate . in the present work |
3,386 | Suppose that you have an abstract for a scientific paper: the direct measurement of the extragalactic background light ( ebl ) is difficult at optical to infrared wavelengths because of the strong foreground radiation originating in the solar system .
very high energy ( vhe , e@xmath0100 gev ) gamma rays interact with ebl photons of these wavelengths through pair production . in this work ,
the available vhe spectra from six blazars are used to place upper limits on the ebl .
these blazars have been detected over a range of redshifts and a steepening of the spectral index is observed with increasing source distance .
this can be interpreted as absorption by the ebl . in general , knowledge of the intrinsic source spectrum
is necessary to determine the density of the intervening ebl .
motivated by the observed spectral steepening with redshift , upper limits on the ebl are derived by assuming that the intrinsic spectra of the six blazars are @xmath1 .
upper limits are then placed on the ebl flux at discrete energies without assuming a specific spectral shape for the ebl .
this is an advantage over other methods since the ebl spectrum is uncertain . .
And you have already written the first three sentences of the full article: the measurement of the extragalactic background light ( ebl ) is important for vhe gamma - ray astronomy as well as for astronomers modeling star formation and galaxy evolution .
second only in intensity to the cosmic microwave background , the optical and infrared ( ir ) ebl contains the imprint of galaxy evolution since the big bang .
this includes the light produced during formation and re - processing of stars ..
Please generate the next two sentences of the article | current measurements of the ebl are summarized in fig . [
fig : ebl_ir ] . |
3,387 | Suppose that you have an abstract for a scientific paper: harmonic emission from cluster nanoplasmas subject to short intense infrared laser pulses is studied . in a previous publication [ m. kundu _ et al .
_ , , 033201 ( 2007 ) ] we reported particle - in - cell simulation results showing resonant enhancements of low - order harmonics when the mie plasma frequency of the ionizing and expanding cluster resonates with the respective harmonic frequency .
simultaneously we found that high - order harmonics were barely present in the spectrum , even at high intensities .
the current paper is focused on the analytical modeling of the process .
we show that dynamical stochasticity owing to nonlinear resonance inhibits the emission of high order harmonics . .
And you have already written the first three sentences of the full article: the study of rare gas and metal clusters interacting with intense infrared , optical , and ultraviolet laser pulses has emerged as a new promising research area in strong field physics ( see @xcite for reviews ) .
the generation of fast electrons and ions , the production of high charge states , the generation of x - rays and nuclear fusion ( in the case of deuterium - enriched clusters ) was observed using cluster targets in strong laser fields of intensities up to @xmath0w/@xmath1 .
hot and dense nonuniform , nonequilibrium and nonstationary plasmas produced under such conditions and confined on a femto- or picosecond time scale to nanometer sizes so - called _.
Please generate the next two sentences of the article | nanoplasmas_are new physical objects with unusual properties .
one of the most important features of nanoplasmas is the very efficient energy transfer from light to charged particles , which is much higher ( per particle ) than for an atomic gas of the same average density @xcite . although the particular mechanisms responsible for the laser energy deposition in clusters still remain debated @xcite , the pivotal role of collective plasma dynamics ( in particular the excitation of surface plasmons ) and of nonlinear resonance ( a definition is given below in sec . |
3,388 | Suppose that you have an abstract for a scientific paper: an interaction between dark matter and dark energy , proportional to the product of their energy densities , results in a scaling behavior of the ratio of these densities with respect to the scale factor of the robertson - walker metric .
this gives rise to a class of cosmological models which deviate from the standard model in an analytically tractable way .
in particular , it becomes possible to quantify the role of potential dark - energy perturbations .
we investigate the impact of this interaction on the structure formation process . using the ( modified ) camb code
we obtain the cmb spectrum as well as the linear matter power spectrum .
it is shown that the strong degeneracy in the parameter space present in the background analysis is considerably reduced by considering _ planck
_ data .
our analysis is compatible with the @xmath0cdm model at the @xmath1 confidence level with a slightly preferred direction of the energy flow from dark matter to dark energy . .
And you have already written the first three sentences of the full article: according to the currently most favored cosmological model , the @xmath0cdm model ( @xmath0 denotes the cosmological constant , cdm stands for cold dark matter ) , our observable universe is geometrically flat and normal " , i.e. baryonic , matter is only responsible for about 4 - 5@xmath2 of its content .
most of the universe is composed of two exotic fluids " : dark matter ( dm ) and dark energy ( de ) .
neither of these exotic components can be observed directly so far , but there are arguments that support their existence ..
Please generate the next two sentences of the article | dm explains galaxy rotation curves and plays a crucial role in cosmic structure formation .
de is seen as an effective fluid with negative pressure , possibly associated with the quantum vacuum . |
3,389 | Suppose that you have an abstract for a scientific paper: we study the evolution of time - like congruences in the vacuum solutions of weyl conformal theory of gravity . using the raycaudhuri equation , we show that for positive values of the coefficient of the linear term in the solution and in the absence of the cosmological constant , the incoming rays converge .
the evolution of the congruence for negative values is investigated for different values of the parameters .
the behavior of the congruence under conformal transformations is also studied .
+ pacs : 04.20cv , 04.50kd .
And you have already written the first three sentences of the full article: the existence of space - time singularities is a common property of most solutions of the general theory of relativity , including various black - hole or cosmological ones .
the well - known raychaudhuri equation @xcite has played a key role in describing such singularities @xcite .
this equation has also been used in different other contexts @xcite ..
Please generate the next two sentences of the article | it has also attracted some attention beyond the classical descriptions , for example , a bohmian quantum version of the equation was recently introduced in ref.@xcite . in the present work
, we aim to investigate this equation in the framework of the weyl conformal theory of gravity by considering time - like world - lines . |
3,390 | Suppose that you have an abstract for a scientific paper: frustrated quantum magnets can harbor unconventional spin - liquid ground states in which the elementary magnetic moments fractionalize into new emergent degrees of freedom . while the fractionalization of quantum numbers is one of the recurring themes in modern condensed matter physics
, it often remains a challenge to devise a controlled analytical framework tracking this phenomenon .
a notable exception is the exactly solvable kitaev model , in which spin degrees of freedom fractionalize into majorana fermions and a z@xmath0 gauge field .
here we discuss the physics of fractionalization in _ three - dimensional _ kitaev models and demonstrate that the itinerant majorana fermions generically form a ( semi)metal which , depending on the underlying lattice structure , exhibits majorana fermi surfaces , nodal lines , or topologically protected weyl nodes .
we show that the nature of these majorana metals can be deduced from an elementary symmetry analysis of the projective time - reversal and inversion symmetries for a given lattice .
this allows us to comprehensively classify the gapless spin liquids of kitaev models for the most elementary tricoordinated lattices in three dimensions .
we further expand this classification by addressing the effects of time - reversal symmetry breaking and additional interactions . .
And you have already written the first three sentences of the full article: the low - temperature collective physics of interacting quantum many - body systems often calls for a novel description in terms of emergent degrees of freedom that are not only distinct from those of the original constituents of the system , but describe certain `` fractions '' thereof .
familiar examples include the spin - charge separation in one - dimensional metals @xcite , the electron fractionalization in fractional quantum hall states of two - dimensional electron gases @xcite , as well as the emergence of monopoles in spin ice @xcite or chiral magnets @xcite .
quantum spin liquids in frustrated quantum magnets @xcite provide another important venue for such quantum number fractionalization ..
Please generate the next two sentences of the article | for these spin liquids the theoretical formulation of this phenomenon is often closely linked to a lattice gauge theory description of the quantum magnet ; the spin degrees of freedom typically decompose into spinons coupled to an emergent @xmath1 or z@xmath0 gauge field whose elementary excitations remain deconfined @xcite .
one of the paradigmatic examples of a model harboring a z@xmath0 spin liquid ground state is kitaev s exactly solvable honeycomb model @xcite . |
3,391 | Suppose that you have an abstract for a scientific paper: applying the local density approximation ( lda ) and dynamical mean field theory ( dmft ) to paramagnetic @xmath0iron , we revisit a problem of theoretical description of its magnetic properties .
the analysis of local magnetic susceptibility shows that at sufficiently low temperatures @xmath1 k , both , @xmath2 and @xmath3 states equally contribute to the formation of the effective magnetic moment with spin @xmath4 .
the self - energy of @xmath3 states shows sizable deviations from fermi - liquid form , which accompanies earlier found non - quasiparticle form of @xmath2 states . by considering the non - uniform magnetic susceptibility
we find that the non - quasiparticle form of @xmath2 states is crucial for obtaining ferromagnetic instability in @xmath0-iron .
the main contribution to the exchange interaction , renormalized by the effects of electron interaction , comes from the hybridization between @xmath3 and @xmath2 states .
we furthermore suggest the effective spin - fermion model for @xmath0-iron , which allows us to estimate the exchange interaction from paramagnetic phase , which is in agreement with previous calculations in the ordered state within the lda approaches .
elemental iron in its low - temperature body - centered cubic ( bcc ) phase , which is stable below approximately 1200 k , provides unique example of itinerant magnetic @xmath5-electron systems , where formation of well - defined local magnetic moments can be expected .
indeed , the rhodes - wolfarth ratio @xmath6 for this substance is very close to one , which is characteristic feature of systems , containing ( almost ) localized @xmath5electrons ( @xmath7 corresponds to the magnetic moment , extracted from the curie
weiss law for magnetic susceptibility in the paramagnetic phase @xmath8 , and @xmath9 is the saturation moment , @xmath10 is a lande factor , @xmath11 denotes temperature ) . at the same time , the moment @xmath12 has a small fractional part , which is natural for the itinerant material .
....
And you have already written the first three sentences of the full article: we test below the stability of our results to change of model parameter values : results of the calculations by using the same method as in the main text but the other choice of parameters ( @xmath90 and @xmath91 ev ) , which are close to those of ref . .
the results for the temperature dependence of the inverse local magnetic susceptibility are shown in fig .
[ fig : chi_loc2 ] ..
Please generate the next two sentences of the article | we find the crossover discussed in the main text at lower @xmath128 k. the calculation of momentum dependent irreducible susceptibility yields only the uniform ( with respect to @xmath129 ) renormalization without change of qualitative tendencies ( see fig .
[ fig : chi_irr_q2 ] , cf . fig . |
3,392 | Suppose that you have an abstract for a scientific paper: we calculate the power spectrum of metric fluctuations in inflationary cosmology starting with initial conditions which are imposed mode by mode when the wavelength equals some critical length @xmath0 corresponding to a new energy scale @xmath1 at which trans - planckian physics becomes important . in this case
, the power spectrum can differ from what is calculated in the usual framework ( which amounts to choosing the adiabatic vacuum state ) .
the fractional difference in the results depends on the ratio @xmath2 between the hubble expansion rate @xmath3 during inflation and the new energy scale @xmath1 .
we show how and why different choices of the initial vacuum state ( stemming from different assumptions about trans - planckian physics ) lead to fractional differences which depend on different powers of @xmath2 . as we emphasize
, the power in general also depends on whether one is calculating the power spectrum of density fluctuations or of gravitational waves . .
And you have already written the first three sentences of the full article: the exponential expansion of space in inflationary cosmology leads to the stretching of modes which were in the trans - planckian regime at the beginning of inflation into the observable range .
this leads to the possibility , first raised explicitly in @xcite , that trans - planckian physics might be observable today in the cosmic microwave background . in earlier work
@xcite we addressed this issue in a simple toy model obtained by replacing the linear dispersion relation of the cosmological fluctuations by new dispersion relations which differ from the linear one on length scales smaller than the planck length ( the same dispersion relations had been used earlier @xcite in the context of an analysis of possible trans - planckian effects on black hole radiation ) ..
Please generate the next two sentences of the article | we were able to construct dispersion relations which give rise to large ( order one ) corrections to the usual spectrum of fluctuations , but the price to pay is a fine - tuning of the parameters describing the model and/or a back - reaction problem
. this question has been further analyzed in many papers ( see for instance refs . |
3,393 | Suppose that you have an abstract for a scientific paper: in this work we investigate the background dynamics when dark energy is coupled to dark matter with a suitable interaction in the universe described by einstein - aether gravity .
dark energy in the form of modified chaplygin gas is considered . a suitable interaction between dark energy and dark matter
is considered in order to at least alleviate ( if not solve ) the cosmic coincidence problem .
the dynamical system of equations is solved numerically and a stable scaling solution is obtained .
a significant attempt towards the solution of the cosmic coincidence problem is taken .
the statefinder parameters are also calculated to classify the dark energy models .
graphs and phase diagrams are drawn to study the variations of these parameters .
it is also seen that the background dynamics of modified chaplygin gas in einstein - aether gravity is completely consistent with the notion of an accelerated expansion in the late universe .
finally , it has been shown that the universe follows the power law form of expansion around the critical point . 0.2 cm 0.2 cm 0.2 cm 0.2 cm 0.2 cm .
And you have already written the first three sentences of the full article: at the turn of the last century observations from ia supernova and cosmic microwave background ( cmb)radiation confirmed that our universe is suffering from an accelerated expansion @xcite , but the physical origin of this acceleration is yet to be known .
the standard explanation invokes an unknown `` dark energy '' component which has the property that positive energy density and negative pressure .
observations indicate that dark energy occupies about 70% of the total energy of the universe , and the contribution of dark matter is @xmath0 26% ..
Please generate the next two sentences of the article | this accelerated expansion of the universe has also been strongly confirmed by some other independent experiments like sloan digital sky survey ( sdss ) @xcite , baryonic acoustic oscillation ( bao ) @xcite , wmap data analysis @xcite etc . over the past decade
there have been many theoretical models for mimicking the dark energy behaviors , such as the simplest ( just ) cosmological constant in which the equation of state is independent of the cosmic time and which can fit the observations well . |
3,394 | Suppose that you have an abstract for a scientific paper: the fusion excitation function is the important quantity in planning experiments for the synthesis of superheavy elements .
its values seem to be determined by the experimental study of the hindrance to complete fusion by the observation of mass , angular and energy distributions of the fissionlike fragments .
there is ambiguity in establishment of the reaction mechanism leading to the observed binary fissionlike fragments .
the fissionlike fragments can be produced in the quasifission , fast fission , and fusion - fission processes which have overlapping in the mass ( angular , kinetic energy ) distributions of fragments .
the branching ratio between quasifission and complete fusion strongly depends on the characteristics of the entrance channel . in this paper
we consider a wide set of reactions ( with different mass asymmetry and mass symmetry parameters ) with the aim to explain the role played by many quantities on the reaction mechanisms .
we also present the results of study of the @xmath0ca+@xmath1bk reaction used to synthesize superheavy nuclei with z = 117 by the determination of the evaporation residue cross sections and the effective fission barriers @xmath2 of excited nuclei formed along the de - excitation cascade of the compound nucleus . .
And you have already written the first three sentences of the full article: the experimental and theoretical investigations of reaction dynamics connected with the formation of composed system is nowadays the main subject of the nuclear reactions . at the first stage of reaction of heavy ion collisions the full momentum transfer can occur ( this event is defined as capture ) if there is a well in the nucleus - nucleus potential in dependence on the values of relative kinetic energy and friction coefficients @xcite . at capture , the two reacting nuclei form a rotating nuclear system at near coulomb barrier energies . during its evolution
this system can be transformed into compound nucleus or it re - separates into two fragments which may differ from the initial nuclei in the entrance channel @xcite . during the evolution of dns
its two nuclei may change their masses @xmath3 , @xmath4 and charges @xmath5 , @xmath6 but with constant total mass @xmath7 and charge @xmath8 . the dns should overcome the intrinsic fusion barrier @xmath9 ( it is equal to the difference between the maximum value of the driving potential and its value corresponding to the initial charge asymmetry ) to reach the compound nucleus state through more mass asymmetric configurations ..
Please generate the next two sentences of the article | the intense of the break up of dns into two nuclei ( quasifission channel ) in competition with the complete fusion is characterized by the value of the quasifission barrier @xmath10 ( the depth of the pocket in the nucleus - nucleus potential ) @xcite .
the mass asymmetry parameter of quasifission fragments may be larger or smaller than that of nuclei in the entrance channel . |
3,395 | Suppose that you have an abstract for a scientific paper: due to the high sensitivity of the @xmath0 reaction to the nucleon nucleon potential , bremsstrahlung radiation is used as a tool to investigate details of the nucleon nucleon interaction .
such investigations can be performed at the cooler synchrotron cosy in the research centre jlich , by dint of the cosy11 detection system .
+ the results of the identification of bremsstrahlung radiation emitted via the @xmath1 reaction in data taken with a proton target and a deuteron beam are presented and discussed .
+ the installation of a neutron detector at the cosy-11 facility [ 1,2 ] enables to study a plethora of new reaction channels .
it opens wide possibilities not only to investigate the isospin dependence of the meson production [ 3 ] , but also to measure the bremsstrahlung radiation created in the collisions of nucleons .
the study of the latter process is interested since it is highly sensitive to the kind of the nucleon - nucleon potential , and hence may serve as a tool to discriminate between various existing potential models [ 4,5 ] .
although bremsstrahlung radiation has been studied since many years , it is still the subject of interest of many theoretical and experimental groups [ 4,5,6,7 ] .
+ at the cosy11 experiment a signal from @xmath2quanta was observed in the time of flight distribution for the neutral particles measured between the target and the neutral particle detector [ 2 ] .
this encouraged us to analyse the data in view of the bremsstrahlung radiation in a free @xmath3 and a quasi
free @xmath4 reactions .
data have been taken using a proton target and a deuteron beam with a momentum close to the threshold of the @xmath5 process .
events corresponding to the @xmath3 and @xmath6 reaction have been identified by measuring the outgoing charged as well as neutral ejectiles .
the protons and deuterons are detected by means of drift chambers and scintillator hodoscopes while neutrons and photons are registered in a scintillator
lead sandwich....
And you have already written the first three sentences of the full article: the work has been supported by the european community - access to research infrastructure action of the improving human potential programme , by the daad exchange programme ( ppp - polen ) , by the polish state committe for scientific research ( grants no .
2p03b07123 and pb1060/p03/2004/26 ) and by the research centre jlich ..
Please generate the next two sentences of the article | |
3,396 | Suppose that you have an abstract for a scientific paper: we consider the flux jump instability of the bean s critical state arising in the flux creep regime in type - ii superconductors .
we find the flux jump field , @xmath0 , that determines the superconducting state stability criterion .
we calculate the dependence of @xmath0 on the external magnetic field ramp rate , @xmath1 .
we demonstrate that under the conditions typical for most of the magnetization experiments the slope of the current - voltage curve in the flux creep regime determines the stability of the bean s critical state , _
i.e. _ , the value of @xmath0 . we show that a flux jump can be preceded by the magneto - thermal oscillations and find the frequency of these oscillations as a function of @xmath1 . .
And you have already written the first three sentences of the full article: the bean s critical state model@xcite successfully describes the irreversible magnetization in type - ii superconductors by introducing the critical current density @xmath2 , where @xmath3 is the temperature and @xmath4 is the magnetic field . in the framework of the bean s model
the value of the slope of the stationary magnetic field profile is less or equal to @xmath5 .
this nonuniform flux distribution does not correspond to an equilibrium state and under certain conditions flux jumps arise in the critical state ..
Please generate the next two sentences of the article | the flux jumping process results in a flux redistribution towards the equilibrium state and is accompanied by a strong heating of the superconductor .
flux jumping has been numerously studied in conventional and high - temperature superconductors ( see the review papers @xcite , references therein , and the recent experimental studies @xcite ) . in the general case |
3,397 | Suppose that you have an abstract for a scientific paper: we present results of a cross - disciplinary theoretical research at the interface of spin physics and hot - electron transport .
a moderately strong electric field is assumed to provide the streaming regime where each free charge carrier , an electron or a hole , accelerates quasiballistically in the `` passive '' region until reaching the optical - phonon energy , then emits an optical phonon and starts the next period of acceleration .
the inclusion of spin degree of freedom into the streaming - regime kinetics gives rise to rich and interesting spin - related phenomena .
firstly , in the streaming regime the spin relaxation is substantially modified , and the current - induced spin orientation is remarkably increased . under short - pulsed photoexcitation at the bottom of conduction band
the photoelectrons execute a periodic damped motion in the energy space with the period equal to the free flight time of an electron in the passive region . if the short optical pulse is circularly polarized so that the photocarriers are spin oriented , then the spin energy distribution is oscillating in time as well , which can be detected in the pump - probe time - resolved experiments .
we show that the spin - orbit splitting of the conduction band becomes a source for additional spin oscillations , periodic or aperiodic depending on the value of electric field .
* pacs * 72.25.hg , 72.25.pn , 72.25.rb , 73.63.hs .
* keywords : * spin - orbit splitting , semiconductor heterostructures , streaming .
And you have already written the first three sentences of the full article: spin physics is a rapidly growing area of research in condensed matter science aimed at the creation , manipulation and detection of spins in various systems .
important and interesting fundamental results , also promising for possible future applications , have been obtained in semiconductors and semiconductor nanostructures @xcite .
highly sensitive methods of kerr and faraday rotation spectroscopy give a possibility to probe spin orientation within subpicosecond resolution @xcite . a challenging problem in the spin physics.
Please generate the next two sentences of the article | is how to affect the spin by instantaneous non - magnetic methods , in particular , by static or optical electric fields . in semiconductors ,
optical selection rules allow one to create spin - oriented carriers ( optical orientation ) which may then be accelerated by a static external electric field . |
3,398 | Suppose that you have an abstract for a scientific paper: we report our attempts to locate the progenitor of the peculiar type ic sn 2007gr in _ hst _ pre - explosion images of the host galaxy , ngc 1058 . aligning adaptive optics altair / niri imaging of sn 2007gr from the gemini ( north ) telescope with the pre - explosion _ hst _ wfpc2 images , we identify the sn position on the hst frames with an accuracy of 20mas .
although nothing is detected at the sn position we show that it lies on the edge of a bright source , @xmath0mas ( 6.9pc ) from its nominal centre . based on its luminosity
we suggest that this object is possibly an unresolved , compact and coeval cluster and that the sn progenitor was a cluster member , although we note that model profile fitting favours a single bright star .
we find two solutions for the age of this assumed cluster ; @xmath1myrs and @xmath2myrs , with turn - off masses of @xmath3m@xmath4 and @xmath5m@xmath4 respectively .
pre - explosion ground - based @xmath6-band images marginally favour the younger cluster age / higher turn - off mass . assuming the sn progenitor was a cluster member , the turn - off mass provides the best estimate for its initial mass .
more detailed observations , after the sn has faded , should determine if the progenitor was indeed part of a cluster , and if so allow an age estimate to within @xmath72myrs thereby favouring either a high mass single star or lower mass interacting binary progenitor . .
And you have already written the first three sentences of the full article: direct detection of the progenitors of core - collapse supernovae ( ccsne ) in archival observations of nearby galaxies , particularly those from the _ hubble space telescope _ ( hst ) , has recently proved successful .
luminous red supergiant progenitors of the hydrogen rich type ii - p sne have now been identified @xcite , with initial masses above 8m@xmath4 .
however the progenitors of type ib / c sn , believed to be the cores of massive stars that have lost their outer envelopes , have so far eluded discovery ( e.g. * ? ? ?.
Please generate the next two sentences of the article | the two nearest type ib / c sne with deep pre - explosion images ( sn2002ap in m74 at @xmath79mpc and sn2004gt in ngc4038 at @xmath714mpc ) had no progenitor detected @xcite .
the progenitors were limited to either lower mass stars that were stripped of their hydrogen - rich envelope via binary interaction , or single stars with masses @xmath8 for which radiatively driven mass loss may have been sufficient to remove the outer layers . in the case of the type ib sn 2006jc the progenitor was discovered in an lbv - like outburst state 2 years before explosion , suggesting it was a very massive star @xcite . |
3,399 | Suppose that you have an abstract for a scientific paper: we discovered that past changes in the market correlation structure are significantly related with future changes in the market volatility . by using correlation - based information filtering networks we device a new tool for forecasting the market volatility changes .
in particular , we introduce a new measure , the `` correlation structure persistence '' , that quantifies the rate of change of the market dependence structure .
this measure shows a deep interplay with changes in volatility and we demonstrate it can anticipate market risk variations .
notably , our method overcomes the curse of dimensionality that limits the applicability of traditional econometric tools to portfolios made of a large number of assets .
we report on forecasting performances and statistical significance of this tool for two different equity datasets .
we also identify an optimal region of parameters in terms of true positive and false positive trade - off , through a roc curve analysis .
we find that our forecasting method is robust and it outperforms predictors based on past volatility only .
moreover the temporal analysis indicates that our method is able to adapt to abrupt changes in the market , such as financial crises , more rapidly than methods based on past volatility . .
And you have already written the first three sentences of the full article: forecasting changes in volatility is essential for risk management , asset pricing and scenario analysis .
indeed , models for describing and forecasting the evolution of volatility and covariance among financial assets are widely applied in industry @xcite . among the most popular approaches
are worth mentioning the multivariate extensions of garch @xcite , the stochastic covariance models @xcite and realized covariance @xcite ..
Please generate the next two sentences of the article | however most of these econometrics tools are not able to cope with more than few assets , due to the curse of dimensionality and the increase in the number of parameters @xcite , limiting their insight into the volatility evolution to baskets of few assets only .
this is unfortunate , since gathering insights into systemic risk and the unfolding of financial crises require modelling the evolution of entire markets which are composed by large numbers of assets @xcite . |
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