id
int64 0
203k
| input
stringlengths 66
4.29k
| output
stringlengths 0
3.83k
|
|---|---|---|
8,300 | Suppose that you have an abstract for a scientific paper: a partial wave analysis ( pwa ) of the @xmath0 and @xmath1 systems produced in the reaction @xmath2 at 18 gev/@xmath3 was carried out using an _ isobar _ model assumption .
this analysis is based on 3.0 m @xmath1 events and 2.6 m @xmath0 events and shows production of the @xmath4 , @xmath5 , @xmath6 and @xmath7 resonances .
results of detailed studies of the stability of partial wave fits are presented .
an earlier analysis of 250k @xmath0 events from the same experiment showed possible evidence for a @xmath8 exotic meson with a mass of @xmath91.6 gev/@xmath10 decaying into @xmath11 . in this analysis of a higher statistics sample of the @xmath12 system in two charged modes
we find no evidence of an exotic meson . .
And you have already written the first three sentences of the full article: in this paper we present a partial wave analysis ( pwa ) of a high - statistics sample of events corresponding to the production of the @xmath13 system produced in @xmath14 collisions in two modes : @xmath15 and @xmath16 .
this sample size exceeds , by at least an order of magnitude , the largest published sample size of @xmath17 events to date .
previous @xmath17 analyses led to the discovery and/or determination of properties of the @xmath4 , @xmath5 , @xmath6 , @xmath18 and the @xmath7 resonances @xcite . in 1998 , the e852 collaboration reported evidence for the @xmath19 , a @xmath8 exotic hybrid meson with a mass of 1.6 gev/@xmath10 decaying into @xmath11 @xcite ..
Please generate the next two sentences of the article | that analysis was based on 250,000 events of the reaction @xmath20 collected in 1994 .
we report on the analysis of additional data collected in 1995 including 3.0 m events of the reaction @xmath21 and 2.6 m events of the reaction @xmath20 . |
8,301 | Suppose that you have an abstract for a scientific paper: based on the semiclassical theory , we investigate the thermodynamic properties of a dipolar fermi gas . through a self - consistent procedure ,
we numerically obtain the phase - space distribution function at finite temperature .
we show that the deformations in both momentum and real space become smaller and smaller as the temperature is increased . for the homogeneous case
, we also calculate pressure , entropy , and heat capacity .
in particular , at the low - temperature limit and in the weak interaction regime , we obtain an analytic expression for the entropy which agrees qualitatively with our numerical result .
the stability of a trapped gas at finite temperature is also explored . .
And you have already written the first three sentences of the full article: the experimental success in creating ultracold @xmath0k@xmath1rb molecular gas near quantum degeneracy @xcite has drawn considerable attention to in studying the fundamental properties of degenerate dipolar fermi gases . within the framework of the semi - classical theory ,
the ground state properties , the collective excitation , and the free expansion dynamics of a normal state dipolar fermi gas were studied theoretically @xcite .
a recent theoretical work based on a variational approach reveals that , due to the fock exchange interaction , the momentum distribution is stretched along the direction of dipole moment such that the fermi surface becomes an ellipsoid @xcite ..
Please generate the next two sentences of the article | this result was confirmed numerically for both homogeneous @xcite and trapped @xcite systems .
taking into account the effect of the exchange interaction , further theoretical work regarding the normal state of the zero temperature dipolar fermi gas includes studying the free expansion @xcite , collective excitation @xcite , zero sound @xcite , and the fermi liquid properties @xcite . |
8,302 | Suppose that you have an abstract for a scientific paper: measurements of the lateral distribution of cherenkov photons with the wide - angle atmospheric cherenkov light detector array airobicc and of the charged particle lateral distribution with the scintillator matrix of the hegra air - shower detector complex in air showers are reported .
they are used in conjunction to determine the energy spectrum and coarse chemical composition of charged cosmic rays in the energy interval from 0.3pev to 10pev . with the atmospheric shower - front sampling technique these detectors measure the electromagnetic component of an extensive air shower via the lateral density distribution of the shower particles and of the cherenkov photons .
the data are compared with events generated with the corsika program package with the qgsjet hadronic - event generator .
consistency checks performed with primary energy - reconstruction methods based on different shower observables indicate satisfactory agreement between these extensive air shower simulations and the experimental data .
this permits to derive results concerning the energy spectrum and composition of charged cosmic rays .
+ the energy spectrum features a so called `` knee '' at an energy of @xmath0=@xmath1pev .
power law fits to the differential energy spectrum yield indices of @xmath2 below and @xmath3 above the knee .
+ the best - fit elongation rate for the whole energy range is determined to 78.3 @xmath4 1.0 ( stat ) @xmath4 6.2 ( syst ) g/@xmath5 . at the highest energies it seems to decrease slightly .
the best - fit fraction of light nuclei decreases from @xmath6 ( combined statistical and systematic ) to @xmath7 ( combined statistical and systematic ) in the energy range discussed here .
a detailed study of the systematic errors reveals that a non - changing composition can not be excluded . .
And you have already written the first three sentences of the full article: the origin of extra solar cosmic rays ( cr ) is one of the important unresolved astrophysical questions .
galactic shell type supernova remnants ( snr ) have been proposed as plausible acceleration sites for cosmic rays up to energies of several pev ( @xcite ) and - for very massive sn progenitors - to even higher energies ( @xcite ) .
recently direct experimental evidence for electron acceleration in these objects has been found in the x - ray ( @xcite ; @xcite ; @xcite ) and tev @xmath8-ray range ( @xcite ) . somewhat surprisingly , similar searches for evidence of hadron acceleration have only yielded upper limits on the expected @xmath8-ray emission from the interaction of the hadrons with interstellar matter up to now ( @xcite ; @xcite ; @xcite ) . +.
Please generate the next two sentences of the article | an indirect approach to distinguish between different theoretical models aiming to describe the acceleration of charged cosmic rays ( cr ) is to measure the energy spectrum and composition of cr and compare the results with model predictions . here
the energy regime around the so called `` knee '' between 1 and 10pev is especially interesting(@xcite ) . in this energy range the all - particle cr energy spectral slope - that is constant within measurement errors for lower energies - suddenly increases . |
8,303 | Suppose that you have an abstract for a scientific paper: we show that the experiential @xmath0 , @xmath1 , @xmath2 and @xmath3 correlations ( where @xmath4 is the time - averaged luminosity of the prompt emission , @xmath5 is the spectral peak energy , @xmath6 is the bulk lorentz factor and @xmath7 is the emission efficiency of gamma - ray bursts ) are well consistent with the relations between the resembling parameters predicted in the photospheric radiation model of the prompt emission of gamma - ray bursts . the time - resolved thermal radiation of grb 090902b does follow the @xmath0 and @xmath1 correlations
. a reliable interpretation of the four correlations in alternative models is still lacking .
these facts may point towards a photospheric origin of prompt emission of some gamma - ray bursts . .
And you have already written the first three sentences of the full article: in the past fifteen years , our understanding of gamma - ray bursts ( grbs ) had been revolutionized . as usual ,
some aspects are understood better than others .
for example , the detection of a bright supernova component in the afterglow of some nearby long grbs establishes their collapsar origin and the late ( @xmath8 s after the trigger of the burst ) afterglow data support the external forward shock model ( piran 2004 ; zhang & mszros 2004 ) . yet.
Please generate the next two sentences of the article | the physical origin of the prompt emission of grbs is still not clear .
the leading " internal shock model is found hard to explain some observational facts , motivating people to develop the internal magnetic energy dissipation models and the photosphere models ( see * ? ? ? * ; * ? ? ? * for reviews ) . |
8,304 | Suppose that you have an abstract for a scientific paper: calculations of heavy quark and charmonium hadroproduction are presented in the @xmath0-factorization approach .
the resulting differential cross sections are compared to experimental values and nlo collinear predictions .
the application of the full effective fadin - lipatov-@xmath1-production - vertex has an important influence on the results and in particular leads to a strong suppression of certain color octet contributions which are related to the outstanding problem of the production of polarized @xmath2 . .
And you have already written the first three sentences of the full article: at very high energies @xmath3 in the small-@xmath4-region the multi - regge - kinematics ( mrk ) respectively the quasi - mrk ( qmrk ) is an especially suited approximation for the calculation of lepto- and hadroproduction cross sections .
we consider the central heavy quark - antiquark - hadroproduction process in figs .
[ fig1],[fig2 ] and choose the frame where the proton momenta are given by @xmath5 in the qmrk we have then an almost transverse momentum transfer @xmath6 and for the t - channel momenta the relations @xmath7 but in general no strong ordering of the momenta of the produced heavy quark and antiquark @xmath8 ..
Please generate the next two sentences of the article | this kinematics corresponds to the production of a @xmath9-cluster with finite invariant mass and therefore makes the production of a @xmath10-bound state possible .
the associated factorization scheme is the @xmath11-factorization and the particles in the t - channel are allowed to have finite transverse momenta . |
8,305 | Suppose that you have an abstract for a scientific paper: measurements of the higgs - boson production cross section at the lhc are an important tool for studying electroweak symmetry breaking at the quantum level , since the main production mechanism @xmath0 is loop - suppressed in the standard model ( sm ) .
higgs production in extra - dimensional extensions of the sm is sensitive to the kaluza - klein ( kk ) excitations of the quarks , which can be exchanged as virtual particles in the loop . in the context of the minimal randall - sundrum ( rs )
model with bulk fields and a brane - localized higgs sector , we derive closed analytical expressions for the gluon - gluon fusion process , finding that the effect of the infinite tower of virtual kk states can be described in terms of a simple function of the fundamental ( 5d ) yukawa matrices . given a specific rs model , this will allow one to easily constrain the parameter space , once a higgs signal has been established .
we explain that discrepancies between existing calculations of higgs production in rs models are related to the non - commutativity of two limits : taking the number of kk states to infinity and removing the regulator on the higgs - boson profile , which is required in an intermediate step to make the relevant overlap integrals well defined . even though the one - loop @xmath0 amplitude is finite in rs scenarios with a brane - localized higgs sector , it is important to introduce a consistent ultraviolet regulator in order to obtain the correct result .
mz - th/12 - 13 + march 30 , 2012 + revised july 20 , 2012 * higgs production in a warped extra dimension * marcela carena@xmath1 , sandro casagrande@xmath2 , florian goertz@xmath3 , + ulrich haisch@xmath4 and matthias neubert@xmath5 + .
And you have already written the first three sentences of the full article: in the past decades there has been an enormous effort , both theoretically and experimentally , in trying to understand the origin of electroweak symmetry breaking . within the standard model ( sm ) ,
the higgs mechanism provides a solution that demands the existence of a fundamental self - interacting scalar field , the higgs boson . after the analysis of significant amounts of data , the lhc and tevatron experiments seem to observe , for the first time , an excess of events that could be associated with a higgs - boson signal .
if this excess is confirmed , a new set of questions will need to be addressed ..
Please generate the next two sentences of the article | in particular , it will be crucial to understand how the electroweak scale @xmath6 is related , if at all , to other scales in nature such as the planck scale @xmath7 .
searching for a framework that provides a natural connection between these scales has been one of the main reasons to propose theories beyond the sm . |
8,306 | Suppose that you have an abstract for a scientific paper: it is shown that the truncated euler equations , _ i_.e .
a finite set of ordinary differential equations for the amplitude of the large - scale modes , can correctly describe the complex transitional dynamics that occur within the turbulent regime of a confined @xmath0d navier - stokes flow with bottom friction and a spatially periodic forcing .
in particular , the random reversals of the large scale circulation on the turbulent background involve bifurcations of the probability distribution function of the large - scale circulation velocity that are described by the related microcanonical distribution which displays transitions from gaussian to bimodal and broken ergodicity .
a minimal @xmath1-mode model reproduces these results .
the formation of large scale coherent structures is widely observed in atmospheric and oceanic flows and ascribed to the nearly bi - dimensional nature of these flows .
kraichnan showed that in two - dimensional ( 2d ) turbulence , the energy is transferred from the forcing scale to larger scales due to the conservation of both energy and enstrophy by the inviscid dynamics @xcite . in a confined flow domain and without large scale friction ,
the energy accumulates at the largest possible scale , thus generating coherent structures in the form of large scale vortices . it has been observed in laboratory experiments that the large scale circulation generated by forcing a nearly @xmath0d flow at small scale can display random reversals @xcite .
the large scale velocity has a bimodal probability density function ( pdf ) with two symmetric maxima related to the opposite signs of the large scale circulation .
this regime bifurcates from another turbulent regime with a gaussian velocity field with zero mean when the large scale friction is decreased .
when the friction is decreased further , the reversals become less and less frequent and a condensed state with most of its kinetic energy in the large scale circulation is reached @xcite .
a similar sequence of....
And you have already written the first three sentences of the full article: we give here explicitly the set of thirteen ordinary differential equations ( odes ) for the amplitudes of the fourier modes @xmath88 that define the truncated euler equation ( tee ) in the case @xmath89 .
note that @xmath88 are real numbers because of the free - slip boundary conditions ( see text ) .
@xmath90 \end{split}\ ] ].
Please generate the next two sentences of the article | |
8,307 | Suppose that you have an abstract for a scientific paper: according to a fluid dynamic expansion of the fireball we investigate how the inhomogeneity of the system influences the chiral phase transition of qcd .
we compare the averaged values of the order parameter in equilibrium with that of a homogeneous system .
if the temperature is averaged over a certain region of the fireball the corresponding correlation length does not diverge in an expansion with a critical point . .
And you have already written the first three sentences of the full article: the search for a possible critical point of qcd is one of the driving motivations for the low energy runs at rhic / bnl and the upcoming facilities fair at gsi / darmstadt and nica in dubna .
the assumed existence of a critical point is based on two observations : at vanishing baryochemical potential highly sophisticated lattice qcd calculations revealed an analytic crossover @xcite and at high baryochemical potentials various approaches to effective models in mean - field and beyond find a first order phase transition , which then necessarily terminates in a critical point @xcite . at both ,
the first order phase transition and the critical point , an enhancement of fluctuations is predicted to be seen in heavy - ion collisions . for the first order phase transition these are based on the growth of fluctuations due to the nonequilibrium effect of supercooling leading to nucleation and spinodal decomposition @xcite ..
Please generate the next two sentences of the article | such fluctuations should be visible in studies of single event particle distributions .
the critical point , however , is supposed to imprint its signals in event - by - event fluctuations of conserved quantities , such as net - charge or net - baryon number distributions @xcite . in thermodynamic systems |
8,308 | Suppose that you have an abstract for a scientific paper: let @xmath0 be a @xmath1-dimensional symplectic vector space over an algebraically closed field @xmath2 .
let @xmath3 be the two - sided ideal of the brauer algebra @xmath4 over @xmath2 generated by @xmath5 , where @xmath6 $ ] .
let @xmath7 be the subspace of partially harmonic tensors of valence @xmath8 in @xmath9 . in this paper , we prove that @xmath10 and @xmath11 are both independent of @xmath2 , and the natural homomorphism from @xmath12 to @xmath13 is always surjective .
we show that @xmath7 has a weyl filtration and is isomorphic to the dual of @xmath14 as a @xmath15-@xmath16-bimodule . we obtain a @xmath15-@xmath17-bimodules filtration of @xmath18 such that each successive quotient is isomorphic to some @xmath19 with @xmath20 , @xmath21 and @xmath22 $ ] , where @xmath23 is the co - weyl module associated to @xmath24 and @xmath25 is an explicitly constructed maximal vector of weight @xmath24 . as a byproduct ,
we show that each right @xmath17-module @xmath26 is integrally defined and stable under base change . .
And you have already written the first three sentences of the full article: let @xmath27 .
let @xmath2 be an algebraically closed field and @xmath0 a @xmath1-dimensional symplectic vector space over @xmath2 .
the symplectic group @xmath15 acts naturally on @xmath0 from the left hand side , and hence on the @xmath28-tensor space @xmath18 ..
Please generate the next two sentences of the article | let @xmath29 be the brauer algebra over @xmath2 with generators @xmath30 @xmath31 and parameter @xmath32 ( see [ dfn1 ] for their definitions ) .
there is a right action of @xmath17 on @xmath9 which commutes with the left action of @xmath15 . |
8,309 | Suppose that you have an abstract for a scientific paper: we identify 17 possible 8.0 @xmath0m - selected counterparts to the submillimeter galaxies in the cudss 14@xmath1 field , derived from deep imaging carried out with the irac and mips instruments aboard the _ spitzer space telescope_. ten of the 17 counterparts are not the same as those previously identified at shorter wavelengths .
we argue that 8.0 @xmath0 m selection offers a better means for identifying counterparts to submillimeter galaxies than near - infrared or optical selection . based on the panchromatic seds ,
most counterparts appear to be powered by ongoing star formation .
power - law fits to the seds suggest that five objects in the 8.0 @xmath0m - selected counterpart sample harbor dominant agns ; a sixth object is identified as a possible agn .
the 3.6 - 8.0 @xmath0 m colors of the infrared - selected counterparts are significantly redder than the general irac galaxy population in the cudss 14@xmath1 field . .
And you have already written the first three sentences of the full article: observations at 850 , initially with the submillimeter common user bolometer array ( scuba ) and subsequently with the max planck millimeter bolometer ( mambo ) , have revealed galaxies that are strong sources of dust emission but faint at visible wavelengths ( smail , ivison & blain 1997 , hughes et al .
1998 , barger et al .
1998 , eales etal 1999 , clements et al . 2004 ) ..
Please generate the next two sentences of the article | the scuba galaxy populations are important because they seem to represent the most luminous star - forming galaxies during the epoch when star formation rates were highest .
the space density of submillimeter galaxies is orders of magnitude greater than that of @xmath2@xmath3 galaxies at low redshift ( blain et al . |
8,310 | Suppose that you have an abstract for a scientific paper: we present evidence for the existence of a new supersymmetric quartet of nuclei in the @xmath0 mass region .
the analysis is based on new experimental information on the odd - odd nucleus @xmath1ir from transfer and neutron capture reactions .
the new data allow the identification of a new supersymmetric quartet , consisting of the @xmath2os and @xmath3ir nuclei .
we make explicit predictions for @xmath4os , and suggest that its spectroscopic properties be measured in dedicated experiments .
finally , we study correlations between different transfer reactions .
address = icn - unam , ap 70 - 543 , 04510 mxico df , mxico address = center for theoretical physics , sloane physics laboratory , yale university , p.o . box 208210 , new haven , connecticut 06520 - 8120 , u.s.a .
address = icn - unam , ap 70 - 543 , 04510 mxico df , mxico address = sektion physik , ludwig - maximilians - universit " at m " unchen , d-85748 garching , germany address = fakultt fr physik , ludwig - maximilians - universit " at m " unchen , d-85748 garching , germany address = institut f " ur kernphysik , universit " at zu k " oln , d-50937 k " oln , germany address = sektion physik , ludwig - maximilians - universit " at m " unchen , d-85748 garching , germany .
And you have already written the first three sentences of the full article: the @xmath0 mass region is a particularly complex one , displaying transitional behavior such as prolate - oblate deformed shapes , @xmath5-unstability , triaxial deformation and/or coexistence of different configurations which present a daunting challenge to nuclear structure models . despite this complexity
, the @xmath0 mass region has been a rich source of empirical evidence for the existence of dynamical symmetries in nuclei both for even - even , odd - proton , odd - neutron and odd - odd nuclei , as well as supersymmetric pairs @xcite and quartets of nuclei @xcite . in this contribution , we present evidence for the existence of a new supersymmetric quartet in the @xmath0 mass region , consisting of the @xmath2os and @xmath3ir nuclei , and study correlations between different one- and two - nucleon transfer reactions .
dynamical supersymmetries ( susy ) were introduced in nuclear physics in the context of the interacting boson model ( ibm ) and its extensions @xcite ..
Please generate the next two sentences of the article | the ibm describes collective excitations in even - even nuclei in terms of a system of interacting monopole ( @xmath6 ) and quadrupole ( @xmath7 ) bosons @xcite .
the bosons are associated with the number of correlated proton and neutron pairs , and hence the number of bosons @xmath8 is half the number of valence nucleons . for odd - mass nuclei |
8,311 | Suppose that you have an abstract for a scientific paper: we derive inner and outer bounds on the capacity region for a class of three - user partially connected interference channels .
we focus on the impact of topology , interference alignment , and interplay between interference and noise .
the representative channels we consider are the ones that have clear interference alignment gain . for these channels ,
z - channel type outer bounds are tight to within a constant gap from capacity .
we present near - optimal achievable schemes based on rate - splitting and lattice alignment .
interference channel , interference alignment , nested lattice code , side information graph , topological interference management . .
And you have already written the first three sentences of the full article: the capacity of the interference channel remains one of the most challenging open problems in the domain of network information theory .
the capacity region is not known in general , except for a specific range of channel parameters .
for the two - user scalar gaussian interference channel , where the interference alignment is not required , the approximate capacity region to within one bit is known @xcite . for the channels where interference alignment is required such as the @xmath0-user gaussian interference channel @xcite and the gaussian x - channel @xcite , a tight characterization of the capacity region.
Please generate the next two sentences of the article | is not known , even for symmetric channel cases .
a tractable approach to the capacity of interference channels is to consider partial connectivity of interference links and analyze the impact of topology on the capacity . |
8,312 | Suppose that you have an abstract for a scientific paper: the collision of two @xmath0-dimensional , ultra - relativistic particles , described in general relativity as aichelberg - sexl shock waves , is inelastic . in first order perturbation theory ,
the fraction of the initial centre of mass energy radiated away was recently shown to be @xmath1 . here ,
we extend the formalism to higher orders in perturbation theory , and derive a general expression to extract the inelasticity , valid non - perturbatively , based on the bondi mass loss formula .
then , to clarify why perturbation theory captures relevant physics of a strong field process in this problem , we provide one variation of the problem where the perturbative framework breaks down : the collision of ultra - relativistic _ charged _ particles .
the addition of charge , and the associated repulsive nature of the source , originates an extra radiation burst , which we argue to be an artifact of the perturbative framework , veiling the relevant physics . .
And you have already written the first three sentences of the full article: recently @xcite , we have studied the collision of two @xmath0-dimensional aichelburg - sexl ( as ) shock waves @xcite , using a method first developed ( in @xmath2 ) by death and payne @xcite , with the goal of obtaining the radiated energy .
this method is conceptually and technically elaborate , involving both analytical and numerical studies . remarkably , the fraction of radiated energy - which we refer to as the _ inelasticity of the collision _ - agrees in first order perturbation theory , within the numerical error of the method ( less than 0.1% ) , with the simple formula _
1st order= - ..
Please generate the next two sentences of the article | [ miracle ] asymptotically , @xmath3 , which agrees with the _ bound _
, @xmath4 , obtained by computing the apparent horizon ( ah ) on the past light cone @xcite ( or on the future one @xcite ) for a head - on collision of two as shock waves : @xmath5 where @xmath6 is the volume of the unit @xmath7-sphere . |
8,313 | Suppose that you have an abstract for a scientific paper: i present empirical measurements of the rate of relaxation in @xmath0-body simulations of stable spherical systems and distinguish two separate types of relaxation : energy diffusion that is largely independent of particle mass , and energy exchange between particles of differing masses .
while diffusion is generally regarded as a fokker - planck process , it can equivalently be viewed as the consequence of collective oscillations that are driven by shot noise .
empirical diffusion rates scale as @xmath1 in inhomogeneous models , in agreement with fokker - planck predictions , but collective effects cause relaxation to scale more nearly as @xmath2 in the special case of a uniform sphere .
i use four different methods to compute the gravitational field , and a 100-fold range in the numbers of particles in each case .
i find the rate at which energy is exchanged between particles of differing masses does not depend at all on the force determination method , but i do find the energy diffusion rate is marginally lower when a field method is used .
the relaxation rate in 3d is virtually independent of the method used because it is dominated by distant encounters ; any method to estimate the gravitational field that correctly captures the contributions from distant particles must also capture their statistical fluctuations and the collective modes they drive .
[ firstpage ] galaxies : kinematics and dynamics methods : numerical .
And you have already written the first three sentences of the full article: the topic of relaxation driven by stellar encounters in star systems has a long and distinguished history @xcite and has important implications for the evolution of star clusters @xcite and of active galactic nuclei @xcite .
however , it is widely believed that relaxation through star - star encounters occurs at a negligible rate in the bulk of galaxies , and therefore @xmath0-body simulations of galaxies should mimic this collisionless property .
the study presented here focuses on just one small aspect of the general problem of relaxation in simulations ..
Please generate the next two sentences of the article | although the computational power available to simulators has risen steadily over time , calculations with billions of particles are still not routinely possible and most simulations employ fewer , more massive particles .
a rough estimate of the relaxation time @xmath3 in a simulation of @xmath0 equal mass particles is @xcite @xmath4 with @xmath5 being a typical crossing time . |
8,314 | Suppose that you have an abstract for a scientific paper: a scheme of universal quantum computation on a chain of qubits is described that does not require local control .
all the required operations , an ising - type interaction and spatially uniform simultaneous one - qubit gates , are translation - invariant . .
And you have already written the first three sentences of the full article: symmetry reduces complexity . in physical systems realizing quantum computers ,
the highest degree of symmetry is therefore not the most desirable .
a quantum computer needs to be sufficiently simple and robust to be controllable in an experiment yet complex enough to be universal ..
Please generate the next two sentences of the article | one may therefore ask the question `` how much symmetry does a quantum computer allow for ? '' .
in fact , a number of physical systems considered for the realization of a quantum computer such as optical lattices @xcite or arrays of micro - lenses @xcite are translation invariant , and the above question acquires a practical aspect . quite surprisingly , it turns out that universal quantum computation can tolerate a fair amount of symmetry . |
8,315 | Suppose that you have an abstract for a scientific paper: increasing requirements in the sensitivity of interferometric measurements is a common feature of several research fields , from gravitational wave detection to quantum optics .
this motivates refined studies of high reflectivity mirrors and of noise sources that are tightly related to their structure . in this work we present an experimental characterization of photothermal and thermo - refractive effects in high reflectivity mirrors , i.e. , of the variations in the position of their effective reflection plane due to weak residual power absorption .
the measurements are performed by modulating the impinging power in the range 10 hz @xmath0 100 khz .
the experimental results are compared with an expressly derived theoretical model in order to fully understand the phenomena and exploit them to extract useful effective thermo - mechanical parameters of the coating .
the measurements are extended at cryogenic temperature , where most high sensitivity experiments are performed ( or planned in future versions ) and where characterizations of dielectric film coatings are still poor . .
And you have already written the first three sentences of the full article: extremely sensitive interferometric measurements are implied in several frontier experiments . for instance , large baseline gravitational wave detectors presently surpass the limit of @xmath1 hz@xmath2 in relative displacement spectral noise @xcite .
an improvement of more than one order of magnitude is planned for their advanced versions @xcite , and a sensitivity of @xmath3 m/@xmath4 is envisaged in the khz range for possible future massive , cryogenic detectors @xcite . on the small scale ,
very low - noise background is also obtained in small scale quantum opto - mechanics experiments @xcite . with such extreme requirements ,.
Please generate the next two sentences of the article | critical limits are imposed by several noise sources associated with the interferometer optical components @xcite , and a crucial role is played in particular by the high - reflection coating .
for instance , brownian thermal noise of the dielectric layers is the most stringent foreseen limiting factor in the @xmath5khz range for the next generation of gravitational wave detectors . |
8,316 | Suppose that you have an abstract for a scientific paper: volume estimates of metric balls in manifolds find diverse applications in information and coding theory . in this paper ,
some new results for the volume of a metric ball in unitary group are derived via various tools from random matrix theory .
the first result is an integral representation of the exact volume , which involves a toeplitz determinant of bessel functions .
the connection to matrix - variate hypergeometric functions and szeg s strong limit theorem lead independently from the finite size formula to an asymptotic one .
the convergence of the limiting formula is exceptionally fast due to an underlying mock - gaussian behavior .
the proposed volume estimate enables simple but accurate analytical evaluation of coding - theoretic bounds of unitary codes .
in particular , the gilbert - varshamov lower bound and the hamming upper bound on cardinality as well as the resulting bounds on code rate and minimum distance are derived .
moreover , bounds on the scaling law of code rate are found .
lastly , a closed - form bound on diversity sum relevant to unitary space - time codes is obtained , which was only computed numerically in literature .
coding - theoretic bounds , random matrix theory , unitary group , volume of metric balls . .
And you have already written the first three sentences of the full article: determining the volume of metric balls in riemannian manifold , in particular unitary group , is the key to understand several coding and information theoretical quantities .
performance analysis of unitary space - time codes @xcite requires the knowledge of volume in the unitary group @xcite . for channel quantizations in precoded multi - antenna systems , the characterization of rate - distortion tradeoff
is directly related to volume calculations in the manifold of interest @xcite ..
Please generate the next two sentences of the article | estimating fundamental coding bounds such as gilbert - varshamov and hamming bounds relies on the volume of the corresponding metric ball @xcite . despite the need to accurately estimate the volume of metric balls in the unitary group , results in this direction are rather limited .
volume estimates have been derived in @xcite when the radius of metric ball is small . in this paper |
8,317 | Suppose that you have an abstract for a scientific paper: we prove existence and a.e .
regularity of an area minimizing soap film with a bound on energy spanning a given jordan curve in @xmath0 . .
And you have already written the first three sentences of the full article: given a simple , closed curve in three - space is there a surface with minimal area spanning it ?
solutions to the problem of plateau depend , of course , on the class of spanning surfaces permitted .
douglas @xcite won the first fields medal for his proof of the existence of an area minimizing mapping of the 2-disk whose image spans the jordan curve ..
Please generate the next two sentences of the article | regularity took many years to establish @xcite and some aspects are still unresolved .
federer and fleming s solutions @xcite are area minimizing in the class of integral currents . |
8,318 | Suppose that you have an abstract for a scientific paper: the success of any alma phase - calibration strategy , which incorporates phase transfer , depends on a good understanding of how the atmospheric path delay changes with frequency ( e.g. @xcite ) .
we explore how the wet dispersive path delay varies for realistic atmospheric conditions at the alma site using the atmtransmission code .
we find the wet dispersive path delay becomes a significant fraction ( @xmath0per cent ) of the non - dispersive delay for the high - frequency alma bands ( @xmath1ghz , bands 5 to 10 ) .
additionally , the variation in dispersive path delay across alma s 4-ghz contiguous bandwidth is not significant except in bands 9 and 10 .
the ratio of dispersive path delay to total column of water vapour does not vary significantly for typical amounts of water vapour , water vapour scale heights and ground pressures above chajnantor .
however , the temperature profile and particularly the ground - level temperature are more important . given the likely constraints from alma s ancillary calibration devices ,
the uncertainty on the dispersive - path scaling will be around 2per cent in the worst case and should contribute about 1per cent overall to the wet path fluctuations at the highest frequencies .
[ firstpage ] .
And you have already written the first three sentences of the full article: the performance of interferometers at ( sub)millimetre wavelengths is often limited by differential fluctuations in the atmospheric path along the line of sight to each of the constituent antennas .
if uncorrected , these fluctuations lead to a loss in sensitivity , imaging artefacts and a limit on the maximum usable baseline ( e.g. @xcite ; @xcite ) .
alma will correct such path variations using a combination of techniques : 1 ..
Please generate the next two sentences of the article | fast - switching observations of bright calibrator sources ( e.g. quasars ) .
water vapour radiometry using dedicated 183-ghz radiometers ( wvrs ) , installed in every 12-m alma antenna . |
8,319 | Suppose that you have an abstract for a scientific paper: we present analysis of extensive monitoring of ss433 by the rxte observatory collected over the period 1996 - 2005 .
the difference between energy spectra taken at different precessional and orbital phases shows the presence of a strong photoabsorption near the optical star , probably due to its powerful dense wind . assuming that a precessing accretion disk is thick
, we recover the temperature profile in the x - ray emitting jet that best fits the observed precessional variations of the x - ray emission temperature .
the hottest visible part of the x - ray jet is located at a distance of @xmath0 , or @xmath1 cm from the central compact object and has a temperature of about @xmath2 kev .
we discovered appreciable orbital x - ray eclipses at the `` crossover '' precessional phases ( jets are in the plane of the sky , disk is edge - on ) which put a lower limit on the size of the optical component @xmath3 and an upper limit on a mass ratio of binary companions @xmath4 .
the size of the eclipsing region can be larger than secondary s roche lobe because of substantial photoabsorption by dense stellar wind .
this must be taken into account when evaluating the mass ratio from analysis of x - ray eclipses .
# 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: ss 433 is a binary system which is thought to consist of a compact object ( probably a black hole ) and optical star filling its roche lobe .
there is a supercritical accretion rate in the system ( fabrika 2004 ) , which leads to formation of the geometrically thick accretion disk around compact object and two oppositely directed highly collimated jets .
the main contribution to the observed x - ray emission from the system comes from the optically thin multitemperature plasma in the jets via bremsstrahlung mechanism . the x - ray emission from ss433 is subjected to systematic variations due to the thick accretion disk precession ( @xmath5 days ) , nutation ( @xmath6 days ) and orbital ( @xmath7 days ) motion in the binary system ( fabrika 2004 ) ..
Please generate the next two sentences of the article | eclipses by the thick accretion disk and optical star result in obscuring the innermost the hottest parts of the jets from the observer which leads to the drop of the maximum temperature of the registered x - ray emission ( fig.1 ) . in order to find the spectral contribution from the innermost ( the hottest ) regions of the jet we examine differences between spectra taken during eclipses and off eclipses .
the result is presented in the fig.2 . |
8,320 | Suppose that you have an abstract for a scientific paper: lipid bilayer membranes are not uniform and clusters of lipids in a more ordered state exist within the generally disorder lipid milieu of the membrane . these clusters of ordered lipids microdomains are now referred to as lipid rafts .
recent reports attribute the formation of these microdomains to the geometrical and molecular mechanical mismatch of lipids of different species on the boundary . here
we introduce the geodesic curvature to characterize the geometry of the domain boundary , and develop a geodesic curvature energy model to describe the formation of these microdomains as a result of energy minimization .
our model accepts the intrinsic geodesic curvature of any binary lipid mixture as an input , and will produce microdomains of the given geodesic curvature as demonstrated by three sets of numerical simulations .
our results are in contrast to the surface phase separation predicted by the classical surface cahn - hilliard equation , which tends to generate large domains as a result of the minimizing line tension .
our model provides a direct and quantified description of the structure inhomogeneity of lipid bilayer membrane , and can be coupled to the investigations of biological processes on membranes for which such inhomogeneity plays essential roles .
lipid bilayer membrane ; lipid domain ; geodesic curvature ; surface phase separation ; phase field method ; variational principle ; numerical simulations 53b10 , 65d18 , 92c15 .
And you have already written the first three sentences of the full article: this work is motivated by the formation of lipid rafts in lipid membranes .
lipid bilayer membranes are of utmost importance for the survival of cells .
they separate the interior of cells from the extracellular environment and compartmentalize subcellular organelles so suitable micro - environment can be maintained in the enclosed domains for various vital biochemical and biophysical reactions ..
Please generate the next two sentences of the article | they are material basis for morphological changes such as budding , tubulation , fission and fussion that occur during cell division , biological reproduction , and intracellular membrane trafficking .
they also provide a physical platform to store and transduce energy as electrochemical gradients , to segregate or disperse particular membrane proteins , and to act as messengers in signal transduction and molecular recognition processes @xcite . while most of these functionalities depends on the fluidity of the lipids and thereby the free diffusion of lipids and proteins in the bilayer , |
8,321 | Suppose that you have an abstract for a scientific paper: we present results of numerical simulations of wind variability in the magnetic b1 i ve star @xmath0 cephei .
2d - mhd simulations are used to determine the structure of the wind . from these wind models
we calculate line profiles for different aspect angles to simulate rotation .
the results are compared with the observed uv wind line profiles . .
And you have already written the first three sentences of the full article: winds of many early - type stars show cyclic , or even strictly periodic , variability on a rotational timescale .
this behaviour was extensively studied in the uv with the iue satellite .
both pulsations and magnetic fields have been suggested as the cause for this variability ..
Please generate the next two sentences of the article | it is clear that kg magnetic fields as observed in the bp stars can explain the observed , strictly periodic , variability . for other early - type stars where
no such fields have been detected and which can have much denser winds , the origin of the variability is still unknown . |
8,322 | Suppose that you have an abstract for a scientific paper: electron spectra measured with alice at mid - rapidity are used to study the production of hadrons carrying a charm or a beauty quark .
the production cross section of electrons from heavy - flavour hadron decays is measured in pp collisions at @xmath0=7 tev .
electrons from the beauty decays are identified via the displacement from the interaction vertex . from the electron spectra measured in pb
pb collisions , we determine the nuclear modification factor , which is sensitive to the heavy - quark energy loss in a hot strongly interacting medium .
the measurement of heavy - flavour production cross sections allows an important test for perturbative qcd descriptions of hard processes in hadronic interactions
. moreover , charm and beauty quarks are a sensitive tool to study the flavour dependence of parton energy loss in high energy nucleus - nucleus collisions , the quark - gluon plasma ( qgp ) .
precision measurements of heavy - flavour production in proton - proton collisions provide the necessary reference for the interpretation of the pb
pb collision results within a qgp framework . one channel to measure the heavy - flavour production cross section is semi - leptonic decays of hadrons carrying a charm or a beauty quark .
such decays have a relatively large branching ratio ( of about 10% ) and offer a complementary approach to that of the reconstruction in exclusive hadronic decays .
alice ( a large ion collider experiment ) @xcite at the lhc is well equipped to address these physics topics : it has very good particle identification and spatial resolution for the separation of secondary vertices .
the latest alice heavy - flavour physics results are summarised in @xcite .
this contribution presents the results from the measurement of electron spectra in proton - proton and pb pb collisions at mid - rapidity . .
And you have already written the first three sentences of the full article: electrons are identified at mid - rapidity using the information provided by the time projection chamber ( tpc ) , the transition radiation detector ( trd ) , and the time - of - flight ( tof ) detector .
the time - of - flight of the individual particles is required to be consistent with the electron hypothesis . using the trd information ,
an electron likelihood is computed from the energy deposited in the 6 detector layers by charged particles . in order to provide a good e/@xmath1 separation ,.
Please generate the next two sentences of the article | tracks are required to have at least 5 out of maximum 6 chambers providing information on the energy deposit .
a cut providing an electron selection efficiency of 80% is applied to the likelihood value . |
8,323 | Suppose that you have an abstract for a scientific paper: in this paper , we report for the first time the detailed temperature evolution process of the magnetic flux rope in a failed solar eruption . occurred on january 05 , 2013 , the flux rope was impulsively accelerated to a speed of @xmath0400 km / s in the first minute , then decelerated and came to a complete stop in two minutes .
the failed eruption resulted in a large - size high - lying ( @xmath0100 mm above the surface ) high - temperature fire ball " sitting in the corona for more than two hours .
the time evolution of the thermal structure of the flux rope was revealed through the differential emission measure analysis technique , which produced temperature maps using observations of the atmospheric imaging assembly on board _ solar dynamic observatory_. the average temperature of the flux rope steadily increased from @xmath05 mk to @xmath010 mk during the first nine minutes of the evolution , which was much longer than the rise time ( about three minutes ) of the associated soft x - ray flare .
we suggest that the flux rope be heated by the energy release of the continuing magnetic reconnection , different from the heating of the low - lying flare loops , which is mainly produced by the chromospheric plasma evaporation .
the loop arcade overlying the flux rope was pushed up by @xmath010 mm during the attempted eruption .
the pattern of the velocity variation of the loop arcade strongly suggests that the failure of the eruption be caused by the strapping effect of the overlying loop arcade . .
And you have already written the first three sentences of the full article: magnetic flux ropes play an important role in solar eruptions manifested as coronal mass ejections ( cmes ) and/or flares .
recently , a new line of observational structures , namely euv hot - blobs and/or channels , have been proposed to be the most direct manifestation of flux ropes ( cheng et al .
2011 ; zhang et al . 2012.
Please generate the next two sentences of the article | ; cheng et al . 2013 ; patsourakos et al . 2013 ) with the atmospheric image assembly ( aia ; lemen et al . 2012 ) on board the _ solar dynamics observatory ( sdo ) _ ( pesnell et al . 2012 ) . in particular , zhang et al . (
2012 ) revealed the flux rope as a conspicuous hot channel structure prior to and during a solar eruption , which initially appeared as a writhed sigmoid with a temperature as high as @xmath010 mk , then continuously transformed itself toward a semi - circular shape and acted as the essential driver of the resulting cme . |
8,324 | Suppose that you have an abstract for a scientific paper: we extend the results of a previous analysis of ours showing that , when both heavy and light flavour effects are taken into account , successful minimal ( type i + thermal ) leptogenesis with @xmath0-inspired relations is possible . barring fine tuned choices of the parameters , these relations enforce a hierarchical rh neutrino mass spectrum that results into a final asymmetry dominantly produced by the next - to - lightest rh neutrino decays ( @xmath1 dominated leptogenesis ) .
we present the constraints on the whole set of low energy neutrino parameters . allowing a small misalignment between the dirac basis and the charged lepton basis as in the quark sector
, the allowed regions enlarge and the lower bound on the reheating temperature gets relaxed to values as low as @xmath2 .
it is confirmed that for normal ordering ( no ) there are two allowed ranges of values for the lightest neutrino mass : @xmath3 and @xmath4 . for @xmath5 the allowed region in the plane
@xmath6-@xmath7 is approximately given by @xmath8 , while the neutrinoless double beta decay effective neutrino mass falls in the range @xmath9 for @xmath10 .
for @xmath11 , one has quite sharply @xmath12 and an upper bound @xmath13 .
these constraints will be tested by low energy neutrino experiments during next years .
we also find that inverted ordering ( io ) , though quite strongly constrained , is not completely ruled out .
in particular , we find approximately @xmath14 , that will be fully tested by future experiments .
c i u
# 1 # 1#1 # 1 # 1#2#3phys
. lett .
* b # 1 * ( # 2 ) # 3 # 1#2#3nucl .
phys .
* b # 1 * ( # 2 ) # 3 # 1#2#3phys .
rev .
lett . *
# 1 * ( # 2 ) # 3 # 1#2#3phys .
rev .
* d # 1 * ( # 2 ) # 3 # 1#2#3z .
phys .
* c # 1 * ( # 2 ) # 3 # 1#2#3class . and quantum grav .
* # 1 * ( # 2 ) # 3 # 1#2#3commun . math .
phys . *
# 1 * ( # 2 ) # 3 # 1#2#3j . math .
phys . *
# 1 * ( # 2 ) # 3 # 1#2#3ann . of phys .
* # 1 * ( # 2 ) # 3 #....
And you have already written the first three sentences of the full article: with the discovery of neutrino masses and mixing in neutrino oscillation experiments , leptogenesis @xcite has become the most attractive model of baryogenesis to explain the observed matter - antimatter asymmetry of the universe .
this can be expressed for example in terms of the baryon - to - photon number ratio and is very well measured by cmb observations @xcite to be [ etabobs ] _
b^cmb = ( 6.2 0.15)10 ^ -10 ..
Please generate the next two sentences of the article | leptogenesis originates from the see - saw mechanism @xcite that is based on a simple extension of the standard model where right - handed ( rh ) neutrinos with a majorana mass matrix @xmath15 and yukawa couplings @xmath16 to leptons and higgs are added . within @xmath0 models , three rh neutrinos @xmath17
( @xmath18 ) are nicely predicted and for this reason they are traditionally regarded as the most appealing theoretical framework to embed the seesaw mechanism . |
8,325 | Suppose that you have an abstract for a scientific paper: a key question in physics education is the effectiveness of the teaching methods .
a curriculum that has been investigated at the university of central florida ( ucf ) over the last two years is the use of particular elements of _ the physics suite_.
select sections of the introductory physics classes at ucf have made use of _ interactive lecture demonstrations _ as part of the lecture component of the class .
the lab component of the class has implemented the _ realtime physics _
curriculum , again in select sections .
the remaining sections have continued with the teaching methods traditionally used . using pre- and post - semester concept inventory tests , a student survey , student interviews , and a standard for successful completion of the course , the preliminary data indicates improved student learning . .
And you have already written the first three sentences of the full article: the university of central florida ( ucf ) is a large metropolitan university located in orlando , florida . shortly before this study was started , the u.s .
department of education national center for education statistics ranked ucf as the sixth largest university in the country based on a fall 2006 enrollment of 46,646 students @xcite . since that time
, the university s enrollment has grown to over 55,000 , making ucf the third largest university in the united states going into the fall 2009 semester @xcite ..
Please generate the next two sentences of the article | the calculus - based introductory physics courses , physics i ( newtonian mechanics ) and physics ii ( electricity and magnetism with some optics ) are required for all students of the college of engineering and computer science .
this college alone had an enrollment of over 6000 in the spring of 2009 @xcite . |
8,326 | Suppose that you have an abstract for a scientific paper: recent observations of several @xmath0-ray burst ( grb ) afterglows have shown evidence for a large amount of x - ray line emitting material , possibly arising from ionized iron .
a significant detection of an x - ray spectral feature , such as that found in the _ chandra _ observation of grb 991216 , may provide important constraints on the immediate environment of the burst and hence on progenitor models . the large fe k@xmath1 equivalent widths inferred from the x - ray observations favor models in which the line is produced when the primary x - ray emission from the source strikes thomson - thick material and compton scatters into our line of sight .
we present such reflection spectra here , computed in a fully self - consistent manner , and discuss the range of ionization parameters that may be relevant to different models of grbs .
we argue that the presence of a strong hydrogen - like k@xmath1 line is unlikely , because fe xxvi photons would be trapped resonantly and removed from the line core by compton scattering .
in contrast , a strong narrow emission line from he - like fe xxv is prominent in the model spectra . we briefly discuss how these constraints may affect the line energy determination in grb 991216 . .
And you have already written the first three sentences of the full article: the detection of spectral signatures associated with the environment of a @xmath0-ray burst ( grb ) would provide important clues about the triggering mechanism and the progenitor ( mszros & rees 1998 ; lazzati , campana & ghisellini 1999 ; bttcher 2000 ) .
observations with _
chandra _ , _ asca _ and _.
Please generate the next two sentences of the article | beppo_sax have provided tentative evidence for fe k@xmath1 line and edge features in at least five bursts ; grb 970508 ( piro et al . 1999 ) , grb 970828 ( yoshida et al . 1999 ) , grb 991216 ( piro et al .
2000 ) and grb 000214 ( antonelli et al . |
8,327 | Suppose that you have an abstract for a scientific paper: i consider a topographic projection between two neuronal layers with different densities of neurons . given the number of output neurons connected to each input neuron ( divergence ) and the number of input neurons synapsing on each output neuron ( convergence ) i determine the widths of axonal and dendritic arbors which minimize the total volume of axons and dendrites .
analytical results for one - dimensional and two - dimensional projections can be summarized qualitatively in the following rule : neurons of the sparser layer should have arbors wider than those of the denser layer .
this agrees with the anatomical data from retinal and cerebellar neurons whose morphology and connectivity are known .
the rule may be used to infer connectivity of neurons from their morphology . 2 .
And you have already written the first three sentences of the full article: understanding brain function requires knowing connections between neurons . however , experimental studies of inter - neuronal connectivity are difficult and the connectivity data is scarce . at the same time
neuroanatomists possess much data on cellular morphology and have powerful techniques to image neuronal shapes .
this suggests using morphological data to infer inter - neuronal connections ..
Please generate the next two sentences of the article | such inference must rely on rules which relate shapes of neurons to their connectivity .
the purpose of this paper is to derive such a rule for a frequently encountered feature in the brain organization : a topographic projection . |
8,328 | Suppose that you have an abstract for a scientific paper: multiple parton scatterings in high - energy @xmath0 collisions involve multi - parton correlation inside the projectile and color coherence of multiple jets which will lead to nuclear modification of final hadron spectra relative to that in @xmath1 collisions .
such modifications of final hadron spectra in @xmath0 collisions are studied within the hijing 2.1 model . besides parton shadowing and transverse momentum broadening , which influence final hadron spectra at intermediate @xmath2 , modification of parton flavor composition due to multiple scattering and hadronization of many - parton jets system
are shown to lead to suppression of final hadrons at large @xmath2 in @xmath0 collisions at the large hadron collider . in search for the formation of quark - gluon plasma ( qgp ) in high - energy heavy - ion collisions , jet quenching or suppression of high-@xmath2 hadrons @xcite can be used for tomographic study of medium properties @xcite . however , initial multiple parton scatterings in cold nuclei before the formation of qgp can also lead to nuclear modification of final high-@xmath2 hadron spectra that needs to be understood for a quantitative study of qgp properties through jet quenching .
parton shadowing or nuclear modification of parton distributions inside large nuclei is one of the most studied cold nuclear effects .
the qcd evolution , however , dramatically reduces the effect on final high-@xmath2 hadron spectra in @xmath0 collisions @xcite .
modification of parton distributions in the projectile nucleon through parton energy loss @xcite is estimated to have a small effect on hadron spectra in the central rapidity region of high - energy @xmath0 collisions .
these cold nuclear effects have also been studied within the color glass condensate ( cgc ) model @xcite .
however , multiple parton correlations inside the projectile nucleon should also be considered .
energy - momentum and valence quark number conservation alone could modify the momentum and flavor dependence of....
And you have already written the first three sentences of the full article: we thank m. gyulassy for helpful discussions . this work was supported in part by the nsfc under the project no . 10825523 and 11221504 , by self - determined research funds of ccnu from the colleges basic research and operation of moe , helmholtz international center for fair within the framework of the loewe program launched by the state of hesse , and us depart of energy under contract no
. de - ac02 - 05ch11231 and within the framework of the jet collaboration .
r. b. neufeld , i. vitev , b. -w ..
Please generate the next two sentences of the article | zhang , phys .
lett . * b704 * , 590 - 595 ( 2011 ) . |
8,329 | Suppose that you have an abstract for a scientific paper: several experimental groups have reported evidence for baryons with flavor exotic quantum numbers that can not be explained as @xmath0 bound states but require a minimum of five quarks
@xmath1 .
these pentaquark states include the @xmath2 , the @xmath3 and the @xmath4 .
the reported widths of these new states are consistent with experimental resolution and may be as narrow as a few mev/@xmath5 or less .
prior to 2003 , experimental searches for flavor exotic baryons spanning several decades yielded negative results .
there have also been a number of searches carried out since the reports of these new pentaquark states that do not confirm their existence .
this review of both the positive and negative reports seeks to understand the current situation regarding the experimental evidence for pentaquarks . . .
And you have already written the first three sentences of the full article: it is noteworthy that except for one or two possible exceptions in the meson sector , the hundreds of known hadrons can be described as bound states of three quarks ( @xmath0 ) , in the case of baryons , or a quark and anti - quark ( @xmath6 ) , in the case of mesons .
there have been reports of possible evidence of mesons with exotic @xmath7 quantum numbers , not possible for @xmath6 , but until 2003 , no reports of baryons with quantum numbers inconsistent with @xmath0 .
there were searches in the 1960 s and 1970 s for what was then referred to as the @xmath8 a baryon with positive strangeness ..
Please generate the next two sentences of the article | the review by hey and kelly @xcite discusses these early searches , mostly in bubble chamber experiments , and a more recent review by trilling of the current exotic baryon sightings @xcite lists publications reporting on bubble chamber experiments with incident @xmath9 and @xmath10 beams searching for the @xmath8 .
those experiments found no enhancements in @xmath11 baryon channels . |
8,330 | Suppose that you have an abstract for a scientific paper: this article gives an introduction to the multilevel blocking ( mlb ) approach to both the fermion and the dynamical sign problem in path - integral monte carlo simulations .
mlb is able to substantially relieve the sign problem in many situations . besides an exposition of the method ,
its accuracy and several potential pitfalls are discussed , providing guidelines for the proper choice of certain mlb parameters .
simulation results are shown for strongly interacting electrons in a 2d parabolic quantum dot , the real - time dynamics of several simple model systems , and the dissipative two - state dynamics ( spin - boson problem ) . .
And you have already written the first three sentences of the full article: quantum monte carlo ( qmc ) techniques are among the most powerful and versatile methods for the computer simulation of a large variety of interesting quantum systems encountered in physics , chemistry or biology @xcite . in particular , qmc is capable of delivering numerically exact results . despite the great potential of this method , there are several restrictions and handicaps inherent to all qmc techniques , the perhaps most pressing one being due to the _ sign problem _ @xcite
. there are various sign problems , namely the _ fermionic sign problem _ encountered in equilibrium ( imaginary - time ) simulations of strongly correlated many - fermion systems , and the _ dynamical sign problem _ in real - time ( dynamical ) simulations , which already shows up for a single particle .
unfortunately , apart from variational or approximate treatments ( such as the fixed - node approximation ) , a completely general and totally satisfactory solution to the sign problem in qmc simulations is still lacking ..
Please generate the next two sentences of the article | nevertheless , over the past few years considerable and substantial progress has been achieved along several different lines without introducing approximations into the qmc scheme , see , for instance , refs .
@xcite . in these notes focus is put on one specific class of qmc methods called _ path - integral monte carlo ( pimc)_. pimc is based on a discretized path - integral representation of the quantities of interest . |
8,331 | Suppose that you have an abstract for a scientific paper: the intermetallic compound zr@xmath0al is severely deformed by the method of repeated cold rolling . by x - ray diffraction it is shown that this leads to amorphization .
tem investigations reveal that a homogeneously distributed debris of very small nanocrystals is present in the amorphous matrix that is not resolved by x - ray diffraction . after heating to 773 k
, the crystallization of the amorphous structure leads to a fully nanocrystalline structure of small grains ( 10 - 20 nm in diameter ) of the non - equilibrium zr@xmath1al phase .
it is concluded that the debris retained in the amorphous phase acts as nuclei . after heating to 973
k the grains grow to about 100 nm in diameter and the compound zr@xmath0al starts to form , that is corresponding to the alloy composition . .
And you have already written the first three sentences of the full article: the intermetallic compound zr@xmath0al has been of special interest as a nuclear structural material although a drawback of the material is embrittlement under certain irradiation conditions @xcite .
recently , it was shown that nanostructuring of materials can enhance the irradiation resistance , e.g. for the intermetallic compound niti @xcite .
one successful method to achieve nanostructuring in bulk materials is severe plastic deformation ( spd ) ..
Please generate the next two sentences of the article | the formation of the nanocrystalline structure can occur directly by grain refinement of the coarse grained material or by crystallization of spd induced amorphous material .
for example , crystallization of the intermetallic alloy niti amorphized by severe plastic deformation can lead to nanocrystalline structures and by modification of the deformation path and the heat treatment , properties of the alloy can be tailored @xcite . |
8,332 | Suppose that you have an abstract for a scientific paper: mutational neighbourhoods in genotype - phenotype ( gp ) maps are widely believed to be more likely to share characteristics than expected from random chance .
such _ genetic correlations _ should strongly influence evolutionary dynamics .
we explore and quantify these intuitions by comparing three gp maps a model for rna secondary structure , the hp model for protein tertiary structure , and the polyomino model for protein quaternary structure to a simple random null model that maintains the number of genotypes mapping to each phenotype , but assigns genotypes randomly .
the mutational neighbourhood of a genotype in these gp maps is much more likely to contain genotypes mapping to the same phenotype than in the random null model .
such _
neutral correlations _ can be quantified by the robustness to mutations , which can be many orders of magnitude larger than that of the null model , and crucially , above the critical threshold for the formation of large neutral networks of mutationally connected genotypes which enhance the capacity for the exploration of phenotypic novelty .
thus neutral correlations increase evolvability .
we also study _ non - neutral correlations _ : compared to the null model , i ) if a particular ( non - neutral ) phenotype is found once in the 1-mutation neighbourhood of a genotype , then the chance of finding that phenotype multiple times in this neighbourhood is larger than expected ; ii ) if two genotypes are connected by a single neutral mutation , then their respective non - neutral 1-mutation neighbourhoods are more likely to be similar ; iii ) if a genotype maps to a folding or self - assembling phenotype , then its non - neutral neighbours are less likely to be a potentially deleterious non - folding or non - assembling phenotype .
non - neutral correlations of type i ) and ii ) reduce the rate at which new phenotypes can be found by neutral exploration , and so may diminish evolvability , while non - neutral correlations of type iii ) may instead facilitate....
And you have already written the first three sentences of the full article: evolutionary dynamics arise from the interplay of mutations acting on genotypes and natural selection acting on phenotypes . understanding the structure of the genotype - phenotype ( gp ) map is therefore critical for understanding evolutionary processes .
we address a simple question about structure : are the genotypes positively correlated ? that is , will the mutational neighbours of a genotype be more likely to map to similar phenotypes than expected from random chance ?
john maynard smith and others have argued that the intuitive answer is yes ..
Please generate the next two sentences of the article | here we quantify these intuitions by comparing model gp maps for rna secondary structure , protein tertiary structure , and protein quaternary structure to a random gp map .
we find strong neutral correlations : point mutations are orders of magnitude more likely than expected by random chance to link genotypes that map to the same phenotype , which vitally increases the potential for evolutionary innovation by generating neutral networks . |
8,333 | Suppose that you have an abstract for a scientific paper: the @xmath0 paradigm has been proven to be successful in explaining the flavour structure of the standard model and the non - trivial imaginary phase of the @xmath0 matrix is the only know source of @xmath1-violation .
@xmath2-meson decays allow us to precisely determine the fundamental parameters of the @xmath0 matrix and put stringent constraints on the models of new physics .
i present some of the most recent measurements related to the @xmath0 unitarity triangle performed by the experiment , located at the slac national accelerator laboratory .
most results are based on the final dataset , consisting of 467 @xmath3 pairs . .
And you have already written the first three sentences of the full article: in the standard model , the @xmath0 matrix @xcite describes the couplings , through charged weak currents , of up - type quarks with down - type quarks .
the @xmath4 unitary matrix is determined by four parameters : three of those can be interpreted as mixing angles between the three pairs of generations , while the fourth parameter is a non trivial complex phase which is the only known source of @xmath1 violation in the standard model .
the following among the unitarity constraints of the @xmath0 matrix : @xmath5 can be used to construct a triangle in the complex plane , the so - called unitarity triangle ..
Please generate the next two sentences of the article | one of the sides of the triangle has unitary length by construction , whereas the others have lengths : @xmath6 the angles are defined as : @xmath7 \ , , & \displaystyle \beta \equiv \arg \left [ -\frac{v_{cd}v^*_{cb}}{v_{td}v^*_{tb } } \right ] \ , , & \displaystyle \gamma \equiv \arg \left [ -\frac{v_{ud}v^*_{ub}}{v_{cd}v^*_{cb } } \right ] \ , .
\end{array}\ ] ] in the following , a few of the most recent measurements performed by the collaboration , relevant for the determination of the elements of the @xmath0 matrix , will be presented . |
8,334 | Suppose that you have an abstract for a scientific paper: in this paper , we investigate the error correction capability of column - weight - three ldpc codes when decoded using the gallager a algorithm .
we prove that the necessary condition for a code to correct @xmath0 errors is to avoid cycles of length up to @xmath1 in its tanner graph . as a consequence of this result ,
we show that given any @xmath2 such that @xmath3 , no code in the ensemble of column - weight - three codes can correct all @xmath4 or fewer errors .
we extend these results to the bit flipping algorithm . * index terms * low - density parity - check codes , gallager a algorithm , trapping sets , error correction capability .
And you have already written the first three sentences of the full article: gallager in @xcite showed that for @xmath5 and @xmath6 , there exist @xmath7 regular low - density parity - check ( ldpc ) codes for which the bit error probability tends to zero asymptotically whenever we operate below the threshold .
richardson and urbanke in @xcite derived the capacity of ldpc codes for various message passing algorithms and described density evolution , a deterministic algorithm to compute thresholds .
zyablov and pinsker @xcite analyzed ldpc codes under a simpler decoding algorithm known as the bit flipping algorithm and showed that almost all the codes in the regular ensemble with @xmath8 can correct a constant fraction of worst case errors ..
Please generate the next two sentences of the article | sipser and spielman in @xcite used expander graph arguments to analyze bit flipping algorithm .
burshtein and miller in @xcite applied expander based arguments to show that message passing algorithms can also correct a fixed fraction of worst case errors when the degree of each variable node is at least five . |
8,335 | Suppose that you have an abstract for a scientific paper: we prove that hochschild cohomology of a certain class of fully group - graded algebras is a mackey functor .
we use the machinery of transfer maps between the hochschild cohomology of symmetric algebras .
hochschild cohomology , group , graded algebra , mackey functor 20c20 .
And you have already written the first three sentences of the full article: let @xmath0 be a field , @xmath1 be a finite group and let @xmath2 be a fully @xmath1-graded @xmath0-algebra . by definition , @xmath2 has a decomposition @xmath3 where each @xmath4 is a a @xmath0-vector space , for any @xmath5 , such that for all @xmath6 we have @xmath7 in this paper we work only with symmetric fully @xmath1-graded algebras @xmath2 with the property that for any subgroup @xmath8 of @xmath1 we have that @xmath9 is a parabolic subalgebra of @xmath2 , for further details see ( * ? ? ?
* definition 2.3 , definition 5.1 ) .
we begin by giving an example of a group - graded algebra which lies in the above mentioned class of symmetric algebras and which includes the group algebra case ..
Please generate the next two sentences of the article | [ coconet - todea - ex1 ] let @xmath2 be a fully @xmath1-graded algebra such that @xmath10 is a full matrix ring . by ( * ?
* theorem 4 ) we know that @xmath2 is a symmetric @xmath0-algebra . moreover by ( * ? ? ? |
8,336 | Suppose that you have an abstract for a scientific paper: this work uncovers the low - dimensional nature the complex dynamics of actuated separated flows .
namely , motivated by the problem of model - based predictive control of separated flows , we identify the requirements on a model - based observer and the key variables and propose a prototype model in the case of thick airfoils as motivated by practical applications .
the approach in this paper differs fundamentally from the logic behind known models , which are either linear or based on pod - truncations and are unable to reflect even the crucial bifurcation and hysteresis inherent in separation phenomena .
this new look at the problem naturally leads to several important implications , such as , firstly , uncovering the physical mechanisms for hysteresis , secondly , predicting a finite amplitude instability of the bubble , and thirdly to new issues to be studied theoretically and tested experimentally .
more importantly , by employing systematic reasoning , the low - dimensional nature of these complex phenomena at the coarse level is revealed . separation bubble , separation control , low - dimensional modeling , phenomenology , catastrophe theory .
And you have already written the first three sentences of the full article: it is known that dynamic vortex shedding can lead to losses in lift , sharp increases in drag , and destructive pitching moments and buffeting , which all limit an aircraft flight envelope .
therefore , in order to improve aerodynamic characteristics , flow separation control would be highly desirable . the classical approach
an open - loop control achieved either by mechanical or fluidic actuation has demonstrated robustness , but its efficiency is still far from optimal ..
Please generate the next two sentences of the article | this standard control scheme is based on actuator operating schedules , which are usually constructed using extensive and costly experimental studies .
alternatively , from a theoretical point of view , should one be able to construct an accurate solution of the navier - stokes description ( nses ) for a given airfoil shape and flow conditions , it would suggest control strategies . |
8,337 | Suppose that you have an abstract for a scientific paper: we revisited a model for charmonium hybrid meson with a magnetic gluon [ yu . s. kalashnikova and a. v. nefediev , phys .
rev .
d * 77 * , 054025 ( 2008 ) ] and improved the numerical calculations .
these improvements support the hybrid meson interpretation of @xmath0 . within the same model , we computed the hybrid meson mass with an electric gluon which is resolved to be lighter .
relativistic effects and coupling channels decreased also the mass . .
And you have already written the first three sentences of the full article: quantum chromodynamics ( qcd ) is widely believed to be the theory of strong interactions . in this non abelian theory , the gauge bosons , the gluons , carry a color charge .
we are therefore led to observable color singlet configurations made of quarks but also gluons .
glueballs , bound states of only gluons , and hybrid mesons are consequences and predictions of qcd . besides glueballs ,.
Please generate the next two sentences of the article | hybrid mesons deserve much interest .
the gluonic excitation leads to low - lying states with quantum numbers not allowed for usual mesons ( note that the low - lying gluon states are non exotic but glueballs with exotic quantum number also exits and are called oddballs , for a review see ref . |
8,338 | Suppose that you have an abstract for a scientific paper: we present an elaborate version of the hadron resonance gas model with the combined treatment of separate chemical freeze - outs for strange and non - strange hadrons and with an additional @xmath0 factor which accounts for the remaining strange particle non - equilibration . within
suggested approach the parameters of two chemical freeze - outs are connected by the conservation laws of entropy , baryonic charge , third isospin projection and strangeness .
the developed model enables us to perform a high - quality fit of the hadron multiplicity ratios measured at ags , sps and rhic with @xmath1 .
a special attention is paid to a successful description of the strangeness horn .
the well - known problem of selective suppression of @xmath2 and @xmath3 hyperons is also discussed .
the main result is that for all collision energies the @xmath0 factor is about 1 within the error bars , except for the center of mass collision energy 7.6 gev at which we find about 20% enhancement of strangeness .
also we confirm an existence of strong jumps in pressure , temperature and effective number of degrees of freedom at the stage of strange particle chemical freeze - out , when the center of mass collision energy changes from 4.3 to 4.9 gev .
we argue that these irregularities may signal about the quark - hadron phase transition . .
And you have already written the first three sentences of the full article: relativistic nucleus - nucleus ( a+a ) collisions provide us with experimental information about the phase diagram of quantum chromodynamics ( qcd ) and the strongly interacting matter properties . the last stage of such collisions is traditionally analyzed within the statistical approach which gives us an excellent opportunity to reveal the parameters of chemical freeze - out .
this approach is based on the assumption of the thermal equilibrium existence during the last stage of a+a reaction .
such an equilibrium can be reached due to intensive particle scattering ..
Please generate the next two sentences of the article | the stage of the system evolution when the inelastic reactions between hadrons stop is referred to as a chemical freeze - out ( fo ) .
particle yields are determined by the parameters of fo , namely by chemical potentials and temperature . |
8,339 | Suppose that you have an abstract for a scientific paper: we report the detection of weak gravitational lensing of distant background galaxies by two rich , x - ray luminous clusters of galaxies , ms 1137@xmath066 at @xmath1 and rxj 1716@xmath067 at @xmath2 .
we detect a shear signal in each cluster over the radial range @xmath3 700 @xmath4 kpc . assuming the background galaxies lie in a sheet at @xmath5 , we measure a mass of @xmath6 and @xmath7 at @xmath8 kpc radius for ms 1137@xmath066 , and a mass of @xmath9 and @xmath10 for rxj 1716@xmath067 at the same radius . both the optical lightmaps and weak lensing massmaps of rxj 1716@xmath067 show two spatially distinct sub - clusters , as well as a long filamentary structure extending out of the cluster to the northeast .
in contrast , ms 1137@xmath066 is an ultra - compact massive cluster in both massmaps and optical lightmaps , and contains a strongly - lensed arc system in the cluster core .
these data add to the growing number of massive clusters at @xmath11 . .
And you have already written the first three sentences of the full article: the existence of high - mass , x - ray luminous clusters of galaxies at @xmath12 provides a strong constraint on cosmological models ( eke 1996 ) .
the presence of any @xmath13 clusters at @xmath14 invalidates most @xmath15 cdm models ( bahcall _ et al .
_ 1997 , henry 1997 ) ..
Please generate the next two sentences of the article | further , the surface densities , amounts of sub - clustering , and mass to light ratios for these high @xmath16 clusters can place even stronger constraints on cosmological models and the nature of dark matter ( wilson 1997 , crone 1996 ) . currently , x - ray observations provide the most effective way of finding massive clusters at high redshifts .
the einstein extended medium sensitivity survey ( emss ) and the rosat north ecliptic pole ( nep ) survey have , so far , found three @xmath14 clusters of galaxies ( gioia and luppino 1994 , henry 1997 ) . |
8,340 | Suppose that you have an abstract for a scientific paper: chang - refsdal ( c - r ) lensing , which refers to the gravitational lensing of a point mass perturbed by a constant external shear , provides a good approximation in describing lensing behaviors of either a very wide or a very close binary lens .
c - r lensing events , which are identified by short - term anomalies near the peak of a high - magnification lensing light curves , are routinely detected from lensing surveys , but not much attention is paid to them . in this paper , we point out that c - r lensing events provide an important channel to detect planets in binaries , both in close and wide binary systems . detecting planets through the c - r lensing event channel is possible because the planet - induced perturbation occurs in the same region of the c - r lensing - induced anomaly and thus the existence of the planet can be identified by the additional deviation in the central perturbation . by presenting the analysis of the actually observed c - r lensing event ogle-2015-blg-1319
, we demonstrate that dense and high - precision coverage of a c - r lensing - induced perturbation can provide a strong constraint on the existence of a planet in the wide range of the planet parameters
. the sample of an increased number of microlensing planets in binary systems will provide important observational constraints in giving shape to the details of the planet formation scenario which has been restricted to the case of single stars . .
And you have already written the first three sentences of the full article: majority of stars reside in binary systems @xcite .
the mechanism of planet formation around binary systems would be different from that around single stars not only because the environment of the protoplanetary disk would be affected by the binary companion but also because the binary companion would affect the long - term stability of the planet orbit .
therefore , one of the most generic environments to be considered in the study of planet formation should be that of a binary . however , the major planet - formation scenarios that have been developed over the past decades , e.g. , core - accretion theory @xcite and disk instability theory @xcite , were mostly focused on the case of single stars ..
Please generate the next two sentences of the article | although a considerable work has been done about the effect of binary companions on the planet formation ( e.g. , * ? ? ?
* ) and the long - term orbital stability ( e.g. , * ? ? ? |
8,341 | Suppose that you have an abstract for a scientific paper: it is proposed that strain - induced pseudomagnetic fields in weyl materials could be used as chirality sensitive lenses for beams of weyl quasiparticles .
the study of the ( pseudo-)magnetic lenses is performed by using the eikonal approximation for describing the weyl quasiparticles propagation in magnetic and strain - induced pseudomagnetic fields .
analytical expressions for the locations of the principal foci and the focal length are obtained in the paraxial approximation in the models with uniform as well as nonuniform effective magnetic fields inside the lens .
the results show that the left- and right - handed quasiparticles can be focused at different spatial locations when both magnetic and pseudomagnetic fields are applied .
it is suggested that the use of the magnetic and pseudomagnetic lenses could open new ways of producing and manipulating beams of chiral weyl quasiparticles . .
And you have already written the first three sentences of the full article: while a static magnetic field can not change the kinetic energy of charged particles , it affects the direction of their motion due to a lorentz force .
this property is widely used in physics and technology .
for example , magnetic fields play a crucial role in cyclotrons and particle accelerators , where they keep beams of charged particles on correct trajectories ..
Please generate the next two sentences of the article | another application is the mass spectrometry , which utilizes magnetic fields in order to sort charged particles based on their mass - to - charge ratio .
magnetic fields can be also used as lenses for deflecting and focusing beams of charged particles . |
8,342 | Suppose that you have an abstract for a scientific paper: we use the observed number and column - density distributions of intergalactic absorbers to constrain the distribution of metals in the low - redshift intergalactic medium ( igm ) . in this simple model the metals in the absorbers are assumed to be produced in and propagated from low - redshift galaxies drawn from a real sample , in this case the sloan digital sky survey ( sdss ) .
this model can explain the observed @xmath0/@xmath1 of metals seen in absorbers if these metals are dispersed out to @xmath2 kpc by galaxies down to @xmath3 .
massive galaxies ( @xmath4 ) by themselves can not provide the necessary enrichment unless they can enrich volumes out to @xmath5 mpc .
alternatively , our model allows an estimate of the fraction of absorbers directly caused by galaxies rather than hot igm . with this assumption
we explore the possible connections between the intergalactic absorbers and the known populations of highly - ionized high - velocity clouds ( hvcs ) surrounding the milky way .
our model predicts that more sensitive , complete surveys optimized to uncover weaker absorbers will find the tentative turnover below @xmath6 ( ) @xmath7 to be a real effect resulting from the apparently limited volumes over which galaxies can enrich the igm .
if so , it would indicate that metals are not as widespread throughout the low - density igm as they are assumed to be in cosmological simulations of the whim . .
And you have already written the first three sentences of the full article: substantial populations of intergalactic qso absorption - line systems have been detected in highly - ionized oxygen ( ) with the hubble space telescope ( hst ) and the _ far ultraviolet spectroscopic explorer _ ( _ fuse _ ) . because they are probably hot ( @xmath8 k )
, these absorbers may represent a portion of the `` missing baryons '' that are predicted ( cen & ostriker 1999 ; dav et al .
1999 ) to arise at low redshift from continuous structure formation in the warm - hot intergalactic medium ( whim ) ..
Please generate the next two sentences of the article | early surveys of these absorbers with hst ( tripp , savage , & jenkins 2000 ; savage et al .
2002 , tripp 2005 ) found unexpectedly high number densities per unit redshift , @xmath0/@xmath1 @xmath9 , down to 30 - 50 m sensitivity . |
8,343 | Suppose that you have an abstract for a scientific paper: the mixed - field orientation of an asymmetric - rotor molecule with its permanent dipole moment non - parallel to the principal axes of polarizability is investigated experimentally and theoretically .
we find that for the typical case of a strong , nonresonant laser field and a weak static electric field complete 3d orientation is induced if the laser field is elliptically polarized and if its major and minor polarization axes are not parallel to the static field .
for a linearly polarized laser field solely the dipole moment component along the most polarizable axis of the molecule is relevant resulting in 1d orientation even when the laser polarization and the static field are non parallel .
simulations show that the dipole moment component perpendicular to the most - polarizable axis becomes relevant in a strong dc electric field combined with the laser field .
this offers an alternative approach to 3d orientation by combining a linearly - polarized laser field and a strong dc electric field arranged at an angle equal to the angle between the most polarizable axis of the molecule and its permanent dipole moment .
= 1 .
And you have already written the first three sentences of the full article: the ability to control the rotational motion and to angularly confine molecules has various applications in molecular sciences .
this includes studies of steric effects in chemical reactions , both bimolecular and photoinduced , and the possibility to investigate molecules from their own point of view , the molecular frame .
the latter mitigates the usual blurring of experimental observables caused by the random orientation of molecules in uncontrolled samples ..
Please generate the next two sentences of the article | access to molecular frame measurements is crucial in several applications , notably in various modern schemes aiming at observing the ( coupled ) motion of nuclei and electrons during chemical reactions @xcite .
methods based on the use of moderately intense , nonresonant , near - infrared laser pulses have proven particularly useful for controlling the alignment and , in conjunction with weak dc electric fields , orientation of a broad range of molecules . |
8,344 | Suppose that you have an abstract for a scientific paper: rare events are events that are expected to occur infrequently , or more technically , those that have low probabilities ( say , order of @xmath0 or less ) of occurring according to a probability model . in the context of uncertainty quantification , the rare events often correspond to failure of systems designed for high reliability , meaning that the system performance fails to meet some design or operation specifications .
as reviewed in this section , computation of such rare - event probabilities is challenging .
analytical solutions are usually not available for non - trivial problems and standard monte carlo simulation is computationally inefficient .
therefore , much research effort has focused on developing advanced stochastic simulation methods that are more efficient . in this section ,
we address the problem of estimating rare - event probabilities by monte carlo simulation , importance sampling and subset simulation for highly reliable dynamic systems . .
And you have already written the first three sentences of the full article: we focus on rare - event simulation for addressing reliability problems corresponding to dynamic systems . to compute the rare event ( failure ) probability for a dynamic system , both input ( excitation ) and modeling uncertainties
should be quantified and propagated .
therefore , a probability model must be chosen to describe the uncertainty in the future input for the system and then a chosen deterministic or stochastic system model is used , preferably in conjunction with a probability model describing the associated modeling uncertainties , to propagate these uncertainties ..
Please generate the next two sentences of the article | these input and system models define a probabilistic description of the system output ( response ) . for example
, the problem of interest might be to compute the small failure probability for a highly reliable dynamic system such as a bridge or building under uncertain future earthquake excitation , or for an aircraft under uncertain excitation by turbulence , using a finite - element structural model to approximate the dynamics of the system . |
8,345 | Suppose that you have an abstract for a scientific paper: we construct finite group actions on lagrangian floer theory when symplectic manifolds have finite group actions and lagrangian submanifolds have induced group actions . we first define finite group actions on novikov - morse theory . we introduce the notion of a _ spin profile _ as an obstruction class of extending the group action on lagrangian submanifold to the one on its spin structure , which is a group cohomology class in @xmath0 . for a class of lagrangian submanifolds which have the same spin profiles ,
we define a finite group action on their fukaya category . in consequence ,
we obtain the @xmath1-equivariant fukaya category as well as the @xmath1-orbifolded fukaya category for each group cohomology class @xmath1 .
we also develop a version with @xmath2-equivariant bundles on lagrangian submanifolds , and explain how character group of @xmath2 acts on the theory . as an application , we define an orbifolded fukaya - seidel category of a @xmath2-invariant lefschetz fibration , and also discuss homological mirror symmetry conjectures with group actions . .
And you have already written the first three sentences of the full article: a group action is one of the most important tool in the study of mathematical objects .
finite group actions in symplectic geometry appear in various contexts , such as mirror symmetry , singularity theory , etc . in this paper
, we will construct finite group actions on lagrangian floer theory ..
Please generate the next two sentences of the article | lagrangian floer homology ( developed by floer@xcite , oh@xcite , fukaya - oh - ohta - ono @xcite ) has been a powerful tool , which revolutionized the study of symplectic topology .
furthermore , its categorical versions , fukaya category ( fukaya @xcite ) and fukaya - seidel category ( seidel @xcite , @xcite ) , are the main players of homological mirror symmetry as envisioned by kontsevich @xcite . |
8,346 | Suppose that you have an abstract for a scientific paper: current issues in the studies of heavy flavours in colliders are described with particular emphasis on experiments in which the uk is involved .
results on charm production at hera are examined and compared to those at the tevatron .
@xmath0 production rates at the tevatron as well as the status of @xmath0 lifetimes and mixing in the lep collaborations and at the tevatron are highlighted .
the measurement of @xmath1 from cdf is described as well as the most recent results on top physics at the tevatron . to for publication . .
And you have already written the first three sentences of the full article: in this paper the status of heavy flavours , charm , bottom and top , is reviewed .
for the charm quark , emphasis is placed on measurements of the production rates and the differential cross sections at hera and the tevatron and of the extraction of the gluon structure function from the proton at hera using charm .
the large kinematic range at hera leads to a number of models with limits on applicability ..
Please generate the next two sentences of the article | these models can not be directly applied to the tevatron and the work to understand charm production is not complete . for bottom physics , the current status of the lifetime ratios between charged and neutral mesons is examined in the context of the spectator model .
the production cross section at hera and the tevatron is also studied revealing an area that needs further study . |
8,347 | Suppose that you have an abstract for a scientific paper: large - scale cloud radio access network ( ls - cran ) is a highly promising next - generation cellular network architecture whereby lots of base stations ( bss ) equipped with a massive antenna array are connected to a cloud - computing based central processor unit via digital front / backhaul links .
this paper studies an asymptotic behavior of downlink ( dl ) performance of a ls - cran with three practical constraints : 1 ) limited transmit power , 2 ) limited front / backhaul capacity , and 3 ) limited pilot resource . as an asymptotic performance measure , the scaling exponent of the signal - to - interference - plus - noise - ratio ( sinr )
is derived for interference - free ( if ) , maximum - ratio transmission ( mrt ) , and zero - forcing ( zf ) operations .
our asymptotic analysis reveals four fundamental operating regimes and the performances of both mrt and zf operations are fundamentally limited by the ul transmit power for estimating user s channel state information , not the dl transmit power .
we obtain the conditions that mrt or zf operation becomes interference - free , i.e. , order - optimal with three practical constraints . specifically , as higher ul transmit power is provided , more users can be associated and the data rate per user can be increased simultaneously while keeping the order - optimality as long as the total front / backhaul overhead is @xmath0 and @xmath1 pilot resources are available .
it is also shown that how the target quality - of - service ( qos ) in terms of sinr and the number of users satisfying the target qos can simultaneously grow as the network size increases and the way how the network size increases under the practical constraints , which can provide meaningful insights for future cellular systems . .
And you have already written the first three sentences of the full article: , mobile data traffic is explosively and continuously rising due to smart phone and tablet users and it is expected that next - generation ( a.k.a . the 5th generation )
cellular networks will offer a 1000x increase in network capacity as well as a 1000x increase in energy - efficiency in the following decade to meet such an excessively high user demand @xcite .
the most prominent way to increase the network capacity is the _ network densification _.
Please generate the next two sentences of the article | @xcite by either implementing more antennas at base stations ( bss ) called large - scale antenna system ( lsas ) @xcite or adding more small cells at hot spot areas called ultra - dense network ( udn ) @xcite . by using a lot of antennas at each bs
, the lsas can exploit massive spatial dimension to generate a sharp beam and thus it can provide higher spectral efficiency and also lower power consumption @xcite . |
8,348 | Suppose that you have an abstract for a scientific paper: we present x - ray photon correlation spectroscopy measurements of the atomic dynamics in a zr@xmath0ni@xmath1 metallic glass , well below its glass transition temperature .
we find that the decay of the density fluctuations can be well described by compressed , thus faster than exponential , correlation functions which can be modeled by the well - known kohlrausch - williams - watts function with a shape exponent @xmath2 larger than one .
this parameter is furthermore found to be independent of both waiting time and wave - vector , leading to the possibility to rescale all the correlation functions to a single master curve .
the dynamics in the glassy state is additionally characterized by different aging regimes which persist in the deep glassy state .
these features seem to be universal in metallic glasses and suggest a non diffusive nature of the dynamics .
this universality is supported by the possibility of describing the fast increase of the structural relaxation time with waiting time using a unique model function , independently of the microscopic details of the system . \\ .
And you have already written the first three sentences of the full article: understanding physical aging in glasses is essential at a technological level , for controlling the material properties and their temporal evolution , as well as at a fundamental level , since glasses are often considered as archetypes for systems far from thermodynamical equilibrium @xcite .
however , and despite the strong efforts done in the field , a complete picture of the dynamics in the glassy state is still missing .
the main difficulty arises from the complexity of the glassy properties ..
Please generate the next two sentences of the article | when a supercooled liquid is cooled below its glass transition temperature , @xmath3 , the system falls out of equilibrium in a metastable state which depends on the previous thermal history , and which evolves , with waiting time , through different states toward the corresponding supercooled equilibrium liquid phase .
the existence of a multitude of different metastable glassy states which can be explored through different annealing procedures or cooling rates , makes difficult the development of a universal theory for glasses or even a plain comparison between different experimental results . |
8,349 | Suppose that you have an abstract for a scientific paper: accurate quantum tomography is a vital tool in both fundamental and applied quantum science .
it is a task that involves processing a noisy measurement record in order to construct a reliable estimate of an unknown quantum state , and is central to quantum computing , metrology , and communication . to date , many different approaches to quantum state estimation have been developed , yet no one method fits all applications , and all fail relatively quickly as the dimensionality of the unknown state grows . in this work , we suggest that projected gradient descent is a method that can evade some of these shortcomings .
we present three novel tomography algorithms that use projected gradient descent and compare their performance with state - of - the - art alternatives , i.e. the diluted iterative algorithm and convex programming .
our results find in favour of the general class of projected gradient descent methods due to their speed , applicability to large states , and the range of conditions in which they perform . .
And you have already written the first three sentences of the full article: the reconstruction of an unknown quantum state known as quantum tomography is a fundamental task in quantum information science , where a myriad of new technologies promise to exploit special features of quantum states in order to enhance communication , metrology , and computation .
since the quantum state represents maximal information about a physical system , all physical properties can be calculated from it .
checking for the existence for a highly entangled state , a state which can violate a bell inequality , or even the initial state required in a gate - based quantum computer are thus just some examples of the importance of inferring the quantum state from laboratory data . as experimental methods progress , the complexity of quantum systems that can be well controlled in the laboratory grows . in recent times , for example , various groups have been able to demonstrate quantum control of a high number of qubits @xcite ..
Please generate the next two sentences of the article | to gain an idea of the challenge of state reconstruction , one need only consider that the number of real parameters required to describe the joint state of @xmath0 qubits scales as order @xmath1 . alternatively , the orbital angular momentum of single photons , for example , is a single degree of freedom with a large amount of internal structure : it has recently been characterised via the reconstruction of a 100,000 dimensional statevector @xcite . quite apart from the challenges presented by preparation and measurement of quantum states , tackling the state reconstruction problem in the face of such complexity calls for sophisticated data processing techniques , which are the focus of this paper .
[ [ section ] ] tomography experiments involve subjecting a system , described by some unknown quantum state , to a well - defined measurement procedure and recording the measurement outcome . the central tenets of quantum theory place severe restrictions on one s ability to characterise an unknown quantum system given measurements made on only a single copy . |
8,350 | Suppose that you have an abstract for a scientific paper: we consider a general class of vector - tensor theories of gravity and show that solutions with accelerated expansion and a future type iii singularity are a common feature in these models .
we also show that there are only six vector - tensor theories with the same small scales behavior as general relativity and , in addition , only two of them can be made completely free from instabilities .
finally , two particular models as candidates for dark energy are proposed : on one hand , a cosmic vector that allows to alleviate the usual naturalness and coincidence problems and , on the other hand , the electromagnetic field is shown to give rise to an effective cosmological constant on large scales whose value can be explained in terms of inflation at the electroweak scale . .
And you have already written the first three sentences of the full article: the standard model of cosmology accounts for the phase of accelerated expansion that the universe is currently undergoing by introducing a cosmological constant term in the gravitational action .
according to observations , the value of this cosmological constant should be @xmath0 ev@xmath1 , which is very far away from the natural scale of gravitation set by the planck mass @xmath2 gev .
this fact poses the so - called naturalness problem associated to the cosmological constant ..
Please generate the next two sentences of the article | however , this could be signaling that the cosmological constant causing the accelerated expansion is not a true constant , but an effective description arising from some underlying physical theory . on the other hand ,
the accelerated expansion could also be caused by some other physical mechanism like a cosmological scalar field or a modification of the gravitational interaction @xcite . |
8,351 | Suppose that you have an abstract for a scientific paper: for a singular riemannian foliation whose leaves are properly embedded , we show in the first part of this article the existence of global tubular neighbourhoods , and we develop a global description of the foliation as stratification by types of leaves .
the second part deals with the further restriction to a foliation without horizontal conjugate points , introduced by lytchak and thorbergsson , which in the special case of an isometric group action equals the concept of variationally completeness .
therefrom , we deduce a global geometric description the focal points of the leaves are exactly the singular points as well as a topological one : tautness of the leaves . .
And you have already written the first three sentences of the full article: it is a classical result of bott and samelson @xcite that the orbits of a variationally complete group action are taut .
isometric group actions are generalized to foliations via the notion of singular riemannian foliation , see @xcite ; and lytchak and thorbergsson defined in @xcite the analog of variational completeness for such foliations via the notion of foliation without horizontally conjugate points .
the main aim of this paper is to show that tautness also holds in this more general situation ..
Please generate the next two sentences of the article | a basic approach is to generalize the explicit construction of linking cycles done by bott and samelson . pursuing this strategy
, we need and find global structural characteristics of the foliations concerned . |
8,352 | Suppose that you have an abstract for a scientific paper: we present a model for the spine of relativistic mhd outflows in the kerr geometry .
meridional self - similarity is invoked to derive semi - analytical solutions close to the polar axis .
the study of the energy conservation along a particular field line gives a simple criterion for the collimation of jets .
such parameter have already been derived in the classical case by sauty et al .
1999 and also extended to the schwarzschild metric by meliani et al . 2006 .
we generalize the same study to the kerr metric .
we show that the rotation of the black hole increases the magnetic self - confinement . + * pacs numbers : * 04.70.-s , 47.75.+f , 95.30.qd .
And you have already written the first three sentences of the full article: several studies have contributed to show the importance of black hole rotation in agn jet formation .
agn jet classification mainly relies on orientation effects and relativistic doppler boosting .
however , they can not explain neither the dichotomy between radio loud and radio quiet agn , nor the difference between fri and frii jets ..
Please generate the next two sentences of the article | there are two main theories to interpret the different characteristics of radio loud and radio quiet galaxies .
the morphological differences may be explained by the different physical properties of the environment in which the relativistic jet propagates @xcite . |
8,353 | Suppose that you have an abstract for a scientific paper: a large class of positive finite presentations of the braid groups is found and studied .
it is shown that no presentations but known exceptions in this class have the property that equivalent braid words are also equivalent under positive relations . .
And you have already written the first three sentences of the full article: we will discover a large class of positive finite presentations of the @xmath0-braid group . roughly speaking , a presentation in this class
has a set of generators determined by a connected graph with @xmath0 vertices immersed in a plane in such a way that each pair of edges intersects at most once .
our class of presentations includes all known positive finite presentations such as the artin presentation@xcite , the band - generator presentation in @xcite and all of sergiescu s presentations in @xcite ..
Please generate the next two sentences of the article | our first objective is to find a ( minimal ) collection of positive relations among generators given by a graph as above so that it becomes a presentation of the @xmath0-braid groups .
the semigroup of all positive words plays a crucial role in the solutions to the word problem and the conjugacy problem for the @xmath0-braid group given by garside@xcite , thurston@xcite , and elrifi - morton@xcite . |
8,354 | Suppose that you have an abstract for a scientific paper: the phase diagram of the multichannel kondo hamiltonian with an xxz spin - exchange anisotropy is revisited , revealing a far richer fixed - point structure than previously appreciated . for a spin-@xmath0 impurity and @xmath1 conduction - electron channels ,
a second ferromagnetic - like domain is found deep in the antiferromagnetic regime .
the new domain extends above a ( typically large ) critical longitudinal coupling @xmath2 , and is separated from the antiferromagnetic domain by a second kosterliz - thouless line . a similar line of stable ferromagnetic - like fixed points with a residual isospin-@xmath0 local moment is shown to exist for large @xmath3 and arbitrary @xmath4 and @xmath5 obeying @xmath6 .
here @xmath7 is the longitudinal spin - exchange coupling , @xmath8 is the transverse coupling , and @xmath5 is the impurity spin . near the free - impurity fixed - point ,
spin - exchange anisotropy is a relevant perturbation for @xmath9 and arbitrary @xmath4 .
depending on the sign of @xmath10 and the parity of @xmath11 , the system flows either to a conventional fermi liquid with no residual degeneracy , or to a @xmath4-channel , spin-@xmath0 kondo effect , or to a line of ferromagnetic - like fixed points with a residual isospin-@xmath0 local moment .
these results are obtained through a combination of perturbative renormalization - group techniques , abelian bosonization , a strong - coupling expansion in @xmath12 , and explicit numerical renormalization - group calculations . .
And you have already written the first three sentences of the full article: for over the last forty years , the kondo effect has occupied a central place in condensed matter physics . while earlier studies of the effect have focused on its single - channel version realized in dilute magnetic alloys and valence - fluctuating systems , later attention has largely shifted to its more exotic multichannel variants where deviations from conventional fermi - liquid behavior can be found .
the overscreened kondo effect is a paradigmatic example for quantum criticality in quantum - impurity systems . besides the possible relevance to certain heavy fermion alloys , @xcite ballistic metal point contacts , @xcite scattering off two - level tunneling systems , @xcite and
the charging of small metallic grains , @xcite the overscreened kondo effect is one of the rare examples of interaction - driven non - fermi - liquid behavior that is well understood and well characterized theoretically ..
Please generate the next two sentences of the article | @xcite the underscreened kondo effect , which might be realized in ultrasmall quantum dots with an even number of electrons , @xcite is a prototype for yet another form of unconventional behavior that of a singular fermi liquid .
@xcite these vastly different ground states , as well as that of an ordinary fermi liquid , can all be described within the single framework of the multichannel kondo hamiltonian , which is among the simplest yet richest models for strong electronic correlations in condensed - matter physics . |
8,355 | Suppose that you have an abstract for a scientific paper: we study the collisional processes that can lead to thermalization in one - dimensional systems . for two body collisions excitations of transverse modes
are the prerequisite for energy exchange and thermalzation . at very low temperatures excitations of transverse modes
are exponentially suppressed , thermalization by two body collisions stops and the system should become integrable . in quantum mechanics
virtual excitations of higher radial modes are possible .
these virtually excited radial modes give rise to effective three - body velocity - changing collisions which lead to thermalization .
we show that these three - body elastic interactions are suppressed by pairwise quantum correlations when approaching the strongly correlated regime .
if the relative momentum @xmath0 is small compared to the two - body coupling constant @xmath1 the three - particle scattering state is suppressed by a factor of @xmath2 , which is proportional to @xmath3 , that is to the square of the three - body correlation function at zero distance in the limit of the lieb - liniger parameter @xmath4 .
this demonstrates that in one dimensional quantum systems it is not the freeze - out of two body collisions but the strong quantum correlations which ensures absence of thermalization on experimentally relevant time scales
. + _ short title _ : * thermalization in a quasi-1d ultracold bosonic gas * .
And you have already written the first three sentences of the full article: one - dimensional ( 1d ) systems @xcite are a model to study the fundamental processes of dynamics and ( de)coherence in interacting many - body quantum systems .
ultracold atoms in strongly elongated traps with @xmath5 ( @xmath6 , @xmath7 being the frequencies of the radial and longitudinal confinement , respectively ) offer the possibility to implement 1d quantum physics if both the temperature @xmath8 and chemical potential @xmath9 are small compared to the energy scale given by the transverse confinement : @xmath10 1d systems of ultra - cold atoms were implemented in both optical lattices @xcite and atom chips @xcite . in the limit of zero temperature
they are a realization of the lieb - liniger model @xcite of spinless bosons with contact ( point - like ) interaction , a prime example of an integrable system ..
Please generate the next two sentences of the article | an important parameter characterizing an 1d system of bosons with point - like interactions described by the ( three dimensional ) @xmath11-wave scattering length @xmath12 is the lieb - liniger parameter @xcite @xmath13 where @xmath14 is the mass ot the bosonic atom , @xmath15 the linear density of the atoms in the 1d trap characterized by the transverse confinement frequency @xmath6 , and @xmath16 is the fundamental length scale of the localization of an atom in the transversal direction given by @xmath17 the limit @xmath18 corresponds to a weakly - interacting regime , whereas @xmath4 signifies strongly - interacting , strongly correlated ( tonks - girardeau ) regime . in an integrable system
@xcite the number of their integrals of motion equals exactly the number of their degrees of freedom . |
8,356 | Suppose that you have an abstract for a scientific paper: a desirable goal of scientific management is to introduce , if it exists , a simple and reliable way to measure the scientific excellence of publicly - funded research institutions and universities to serve as a basis for their ranking and financing .
while citation - based indicators and metrics are easily accessible , they are far from being universally accepted as way to automate or inform evaluation processes or to replace evaluations based on peer review . here
we consider absolute measurements of research excellence at an amalgamated , institutional level and specific measures of research excellence as performance per head .
using biology research institutions in the uk as a test case , we examine the correlations between peer - review - based and citation - based measures of research excellence on these two scales .
we find that citation - based indicators are very highly correlated with peer - evaluated measures of group strength but are poorly correlated with group quality .
thus , and almost paradoxically , our analysis indicates that citation counts could possibly form a basis for deciding on how to fund research institutions but they should not be used as a basis for ranking them in terms of quality . .
And you have already written the first three sentences of the full article: the problem of measuring the scientific excellence of research institutes and universities is one of current and continued importance @xcite .
it is important to be able to detect and support the most promising research groups and to have sound and robust bases to wisely plan and invest for the future .
metrics and indicators of scientific activity may be based on the volume of researchers , the number of published papers , the amount of citations to these publications , the number of phd students and on finances generated by application of scientific ideas , amongst other factors ..
Please generate the next two sentences of the article | it is often argued that automated scientometric or bibliometric indicators may be an inadequate substitute or proxy for peer - review based evaluations of the merit of research institutes @xcite .
there is a lot of arguments against the use of indicators in isolation , suggesting they reflect only one aspect of the research and should only be used as an adjunct to peer review ( for example , see @xcite ) . |
8,357 | Suppose that you have an abstract for a scientific paper: we propose that n - type semiconductor quantum dots with the rashba and dresselhaus spin orbit interactions may be used for single electron manipulation through adiabatic transformations between degenerate states .
all the energy levels are discrete in quantum dots and possess a double degeneracy due to time reversal symmetry in the presence of the rashba and/or dresselhaus spin orbit coupling terms .
we find that the presence of double degeneracy does not necessarily give rise to a finite non - abelian ( matrix ) berry phase .
we show that a distorted two - dimensional harmonic potential may give rise to non - abelian berry phases .
the presence of the non - abelian berry phase may be tested experimentally by measuring the optical dipole transitions . .
And you have already written the first three sentences of the full article: single electron control in semiconductor quantum dots would be valuable for spintronics , quantum information , and spin qubits@xcite .
adiabatic time evolution of degenerate eigenstates of a quantum system provides a means for controlling individual quantum states@xcite .
they exhibit non - abelian gauge structures and often give finite non - abelian berry phases ( they are also called matrix berry phase or holonomic phase ) ..
Please generate the next two sentences of the article | these phases often depend on the geometry of the path traversed in the parameter space of the hamiltonian .
nuclei@xcite , superconducting nanocircuits@xcite , optical systems@xcite , and atomic systems@xcite have such degenerate quantum states . |
8,358 | Suppose that you have an abstract for a scientific paper: we make a detailed assessment of which form of the dipole operator to use in calculating high order harmonic generation within the framework of the strong field approximation , and look specifically at the role the form plays in the inclusion of multielectron effects perturbatively with regard to the contributions of the highest occupied molecular orbital .
we focus on how these corrections affect the high - order harmonic spectra from aligned homonuclear and heteronuclear molecules , exemplified by @xmath0 and co , respectively , which are isoelectronic .
we find that the velocity form incorrectly finds zero static dipole moment in heteronuclear molecules .
in contrast , the length form of the dipole operator leads to the physically expected non - vanishing expectation value for the dipole operator in this case .
furthermore , the so called `` overlap '' integrals , in which the dipole matrix element is computed using wavefunctions at different centers in the molecule , are prominent in the first - order multielectron corrections for the velocity form , and should not be ignored .
finally , inclusion of the multielectron corrections has very little effect on the spectrum .
this suggests that relaxation , excitation and the dynamic motion of the core are important in order to describe multielectron effects in molecular high - order high harmonic generation . .
And you have already written the first three sentences of the full article: high harmonic generation can be used for attosecond imaging of molecules @xcite .
this is a consequence of the fact that the structure of an aligned molecule can be inferred from quantum - interference patterns , which appear in the high - harmonic spectra
. understood in terms of the three - step model , in which an electron reaches the continuum by tunneling or multiphoton ionization , is accelerated by the field and subsequently recombines with a bound state of its parent molecule , emitting a high - order harmonic photon @xcite , this phenomenon occurs due to the electron returning to different spatially separated centers ..
Please generate the next two sentences of the article | the simplest scenario is high - harmonic generation in a diatomic molecule , for which , in principle , recombination and thus high - harmonic emission can take place from either atomic center .
this is a microscopic equivalent to the double slit experiment doubleslit . how to accurately describe the whole process of high harmonic generation ( hhg ) in molecules is still an open problem . |
8,359 | Suppose that you have an abstract for a scientific paper: inter - individual variability has various impacts in animal social behaviour .
this implies that not only collective behaviours have to be studied but also the behavioural variability of each member composing the groups . to understand those effects on group behaviour
, we develop a quantitative methodology based on automated ethograms and autonomous robots to study the inter - individual variability among social animals .
we choose chicks of _ gallus gallus domesticus _ as a classic social animal model system for their suitability in laboratory and controlled experimentation . moreover , even domesticated chicken present social structures implying forms or leadership and filial imprinting .
we develop an imprinting methodology on autonomous robots to study individual and social behaviour of free moving animals .
this allows to quantify the behaviours of large number of animals .
we develop an automated experimental methodology that allows to make relatively fast controlled experiments and efficient data analysis .
our analysis are based on high - throughput data allowing a fine quantification of individual behavioural traits .
we quantify the efficiency of various state - of - the - art algorithms to automate data analysis and produce automated ethograms .
we show that the use of robots allows to provide controlled and quantified stimuli to the animals in absence of human intervention .
we quantify the individual behaviour of 205 chicks obtained from hatching after synchronized fecundation .
our results show a high variability of individual behaviours and of imprinting quality and success .
three classes of chicks are observed : imprinted with variability , indifferent to the imprinting stimuli ( i.e the robots ) and chicks that avoid the imprinting stimuli .
our study shows that the concomitant use of autonomous robots and automated ethograms allows detailed and quantitative analysis of behavioural patterns of animals in controlled laboratory experiments . .
And you have already written the first three sentences of the full article: many species of animal live in group and are capable of making decisions while maintaining group coherence @xcite .
animal living in groups are constrained by what they can perceive thus most of the time they can not have a global view of the group and their environment .
yet those species are capable of remarkable group behaviours ..
Please generate the next two sentences of the article | the question arises as to understand what kind of mechanism allows the group to perform so well given their individual limitations .
several forms of social structures exists that go from all individuals apparently having the same weight in the group to various forms of leadership and social hierarchy . + among the many group - living species , the chicken ( _ gallus gallus domesticus _ ) is an interesting animal model : the chickens are social animals and chicks present a social attachment to their siblings and to their mother . |
8,360 | Suppose that you have an abstract for a scientific paper: extragalactic jets are a common feature of radio - loud active galaxies .
the nature of the observed jets in relation to the bulk flow is still unclear . in particular
it is not clear whether the observations of parsec - scale jets using the very long baseline interferometric technique ( vlbi ) reveal wave - like structures that develop and propagate along the jet , or trace the jet flow itself . in this contribution
i review the evidence collected during the last years showing that the ridge - lines of helical radio - jets do not correspond to observational artifacts .
this conclusion was reached by studying a number of vlbi observations of the radio jet in the quasar s5 0836 + 710 at different frequencies and epochs .
the ridge - line of the emission in the jet coincides at all frequencies within the errors .
moreover , small differences between the ridge - lines as observed at different epochs reveal wave - like motion transversal to the jet propagation axis .
i also discuss similar results , albeit with different interpretations , obtained by other authors .
the current challenge is to measure the propagation velocities of these waves and to try to characterise them in terms of simple perturbations or kelvin - helmholtz instability , which would help understanding the physical conditions of the flow where the waves develop .
this problem can only be tackled by high - resolution observations such as those that can be achieved by the space radio - antenna _ .
And you have already written the first three sentences of the full article: extragalactic jets are a common feature of radio - loud active galaxies @xcite .
these galaxies presumably host a supermassive black hole in their nuclei ( @xmath0 ) , and the accretion disks of matter that form around them originate the observed strong optical / uv emission . around one per cent of active galaxies are radio - loud , with the radio emission being emitted from jets .
current models suggest that the strong magnetic fields in these systems are able to extract energy from the black - hole or the accretion disk @xcite ..
Please generate the next two sentences of the article | the particles get collimated and accelerated by the magnetic fields , acquiring terminal speeds close to the speed of light @xcite .
jets propagate through the host galaxy and even outside , bringing large amounts of particles and energy from the central regions of the host galaxies to regions hundreds of kiloparsecs away ( @xmath1 during @xmath2 for powerful jets ) . |
8,361 | Suppose that you have an abstract for a scientific paper: ashkin - teller type perceptron models are introduced .
their maximal capacity per number of couplings is calculated within a first - step replica - symmetry - breaking gardner approach .
the results are compared with extensive numerical simulations using several algorithms . 2 .
And you have already written the first three sentences of the full article: the perceptron which was first analyzed with statistical mechanics techniques in the seminal paper of gardner @xcite is by now a well - known and standard model in theoretical studies and practical applications in connection with learning and generalization @xcite .
a number of extensions of the perceptron model have been formulated , including many - state and graded - response perceptrons ( e.g. , @xcite ) . here
we present some new extensions allowing for so - called coloured or ashkin - teller type neurons , i.e. , different types of binary neurons at each site possibly having different functions ..
Please generate the next two sentences of the article | the idea of looking at such a model is based upon our recent work on ashkin - teller recurrent neural networks @xcite .
there we showed that for this model with two types of binary neurons interacting through a four - neuron term and equipped with a hebb learning rule , both the thermodynamic and dynamic properties suggest that such a model can be more efficient than a sum of two hopfield models . |
8,362 | Suppose that you have an abstract for a scientific paper: this paper introduces the formalism which connects between rotation measure ( @xmath0 ) measurements for extragalactic sources and the cosmological magnetic field power spectrum .
it is shown that the amplitude and shape of the cosmological magnetic field power spectrum can be constrained by using a few hundred radio sources , for which faraday @xmath0s are available .
this constraint is of the form @xmath1 h $ ] nano - gauss ( ng ) on @xmath2 scales , with @xmath3 the average baryon density and @xmath4 the hubble parameter in @xmath5 km s@xmath6 mpc@xmath6 units .
the constraint is superior to and supersedes any other constraint which come from either cmb fluctuations , baryonic nucleosynthesis , or the first two multipoles of the magnetic field expansion .
the most adequate method for the constraint calculation uses the bayesian approach to the maximum likelihood function .
i demonstrate the ability to detect such magnetic fields by constructing simulations of the field and mimicking observations .
this procedure also provides error estimates for the derived quantities . the two main noise contributions due to the galactic rm and the internal rm are treated in a statistical way following an evaluation of their distribution .
for a range of magnetic field power spectra with power indices @xmath7 in a flat cosmology ( @xmath8=1 ) we estimate the signal - to - noise ratio , @xmath9 , for limits on the magnetic field @xmath10 on @xmath11 scale .
employing one patch of a few square degrees on the sky with source number density @xmath12 , an approximate estimate yields @xmath13 .
an all sky coverage , with much sparser , but carefully tailored sample of @xmath14 sources , yields @xmath15 with the same scaling .
an ideal combination of small densely sampled patches and sparse all - sky coverage yields @xmath16 with better constraints for the power index .
all of these estimates are corroborated by the simulations .
epsf.sty = cmr10 # 1#2.5pt 2 degm^-2 2 radm^-2 .
And you have already written the first three sentences of the full article: there is plenty evidence for magnetic fields on the scale of the earth , the solar system , the interstellar medium , galaxies and clusters of galaxies [ for the extragalactic magnetic field see review by kronberg ( 1994 , k94 ) and references therein ] .
we still do nt know however whether any larger scale magnetic fields exist .
there are various upper limits on the rms value of the cosmological magnetic field , but the upper limits are still too high to exclude any relevance to magnetic fields observed on smaller scales ..
Please generate the next two sentences of the article | cosmological magnetic fields might help to resolve the bothersome question of the origin of the @xmath17 g magnetic field which exists on galactic scales or fields of similar size seen on the scales of galaxy clusters . a primordial ( pre galaxy formation )
magnetic field amplified by the gravitational collapse , and then by processes like differential rotation and dynamo amplification ( parker 1979 ) , can serve to seed these observed smaller scale magnetic fields . |
8,363 | Suppose that you have an abstract for a scientific paper: we analyse a sample of 71 triplets of luminous galaxies derived from the work of @xcite .
we compare the properties of triplets and their members with those of control samples of compact groups , the ten brightest members of rich clusters , and galaxies in pairs .
the triplets are restricted to have members with spectroscopic redshifts in the range @xmath0 and absolute r - band luminosities brighter than @xmath1 . for these member galaxies ,
we analyse the stellar mass content , the star formation rates , the @xmath2 parameter and ( @xmath3 ) colour index .
since galaxies in triplets may finally merge in a single system , we analyse different global properties of these systems .
we calculate the probability that the properties of galaxies in triplets are strongly correlated .
we also study total star formation activity and global colours , and define the triplet compactness as a measure of the percentage of the system total area that is filled by the light of member galaxies .
we concentrate in the comparison of our results with those of compact groups to assess how the triplets are a natural extension of these compact systems .
our analysis suggest that triplet galaxy members behave similarly to compact group members and galaxies in rich clusters .
we also find that systems comprising three blue , star - forming , young stellar population galaxies ( blue triplets ) are most probably real systems and not a chance configuration of interloping galaxies .
the same holds for triplets composed by three red , non star - forming galaxies , showing the correlation of galaxy properties in these systems . from the analysis of the triplet as a whole ,
we conclude that , at a given total stellar mass content , triplets show a total star formation activity and global colours similar to compact groups . however , blue triplets show a high total star formation activity with a lower stellar mass content . from an analysis of the compactness parameter of the systems we find that light is even more....
And you have already written the first three sentences of the full article: it is well known that several properties of galaxies depend on environment .
pioneering work by @xcite shows that galaxy morphology depends on local galaxy density : late type galaxies prefer low density environments , while dense environments tend to be populated by early type galaxies .
there is also a strong correlation between galaxy star formation rates ( sfrs ) and environment : galaxies in high density environments present a decrease in sfrs compared to field galaxies @xcite ..
Please generate the next two sentences of the article | the effect of local environment on galaxy colours has been studied by @xcite .
this authors find that at @xmath4 faint galaxies show a clear increase in the fraction of red galaxy as the local density increases . on the other hand , bright galaxies , present a constant red galaxy fraction . |
8,364 | Suppose that you have an abstract for a scientific paper: in quantum metrology schemes , one generally needs to prepare @xmath0 copies of @xmath1 entangled particles , such as entangled photon states , and then they are detected in a destructive process to estimate an unknown parameter . here ,
we present a novel experimental scheme for estimating this parameter by using repeated indirect quantum nondemolition measurements in the setup called `` photon box '' .
this interaction - based scheme is able to achieve the phase sensitivity scaling as @xmath2 with a fock state of @xmath1 photons .
moreover , we only need to prepare one initial @xmath1-photon state and it can be used repetitively for @xmath0 trials of measurements . this new scheme is shown to sustain the quantum advantage for a much longer time than the damping time of fock state and be more robust than the common strategy with exotic entangled states . to overcome the @xmath3 periodic error in the estimation of the true parameter
, we can employ a cascaded strategy by adding a real - time feedback interferometric layout . .
And you have already written the first three sentences of the full article: quantum parameter estimation , the emerging field of quantum technology , aims to use entanglement and other quantum resources to yield higher statistical precision of a parameter @xmath4 than purely classical approaches @xcite .
the precision of estimation of @xmath4 will depend on the available resources used in the measurement .
it has been shown that standard quantum limit ( sql ) or called shot noise limit scaling as @xmath5 with @xmath6 the number of particles can be surpassed by using coherent light with squeezed vacuum @xcite ..
Please generate the next two sentences of the article | it is also commonly considered that using non - gaussian states like noon states @xcite and quantum entanglement allows one to achieve a sub - shot noise accuracy .
heisenberg limit scaling as @xmath7 is the ultimate limit set by quantum mechanics . |
8,365 | Suppose that you have an abstract for a scientific paper: an overview is presented of a recently proposed `` radically conservative '' solution to the problem of dark energy in cosmology .
the proposal yields a model universe which appears to be quantitatively viable , in terms of its fit to supernovae luminosity distances , the angular scale of the sound horizon in the cosmic microwave background ( cmb ) anisotropy spectrum , and the baryon acoustic oscillation scale .
it may simultaneously resolve key anomalies relating to primordial lithium abundances , cmb ellipticity , the expansion age of the universe and the hubble bubble feature .
the model uses only general relativity , and matter obeying the strong energy condition , but revisits operational issues in interpreting average measurements in our presently inhomogeneous universe , from first principles .
the present overview examines both the foundational issues concerning the definition of gravitational energy in a dynamically expanding space , the quantitative predictions of the new model and its best fit cosmological parameters , and the prospects for an era of new observational tests in cosmology .
= cmr5=cmr7=cmmi7 # 1 _ # 1|#1 # 1 # 1#2#3#1#3#1#2 # 1#2#1#1#2 # 1 _ # 1 _ # 1 # 1#2 # 1 # 1astrophys .
j. * # 1 * # 1phys .
lett . *
# 1 * # 1astron . j. * # 1 * # 1class .
quantum grav .
* # 1 * # 1gen . relativ .
grav . * # 1 * # 1astron .
astrophys . * # 1 * # 1phys .
rev .
lett . *
# 1 * # 1phys .
rev .
* # 1 * # 1mon . not .
r. astr .
soc . * # 1 * .
And you have already written the first three sentences of the full article: dark energy is widely described as the biggest problem in cosmology today ; one which may demand new physics and a theoretical paradigm shift@xcite . in this paper
i suggest that the solution to the problem of dark energy is intimately related to the correct understanding of observational anomalies in particular , the observed abundance and emptiness of voids , which has also elicited separate calls for a paradigm shift@xcite .
i propose that the paradigm shift that is required to understand both these issues actually entails no `` new '' physics , but a revisiting of fundamental issues relating to the subtlety of the definition of gravitational energy within general relativity , and its relation to the careful modelling of the distribution of matter that we actually observe ..
Please generate the next two sentences of the article | the punchline is that cosmic acceleration can be understood as an apparent effect , and dark energy as a misidentification of those aspects of cosmological gravitational energy which by virtue of the strong equivalence principle can not be localized@xcite , namely gradients in the quasilocal gravitational energy associated with spatial curvature gradients , and the kinetic energy of expansion , between bound systems and the volume average position in freely expanding space . with this interpretation ,
a two scale model can be constructed@xcite , and a simple exact solution@xcite of the relevant equations of cosmic evolution , the buchert equations@xcite , can be found . |
8,366 | Suppose that you have an abstract for a scientific paper: a riemannian metric with a local contraction property can be used to prove existence and uniqueness of a periodic orbit and determine a subset of its basin of attraction . while the existence of such a contraction metric is equivalent to the existence of an exponentially stable periodic orbit , the explicit construction of the metric is a difficult problem . in this paper , the construction of such a contraction metric
is achieved by formulating it as an equivalent problem , namely a feasibility problem in semidefinite optimization .
the contraction metric , a matrix - valued function , is constructed as a continuous piecewise affine ( cpa ) function , which is affine on each simplex of a triangulation of the phase space .
the contraction conditions are formulated as conditions on the values at the vertices .
the paper states a semidefinite optimization problem .
we prove on the one hand that a feasible solution of the optimization problem determines a cpa contraction metric and on the other hand that the optimization problem is always feasible if the system has an exponentially stable periodic orbit and the triangulation is fine enough .
an objective function can be used to obtain a bound on the largest floquet exponent of the periodic orbit . .
And you have already written the first three sentences of the full article: in this paper we consider a time - periodic ode of the form @xmath0 , where @xmath1 for all @xmath2 with a fixed period @xmath3 , and study the basin of attraction of a periodic solution .
the basin of attraction can be computed using a variety of methods : * invariant manifolds * form the boundaries of basins of attraction , and their computation can thus be used to find a basin of attraction @xcite .
however , this method needs additional arguments to ensure that a certain region is the basin of attraction of an attractor , and that , for example , there are no other attractors in that region . other approaches to compute the basin of attraction are for example the * cell mapping approach * @xcite or * set oriented methods * @xcite which divide the phase space into cells and compute the dynamics between these cells . * lyapunov functions * @xcite are a natural way of analysing the basin of attraction , since they start from the attractive solution , not from the boundary ..
Please generate the next two sentences of the article | moreover , through their level sets , they give additional information about the basin of attraction than just the boundary . *
converse theorems * which guarantee the existence of a lyapunov function under certain conditions have been given by many authors , for an overview see @xcite . |
8,367 | Suppose that you have an abstract for a scientific paper: in the following paper we consider a simulation technique for stochastic trees .
one of the most important areas in computational genetics is the calculation and subsequent maximization of the likelihood function associated to such models .
this typically consists of using importance sampling ( is ) and sequential monte carlo ( smc ) techniques .
the approach proceeds by simulating the tree , backward in time from observed data , to a most recent common ancestor ( mrca ) .
however , in many cases , the computational time and variance of estimators are often too high to make standard approaches useful . in this paper
we propose to stop the simulation , subsequently yielding biased estimates of the likelihood surface .
the bias is investigated from a theoretical point of view .
results from simulation studies are also given to investigate the balance between loss of accuracy , saving in computing time and variance reduction .
+ * key words * : stochastic trees , sequential monte carlo , coalescent . .
And you have already written the first three sentences of the full article: there is currently much interest in performing ancestral inference from molecular population genetic data . to facilitate this inference ,
there has been an explosion of research in developing computationally efficient methods .
these techniques are designed either to compute the likelihood , for maximum likelihood estimation , of a sample of genes or for deriving the posterior distribution on parameters in coalescent models , which describe the ancestry of the genes ..
Please generate the next two sentences of the article | broadly speaking there are three main approaches to inference in molecular population genetics : ( i ) importance sampling for likelihood evaluation , whose application in population genetics was pioneered by ( griffiths & tavar , 1994a , b , c ) ( ii ) markov chain monte carlo methods ( e.g. kuhner et al .
( 1995 ) , wilson & balding ( 1998 ) ) ( iii ) approximate bayesian computation ( abc ) ( del moral et al . |
8,368 | Suppose that you have an abstract for a scientific paper: the time evolution of several interacting ginzburg - landau vortices according to an equation of schrdinger type is approximated by motion on a finite - dimensional manifold . that manifold is defined as an unstable manifold of an auxiliary dynamical system , namely the gradient flow of the ginzburg - landau energy functional . for two vortices
the relevant unstable manifold is constructed numerically and the induced dynamics is computed .
the resulting model provides a complete picture of the vortex motion for arbitrary vortex separation , including well - separated and nearly coincident vortices .
nlin.ps/0201047 + hwm01 - 44 24 pt unstable manifolds and schrdinger dynamics + of ginzburg - landau vortices o. lange and b. j. schroers + department of mathematics , heriot - watt university + edinburgh eh14 4as , united kingdom january 2002 ams classification scheme numbers : 35q55 , 37k05 , 70k99 .
And you have already written the first three sentences of the full article: vortices play a fundamental role in a large variety of physical systems , ranging from ordinary fluids over condensed matter to the early universe .
this variety is reflected in the mathematical models used to describe the formation , structure and dynamics of vortices . in fluid dynamics ,
the basic ingredient of the mathematical model is the velocity field of the fluid , and the vortex is a particular configuration of that velocity field . in condensed matter theory , the mathematical models are field theories . the basic field of such models is a complex valued scalar field , and vortices are particular configurations of that field ..
Please generate the next two sentences of the article | one important difference between vortices in ordinary fluids and those in condensed matter systems is that the total vorticity can take arbitrary real values in the former but is quantised in the latter .
nonetheless , it is sometimes possible to establish a precise mathematical connection between field theory models and those used in ordinary fluid dynamics . in this paper |
8,369 | Suppose that you have an abstract for a scientific paper: the spin fluctuations of electron and hole doped self - assembled quantum dot ensembles are measured optically in the low - intensity limit of a probe laser in absence and presence of longitudinal or transverse static magnetic fields .
the experimental results are modeled by two complementary approaches based either on semiclassical or quantum mechanical descriptions .
this allows us to characterize the hyperfine interaction of electron and hole spins with the surrounding bath of nuclei on time scales covering several orders of magnitude .
our results demonstrate ( i ) the intrinsic precession of the electron spin fluctuations around the effective nuclear overhauser field caused by the host lattice nuclear spins , ( ii ) the comparably long time scales for electron and hole spin decoherence , as well as ( iii ) the dramatic enhancement of the spin lifetimes induced by a longitudinal magnetic field due to the decoupling of nuclear and charge carrier spins . .
And you have already written the first three sentences of the full article: since the beginning of the 21st century , the spectroscopy of spin noise @xcite has emerged as a competitive tool to study spin dynamics in close to thermal equilibrium conditions .
the rapid development of this technique has started with detailed investigations of the spin fluctuations in atomic gases in 2004 @xcite , and then moved to studies of spin noise in semiconductor systems , such as bulk crystals @xcite or nanostructures @xcite , because this class of materials may be the building blocks of future spin - based devices .
for many applications , self - assembled semiconductor quantum dots ( qds ) have been considered , because qds can be grown epitaxially and implemented into established semiconductor environment @xcite ..
Please generate the next two sentences of the article | the direct band gap in combination with a giant optical dipole moment allows for spin control operations that can be performed at a terahertz rate or even faster , see , e.g. , @xcite . to that end , it is mandatory for such applications to have detailed knowledge on the interactions of the involved carrier spins and the resulting dynamics .
the spin dynamics of the confined spins of single electrons and holes are mostly determined by the interaction with the surrounding nuclei in the dot , which are theoretically treated usually by the central spin model ( csm ) . |
8,370 | Suppose that you have an abstract for a scientific paper: we study the diffractive photo- and leptoproductions of @xmath0 and @xmath1 on the proton , and examine the validity of the small - size color dipole approximation to the production of radially excited heavy quarkonium .
the dipole model predicts a small ratio of @xmath1 to @xmath0 photoproduction cross sections , which does not agree with experimental data .
we show that this discrepancy originates from a large transverse size of @xmath1 which makes the convergence of the transverse size expansion questionable , and the calculation without the dipole approximation turns out to be consistent with the data .
productions of @xmath2 are also discussed , and the dipole approximation is found to be reasonable for the @xmath3-family . .
And you have already written the first three sentences of the full article: recently diffractive phenomena in qcd have attracted considerable theoretical and experimental interests .
in particular , diffractive photo- and leptoproductions of vector mesons off the proton , @xmath4 , provide crucial constraints on properties of the qcd pomeron and the vector meson wave functions@xcite . in this report , we focus on the heavy quarkonium production , where the heavy quark mass plays a role of the hard scale . due to the regge kinematics
, the vector meson production can be understood as the scattering of the color dipole with the target nucleon . in this case.
Please generate the next two sentences of the article | we expect the amplitude to be dominated by the four diagrams illustrated in fig.1 .
the upper part of each diagram , where the heavy quarks interact with two - gluons , is assumed to be calculated within perturbative qcd even for the photoproduction . on the other hand , the lower blob represents both non - perturbative structure ( impact factor ) of the proton and complicated gluon dynamics at small-@xmath5 which is identified with the qcd pomeron . |
8,371 | Suppose that you have an abstract for a scientific paper: in @xcite the concept of a @xmath0-divisible graceful @xmath1-labeling has been introduced as a generalization of classical @xmath1-labelings and it has been shown how it is useful to obtain certain cyclic graph decompositions . in the present paper
it is proved the existence of @xmath0-divisible graceful @xmath1-labelings of @xmath2 for any integers @xmath3 , @xmath4 for several values of @xmath0 .
* keywords : * graceful labeling ; @xmath1-labeling ; graph decomposition . + * msc(2010 ) : * 05c78 . .
And you have already written the first three sentences of the full article: we assume familiarity with the basic concepts about graphs . + as usual , we denote by @xmath5 and @xmath6 the _ complete graph on @xmath7 vertices _ and the _
complete @xmath8-partite graph with parts of size @xmath9 _ , respectively . also , let @xmath10 , @xmath11 , be the cycle on @xmath12 vertices and let @xmath13 , @xmath14 , be the path on @xmath8 vertices .
graphs of the form @xmath15 can be viewed as grids on cylinders and they are bipartite if and only if @xmath12 is even . if @xmath16 , @xmath17 is nothing but the prism @xmath18 on @xmath19 vertices . for any graph @xmath20.
Please generate the next two sentences of the article | we write @xmath21 for the set of its vertices and @xmath22 for the set of its edges .
if @xmath23 , we say that @xmath20 has _ size _ @xmath24 . given a subgraph @xmath20 of a graph @xmath25 , a @xmath20-_decomposition of _ |
8,372 | Suppose that you have an abstract for a scientific paper: friib radio galaxies provide a modified standard yardstick that allows constraints to be placed on global cosmological parameters .
this modified standard yardstick is analogous to the modified standard candle provided by type ia supernovae .
the radio galaxy and supernova methods provide a measure of the coordinate distance to high - redshift sources , and the coordinate distance is a function of global cosmological parameters .
a sample of 20 friib radio galaxies with redshifts between zero and two are compared with the parent population of 70 radio galaxies to determine the coordinate distance to each source .
the coordinate distance determinations are used to constrain the current mean mass - energy density of quintessence @xmath0 , the equation of state of the quintessence @xmath1 , and the current mean mass - energy density of non - relativistic matter @xmath2 ; zero space curvature is assumed .
radio galaxies alone indicate that the the universe is currently accelerating in its expansion ( with 84% confidence ) ; most of the allowed parameter space falls within the accelerating universe region on the @xmath3 plane .
this provides verification of the acceleration of the universe indicated by high - redshift supernovae , and suggests that neither method is plagued by systematic errors .
it is found that @xmath2 must be less than about 0.5 and the equation of state @xmath1 of the quintessence must lie between -0.25 and -2.5 at about 90% confidence .
fits of the radio galaxy data constrain the model parameter @xmath4 , which describes a relation between the beam power of the agn and the total energy expelled through large - scale jets .
it is shown that the empirically determined model parameter is consistent with models in which the outflow results from the electromagnetic extraction of rotational energy from the central compact object . a specific relation between the strength of the magnetic field near the agn , and the spin angular momentum per unit mass of the central compact....
And you have already written the first three sentences of the full article: there are several independent ways to determine the global cosmological parameters that describe the current state of the universe .
it is important to have several complementary and independent methods that yield consistent results since any given method could be plagued by unknown systematic errors .
a particularly useful way to determine global cosmological parameters is through measurements of the coordinate distance to high - redshift sources ..
Please generate the next two sentences of the article | this method is particularly useful because the coordinate distance depends only upon global cosmological parameters , and is independent of the clustering properties of the mass - energy components that control the expansion rate of the universe , as long as each component is homogeneous and isotropic on very large scales .
the coordinate distance is also independent of whether different components cluster differently , known as biasing , and on whether the dark matter is cold , warm , or hot ( though it does depend on the equation of state of each component ) . |
8,373 | Suppose that you have an abstract for a scientific paper: it has been suggested that the volume dependence of the spectral weight could be utilized to distinguish single and multi - particle states in monte carlo simulations . in a recent study using a solvable model , the lee model
, we found that this criteria is applicable only for stable particles and narrow resonances , not for the broad resonances . in this paper , the same question is addressed within the finite size formalism outlined by lscher . using a quantum mechanical scattering model , the conclusion that was found in previous lee model study
is recovered .
then , following similar arguments as in lscher s , it is argued that the result is valid for a general massive quantum field theory under the same conditions as the lscher s formulae . using the spectral weight function ,
a possibility of extracting resonance parameters is also pointed out . , ,
, spectral weight , finite - size technique , lattice qcd . .
And you have already written the first three sentences of the full article: low - energy hadron - hadron scattering plays an important role in the understanding of non - perturbative physics of strong interaction .
due to its genuine non - perturbative nature , such problems can only be studied from first principles using non - perturbative methods like lattice qcd .
lscher has outlined a finite - size formalism which enables us to calculate the elastic scattering phase shifts using lattice simulations @xcite . over the years.
Please generate the next two sentences of the article | , extensive numerical simulations have been carried out to the study on hadron - hadron scattering using lscher s formalism , both within the quenched approximations and using gauge field configurations with dynamical quarks @xcite . in lattice study on hadron spectroscopy and hadron - hadron scattering ,
the most important physical quantity is the energy of the system which is obtained via the measurements of various correlation functions . |
8,374 | Suppose that you have an abstract for a scientific paper: a model for gas outflows is proposed which simultaneously explains the correlations between the ( i ) equivalent width of low ionization and ly@xmath0 lines , ( ii ) outflow velocity , and ( iii ) star formation rate observed in lyman break galaxies ( lbgs ) .
our interpretation implies that lbgs host short - lived ( @xmath1 myr ) starburst episodes observed at different evolutionary phases .
initially , the starburst powers a hot wind bound by a denser cold shell , which after @xmath2 myr becomes dynamically unstable and fragments ; afterwards the fragment evolution is approximately ballistic while the hot bubble continues to expand . as the fragments are gravitationally decelerated , their screening ability of the starlight decreases as the uv starburst luminosity progressively dims .
lbg observations sample all these evolutionary phases .
finally , the fragments fall back onto the galaxy after @xmath3 myr .
this phase can not be easily probed as it occurs when the starburst uv luminosity has already largely faded ; however , galaxies dimmer in the uv than lbgs should show infalling gas .
cosmology : theory galaxies : formation .
And you have already written the first three sentences of the full article: recent observations ( adelberger 2003 , shapley 2003 ( s03 ) , steidel 2003 , adelberger 2005 ) based on a combination of quasar absorption - line and faint - galaxy techniques applied to the same cosmic volumes have revealed that uv - selected , star forming galaxies at redshift @xmath4 ( in brief , lyman break galaxies , lbgs ) show spectral absorption lines due to heavy elements .
these absorption lines , which can be very strong ( @xmath5 @xmath6 ) , are often called interstellar " because they resemble the absorption lines produced by interstellar material in local galaxies .
nevertheless , these lines appear ( without exception ) to be _ blueshifted _ with respect to the galaxy systemic velocity deduced from nebular lines ..
Please generate the next two sentences of the article | the typical velocity difference is @xmath7 km s@xmath8 , but a non - negligible fraction of lbgs show differences in excess of 300 km s@xmath8 ( pettini 2002 ) .
these absorbing systems are often interpreted as arising in cool and/or neutral structures ( maybe a shell ) part of an outflow powered by supernovae associated with the detected galaxy star formation activity . |
8,375 | Suppose that you have an abstract for a scientific paper: spin-1/2 magnets with kagom geometry , being for years a generic object of theoretical investigations , have few real material realizations . recently , a dft - based microscopic model for two such materials , kapellasite cu@xmath0zn(oh)@xmath1cl@xmath2 and haydeeite cu@xmath0mg(oh)@xmath1cl@xmath2 , was presented @xmath3janson o , richter j and rosner h , arxiv:0806.1592@xmath4 $ ] . here ,
we focus on the intrinsic properties of real spin-1/2 kagom materials having influence on the magnetic ground state and the low - temperature excitations .
we find that the values of exchange integrals are strongly dependent on o
h distance inside the hydroxyl groups , present in most spin-1/2 kagom compounds up to date .
besides the original kagom model , considering only the nearest neighbour exchange , we emphasize the crucial role of the exchange along the diagonals of the kagom lattice .
two - dimensional ( 2d ) magnets with a kagom lattice arrangement of magnetic ions ( figure [ str ] ) are geometrically frustrated due to a triangular - like arrangement of nearest neighbours ( nn ) leading to an unusual highly degenerate classical ground state ( gs ) @xcite .
strong quantum fluctuations arising from spin-1/2 ions can lift the classical degeneracy and drive the system into a magnetically disordered quantum paramagnetic state , which might be applied for future quantum computational applications @xcite . nonetheless , in real materials couplings to further neighbours @xcite and between the kagom layers @xcite are always present and influence the gs and the thermodynamics . in a recent paper @xcite we have performed dft calculations for two new natural isostructural materials with spin-1/2 kagom lattice kapellasite cu@xmath0zn(oh)@xmath1cl@xmath2 @xcite and haydeeite cu@xmath0mg(oh)@xmath1cl@xmath2 @xcite .
the local density approximation ( lda ) yields a metallic solution ( left panel in figure [ dos ] ) in contrast to the experimentally observed insulating behaviour due to....
And you have already written the first three sentences of the full article: 10 url # 1#1urlprefix[2][]#2 lhuillier c , sindzingre p and fouet j b 2001 _ can .
j. phys . _ * 79 * 15251535 ; arxiv : cond - mat/0009336.
Please generate the next two sentences of the article | |
8,376 | Suppose that you have an abstract for a scientific paper: the magnetic ground - state properties of the periodic anderson model with a regular depletion of the correlated sites are analyzed within different theoretical approaches .
we consider the model on the one - dimensional chain and on the two - dimensional square lattice with hopping between nearest neighbors . at half - filling and with correlated impurities present at every second site ,
the depleted anderson lattice is the most simple system where the indirect magnetic coupling mediated by the conduction electrons is ferromagnetic .
we discuss the underlying electronic structure and the possible mechanisms that result in ferromagnetic long - range order . to this end
, different numerical and analytical concepts are applied to the depleted anderson and also to the related depleted kondo lattice and are contrasted with each other .
this includes numerical approaches , i.e. hartree - fock theory , density - matrix renormalization and dynamical mean - field theory , as well as analytical concepts , namely a variant of the lieb - mattis theorem and the concept of flat - band ferromagnetism , and finally perturbative approaches , i.e. the effective rkky exchange in the limit of weak and the `` inverse indirect magnetic exchange '' in the limit of strong coupling between the conduction band and the impurities . .
And you have already written the first three sentences of the full article: local magnetic moments resulting from partially filled localized orbitals can experience an indirect magnetic exchange coupling mediated via a system of conduction electrons .
the prime example is the ruderman - kittel - kasuya - yoshida ( rkky ) effective interaction @xcite which has an oscillatory dependence on the distance between the magnetic impurities .
@xcite in particular , the rkky mechanism in many cases explains the coupling of magnetic adatoms on non - magnetic metallic surfaces . due to the recent methodical advances in spin - resolved scanning tunneling microscopy techniques @xcite it is nowadays possible to map out the strength and the oscillatory distance dependence of the rkky interaction with atomic resolution ..
Please generate the next two sentences of the article | @xcite moreover , the possibility to manipulate the positions of individual magnetic atoms offers the exciting perspective to build artificial adatom magnetic nanostructures with tailored magnetic properties .
@xcite in view of possible future applications for magnetic data storage , ferromagnetically ordered nanostructures deserve particular attention . |
8,377 | Suppose that you have an abstract for a scientific paper: we observe the 1.2 mm continuum emission around the ob cluster forming region g10.6 - 0.4 , using the iram 30 m telescope mambo-2 bolometer array and the submillimeter array .
comparison of the spitzer 24 @xmath0 m and 8 @xmath0 m images with our 1.2 mm continuum maps reveals the ionization front of an hii region , the photon dominated layer , and several 5 pc scale filaments following the outer edge of the photon dominated layer .
the filaments , which are resolved in the mambo-2 observations , show regularly spaced parsec
scale molecular clumps , embedded with a cluster of submillimeter molecular cores as shown in the sma 0.87 mm observations . toward the center of the g10.6 - 0.4 region , the combined sma+iram 30 m continuum image reveals several , parsec scale protrusions .
they may continue down to within 0.1 pc of the geometric center of a dense 3 pc size structure , where a 200 m@xmath1 ob cluster resides .
the observed filaments may facilitate mass accretion onto the central cluster forming region in the presence of strong radiative and mechanical stellar feedbacks .
their filamentary geometry may also facilitate fragmentation .
we did not detect any significant polarized emission at 0.87 mm in the inner 1 pc region with the sma . .
And you have already written the first three sentences of the full article: accretion and clustering are the most fundamental aspects of ob star formation ( see garay & lizano 1999 , mckee & ostriker 2007 and zinnecker & yorke 2007 for reviews ) .
ob stars are observed to form in very special regions of molecular clouds massive molecular clumps , typically of parsec scale in size .
large mass and high density are needed for the accretion flow to feed the forming massive stars as well as the associated stellar cluster at a high enough rate ..
Please generate the next two sentences of the article | however , how the massive clumps form , whether the internal conditions of the massive clumps facilitate the accretion process , and how the massive clumps fragment into clusters , are still open questions . in the present work ,
we improve our understanding of these issues observationally , using the submillimeter array ( sma ; ho , moran , & lo 2004 ) and the iram 30 m telescope . |
8,378 | Suppose that you have an abstract for a scientific paper: in accretion - based models for sgr a * the x - ray , infrared , and millimeter emission arise in a hot , geometrically thick accretion flow close to the black hole .
the spectrum and size of the source depend on the black hole mass accretion rate @xmath0 . since gillessen et al .
have recently discovered a cloud moving toward sgr a * that will arrive in summer 2013 , @xmath0 may increase from its present value @xmath1 .
we therefore reconsider the `` best - bet '' accretion model of moscibrodzka et al . , which is based on a general relativistic mhd flow model and fully relativistic radiative transfer , for a range of @xmath0 .
we find that for modest increases in @xmath0 the characteristic ring of emission due to the photon orbit becomes brighter , more extended , and easier to detect by the planned event horizon telescope submm vlbi experiment . if @xmath2 this `` silhouette '' of the black hole will be hidden beneath the synchrotron photosphere at @xmath3ghz , and for @xmath4 the silhouette is hidden at @xmath5ghz .
we also find that for @xmath6 the near - horizon accretion flow becomes a persistent x - ray and mid - infrared source , and in the near - infrared sgr a * will acquire a persistent component that is brighter than currently observed flares . .
And you have already written the first three sentences of the full article: the recent discovery of a cloud moving towards the galactic center @xcite creates a potential opportunity for testing models of sgr a*. the @xmath7 cloud will interact strongly with gas near nominal pericenter at @xmath8 ( @xmath9 black hole mass ) , and may change the black hole accretion rate @xmath0 . since the structure of the cloud and the surrounding medium are uncertain , possible outcomes range from very small changes in the accretion rate over timescales of decades to rapid , large changes in the accretion rate .
the dynamical timescale at @xmath10 is @xmath11yr , and the viscous timescale @xmath12yr @xmath13 , assuming @xmath14 and @xmath15 , i.e. a hot , radiatively inefficient accretion flow .
after an initial transient phase while the flow circularizes accompanied by transient emission .
Please generate the next two sentences of the article | it is natural to think the flow will settle into a steady state .
the settling timescale could be as little as a few @xmath16 , and so the steady state may arrive as soon as mid-2014 . if the resulting flow can be modeled as a steady disk , the excess mass will drain away on the viscous timescale , i.e. the source will remain bright well into the 22nd century . |
8,379 | Suppose that you have an abstract for a scientific paper: we derive closed expressions for the nuclear breakup cross sections in the adiabatic limit using the austern - blair theory .
these expressions are appropriate for the breakup of weakly bound nuclei .
the concept of an exit doorway that mediates the coupling between the entrance channel and the breakup continuum is used .
we prove the validity of the scaling law that dictates that the nuclear breakup cross section scales linearly with the radius of the target .
we also compare our results for the nuclear breakup cross section of @xmath0be , @xmath1b on several targets with recent cdcc calculation .
the breakup of nuclei is a common occurance when the bombarding energy is high enough and/or the binding energies are sufficiently low . in the case of weakly bound nuclei the threshold for breakup is small and more so for bound unstable nuclei .
the mechanism of breakup is assumed to consist of elongating the projectile , through the action of the interaction , which eventually leads to the production of two or more fragments .
this interaction is composed of a short range , nuclear piece and a longer ranged electromagnetic one .
a debate has been going on in the literature concerning the way the nuclear part of the breakup cross section depends on the mass of the target nucleus which supplies the interaction . in most references @xcite , it is assumed that the dependence goes as the cubic root of the mass number . in reference
@xcite , however , it is claimed that this dependence is more like linear ! in a recent paper @xcite , through a careful continuum discretized coupled channels ( cdcc ) calculation , the former dependence ( a@xmath2 ) has been established , which corroborates the contention that the nuclear breakup cross section should follow the prediction of the serber model @xcite .
it is interesting to compare the numerical cdcc calculation alluded to above with those of simpler analytical models .
specifically , the ausern - blair adiabatic theory for inelastic scattering....
And you have already written the first three sentences of the full article: this work is supported in part by fundao de amparo pesquisa do estado de so paulo ( fapesp ) and the conselho nacional de desenvolvimento cientfico e tecnolgico ( cnpq ) .
m.s.h is the martin gutzwiller fellow , 2007/2008 ..
Please generate the next two sentences of the article | |
8,380 | Suppose that you have an abstract for a scientific paper: the double perovskite ba@xmath0naoso@xmath1 ( bnoo ) , an exotic example of a very high oxidation state ( heptavalent ) osmium @xmath2 compound and also uncommon by being a ferromagnetic mott insulator without jahn - teller ( jt ) distortion , is modeled using the density functional theory ( dft ) hybrid functional based exact exchange for correlated electrons ( oeehyb ) method and including spin - orbit coupling ( soc ) .
the experimentally observed narrow gap ferromagnetic insulating ground state is obtained , with easy axis along [ 110 ] in accord with experiment , providing support that this approach provides a realistic method for studying this system . the predicted spin density for [ 110 ] spin orientation is nearly cubic ( unlike for other directions ) , providing an explanation for the absence of jt distortion . an orbital moment of -0.4@xmath3 strongly compensates the + 0.5@xmath3 spin moment on os , leaving a strongly compensated moment more in line with experiment .
remarkably , the net moment lies primarily on the oxygen ions .
an insulator - metal transition by rotating the magnetization direction with an external field under moderate pressure is predicted as one consequence of strong soc , and metallization under moderate pressure is predicted .
comparison is made with the isostructural , isovalent insulator ba@xmath4lioso@xmath5 which however orders antiferromagnetically . .
And you have already written the first three sentences of the full article: over the last three decades the orbital physics of @xmath6 systems and its interplay with spin has focused primarily on transition metal oxides , especially 3@xmath7 transition metals ( tms ) .
while the magnetic @xmath6 configuration has been studied mostly in @xmath8 systems , it can also occur in mid- to late-5@xmath7 tm ionic systems .
for these heavy ions spin - orbit coupling ( soc ) becomes a competing factor , mixing the various spin , orbital , charge , and lattice degrees of freedom ..
Please generate the next two sentences of the article | the interplay of strong electron correlation and large soc is relatively less explored , and certainly not well understood at all , because the behavior involves so many comparable energy scales .
this situation arises in a broad family of magnetic mott insulating systems in which three - fold degenerate @xmath9 orbitals are partially filled.@xcite in such systems orbital degeneracy is protected only by cubic lattice symmetry , and typically the crystal field splitting is large enough that @xmath10 orbitals are out of the picture . in @xmath11 @xmath9 |
8,381 | Suppose that you have an abstract for a scientific paper: the carriers of diffuse interstellar bands are still mysterious species . there exist many arguments that diffuse bands at 5797 and 5850 angstroms have the same carrier . using high - resolution spectra of few dozens of reddened stars
we have searched mutual correlation between intensities of considered bands .
results of our analysis indicate that 5797 and 5850 really tend to have the same carrier .
# 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: diffuse interstellar bands ( dibs ) are mysterious absorption structures of interstellar origin observed in spectra of reddened stars of early spectral types .
the detection of the first two dibs was described by heger in 1922 .
these structures , as we know them today , are scattered within the whole region of visible light and in the near infrared ( see e.g. herbig 1995 ) ..
Please generate the next two sentences of the article | individual dibs differ between themselves in intensity , line width and profile shapes .
there are many arguments that 5797 and 5850 dibs have the same carrier . almost all procedures isolating dibs families indicate that 5797 and 5850 bands tend to belong to the same family ( e.g. chlewicki et al . 1986 , |
8,382 | Suppose that you have an abstract for a scientific paper: we present ubvri photometry for the young open cluster ngc 2362 . from analysis of the appropriate color - color and color - magnitude diagrams we derive the fundamental parameters of the ngc 2362 cluster to be : age @xmath0 5@xmath1 myr , distance @xmath0 1480 pc , @xmath2 0.10 mag .
the cluster age was independently determined for both high mass ( @xmath3m@xmath4 ) and low mass ( @xmath5m@xmath4 ) stars with excellent agreement between the ages derived using post - main sequence @xcite and pre - main sequence @xcite evolutionary tracks for the high and low mass stars respectively .
analysis of this cluster s color - magnitude diagram reveals a well defined pre - main sequence ( covering @xmath6 v @xmath7 9 magnitudes in @xmath8 and extending from early a stars to near the hydrogen burning limit ) which makes this cluster an ideal laboratory for pre - main sequence evolution studies . .
And you have already written the first three sentences of the full article: the evolution of pre - main - sequence ( pms ) stars young contracting stars on their way to the main sequence is poorly understood although significant progress have been made in recent years ( see * ? ? ?
* ; * ? ? ?
* for reviews ) ..
Please generate the next two sentences of the article | observationally , these stars are also among the hardest to study because they are usually heavily extincted by their parental molecular cloud and are often seen in projection against bright hii regions
. the ideal laboratory of pre - main - sequence stellar evolution would then be the youngest possible galactic cluster free from dust extinction and nebula contamination , at a distance that permits detection of low - mass members to at least the hydrogen burning limit . |
8,383 | Suppose that you have an abstract for a scientific paper: this paper determines the range of feasible values of standard error exponents for binary - input memoryless symmetric channels of fixed capacity @xmath0 and shows that extremes are attained by the binary symmetric and the binary erasure channel .
the proof technique also provides analogous extremes for other quantities related to gallager s @xmath1 function , such as the cutoff rate , the bhattacharyya parameter , and the channel dispersion . .
And you have already written the first three sentences of the full article: in the context of coded communication , the channel coding theorem relates the error probability and the code rate , showing that there exist codes whose error probability tends to zero provided that the code rate is smaller than the channel capacity . for uncoded systems , the error probability and the channel capacity
are also related . in particular , references @xcite show that given one of the two values , tight bounds on the other can be given for the family of binary - input memoryless and symmetric ( bims ) channels .
such channels are described by the channel transition probability @xmath2 , where @xmath3 and @xmath4 ..
Please generate the next two sentences of the article | we assume that the channel output alphabet @xmath5 has finite size , though our approach also holds for well - behaved channels with infinite alphabet size , like the binary - input additive white gaussian noise ( biawgn ) channel .
we adopt gallager s definition of symmetric channel @xcite , that is , a channel is said symmetric if the channel transition probability matrix ( rows corresponding to input values ) is such that it can be partitioned in submatrices for which each row is a permutation of any other row and each column is a permutation of any other column . |
8,384 | Suppose that you have an abstract for a scientific paper: we theoretically investigate the membrane fluctuations of red blood cells with focus laid on the role of the cytoskeleton , viewing the system as a membrane coupled to sparse spring network .
this model is exactly solvable and enables us to examine the coupling strength dependence of the membrane undulation .
we find that the coupling modifies the fluctuation spectrum at wavelengths longer than the mesh size of the network , while leaving the fluid - like behavior of the membrane intact at shorter wavelengths .
the fluctuation spectra can be markedly different , depending on not only the relative amplitude of the bilayer bending energy with respect to the cytoskeleton deformation energy but also the bilayer - cytoskelton coupling strength . .
And you have already written the first three sentences of the full article: a red blood cell ( rbc ) has been a standard test bed of membrane physics due to its simple structure lacking a nucleus and organelles .
early studies , treating a rbc as a lipid bilayer bag , already rendered insightful understanding of various properties , to name a few , biconcave shapes@xcite , flickering phenomenon @xcite , and tank - treading motion @xcite .
still there are certain features signifying the role of other substructure ; a spectrin network ( cytoskeleton ) coupled to the bilayer is found to be responsible for the shape transformation sequence @xcite , large - scale shape changes under shear flow @xcite , and crenated shapes @xcite ..
Please generate the next two sentences of the article | many attempts have been made in order to provide simplified descriptions of the cytokeleton as for its effects on non - trivial shapes and fluctuation of rbcs @xcite . meanwhile , theoretical works @xcite analyzed the fluctuation spectrum measured by zilker _
et al . _ |
8,385 | Suppose that you have an abstract for a scientific paper: the production of heavy quarks at large @xmath0 ( @xmath1 ) in hadronic collisions is considered .
the analysis is carried out in the framework of perturbative fragmentation functions , thereby allowing a resummation at the nlo level of final state large mass logarithms of the kind @xmath2 .
the case of @xmath3-quark production is considered in detail .
the resulting theoretical uncertainty from factorization / renormalization scales at large @xmath0 is found to be much smaller than that shown by the full @xmath4 perturbative calculation .
[ cols= " < " , ] large @xmath5 hadroproduction + of heavy quarks + + + ' '' '' e - mail addresses : = [email protected] + [email protected] .
And you have already written the first three sentences of the full article: much of the theoretical and experimental interest has been recently devoted to the study of the production of heavy quarks in hadronic collisions . on the theoretical side the calculation in perturbative qcd of the differential and total cross sections to order
@xmath6 has been performed by two groups @xcite , providing a firm basis for a detailed study of the properties of the bottom and charm quarks , and leading to reliable predictions for the production rate of the top quark @xcite .
these results do however present a non - negligible residual renormalization / factorization scale dependence , particularly at large @xmath0 ..
Please generate the next two sentences of the article | furthermore , the validity of this next - to - leading ( nlo ) @xmath4 calculation is limited when @xmath7 , @xmath8 being the large quark mass , by the appearance of potentially large logarithms of the type @xmath2 , which have to be resummed to all orders .
the physical reason for that is quite clear . |
8,386 | Suppose that you have an abstract for a scientific paper: spectral features can arise by reflection of coronal x - rays on a black hole accretion disc .
the resulting profile bears various imprints of strong gravitational field acting on the light emitting gas .
the observed shape of the reflection line is formed by integrating contributions over a range of radii across the accretion disc plane , where the individual photons experience different level of energy shifts , boosting , and amplification by relativistic effects .
these have to be convolved with the intrinsic emissivity of the line , which is a function of radius and the emission angle in the local frame .
we study if the currently discussed instruments on - board x - ray satellites will be able to reveal the departure of the line radial emissivity from a simple smooth power - law function , which is often assumed in data fitting and interpretation .
such a departure can be a result of excess emission occurring at a certain distance .
this could be used to study variations with radius of the line production or to constrain the position of the inner edge of the accretion disc . by simulating artificial data from a bright active galactic nucleus of a type-1 seyfert galaxy ( inclination @xmath0 deg , x - ray flux @xmath12 mcrab in kev energy band )
we show that the required sensitivity and energy resolution could be reached with large area detector of the proposed loft mission .
galactic black holes will provide another category of potentially suitable targets if the relativistic spectral features are indeed produced by reflection from their accretion discs .
[ firstpage ] black hole physics accretion , accretion disks galaxies : nuclei .
And you have already written the first three sentences of the full article: various pieces of evidence support the idea that the x - ray emission from active galactic nuclei ( agn ; see * ? ? ?
* ; * ? ? ?
* ) and stellar - mass black - holes @xcite originates from an accretion disc and the surrounding corona ..
Please generate the next two sentences of the article | these are thought to be situated near a central black hole , no more than a few tens gravitational radii from the event horizon , giving rise to the relativistic effects in 67 kev iron line complex and the underlying continuum .
the standard scheme of accretion discs @xcite captures the main properties of accreting black holes surprisingly well , nevertheless , the model omits some important aspects . |
8,387 | Suppose that you have an abstract for a scientific paper: transiting planet discoveries have yielded a plethora of information towards understanding the structure and atmospheres of extra - solar planets .
these discoveries have been restricted to the short - period or low - periastron distance regimes due to the bias inherent in the geometric transit probability . through the refinement of planetary orbital parameters , and hence reducing the size of transit windows , long - period planets become feasible targets for photometric follow - up . here
we describe the terms project which is monitoring these host stars at predicted transit times . .
And you have already written the first three sentences of the full article: monitoring known radial velocity planets at predicted transit times presents an avenue through which to explore the mass - radius relationship of exoplanets into regions of period / periastron space beyond that which is currently encompassed @xcite .
this is particularly true for those planets in relatively eccentric orbits @xcite , as demonstrated by the the variation in transit probability with the argument of periastron ( see figure 1 , left panel ) . here
we describe techniques for refining ephemerides and performing follow - up observations @xcite ..
Please generate the next two sentences of the article | these methods are being employed by the transit ephemeris refinement and monitoring survey ( terms ) .
the transit window as described here is defined as a specific time period during which a complete transit ( including ingress and egress ) could occur for a specified planet . |
8,388 | Suppose that you have an abstract for a scientific paper: consider the fulton - macpherson configuration space of @xmath0 points on @xmath1 , which is isomorphic to a certain moduli space of stable maps to @xmath1 .
we compute the cone of effective @xmath2-invariant divisors on this space .
this yields a geometric interpretation of known asymptotic formulas for the number of integral points of bounded height on compactifications of @xmath3 in the space of binary forms of degree @xmath4 . .
And you have already written the first three sentences of the full article: in this paper , we compute the @xmath2-invariant cone of effective divisors of the fulton - macpherson configuration space of @xmath0 points on @xmath1 .
this space is isomorphic to the moduli space @xmath5 of stable maps of degree one from genus zero curves with @xmath0 marked points to @xmath1 .
we also compute the effective cone of the generic fiber of the natural map @xmath6 our motivation is to provide a geometric explanation of a formula , obtained by duke , rudnick and sarnak , giving the asymptotic behavior of the number of binary forms of degree @xmath0 with fixed discriminant and bounded integral coefficients ..
Please generate the next two sentences of the article | this fits into a larger program to predict and prove asymptotic formulas for the number of rational and integral points of bounded height on algebraic varieties .
we introduce a counting function for integral points on an algebraic variety as follows : given a variety @xmath7 over a ring of integers @xmath8 and functions @xmath9 , regular on @xmath7 , define @xmath10 where @xmath11 is a valuation on @xmath8 . |
8,389 | Suppose that you have an abstract for a scientific paper: one strategy for winning a coevolutionary struggle is to evolve rapidly .
most of the literature on host - pathogen coevolution focuses on this phenomenon , and looks for consequent evidence of coevolutionary arms races .
an alternative strategy , less often considered in the literature , is to deter rapid evolutionary change by the opponent . to study how this can be done ,
we construct an evolutionary game between a controller that must process information , and an adversary that can tamper with this information processing . in this game ,
a species can foil its antagonist by processing information in a way that is hard for the antagonist to manipulate .
we show that the structure of the information processing system induces a fitness landscape on which the adversary population evolves .
complex processing logic can carve long , deep fitness valleys that slow adaptive evolution in the adversary population .
we suggest that this type of defensive complexity on the part of the vertebrate adaptive immune system may be an important element of coevolutionary dynamics between pathogens and their vertebrate hosts .
furthermore , we cite evidence that the immune control logic is phylogenetically conserved in mammalian lineages .
thus our model of defensive complexity suggests a new hypothesis for the lower rates of evolution for immune control logic compared to other immune structures . .
And you have already written the first three sentences of the full article: coevolution is often antagonistic , such that one species benefits from the other s loss .
classic examples include predators and their prey , and pathogens and their hosts .
antagonistic coevolution is commonly thought to result in rapid co - evolutionary arms races @xcite ..
Please generate the next two sentences of the article | when participants in a coevolutionary arms race can tamper with their opponents control systems , as microbial pathogens do with host immune regulation @xcite , we might expect to see a series of subversion efforts and subsequent countermeasures deployed over evolutionary time
. thus one might expect rapid evolutionary divergence of the systems involved in controlling and regulating the attacks and defenses used in antagonistic interactions @xcite . |
8,390 | Suppose that you have an abstract for a scientific paper: this talk provides a progress report on an extended collaboration which has aimed to address two basic questions , namely : should one expect to see cuspy , triaxial galaxies in nature ? and can one construct realistic cuspy , triaxial equilibrium models that are robust ?
three technical results are described : ( 1 ) unperturbed chaotic orbits in cuspy triaxial potentials can be extraordinarily sticky , much more so than orbits in many other three - dimensional potentials .
( 2 ) even very weak perturbations can be important by drastically reducing , albeit not completely eliminating , this stickiness .
( 3 ) a simple toy model facilitates a simple understanding of why black holes and cusps can serve as an effective source of chaos .
these results suggest that , when constructing models of galaxies using schwarzschild s method or any analogue thereof , astronomers would be well advised to use orbital building blocks that have been perturbed by ` noise ' or other weak irregularities , since such building blocks are likely to be more nearly time - independent than orbits evolved in the absence of all perturbations .
a contributed talk at:_the international conference on stellar dynamics : from _ .2 in _ from classical to modern _ , sobolev astronomical institute , august 2000 .2 in .
And you have already written the first three sentences of the full article: the results reported here derive from a numerical analysis of orbits in the triaxial dehnen potentials , where ( _ cf . _
merritt & fridman 1996 ) @xmath0 with @xmath1 assuming fixed axis ratios @xmath2 and @xmath3 but allowing for a variable cusp index @xmath4 and a variable black hole mass @xmath5 .
different segments of the same chaotic orbit can be extremely different in terms of their visual appearance and their degree of exponential sensitivity ( siopis & kandrup 2000 ) ..
Please generate the next two sentences of the article | these differences can be quantified in terms of the sizes of short time lyapunov exponents ( _ cf .
_ kandrup & mahon 1994 ) or the _ complexity _ of their fourier spectra , _ |
8,391 | Suppose that you have an abstract for a scientific paper: are microlensing searches likely to discover planets that harbor life ? given our present state of knowledge , this is a difficult question to answer .
we therefore begin by asking a more narrowly focused question : are conditions on planets discovered via microlensing likely to be similar to those we experience on earth ? in this paper
i link the microlensing observations to the well - known goldilocks problem " ( conditions on the earth - like planets need to be _ just right " _ ) , to find that earth - like planets discovered via microlensing are likely to be orbiting stars more luminous than the sun .
this means that light from the ps .
s central star may contribute a significant fraction of the baseline flux relative to the star that is lensed .
such blending of light from the lens with light from the lensed source can , in principle , limit our ability to detect these events .
this turns out not to be a significant problem , however .
a second consequence of blending is the opportunity to determine the spectral type of the lensed star .
this circumstance , plus the possibility that finite - source - size effects are important , implies that some meaningful follow - up observations are likely to be possible for a subset earth - like planets discovered via microlensing .
in addition , calculations indicate that reasonable requirements on the planet s density and surface gravity imply that the mass of earth - like planets is likely to be within a factor of @xmath0 of an earth mass
. _ earth - mass _ # 1#2#3#4 # 1#2 -.4 true in -.2 true in .
And you have already written the first three sentences of the full article: recent and ongoing advances in technology have led to the discovery of extrasolar planets ( e.g. , mayor & queloz 1995 , marcy _ et el .
_ 1997a , b , butler & marcy 1996 , marcy & butler 1996 , cochran _ et al .
_ 1997 , noyes _.
Please generate the next two sentences of the article | _ 1997 ; see also the references listed in the encyclopedia of extrasolar planets , www.obspm.fr/darc/planets/encycl.html ) , and promise the discovery and even the imaging of additional planets ( angel & woolf 1997 ; fraclas & shelton 1997 ; labeyrie 1996 ; brown 1996 ) .
these developments excite the imagination because they seem to bring us closer to the possible discovery of extraterrestrial life . |
8,392 | Suppose that you have an abstract for a scientific paper: the most popular models for the complex phase and time lags in the rapid aperiodic variability of galactic x - ray binaries are based comptonization of soft seed photons in a hot corona , where small - scale flares are induced by flares of the soft seed photon input ( presumably from a cold accretion disc ) .
however , in their original version , these models have neglected the additional cooling of the coronal plasma due to the increased soft seed photon input , and assumed a static coronal temperature structure . in this paper ,
our monte - carlo / fokker - planck code for time - dependent radiation transfer and electron energetics is used to simulate the self - consistent coronal response to the various flaring scenarios that have been suggested to explain phase and time lags observed in some galactic x - ray binaries .
it is found that the predictions of models involving slab - coronal geometries are drastically different from those deduced under the assumption of a static corona . however , with the inclusion of coronal cooling they may even be more successful than in their original version in explaining some of the observed phase and time lag features .
the predictions of the model of inward - drifting density perturbations in an adaf - like , two - temperature flow also differ from the static - corona case previously investigated , but may be consistent with the alternating phase lags seen in grs 1915 + 105 and xte j1550 - 564 .
models based on flares of a cool disc around a hot , inner two - temperature flow may be ruled out for most objects where significant fourier - frequency - dependent phase and time lags have been observed .
accepted for publication in _ the astrophysical journal _ , vol .
553 ( june 1 , 2001 ) .
And you have already written the first three sentences of the full article: the x - ray emission from galactic x - ray binaries is known to exhibit aperiodic variability on a vast variety of time scales , from months down to milliseconds ( for reviews see , e.g. @xcite ) .
the pca on board the _ rossi x - ray timing explorer _ ( rxte ) , has accumulated a large amount of data on the rapid aperiodic variability ( rav ) and its photon - energy dependence for a large number of x - ray binaries .
this information contains valuable hints about the source of high - energy emission in these objects ..
Please generate the next two sentences of the article | since it is generally believed that the x - ray emission above @xmath0 10 kev is due to comptonization of soft photons in a hot , tenuous coronal gas , it is natural to assume that the rav of this emission component also reveals detailed information about the size scales , dominant physical ( heating and cooling ) mechanisms , and geometry of the comptonizing region .
theoretical calculations of the expected time - dependent signatures of comptonization in a hot , tenuous , static corona had been done for the case of a homogeneous corona ( @xcite ) and for inhomogeneous temperature and density distributions in the corona ( kazanas , hua & titarchuk 1997 , hua , kazanas & titarchuk 1997 ) for the case of central injection of soft photons into a spherical region . |
8,393 | Suppose that you have an abstract for a scientific paper: in this paper we study the asymptotics ( as @xmath0 ) of the sequences of laguerre polynomials with varying complex parameters @xmath1 depending on the degree @xmath2 .
more precisely , we assume that @xmath3 and @xmath4 .
this study has been carried out previously only for @xmath5 , but complex values of @xmath6 introduce an asymmetry that makes the problem more difficult .
the main ingredient of the asymptotic analysis is the right choice of the contour of orthogonality , which requires the analysis of the global structure of trajectories of an associated quadratic differential on the complex plane , which may have an independent interest .
while the weak asymptotics is obtained by reduction to the theorem of gonchar rakhmanov stahl , the strong asymptotic results are derived via the non - commutative steepest descent analysis based on the riemann - hilbert characterization of the laguerre polynomials .
trajectories and orthogonal trajectories of a quadratic differential , riemann - hilbert problems , generalized laguerre polynomials , strong and weak asymptotics , logarithmic potential , equilibrium . .
And you have already written the first three sentences of the full article: one of the motivations of this paper is the asymptotic analysis of the generalized laguerre polynomials , denoted by @xmath7 , with complex varying parameters , whose definition and properties can be found for instance in chapter v of szeg s classic memoir @xcite .
they can be given explicitly by @xmath8 or , equivalently , by the well - known rodrigues formula @xmath9\,.\ ] ] expressions and make sense for complex values of the parameter @xmath1 , showing that @xmath7 depend analytically on @xmath1 .
when indeterminacy occurs in evaluating the coefficients in , we understand them in the sense of their analytic continuation with respect to @xmath1 . with this convention.
Please generate the next two sentences of the article | we see that @xmath10 so that @xmath11 for all @xmath12 .
moreover , for any @xmath12 , @xmath7 is the unique ( up to a multiplicative constant ) polynomial solution of the differential equation @xmath13 which shows that every zero of @xmath7 different from @xmath14 must be simple . |
8,394 | Suppose that you have an abstract for a scientific paper: lidov - kozai oscillations of planets in stellar binaries , combined with tidal dissipation , can lead to the formation of hot jupiters ( hjs ) or tidal disruption of planets .
recent population synthesis studies have found that the fraction of systems resulting in hjs ( @xmath0 ) depends strongly on the planet mass , host stellar type and tidal dissipation strength , while the total migration fraction @xmath1 ( including both hj formation and tidal disruption ) exhibits much weaker dependence .
we present an analytical method for calculating @xmath0 and @xmath2 in the lidov - kozai migration scenario .
the key ingredient of our method is to determine the critical initial planet - binary inclination angle that drives the planet to reach sufficiently large eccentricity for efficient tidal dissipation or disruption .
this calculation includes the effects of octupole potential and short - range forces on the planet .
our analytical method reproduces the resulting planet migration / disruption fractions from population synthesis , and can be easily implemented for various planet , stellar / companion types , and for different distributions of initial planetary semi - major axes , binary separations and eccentricities .
we extend our calculations to planets in the super - earth mass range and discuss the conditions for such planets to survive lidov - kozai migration and form close - in rocky planets .
[ firstpage ] binaries : general planets : dynamical evolution and stability star : planetary system .
And you have already written the first three sentences of the full article: the occurrence of hot jupiters " ( hjs ) gas giants with periods @xmath3 days is estimated to be around @xmath4 for fgk stars @xcite .
it is commonly believed that these planets formed at larger separations from their host stars ( presumably beyond the ice line ) and subsequently migrated " to semi - major axes of less than @xmath5 au .
the known migration mechanisms can be ( i ) disc mediated " due to planet - disc interaction ( e.g. , * ? ? ?.
Please generate the next two sentences of the article | * ; * ? ? ?
* ) , ( ii ) planet mediated " , including strong planet - planet scatterings and various forms of secular interactions among multiple planets ( e.g. * ? ? ? |
8,395 | Suppose that you have an abstract for a scientific paper: we report and interpret _ hst_/space telescope imaging spectrograph ( stis ) long - slit observations of the optical and ultraviolet ( uv ) ( @xmath0 ) emission - line spectra of the rapidly brightening spot 1 on the equatorial ring of sn 1987a between 1997 september and 1999 october ( days 3869 4606 after outburst ) .
the emission is caused by radiative shocks created where the supernova blast wave strikes dense gas protruding inward from the equatorial ring .
we measure and tabulate line identifications , fluxes and , in some cases , line widths and shifts .
we compute flux correction factors to account for substantial interstellar line absorption of several emission lines .
nebular analysis shows that optical emission lines come from a region of cool ( @xmath1 ) and dense ( @xmath2 ) gas in the compressed photoionized layer behind the radiative shock .
the observed line widths indicate that only shocks with shock velocities @xmath3 have become radiative , while line ratios indicate that much of the emission must have come from yet slower ( @xmath4 ) shocks .
such slow shocks can be present only if the protrusion has atomic density @xmath5 , somewhat higher than that of the circumstellar ring .
we are able to fit the uv fluxes with an idealized radiative shock model consisting of two shocks ( @xmath6 and @xmath7 ) .
the observed uv flux increase with time can be explained by the increase in shock surface areas as the blast wave overtakes more of the protrusion
. the observed flux ratios of optical to highly - ionized uv lines are greater by a factor of @xmath8 than predictions from the radiative shock models and we discuss the possible causes
. we also present models for the observed @xmath9 line widths and profiles , which suggests that a chaotic flow exists in the photoionized regions of these shocks .
we discuss what can be learned with future observations of all the spots present on the equatorial ring . .
And you have already written the first three sentences of the full article: supernova 1987a ( sn 1987a ) in the large magellanic cloud provides an unprecedented opportunity to observe the birth and development of a supernova remnant . _ international ultraviolet explorer _ ( _ iue _ ) observations @xcite found narrow line emission about 80 days after the explosion , demonstrating the presence of circumstellar gas around sn 1987a . images taken with the _ hubble space telescope _ ( _ hst _ ) showed that this gas consists of an equatorial inner ring ( radius @xmath10 light year , @xmath11 ) and two outer rings ( @xmath12 times the size of the inner ring , @xmath13 ) tilted towards the observer at @xmath14 @xcite .
the circumstellar ring system was excited by the ionizing radiation from the supernova during the shock breakout @xcite . in the interacting winds model ,
the sn 1987a ring system is part of a bipolar shell around the supernova @xcite . the first signal of ongoing interaction between the sn 1987a debris and the circumstellar gas was the rebirth of the supernova in x - ray ( beuermann , brandt , & pietsch 1994 ; gorenstein , hughes , & tucker 1994 ; hasinger , aschenbach , & trmper 1996 ) and radio @xcite wavelengths around day 1000 ..
Please generate the next two sentences of the article | the size of the radio - emitting region indicated that the supernova debris expanded unimpeded at velocity @xmath15 up to @xmath16 day 1000 before slowing down to @xmath17 by the interaction @xcite . the x - ray and radio observations
have been explained as the interaction of the supernova ejecta with a rather dense ( @xmath18 ) region that separates the shocked stellar wind of the supernova progenitor from the denser gas of the inner ring @xcite . |
8,396 | Suppose that you have an abstract for a scientific paper: ngc6369 is a double - shell planetary nebula ( pn ) consisting of a bright annular inner shell with faint bipolar extensions and a filamentary envelope .
we have used ground- and space - based narrow - band optical and near - ir images , broad - band mid - ir images , optical long - slit echelle spectra , and mid - ir spectra to investigate its physical structure .
these observations indicate that the inner shell of ngc6369 can be described as a barrel - like structure shape with polar bubble - like protrusions , and reveal evidence for h@xmath0 and strong polycyclic aromatic hydrocarbons ( pahs ) emission from a photo - dissociative region ( pdr ) with molecular inclusions located outside the bright inner shell .
high - resolution _ hst _ narrow - band images reveal an intricate excitation structure of the inner shell and a system of `` cometary '' knots .
the knotty appearance of the envelope , the lack of kinematical evidence for shell expansion and the apparent presence of emission from ionized material outside the pdr makes us suggest that the envelope of ngc6369 is not a real shell , but a flattened structure at its equatorial regions .
we report the discovery of irregular knots and blobs of diffuse emission in low - excitation and molecular line emission that are located up to 80 from the central star , well outside the main nebular shells .
we also show that the filaments associated to the polar protrusions have spatial extents consistent with post - shock cooling regimes , and likely represent regions of interaction of these structures with surrounding material .
[ firstpage ] ( ism : ) planetary nebulae : individual : ngc 6369 ism : jets and outflows infrared : ism ism : lines and bands .
And you have already written the first three sentences of the full article: the planetary nebula ( pn ) ngc6369 possesses a double - shell morphology consisting of a round bright inner shell and a fainter filamentary outer shell or envelope @xcite .
its most remarkable morphological features are two disparate extensions of the inner shell along the east and west directions ; the latter appears as a large , filamentary blister or _ ansae _ , whilst the former is a bifurcated structure . using low - dispersion spectroscopy , @xcite modelled the peculiar morphology of ngc6369 as a tilted collar of gas and two symmetrically located caps of emission .
this interpretation is consistent with the spheroidal shell and faint bipolar extensions proposed by @xcite based on a single long - slit high - dispersion spectrum obtained along the nebular major axis ..
Please generate the next two sentences of the article | these simplified models do not deal with the bifurcated structure to the eastern side of the inner shell , nor they consider the filamentary appearance of the envelope .
these have been proposed to represent fast low ionisation emission regions ( fliers , * ? ? ? |
8,397 | Suppose that you have an abstract for a scientific paper: @xcite asserted that statistical tests disprove the standard view of lbvs , and proposed a far more complex scenario to replace it . but @xcite showed that smith and tombleson s magellanic `` lbv '' sample was a mixture of physically different classes of stars , and genuine lbvs are in fact statistically consistent with the standard view .
@xcite recently objected at great length to this result . here
we note that he misrepresented some of the arguments , altered the test criteria , ignored some long - recognized observational facts , and employed inadequate statistical procedures .
this case illustrates the dangers of uncareful statistical sampling , as well as the need to be wary of unstated assumptions . .
And you have already written the first three sentences of the full article: @xcite proposed an unorthodox explanation for luminous blue variable stars ( lbvs / s dor variables ) . in their scenario
all lbvs have gained mass from companion stars , with various consequences .
far more complex than the standard view , this idea was motivated by a statistical allegation that lbvs tend to be spatially `` isolated '' from young objects such as o - type stars . according to smith and tombleson.
Please generate the next two sentences of the article | , each pre - lbv star has an extended lifetime due to the mass that it has gained , and an extra velocity due to the `` kick '' ( i.e. , recoil ) when its companion becomes a supernova .
these two effects are said to explain the alleged isolation . |
8,398 | Suppose that you have an abstract for a scientific paper: a recent example of a non - hyponormal injective composition operator in an @xmath0-space generating stieltjes moment sequences , invented by three of the present authors , was built over a non - locally finite directed tree .
the main goal of this paper is to solve the problem of whether there exists such an operator over a locally finite directed graph and , in the affirmative case , to find the simplest possible graph with these properties ( simplicity refers to local valency ) .
the problem is solved affirmatively for the locally finite directed graph @xmath1 , which consists of two branches and one loop .
the only simpler directed graph for which the problem remains unsolved consists of one branch and one loop .
the consistency condition , the only efficient tool for verifying subnormality of unbounded composition operators , is intensively studied in the context of @xmath1 , which leads to a constructive method of solving the problem .
the method itself is partly based on transforming the krein and the friedrichs measures coming either from shifted al - salam - carlitz or from a quartic birth and death process . .
And you have already written the first three sentences of the full article: the theory of bounded subnormal operators was initiated by halmos ( cf .
@xcite ) . the definition and the first characterization of their unbounded counterparts were given independently by bishop ( cf.@xcite ) and foia ( cf .
the foundations of the theory of unbounded ( i.e. , not necessarily bounded ) subnormal operators were developed by the fourth - named author and szafraniec ( cf ..
Please generate the next two sentences of the article | the study of this topic turned out to be highly successful .
it led to a number of challenging problems and nontrivial results in various branches of mathematics including functional analysis and mathematical physics ( see , e.g. , @xcite for the case of bounded operators and @xcite for unbounded ones ) . |
8,399 | Suppose that you have an abstract for a scientific paper: for @xmath0 and @xmath1 let @xmath2}^d \to { \mathbb{z}\left[\mathrm{i}\right]}^d$ ] , where @xmath3 @xmath4 for @xmath5 , denote the _ ( d - dimensional ) gaussian shift radix system associated with @xmath6_. @xmath7 is said to have the _
finiteness property _
iff all orbits of @xmath7 end up in @xmath8 ; the set of all corresponding @xmath1 is denoted by @xmath9 .
it has a very complicated structure even for @xmath10 . in the present paper a conjecture on the full characterization of @xmath11 - which is known as peth s loudspeaker - is formulated and proven in substantial parts .
it is shown that @xmath11 is contained in a conjectured characterizing set @xmath12 .
the other inclusion is settled algorithmically for large regions leaving only small areas of uncertainty .
furthermore the circumference and area of the loudspeaker are computed under the assumption that the conjecture holds .
the proven parts of the conjecture also allow to fully identify all so - called critical and weakly critical points of @xmath11 . .
And you have already written the first three sentences of the full article: in 2005 akiyama _ et al . _
@xcite introduced so - called _ shift radix systems _ ( cf . also @xcite ) . for a natural number @xmath13 and a real vector @xmath14 the mapping @xmath15 defined by @xmath16
is called the _ d - dimensional shift radix system associated with @xmath6 _ ( _ srs _ ) and @xmath6 its _ parameter_. in @xcite the notion has been generalized to the complex setting . for a complex vector @xmath1 the analogously defined mapping @xmath2}^d \to { \mathbb{z}\left[\mathrm{i}\right]}^d$ ].
Please generate the next two sentences of the article | is called the _ d - dimensional gaussian shift radix system associated with @xmath6 _ ( _ gsrs _ ) ( note that @xmath17 and @xmath18 for @xmath19 ) . let ] @xmath20}^d : { \exists\:}(m , n ) \in { \mathbb{n}}^2 : m \neq n \land \gamma_{{\mathbf{r}}}^m({{\mathbf{a } } } ) = \gamma_{{\mathbf{r}}}^n({{\mathbf{a } } } ) \right\}}\\ { \mathcal{g}_{d}^{(0 ) } } & { \:\colonequals\:}{\left\ { { { \mathbf{r } } } \in { \mathbb{c}}^d \mid { \forall\:}{{\mathbf{a } } } \in { \mathbb{z}\left[\mathrm{i}\right]}^d : { \exists\:}n \in { \mathbb{n } } : \gamma_{{\mathbf{r}}}^n({{\mathbf{a } } } ) = { { \mathbf{0 } } } \right\}}\end{aligned}\ ] ] where for any @xmath21 , @xmath22 means the @xmath23-fold iterative application of @xmath7 to @xmath24 .
the gsrs @xmath7 is said from now on a real vector @xmath6 and its associated gsrs @xmath7 shall be identified in terms of properties . ] to have the _ |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.