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7,000 | Suppose that you have an abstract for a scientific paper: we investigate the evolution of mass density profiles in secular disk galaxy models , paying special attention to the development of a two - component profile from a single initial exponential disk free of cosmological evolution ( i.e. , no accretion or interactions ) . as the source of density profile variations , we examine the parameter space of the spin parameter , halo concentration , virial mass , disk mass and bulge mass , for a total of 162 simulations in the context of a plausible model of star formation and feedback .
the isolated galaxy models are based on the method of springel & white ( 1999 ) and were evolved using the n - body / sph code gadget-2 .
the initially pure exponential disks have a minimum of 1.4 million particles and most models were evolved over a period of 10 gyr .
we find that the slope of the outer density profile is in close agreement with that of the initial profile and remains stable over time , whereas the inner density profile slope evolves considerably as a result of angular momentum redistribution .
the evolution of the galaxy mass density profile , including the development of a two - component profile with an inner and outer segment , is controlled by the ratio of the disk mass fraction , @xmath0 , to the halo spin parameter , @xmath1 .
the location of the break between the two components and speed at which it develops is directly proportional to @xmath2 ; the amplitude of the transition between the inner and outer regions is however controlled by the ratio of halo concentration to virial velocity .
the location of the divide between the inner and outer profile does not change with time .
the condition for a two - component profile is roughly @xmath3 .
while the development of a two - component density profile is coupled to bar formation , not all barred galaxies develop a two - component profile .
a galaxy model showing a clear minimum toomre @xmath4 , normally linked to a double exponential in the stellar profile , may never exhibit any two -....
And you have already written the first three sentences of the full article: the evolution of galaxies is a complex process involving angular momentum redistribution , star formation , chemical evolution , feedback and numerous merging events . understanding how and why galaxies have the properties we observe is further complicated by the fact that observations are limited in a number of complicated ways , including dust obscuration and our inability to view a galaxy in all its projections .
one of the key observations of disk galaxy properties is the ubiquitous exponential surface brightness profile ( de vaucouleurs 1959 ; freeman 1970 ) .
freeman , and many others since , modeled galaxies as two component systems with : an inner spheroid where @xmath5 and an outer exponential disk component with @xmath6 ..
Please generate the next two sentences of the article | it is now believed that the inner galaxy components are best modeled by a srsic function , @xmath7 , with @xmath8 ( macarthur et al .
2003 ; pohlen & trujillo 2006 , hereafter pt06 ) . |
7,001 | Suppose that you have an abstract for a scientific paper: we present a conjecture on the exact location of the multicritical point in the phase diagram of spin glass models in finite dimensions . by generalizing our previous work ,
we combine duality and gauge symmetry for replicated random systems to derive formulas which make it possible to understand all the relevant available numerical results in a unified way .
the method applies to non - self - dual lattices as well as to self dual cases , in the former case of which we derive a relation for a pair of values of multicritical points for mutually dual lattices .
the examples include the @xmath0 and gaussian ising spin glasses on the square , hexagonal and triangular lattices , the potts and @xmath1 models with chiral randomness on these lattices , and the three - dimensional @xmath0 ising spin glass and the random plaquette gauge model . .
And you have already written the first three sentences of the full article: properties of finite - dimensional spin glasses are still under debate although the problem is essentially settled for the mean - field model @xcite .
outstanding problems for finite - dimensional spin glasses include the existence or absence of spin glass phase and whether or not the mean - field picture of the spin glass phase applies . another interesting , but less extensively studied , issue is the structure of the phase diagram , in particular where precisely the multicritical point is located and what the values are for the critical exponents characterizing the system behaviour at and away the multicritical point .
the present paper discusses this problem of the location of the multicritical point for finite - dimensional spin glass models by analytical methods ..
Please generate the next two sentences of the article | a number of numerical investigations on this problem exist for various lattices .
however , it has been quite difficult to derive analytical results for regular finite - dimensional lattices until a few years ago when we succeeded in devising a method to predict the exact locations of the multicritical points for the square lattice ising and potts models and four - dimensional random plaquette gauge model using duality , gauge symmetry and the replica method @xcite . in the present paper |
7,002 | Suppose that you have an abstract for a scientific paper: we report on the discovery of a new potential galaxy threshing system in the cosmos 2 square degree field using the prime - focus camera , suprime - cam , on the 8.2 m subaru telescope .
this system consists of a giant elliptical galaxy with @xmath0 and a tidally disrupted satellite galaxy with @xmath1 at a photometric redshift of @xmath2 .
this redshift is consistent with the spectroscopic redshift of 0.079 for the giant elliptical galaxy obtained from the sloan digital sky survey ( sdss ) archive .
the luminosity masses of the two galaxies are @xmath3 and @xmath4 , respectively .
the distance between the two galaxies is greater than 100 kpc .
the two tidal tails emanating from the satellite galaxy extend over 150 kpc .
this system would be the second well - defined galaxy threshing system found so far . .
And you have already written the first three sentences of the full article: hierarchical clustering scenarios suggest that present day galaxies assembled from much smaller building blocks during the course of their evolution ( e.g. , peebles 1993 ) .
recent deep surveys have found small dwarf galaxies ( i.e. , building blocks ) at @xmath5 ( e.g. , pascarelle , windhorst , & keel 1998 ; ellis et al . 2001 ; taniguchi et al .
2003a ; santos et al ..
Please generate the next two sentences of the article | 2004 ; kneib et al .
2004 ; for a review see taniguchi et al . |
7,003 | Suppose that you have an abstract for a scientific paper: motivated by the continuing interest in discrete time hidden markov models ( hmms ) , this paper reexamines these models using a risk - based approach . simple modifications of the classical optimization criteria for hidden path inference lead to a new class of hidden path estimators .
the estimators are efficiently computed in the usual forward - backward manner and a corresponding dynamic programming algorithm is also presented .
a particularly interesting subclass of such alignments are sandwiched between the most common _ maximum a posteriori _ ( map ) , or viterbi , path estimator and the minimum error , or _
pointwise maximum a posteriori _ ( pmap ) , estimator .
similar to previous work , the new class is parameterized by a small number of tunable parameters . unlike their previously proposed relatives , the new parameters and class are more explicit and have clear interpretations , and bypass the issue of numerical scaling , which can be particularly valuable for applications .
risk , hmm , hybrid , interpolation , map sequence , viterbi algorithm , symbol - by - symbol , posterior decoding .
And you have already written the first three sentences of the full article: besides their classical and traditional applications in signal processing and communications @xcite ( cf . also further references in @xcite ) and speech recognition @xcite , hidden markov models have recently become indispensable in computational biology and bioinformatics @xcite as well as in natural language modelling @xcite and information security @xcite . at the same time , their spatial extensions , known as hidden markov random field models ( hmrfm ) , have also been immensely influential in spatial statistics @xcite , and particularly in image analysis , restoration , and segmentation @xcite . indeed , hidden markov models are called ` one of the most successful statistical modelling ideas that have [ emerged ] in the last forty years ' @xcite .
hm(rf)ms owe much of their success on the one hand to the persistence of the markov property of the unobserved , or hidden , layer in the presence of observed data , and on the other , to the richness of the observed system @xcite . namely , in bayesian terms , in addition to the prior , the posterior distribution of the hidden layer also possesses a markov property ( albeit generally inhomogeneous even with homogeneous priors ) , whereas the marginal law of the observed layer can still include global , i.e. non - markovian , dependence .
the markov property of the posterior distribution and the conditional independence of the observed variables given the hidden ones , have naturally led to a number of computationally feasible methods for inference about the hidden realizations as well as model parameters ( if any ) ..
Please generate the next two sentences of the article | hmms are naturally a special case of _ graphical models _
@xcite , ( * ? ? ? |
7,004 | Suppose that you have an abstract for a scientific paper: it is widely believed that the assumption of homogeneity is a good zero_th _
order approximation for the expansion of our universe .
we analyze the correction due to subhorizon inhomogeneous gravitational fields . while at early times this contribution ( which may act as a negative pressure component ) is perturbatively subdominant
, we show that the perturbative series is likely to diverge at redshift of order 1 , due to the growth of perturbations .
so , the homogeneous friedmann equation can not be trusted at late times .
we suggest that the puzzling observations of a present acceleration of the universe , may just be due to the unjustified use of the friedmann equation and not to the presence of a dark energy component .
this would completely solve the coincidence problem . .
And you have already written the first three sentences of the full article: since the birth of modern cosmology the theoretical framework used to describe the evolution of the observed universe has been based on the einstein equations applied to a perfectly homogeneous and isotropic model filled with various types of fluid components .
it is universally believed , since the universe on large scales looks almost homogeneous , that the assumption of homogeneity is a good zeroth order approximation for describing our universe , and on top of this one usually adds linear fluctuations ( with initial amplitude of order @xmath0 , as measured by cmb experiments ) in order to describe the growth of density perturbations and the formation of structures .
some steps beyond this paradigm have been made for describing late time behaviour of small scale density perturbations ( which at late times become non - linear ) and more recently in the second order relativistic perturbation theory to catch new effects ( as non - gaussianities in the spectrum of primordial perturbations ) ..
Please generate the next two sentences of the article | however , few efforts have been made to understand how reliable is the assumption of homogeneity .
of course there are corrections to this description due to perturbations : the nonlinearity of einstein equations implies that the presence of perturbations modifies the background . |
7,005 | Suppose that you have an abstract for a scientific paper: ` tree pruning ' ( tp ) is an algorithm for probabilistic inference on binary markov random fields .
it has been recently derived by dror weitz and used to construct the first fully polynomial approximation scheme for counting independent sets up to the ` tree uniqueness threshold . '
it can be regarded as a clever method for pruning the belief propagation computation tree , in such a way to exactly account for the effect of loops . in this paper
we generalize the original algorithm to make it suitable for decoding linear codes , and discuss various schemes for pruning the computation tree .
further , we present the outcomes of numerical simulations on several linear codes , showing that tree pruning allows to interpolate continuously between belief propagation and maximum a posteriori decoding . finally , we discuss theoretical implications of the new method . .
And you have already written the first three sentences of the full article: statistical inference is the task of computing marginals ( or expectation values ) of complex multi - variate distributions . _
belief propagation _ ( bp ) is a generic method for accomplishing this task quickly but approximately , when the multivariate distribution factorizes according to a sparse graphical structure .
the advent of sparse graph codes and iterative bp decoding @xcite has naturally made decoding become an important case of this general problem ..
Please generate the next two sentences of the article | the present paper builds on this connection by ` importing ' an algorithm that has been recently developed in the context of approximate counting and inference @xcite .
we will refer to the new algorithm as _ tree pruning _ ( tp ) _ |
7,006 | Suppose that you have an abstract for a scientific paper: we present initial results from a field survey for extremely red objects ( eros , defined here as ( @xmath0-@xmath1 ) @xmath2 6@xmath3 ) covering 154 square arcminutes of sky , from the first of 7 deep , wide - field @xmath1 images obtained as part of the calar alto deep imaging survey ( cadis ) .
the 5@xmath4 point source detection limits are @xmath1
@xmath5 205 and @xmath0 @xmath5 250 , while extended - source limits are up to 050075 brighter .
we identify a total of 8 bright eros with @xmath1 @xmath6 190 .
six of these bright eros are resolved and are likely to be galaxies , while the remaining 2 are unresolved , with colors consistent with their being low - mass galactic stars .
we derive a surface density for the 6 bright , extragalactic eros of [email protected] arcmin@xmath8 , higher by a factor of 4 than previous values .
we estimate that the volume density of bright eros to be as high as that of nearby seyfert galaxies . .
And you have already written the first three sentences of the full article: significant numbers of massive galaxies have been identified in the near - infrared with colors so red that they are not found in surveys that select galaxies at visual wavelengths .
such objects have been named _ extremely red objects _ ( eros ) . with surface densities similar to that of bright quasars ( hu & ridgeway , 1994 )
, they represent an important component of the population of high - redshift galaxies ..
Please generate the next two sentences of the article | the identification of eros coincided with the development and implementation of infrared arrays for astronomical research , the first eros being noted in the k - band surveys of elston , rieke , & rieke ( 1988 , 1989 ) . since then
, many groups have identified objects with extremely red colors ( mccarthy , persson , & west 1992 ; eisenhardt & dickinson 1992 ; persson et al . |
7,007 | Suppose that you have an abstract for a scientific paper: a new stochastic theory of a foreign exchange markets dynamics is developed . as a result
we have the new probability distribution which well describes statistical and scaling dependencies experimentally observed in foreign exchange markets in recent years .
the developed dynamic theory is compared with well - known phenomenological levy distribution approach which is widely applied to this problem . it is shown that the developed stochastic dynamics and phenomenological approach based on the levy distribution give the same statistical and scaling dependencies . _
pacs _ number(s ) : 02.50 ey , 05.40 .
fb tcilatex .
And you have already written the first three sentences of the full article: statistical behavior of the foreign exchange ( fx ) markets and price fluctuations in currency have been the subject of studies in recent years @xcite , @xcite . the high - frequency data for financial markets has made it possible to investigate market dynamics on timescales as short as 1 min , a value close to the minimum time needed to perform transaction in the market .
it was observed that the short - term price fluctuations in fx market , for example , between us dollar and german mark , has the same statistical behavior as the velocity differences in hydrodynamic turbulence @xcite .
probability distributions in turbulence well fit the experimental data by superposition of the gaussians with log - normal distributions of its variances @xcite,@xcite ..
Please generate the next two sentences of the article | the convergence of the velocity differences distributions toward a gaussian shape corresponds to a decrease of the log - normal variance for increasing of spatial distances @xmath0 . in the fx fluctuation dynamics
the statistical distributions of the price difference separated by time @xmath1 was elaborated by the theoretical model of a levy walk or levy flight @xcite,@xcite . |
7,008 | Suppose that you have an abstract for a scientific paper: a search was made for sub - threshold @xmath0 production from a carbon target using a mixed real and quasi - real bremsstrahlung photon beam with an endpoint energy of 5.76 gev .
no events were observed , which is consistent with predictions assuming quasi - free production .
the results place limits on exotic mechanisms that strongly enhance quasi - free production . .
And you have already written the first three sentences of the full article: one of the main goals of nuclear physics is to understand to what extent a nucleus differs from a loosely bound system of quasi - independent nucleons .
when nucleons are very close spatially , corresponding to rare high momentum components of the single particle wave function , many interesting and potentially exotic configurations can arise .
one way to look for such configurations is with reactions that are significantly sub - threshold to production from a free nucleon . of all such reactions ,.
Please generate the next two sentences of the article | photoproduction of charmonium is one of the cleanest because the charm quark content of a nucleon is expected to be small compared to the light quarks . in light meson photoproduction , the quark content of the mesons can originate in the nuclear target , while in the case of charmonium photoproduction , the quark - interchange mechanism is essentially absent , and the reaction must proceed via gluon exchange in order for color to be conserved .
in addition , the heavy mass of the charm quark ( about 1.5 gev ) ensures a hard scale to the problem , making it more tractable in qcd . the goal of this experiment was to study the production mechanisms in the extreme conditions of matter that may be relevant in heavy ion collisions . |
7,009 | Suppose that you have an abstract for a scientific paper: these notes provide a description of the abelian categories that arise as categories of coherent sheaves on weighted projective lines .
two different approaches are presented : one is based on a list of axioms and the other yields a description in terms of expansions of abelian categories .
a weighted projective line is obtained from a projective line by inserting finitely many weights .
so we describe the category of coherent sheaves on a projective line in some detail , and the insertion of weights amounts to adding simple objects .
we call this process ` expansion ' and treat it axiomatically .
thus most of these notes are devoted to studying abelian categories , including a brief discussion of tilting theory .
we provide many details and have tried to keep the exposition as self - contained as possible . .
And you have already written the first three sentences of the full article: we begin with a brief description of weighted projective lines and their categories of coherent sheaves .
let @xmath0 be an algebraically closed field , let @xmath1 be the projective line over @xmath0 , let @xmath2 be a ( possibly empty ) collection of distinct closed points of @xmath1 , and let @xmath3 be a _ weight sequence _ , that is , a sequence of positive integers .
the triple @xmath4 is called a _ weighted projective line_. geigle and lenzing @xcite have associated to each weighted projective line a category @xmath5 of coherent sheaves on @xmath6 , which is the quotient category of the category of finitely generated @xmath7-graded @xmath8-modules , modulo the serre subcategory of finite length modules . here.
Please generate the next two sentences of the article | @xmath7 is the rank 1 additive group @xmath9 and @xmath10 / ( x_i^{p_i } + \la_{i1 } u - \la_{i0 } v ) , \ ] ] with grading @xmath11 and @xmath12 , where @xmath13 $ ] in @xmath1 .
geigle and lenzing showed that @xmath5 is a hereditary abelian category with finite dimensional hom and ext spaces . |
7,010 | Suppose that you have an abstract for a scientific paper: we present spectra of six luminous quasars at @xmath0 , covering rest wavelengths 1600@xmath13200 .
the fluxes of the uv feii emission lines and mgii @xmath2 doublet , the line widths of mgii , and the 3000 luminosity were obtained from the spectra .
these quantities were compared with those of low - redshift quasars at @xmath3 studied by tsuzuki et al . in a plot of
the feii(uv)/mgii flux ratio as a function of the cental black hole mass , feii(uv)/mgii in our @xmath0 quasars is systematically greater than in the low - redshift quasars .
we confermed that luminosity is not responsible for this excess .
it is unclear whether this excess is caused by rich fe abundance at @xmath0 over low - redshift or by non - abundance effects such as high gas density , strong radiation field , and high microturbulent velocity .
galaxies : abundances galaxies : active line : formation quasars : emission lines .
And you have already written the first three sentences of the full article: according to the models of explosive nucleosynthesis , much of the iron comes from type ia supernovae , while @xmath4 elements such as o and mg come from type ii supernovae . because the difference in lifetime of the progenitors , it is generally considered that the iron enrichment delays relative to @xmath4 elements by 12 billion years ( @xcite ; @xcite , 1998 ) .
if feii / mgii , the relative strengths of feii emission lines and the mgii @xmath2 doublet , reflects the fe / mg abundance ratio , there will be a break in feii / mgii at high redshift . despite of much efforts made by many observational groups
( e.g. , @xcite ; @xcite ; @xcite , 2003 ; @xcite , 2004 ; @xcite ; @xcite ; @xcite ; @xcite , 2008a ; @xcite ) , there have been found no signs of such a break ; feii / mgii looks constant from low - redshift up to @xmath5 with large scatter ..
Please generate the next two sentences of the article | no break in feii / mgii might reflect a significantly shorter delay - time of [email protected] gyr , as suggested by @xcite , @xcite , and @xcite .
the expected break can also be obscured by non - abundance effects . |
7,011 | Suppose that you have an abstract for a scientific paper: we present a new schwarzschildorbit - superposition code that is designed to model discrete datasets composed of velocity measurements of individual kinematic tracers in a dynamical system .
this constitutes an extension of previous implementations that can only address continuous data in the form of ( the moments of ) velocity distributions , thus avoiding potentially important losses of information due to data binning .
furthermore , the code can handle any combination of available velocity components , i.e. , only line - of - sight velocities , only proper motions , or a combination of both .
it can also handle a combination of discrete and continuous data .
the code determines the combination of orbital mass weights ( representing the distribution function ) as a function of the three integrals of motion @xmath0 and @xmath1 that best reproduces , in a maximum - likelihood sense , the available kinematic and photometric observations in a given axisymmetric gravitational potential .
the overall best fit is the one that maximizes the likelihood over a parameterized set of trial potentials .
the fully numerical approach ensures considerable freedom on the form of the distribution function @xmath2 .
this allows a very general modeling of the orbital structure , thus avoiding restrictive assumptions about the degree of ( an)isotropy of the orbits .
we describe the implementation of the discrete code and present a series of tests of its performance based on the modeling of simulated ( i.e. , artificial ) datasets generated from a known distribution function .
we explore pseudo - datasets with varying degrees of overall rotation and different inclinations on the plane of the sky , and study the results as a function of relevant observational variables such as the size of the dataset and the type of velocity information available .
we find that the discrete schwarzschildcode recovers the original orbital structure , mass - to - light ratio , and inclination of the input datasets to....
And you have already written the first three sentences of the full article: the study of the internal dynamics of stellar systems plays an essential role in astronomy . from the observed positions and velocities of the stars in galaxies and globular clusters it is possible to infer their total ( dark+luminous ) mass distribution , which , in particular , provides information on the presence and properties of dark halos and massive black holes . in turn
, this structural knowledge constrains theories for the formation and evolution of these systems .
the dynamical state of a stellar system is determined by its phase space distribution function , @xmath3 , which counts the stars as a function of position @xmath4 and velocity @xmath5 . typically , however , only three of the six phase - space coordinates are available observationally : the projected sky position @xmath6 , and the velocity @xmath7 along the line of sight ( los ) ..
Please generate the next two sentences of the article | proper motion observations can provide the additional velocities @xmath8 , but such data are generally not available ( with the notable exception of some galactic globular clusters ) . to make progress with the limited information available , the dynamical theorist is often forced to make simplifying assumptions about geometry ( e.g. , that the system is spherical ) or about the velocity distribution ( e.g. , that it is isotropic ) .
such assumptions can have strong effects on the inferred mass distribution ( @xcite ) . to obtain the most accurate results |
7,012 | Suppose that you have an abstract for a scientific paper: many advances in physics have in common that some idea which was previously accepted as fundamental , general , and inescapable was subsequently seen to be consequent , special , and dispensable .
the idea was not truly a general feature of the world , but only _ perceived _ to be general because of our special place in the universe and the limited range of our experience .
it was _ excess baggage _ which had to be jettisoned to reach a more a more general perspective .
this article discusses excess baggage from the perspective of quantum cosmology which aims at a theory of the universe s quantum initial state .
we seek to answer the question ` which features of our current theoretical framework are fundamental and which reflect our special position in the universe or its special initial condition ? '
past instances of cosmological excess baggage are reviewed such as the idea that the earth was at the center of the universe or that the second law of thermodynamics was fundamental .
examples of excess baggage in our current understanding are the notion that measurement is central to formulating quantum mechanics , a fundamental quantum mechanical arrow of time , and the idea that a preferred time is needed to formulate quantum theory .
we speculate on candidates for future excess baggage . .
And you have already written the first three sentences of the full article: it is an honor , of course , but also a pleasure for me to join in this celebration of murray gell - mann s sixtieth birthday and to address such a distinguished audience .
murray was my teacher and more recently we have worked together in the search for a quantum framework within which to erect a fundamental description of the universe which would encompass all scales from the microscopic scales of the elementary particle interactions to the most distant reaches of the realm of the galaxies from the moment of the big bang to the most distant future that one can contemplate .
such a framework is needed if we accept , as we have every reason to , that at a basic level the laws of physics are quantum mechanical ..
Please generate the next two sentences of the article | further , as i shall argue below , there are important features of our observations which require such a framework for their explanation .
this application of quantum physics to the universe as a whole has come to be called the subject of quantum cosmology . |
7,013 | Suppose that you have an abstract for a scientific paper: this paper is divided into two sections . in the first
i give reasons for strongly recommending reading some of henkin s expository papers . in the second
i describe leon henkin s work as a social activists in the field of mathematics education , as he labored in much of his career to boost the number of women and underrepresented minorities in the upper echelons of mathematics . .
And you have already written the first three sentences of the full article: henkin was an extraordinary insightful professor with a talent for exposition , and he devoted considerable effort to writing expository papers .
i will mention three of them , while trying to convince you to read them with your students as a source of mutual inspiration .
this is the title of a wonderful expository paper @xcite , which leon henkin published in _ science _ in 1962 , and subtitled : _ an old thesis of russell s is reexamined in the light of subsequent developments in mathematical logic ..
Please generate the next two sentences of the article | _ i recommend that you to give this paper to your students , not only because the historical view provided is comprehensive and synthetic but also because it shows the henkin s characteristic style ; namely , the ability to strongly catch your attention from the start .
_ how does he achieve it ? |
7,014 | Suppose that you have an abstract for a scientific paper: using a dynamical model to make predictions about a system has many sources of error .
these can include errors in how the model was initialised but also errors in the dynamics of the model itself .
for many applications in data assimilation , probabilistic forecasting , or model improvement , these model errors need to be known over the timestep of the model , not over a time - averaged period . using a forecast from a state that combines observational information as well as prior information we can gain an approximation to the statistics of the model errors on the timescale of the model that is required . here
we give bounds on the errors in the estimation of the mean and covariance of the errors in the model equations in terms of the errors made in the state estimation .
this is the first time that such a result has been derived .
the result shows to what extent the state estimation must constrain the analysis in order to obtain a specified error on the mean or covariance of the model errors .
this is particularly useful for experimental design as it indicates the necessary information content required in observations of the dynamical system .
* keywords : * model error estimation , data assimilation , analysis forecast , model error covariance estimation .
And you have already written the first three sentences of the full article: suppose we have a numerical model , @xmath0 , for a dynamical process : @xmath1 where @xmath2 is the state at time indexed by @xmath3 .
then it is almost certain that such a numerical model @xmath0 will contain errors .
a large amount of uncertainty quantification has revolved around providing bounds of the accuracy of the numerical scheme used to approximate the underlying mathematical or statistical problem @xcite ..
Please generate the next two sentences of the article | this ignores one large issue : the underlying mathematical problem does not represent all of the features of the real world system in which one is interested . for example , when modelling wind around a wind farm , drag induced by individual trees / plants will likely not be included . instead , some approximate homogenised quantity will be used . as another example , when modelling carbon fibre composites , specific manufacturing defects will not be included in the model until measurements of the materials response under various loading conditions are incorporated .
the ubiquitous quote on this issue is from @xcite : `` all models are wrong but some are useful '' . the problem we address is how to estimate the distribution of the errors that are made by the mathematical model in simulating a physical system . to get a measure of |
7,015 | Suppose that you have an abstract for a scientific paper: we review the recent programme undertaken to construct , systematically and algorithmically , large classes of heterotic vacua , as well as the search for the mssm therein .
specifically , we outline the monad construction of vector bundles over complete intersection calabi - yau threefolds , their classification , stability , equivariant cohomology and subsequent relevance to string phenomenology .
it is hoped that this top - down algorithmic approach will isolate special corners in the heterotic landscape . .
And you have already written the first three sentences of the full article: ever since the realization @xcite , shortly after the discovery of the heterotic string @xcite , that it provides a promising venue wherein the standard model may be embedded , string phenomenology was born .
indeed , the @xmath0 gauge group of the heterotic string encompasses a natural gauge unification of the standard model @xmath1 group .
a mathematically succinct and physically appealing approach was thereby engendered , where the @xmath0 string was compactified on a calabi - yau threefold @xmath2 ..
Please generate the next two sentences of the article | the tangent bundle @xmath3 of @xmath2 admits , by the calabi - yau nature , an @xmath4 connection and @xmath0 is thus broken to an @xmath5 gut group , the commutant of @xmath4 therein .
this was the initial setup and the @xmath5 particle content is conveniently computed by the cohomology groups taking value in @xmath3 , which , by standard hodge decomposition of khler manifolds @xcite , are simply the hodge numbers of @xmath2 : @xmath6 now , the 27 of an @xmath5 gut theory contains the entirety of the standard model fermions , hence the net number of generations is simply ( the absolute value of ) the difference between the above two terms , which , by rudimentary topology , is half the euler number of @xmath2 . |
7,016 | Suppose that you have an abstract for a scientific paper: the occurence of `` exotic '' shapes in light n = z @xmath0-like nuclei is investigated for @xmath1mg+@xmath2c and @xmath3s+@xmath1 mg .
various approaches of superdeformed and hyperdeformed bands associated with quasimolecular resonant structures with low spin are presented . for both reactions ,
exclusive data were collected with the binary reaction spectrometer in coincidence with euroball iv installed at the vivitron tandem facility of strasbourg .
specific structures with large deformation were selectively populated in binary reactions and their associated @xmath4-decays studied .
the analysis of the binary and ternary reaction channels is discussed .
address = institut pluridisciplinaire hubert curien , umr7178 , cnrs - in2p3 et universit louis pasteur ( strasbourg i ) , b.p .
28 , f-67037 strasbourg cedex 2 , france address = institut pluridisciplinaire hubert curien , umr7178 , cnrs - in2p3 et universit louis pasteur ( strasbourg i ) , b.p .
28 , f-67037 strasbourg cedex 2 , france address = institut pluridisciplinaire hubert curien , umr7178 , cnrs - in2p3 et universit louis pasteur ( strasbourg i ) , b.p .
28 , f-67037 strasbourg cedex 2 , france address = institut pluridisciplinaire hubert curien , umr7178 , cnrs - in2p3 et universit louis pasteur ( strasbourg i ) , b.p .
28 , f-67037 strasbourg cedex 2 , france address = institut pluridisciplinaire hubert curien , umr7178 , cnrs - in2p3 et universit louis pasteur ( strasbourg i ) , b.p .
28 , f-67037 strasbourg cedex 2 , france address = institut pluridisciplinaire hubert curien , umr7178 , cnrs - in2p3 et universit louis pasteur ( strasbourg i ) , b.p .
28 , f-67037 strasbourg cedex 2 , france address = institut pluridisciplinaire hubert curien , umr7178 , cnrs - in2p3 et universit louis pasteur ( strasbourg i ) , b.p .
28 , f-67037 strasbourg cedex 2 , france address = institut pluridisciplinaire hubert curien , umr7178 , cnrs - in2p3 et universit louis pasteur ( strasbourg i ) , b.p .
28 ,....
And you have already written the first three sentences of the full article: rotational bands and deformed shapes in @xmath5ar .
energies of the g.s .
( spherical shape ) and sd bands @xcite ( ellipsoidal shape ) , and the energies of hd band from the quasimolecular resonances observed in the @xmath2c+@xmath1 mg ( open rectangles ) and @xmath6o+@xmath7ne ( full rectangles ) reactions ( dinuclear shape ) are plotted as a function of j(j+1 ) @xcite.,height=359 ] the observation of resonant structures in the excitation functions for various combinations of light @xmath0-cluster ( n = z ) nuclei in the energy regime from the barrier up to regions with excitation energies of e@xmath8 = 20 - 50 mev remains a subject of contemporary debate @xcite ..
Please generate the next two sentences of the article | these resonances have been interpreted in terms of nuclear molecules @xcite .
the question whether quasimolecular resonances always represent true cluster states in the compound systems , or whether they may also simply reflect scattering states in the ion - ion potential is still unresolved @xcite . in many cases , |
7,017 | Suppose that you have an abstract for a scientific paper: we present and discuss our observations of the narrow line quasar pg1404@xmath0226 ( @xmath1 = 0.098 ) with asca and hst , and a re - analysis of our earlier observations with rosat .
the soft x - ray spectrum is very steep and displays an absorption feature ( edge or line at @xmath2 1.1 kev ) .
we have applied a variety of models to the asca and rosat spectra without finding a completely satisfactory fit , and the identification of the edge remains uncertain .
a satisfactory fit of the asca spectrum assuming that the edge is produced by highly ionized iron ( using the code absori in xspec ) is obtained with an overabundance of iron by a factor @xmath3 compared to solar , a suggestion supported by the extremely high equivalent width of the fe k@xmath4 line at 6.4 kev . a warm absorber model ( based on cloudy ) fitting the absorption feature with nevii - nex edges and assuming a peculiar oxygen / neon abundance ratio is consistent with the rosat data but not the asca data . finally , it is also possible that the observed edge is caused by a oviii or ovii edge or line , blueshifted by @xmath5 = 0.2 to 0.5 depending on the specific identification , as has been suggested previously for 2 other narrow line quasars , but there are no other features in the uv and x - ray spectra in support of this suggestion .
two systems of uv absorption lines , one nearly at rest in the source frame , the other blueshifted by @xmath6 km s@xmath7 are identified in the hst / fos spectra .
photoionization models indicate that the uv absorption and the @xmath8 kev absorption are probably caused by absorbers with different physical conditions .
pg1404@xmath0226 is one more case of agn where both uv and x - ray absorption features are detected , thereby increasing further the significance of the previously noted statistical association of the two types of absorbers . .
And you have already written the first three sentences of the full article: narrow line active galactic nuclei form a distinct class of agn on the basis of the properties of their optical / uv spectrum : full width at half maximum ( fwhm ) of the hydrogen lines and other lines in the range 500 - 2000 km s@xmath7 , intense high ionization lines , and intense feii multiplets ( osterbrock & pogge , @xcite ; shuder & osterbrock , @xcite ) . the weakest of these agn , the narrow line seyfert 1 ( nls1 ) , and the somewhat brighter agn with absolute optical luminosity above but close to the lowest limit for quasars of @xmath9 = -23.4 have been extensively studied in the x - ray range ( e.g. laor , fiore , elvis et al . , 1994 ;
boller , brandt & fink , 1996 ; laor et al . , 1997 ) . among all agn ,
the narrow lines agn tend to have the steepest soft x - ray spectra ( rosat ) , and some of them show fast , large amplitude soft x - ray variability with occasionally giant outbursts ( e.g. grupe 1996 and references therein ; boller et al 1996 ) . in the harder 2 - 10 kev band.
Please generate the next two sentences of the article | a comparative study of a large sample of nls1 and broad line seyfert 1s revealed that the 2 - 10 kev asca spectral slopes of nls1 are significantly steeper than those of broad line agn ( brandt , mathur & elvis 1997 ) .
recent bepposax observations of a selected sample of bright nls1 ( comastri , fiore , guainazzi et al . |
7,018 | Suppose that you have an abstract for a scientific paper: we investigate the physics of quantum reference frames . specifically , we study several simple scenarios involving a small number of quantum particles , whereby we promote one of these particles to the role of a quantum observer and ask what is the description of the rest of the system , as seen by this observer ?
we highlight the interesting aspects of such questions by presenting a number of apparent paradoxes . by unravelling these paradoxes
we get a better understanding of the physics of quantum reference frames . .
And you have already written the first three sentences of the full article: reference frames are one of the most basic notions in physics . almost every time a measurement is performed or a formula is written down , a reference frame has been implicitly used .
the choice of reference frame can either be thought of as abstract labelling of space - time , or a description relative to some physical laboratory with a particular set of rulers and clocks . in the latter case ,
the laboratory is always taken to be much heavier than the system under observation , with a well defined velocity and position ..
Please generate the next two sentences of the article | in other words , it is assumed to be fundamentally _
classical_. however , in their seminal papers @xcite , aharonov and susskind showed that the concept of reference frame can be suitably accommodated in quantum theory . |
7,019 | Suppose that you have an abstract for a scientific paper: we study the dark matter halos of galaxies with galaxy - galaxy lensing using the combo-17 survey .
this survey offers an unprecedented data set for studying lens galaxies at @xmath0 including redshift information and spectral classification from 17 optical filters for objects brighter than @xmath1 .
so far , redshifts and classification for the lens galaxies have mainly been available for local surveys like the sloan digital sky survey ( sdss ) .
further , redshifts for the source galaxies have typically not been available at all but had to be estimated from redshift probability distribution which for faint surveys even had to be extrapolated . to study the dark matter halos we parametrize the lens galaxies as singular isothermal spheres ( sis ) or by navarro - frenk - white ( nfw ) profiles . in both cases
we find a dependence of the velocity dispersion or virial radius , respectively , on lens luminosity and colour .
for the sis model , we are able to reproduce the tully - fisher / faber - jackson relation on a scale of @xmath2 . for the nfw profile
we also calculate virial masses , mass - to - light ratios and rotation velocities .
finally , we investigate differences between the three survey fields used here . .
And you have already written the first three sentences of the full article: galaxy - galaxy lensing uses the distortions of background galaxies to study the mass distribution around foreground galaxies . in a typical lens situation ,
the shear from a foreground lens is only weak .
therefore , galaxy - galaxy lensing can only study dark matter halos of galaxies statistically by averaging over thousands of lens galaxies . for reviews on galaxy - galaxy lensing see @xcite and @xcite ..
Please generate the next two sentences of the article | we use the maximum - likelihood technique proposed by @xcite .
first , we have to identify lenses and source galaxies which we do based on accurate photometric redshifts . |
7,020 | Suppose that you have an abstract for a scientific paper: during galaxy mergers the gas falls to the center , triggers star formation , and feeds the rapid growth of supermassive black holes ( smbhs ) .
smbhs respond to this fueling by supplying energy back to the ambient gas .
numerical studies suggest that this feedback is necessary to explain why the properties of smbhs and the formation of bulges are closely related .
this intimate link between the smbh s mass and the large scale dynamics and luminosity of the host has proven to be a difficult issue to tackle with simulations due to the inability to resolve all the relevant length scales simultaneously . in this paper
we simulate smbh growth at high - resolution with _ flash _ , accounting for the gravitational focusing effects of nuclear star clusters ( nscs ) , which appear to be ubiquitous in galactic nuclei . in the simulations ,
the nsc core is resolved by a minimum cell size of about 0.001 pc or approximately @xmath0 of the cluster s radius .
we discuss the conditions required for effective gas funneling to occur , which are mainly dominated by a relationship between nsc velocity dispersion and the local sound speed , and provide a sub - grid prescription for the augmentation of central smbh accretion rates in the presence of nscs . for the conditions expected to persist in the centers of merging galaxies , the resultant large central gas densities in nscs should produce drastically enhanced embedded smbh accretion rates - up to an order of magnitude increase can be achieved for gas properties resembling those in large - scale galaxy merger simulations .
this will naturally result in faster black hole growth rates and higher luminosities than predicted by the commonly used bondi - hoyle - lyttleton accretion formalism . .
And you have already written the first three sentences of the full article: supermassive black holes ( smbhs ; @xmath1 ) are inferred to reside in most galactic nuclei @xcite . when efficiently supplied with gas
, these objects can produce some of the most luminous sources in the universe @xcite .
recent panchromatic surveys have shown that close dual agn are comparatively more luminous at high energies than their isolated counterparts , suggesting that the merger process is intricately tied to the feeding history of the waltzing smbhs @xcite ..
Please generate the next two sentences of the article | gas supply to central smbhs during galaxy mergers directly affects the growth and luminosity of these objects .
therefore , understanding how mass is bestowed to smbhs results in predictions of their number density and luminosity distribution @xcite . in cosmological simulations of merging galaxies , some form of the classical bondi - hoyle - lyttleton ( bhl ) accretion prescription is usually implemented to estimate smbh feeding rates @xcite . |
7,021 | Suppose that you have an abstract for a scientific paper: rare - earth platinum bismuth ( @xmath0ptbi ) has been recently proposed to be a potential topological insulator . in this paper
we present measurements of the metallic surface electronic structure in three members of this family , using angle resolved photoemission spectroscopy ( arpes ) .
our data shows clear spin - orbit splitting of the surface bands and the kramers degeneracy of spins at the @xmath1 and @xmath2 points , which is nicely reproduced with our full - potential augmented plane wave calculation for a surface electronic state .
no direct indication of topologically non - trivial behavior is detected , except for a weak fermi crossing detected in close vicinity to the @xmath1 point , making the total number of fermi crossings odd . in the surface band calculation , however , this crossing is explained by another kramers pair where the two splitting bands are very close to each other .
the classification of this family of materials as topological insulators remains an open question . .
And you have already written the first three sentences of the full article: the discovery of topologically non - trivial states of matter opens up a new realm of knowledge for fundamental condensed matter physics . unlike conventional materials , these topological insulators " exhibit metallic surface states that are protected by time reversal symmetry , while maintaining an insulating bulk electronic structure
this leads to a variety of novel properties including odd number of surface dirac fermions , strict prohibition of back - scattering , etc . , paving the way to potential technical breakthroughs in e.g. quantum computing process via the application of spintronics@xcite .
recently , extensive theoretical and experimental efforts have led to the realization of such fascinating behaviors in e.g. the hgte quantum wells@xcite , the bi@xmath3sb@xmath4 system@xcite and the bi@xmath5x@xmath6 ( x = te , se ) binary compounds@xcite ..
Please generate the next two sentences of the article | numerous half - heusler ternary compounds have been proposed , theoretically , to be potential new platforms for topological quantum phenomena@xcite , where the inherent flexibility of crystallographic , electronic and superconducting parameters provide a multidimensional basis for both scientific and technical exploration .
the experimental determination of their topological class would set the basis for possible spintronic utilization and further studies on the interplay between the topological quantum phenomena versus e.g. the magnetic@xcite , superconducting@xcite and heavy fermionic@xcite behaviors . |
7,022 | Suppose that you have an abstract for a scientific paper: this paper studies the information - theoretic limits of a secondary or cognitive radio ( cr ) network under spectrum sharing with an existing primary radio network . in particular , the fading cognitive multiple - access channel ( c - mac ) is first studied , where multiple secondary users transmit to the secondary base station ( bs ) under both individual transmit - power constraints and a set of interference - power constraints each applied at one of the primary receivers .
this paper considers the long - term ( lt ) or the short - term ( st ) transmit - power constraint over the fading states at each secondary transmitter , combined with the lt or st interference - power constraint at each primary receiver . in each case , the optimal power allocation scheme is derived for the secondary users to achieve the ergodic sum capacity of the fading c - mac , as well as the conditions for the optimality of the dynamic time - division - multiple - access ( d - tdma ) scheme in the secondary network . the fading cognitive broadcast channel ( c - bc ) that models the downlink transmission in the secondary network is then studied under the lt / st transmit - power constraint at the secondary bs jointly with the lt / st interference - power constraint at each of the primary receivers .
it is shown that d - tdma is indeed optimal for achieving the ergodic sum capacity of the fading c - bc for all combinations of transmit - power and interference - power constraints .
broadcast channel , cognitive radio , convex optimization , dynamic resource allocation , ergodic capacity , fading channel , interference temperature , multiple - access channel , spectrum sharing , time - division - multiple - access .
[ section ] [ section ] [ section ] [ section ] [ section ] [ section ] [ section ] .
And you have already written the first three sentences of the full article: ognitive radio ( cr ) , since the name was coined by mitola in his seminal work @xcite , has drawn intensive attentions from both academic ( see , e.g. , @xcite and references therein ) and industrial ( see , e.g. , @xcite and references therein ) communities ; and to date , many interesting and important results have been obtained . in cr networks ,
the secondary users or crs usually communicate over the same bandwidth originally allocated to an existing primary radio network . in such a scenario ,
the cr transmitters usually need to deal with a fundamental tradeoff between maximizing the secondary network throughput and minimizing the resulted performance degradation of the active primary transmissions ..
Please generate the next two sentences of the article | one commonly known technique used by the secondary users to protect the primary transmissions is _ opportunistic spectrum access _ ( osa ) , originally outlined in @xcite and later introduced by darpa , whereby the secondary user decides to transmit over a particular channel only when all primary transmissions are detected to be off . for osa ,
an enabling technology is to detect the primary transmission on / off status , also known as _ spectrum sensing _ , for which many algorithms have been reported in the literature ( see , e.g. , @xcite and references therein ) . |
7,023 | Suppose that you have an abstract for a scientific paper: as the chiral symmetry is widely recognized as an important driver of the strong interaction dynamics , current strange stars models based on mit bag models do not obey such symmetry .
we investigate properties of bare strange stars using the cloudy bag model , in which a pion cloud coupled to the quark - confining bag is introduced such that chiral symmetry is conserved .
the parameters in the model , namely the bag constant and strange quark mass are determined self - consistently by fitting the mass spectrum of baryons .
then the equation of state is obtained by evaluating the energy - momentum tensor of the system .
we find that the stellar properties of the cloudy bag strange stars are similar to those of mit bag models .
however , the decay of pions is a very efficient cooling way .
in fact it can carry out most the thermal energy in a few milliseconds and directly convert them into 100mev photons via pion decay .
this may be a very efficient @xmath0-ray burst mechanism .
numerical results indicate that temperature of a cloudy bag strange star is sufficiently lower than a mit one for the small gap energy of color superconductivity(@xmath1 = 1mev ) . on the other hand
, large gap energy ( @xmath1 = 100mev ) can suppress the pion emissivity and hence the cooling curves of cloudy model and mit model are almost identical .
the long term cooling behaviors of both mit model and cloudy model are determined by the color - flavor locked phase .
the surface luminosity of a bare strange star is higher than that of a neutron star until @xmath2 and @xmath3 for ( @xmath1 = 100mev ) and ( @xmath1 = 1mev ) respectively .
after this period , the surface luminosity of a bare strange star becomes lower than that of a neutron star even rapidly cooling mechanisms , e.g. direct urca process or pion condensation , exist in the neutron stars .
hence , the cooling behavior may provide a possible way to distinguish a compact object between a neutron star , mit strange star and cloudy bag strange star....
And you have already written the first three sentences of the full article: it has been argued that strange quark matter , consisting of @xmath4- , @xmath5- and @xmath6-quarks , is energetically the most favorable state of quark matter @xcite .
@xcite suggested that there are two ways to form strange quark matter : the quark - hadron phase transition in the early universe and conversion of neutron stars into strange ones at ultrahigh densities .
if this strange matter hypothesis is correct , then it has profound impact on physics and astrophysics ..
Please generate the next two sentences of the article | pulsars could be strange stars and not neutron stars as previously thought , and there could even be many strange dwarfs and strange planets in the universe @xcite .
several mechanisms have been proposed for the formation of strange quark stars . |
7,024 | Suppose that you have an abstract for a scientific paper: the spin-1/2 ising model on a square lattice , with fluctuating bond interactions between nearest neighbors and in the presence of a random magnetic field , is investigated within the framework of the effective field theory based on the use of the differential operator relation .
the random field is drawn from the asymmetric and anisotropic bimodal probability distribution @xmath0 , where the site probabilities @xmath1 take on values within the interval @xmath2 $ ] with the constraint @xmath3 ; @xmath4 is the random field variable with strength @xmath5 and @xmath6 the competition parameter , which is the ratio of the strength of the random magnetic field in the two principal directions @xmath7 and @xmath8 ; @xmath6 is considered to be positive resulting in competing random fields .
the fluctuating bond is drawn from the symmetric but anisotropic bimodal probability distribution @xmath9 , where @xmath10 and @xmath11 represent the average value and standard deviation of @xmath12 , respectively .
we estimate the transition temperatures , phase diagrams ( for various values of system s parameters @xmath13 ) , susceptibility , equilibrium equation for magnetization , which is solved in order to determine the magnetization profile with respect to @xmath14 and @xmath5 .
ising model , fluctuating pair interactions , asymmetric bimodal random field , effective field theory , phase diagram , phase transitions , magnetization 05.50.+q , 75.10.hk , 75.10.nr , 75.50.lk .
And you have already written the first three sentences of the full article: prediction of the critical behavior of modified spin models in the presence of site or bond dilution , random bonds , random fields has been the subject of many studies in the last decades ; this modification brings about considerable changes in the critical behavior of these systems , such as replacement of a first - order phase transition ( fopt ) by a second - order phase transition ( sopt ) , depression of tricritical points and critical end points , new critical points and universality classes , etc @xcite .
the study of the aforementioned disordered systems is based on the standard models , such as ising , blume - capel , baxter - wu , heisenberg , etc , modified accordingly to meet the requirements under consideration .
furthermore , extensions and versions of these models can be applied to describe many other different situations , such as multicomponent fluids , ternary alloys , @xmath15he -@xmath16he mixtures , in addition to the magnetic systems for which these were initially conceived . the most extensively investigated model in statistical and condensed matter physics.
Please generate the next two sentences of the article | is the spin-1/2 ising model ( i m ) , since its two dimensional version , without an external magnetic field , was analytically solved by onsager ; it is a simple one relative to other models of cooperative phenomena and has a wide range of applicability to real physical systems .
its three - dimensional version has not yet been solved exactly , for which the only existing results are either from the renormalization group calculations or series expansions and are thus considered to be the `` exact '' ones . in its modified versions , it exhibits a variety of multicritical phenomena , such as a phase diagram with ordered ferromagnetic and disordered paramagnetic phases separated by a transition line that changes from an sopt to an fopt joined at a tricritical point ( tcp ) ; besides these , critical points , critical end points , ordered critical points of various orders , re - entrance can appear as in the presence of random fields . |
7,025 | Suppose that you have an abstract for a scientific paper: a detailed study of the electronic structure and magnetic configurations of the 50 % hole - doped double layered manganite lasr@xmath0mn@xmath0o@xmath1 is presented .
we demonstrate that the on - site coulomb correlation ( u ) of mn d electrons _
( i ) _ significantly modifies the electronic structure , magnetic ordering ( from fm to afm ) , and interlayer exchange interactions , and _
( ii ) _ promotes strong anisotropy in electrical transport , reducing the effective hopping parameter along the _ c _ axis for electrically active @xmath2 electrons .
this findng is consistent with observations of anisotropic transport a property which sets this manganite apart from conventional 3d systems .
a half - metallic band structure is predicted with both the lsda and lsda+u methods .
the experimentally observed a - type afm ordering in lasr@xmath0mn@xmath0o@xmath1 is found to be energetically more favorable with u @xmath3 7 ev .
a simple interpretation of interlayer exchange coupling is given within double and super - exchange mechanisms based on the dependencies on u of the effective exchange parameters and @xmath2 state sub - band widths .
_ keywords : _ double layered manganite ; anisotropy in electrical transport ; half - metallic .
And you have already written the first three sentences of the full article: the double layered cmr manganite materials , la@xmath4sr@xmath5mn@xmath0o@xmath1 @xcite , demonstrate magnetic behaviour that is distinct from the perovskite manganites , la@xmath6sr@xmath7mno@xmath8 , including : ( i ) strong anisotropy of electrical ( magneto- ) transport @xcite ; ( ii ) nearly 2d character of its magnetism and strong afm magnetic correlations above t@xmath9 @xcite ; and ( iii ) anomalous magnetoelastic properties @xcite .
most experimental reports on the layered manganites have concentrated on the la@xmath4sr@xmath5mn@xmath0o@xmath1 compounds with @xmath10 , which are metallic and demonstrate strong magnetoresistive effects .
stochiometric lasr@xmath0mn@xmath0o@xmath1 ( x=0.5 ) exhibits interesting spin , charge and orbital ordering , and its resistivity is of the order of @xmath11 with a rather flat temperature dependence @xcite ..
Please generate the next two sentences of the article | this can be compared with the situation in perovskite manganites where undoped lamno@xmath8 is an antiferromagnetic insulator with strong orbital ordering and la@xmath6sr@xmath7mno@xmath8 with @xmath10 is a metal with strong magnetoresistive effects @xcite . in comparison with the pseudocubic perovskites with three - dimensional networks of mno@xmath12 octahedra ( i.e. , ( la , sr)mno@xmath8 ) , these layered structures + ( la , sr)@xmath8mn@xmath0o@xmath1 have a reduced exchange coupling between the mn ions along the _ c _ direction .
indeed , the pseudo - cubic perovskites show ferromagnetism and metallic conductivity over a wide range of hole doping , suggesting that the double - exchange mechanism is dominant among itinerant _ e@xmath13 _ electrons . in the double - layered case , with the two - dimensional mn - o network , consisting of two perovskite blocks separated by an intervening insulating layer of ( la , sr)o ions along the _ c _ axis , the balance between antiferromagnetism and ferromagnetism is very sensitive to @xmath2 band filling @xcite . |
7,026 | Suppose that you have an abstract for a scientific paper: the inclusive transverse momentum and rapidity distributions for top quark production at the fermilab tevatron are presented both in order @xmath0 in qcd and using the resummation of the leading soft gluon corrections in all orders of qcd perturbation theory .
the resummed results are uniformly larger than the @xmath1 results for both distributions . .
And you have already written the first three sentences of the full article: at present the top quark has not yet been conclusively discovered at the fermilab tevatron , even though there are events which look similar to those expected from top quark decays .
the experimental situation is presently confusing because both the cdf @xcite and d0 @xcite collaborations only have limited statistics .
as more events are collected one expects that the situation will be clarified . at the tevatron.
Please generate the next two sentences of the article | , the top quark should be mainly produced through @xmath2 pair production from the light mass quarks and gluons in the colliding proton and antiproton .
both the top quark and the top antiquark then decay to @xmath3 pairs , and each @xmath4 boson can decay either hadronically or leptonically . |
7,027 | Suppose that you have an abstract for a scientific paper: using accurate distances to individual virgo cluster galaxies obtained by the method of surface brightness fluctuations , we show that virgo s brightest ellipticals have a remarkably collinear arrangement in three dimensions .
this axis , which is inclined by @xmath0 from the line of sight , can be traced to even larger scales where it appears to join a filamentary bridge of galaxies connecting virgo to the rich cluster abell 1367 .
the orientations of individual virgo ellipticals also show some tendency to be aligned with the cluster axis , as does the jet of the supergiant elliptical m87 .
these results suggest that the formation of the virgo cluster , and its brightest member galaxies , have been driven by infall of material along the virgo - a1367 filament . .
And you have already written the first three sentences of the full article: the virgo cluster , at a distance of approximately @xmath1 mpc , is the nearest richly - populated cluster of galaxies and , consequently , one of the best studied .
a number of authors have pointed out that virgo s brightest elliptical galaxies have a remarkably linear arrangement , along a projected position angle of roughly @xmath2 ( measured north through east ) .
@xcite , for example , noted that `` all the e galaxies in the northern half of the virgo cluster fall on a line going through m87 . ''.
Please generate the next two sentences of the article | similarly , @xcite suggested that `` the line connecting m87 and m84 appears as a fundamental axis of the cluster . ''
this can be seen in figure 1 , which plots the distribution of probable member galaxies in the northern portion of the virgo cluster , as seen on the plane of the sky . |
7,028 | Suppose that you have an abstract for a scientific paper: we point out that the recoil electron kinetic energy spectra in the @xmath0-@xmath1 elastic scattering are different for incident @xmath2 or @xmath3 , and hence one can in principle establish the existence of the @xmath3 component in the solar neutrino flux by fitting the shape of the spectrum .
this would be a new model - independent test of the solar neutrino oscillation in a single experiment , free from astrophysical and nuclear physics uncertainties . for the @xmath4be neutrinos , it is possible to determine the @xmath3 component at borexino or kamland , if the background is sufficiently low .
note that this effect is different from the distortion in the incident _ neutrino _ energy spectrum , which has been discussed in the literature .
lbnl-42593 + ucb - pth-98/61 + hep - ph/9812307 + .1 in * establishing a @xmath3 component + in the solar neutrino flux * 0.3 in andr de gouva and hitoshi murayama 0.1 in _ department of physics , university of california + berkeley , ca 94720 _ + and 0.05 in _ theoretical physics group , lawrence berkeley national laboratory + berkeley , ca 94720 _ 0.05 in .1 in .
And you have already written the first three sentences of the full article: the solar neutrino problem , the fact that the detected neutrino flux from the sun is less than the predicted flux , has been known for decades since the pioneering work of r. davis in the homestake mine @xcite . since then , substantial progress has been made .
the kamiokande collaboration confirmed that the neutrinos are indeed coming from the sun in a real - time experiment with directional capability @xcite .
both the kamiokande and super - kamiokande collaborations @xcite also reported a depletion of the predicted flux ..
Please generate the next two sentences of the article | the gallex and sage experiments , which are sensitive to the ( dominant ) @xmath5 component of the solar neutrino flux @xcite , directly related to the solar luminosity , also found a depletion of the predicted flux . without relying on the standard solar model calculations
, one can conclude from the data that the electron neutrino flux from the @xmath6 is almost totally depleted ( see , _ |
7,029 | Suppose that you have an abstract for a scientific paper: we present a new straightforward principal component analysis ( pca ) method based on the diagonalization of the weighted variance covariance matrix through two spectral decomposition methods : power iteration and rayleigh quotient iteration .
this method allows one to retrieve a given number of orthogonal principal components amongst the most meaningful ones for the case of problems with weighted and/or missing data .
principal coefficients are then retrieved by fitting principal components to the data while providing the final decomposition .
tests performed on real and simulated cases show that our method is optimal in the identification of the most significant patterns within data sets .
we illustrate the usefulness of this method by assessing its quality on the extrapolation of sloan digital sky survey quasar spectra from measured wavelengths to shorter and longer wavelengths .
our new algorithm also benefits from a fast and flexible implementation .
[ firstpage ] methods : data analysis quasars : general . .
And you have already written the first three sentences of the full article: principal component analysis ( pca ) is a well - known technique initially designed to reduce the dimensionality of a typically huge data set while keeping most of its variance @xcite .
pca is intimately related to the singular value decomposition ( svd ) since the principal components of a data set , whose arithmetic mean is zero , will be equal to the eigenvectors of the covariance matrix sorted by their corresponding eigenvalue ; or equivalently by the variance they account for .
the principal coefficients are the linear coefficients allowing us to reconstruct the initial data set based on the principal components ..
Please generate the next two sentences of the article | further details about pca will be given in section [ sec : pca ] of this paper .
interested readers are also invited to read @xcite for an accessible tutorial on this technique or @xcite for a deeper analysis . |
7,030 | Suppose that you have an abstract for a scientific paper: we have derived elemental abundances for a sample of nine iras sources with colours similar to those of post - agb stars . for iras 01259 + 6823 , iras 05208 - 2035 ,
iras 04535 + 3747 and iras 08187 - 1905 this is the first detailed abundance analysis based upon high resolution spectra .
mild indication of s - processing for iras 01259 + 6823 , iras 05208 - 2035 and iras 08187 - 1905 have been found and a more comprehensive study of s - process enhanced objects iras 17279 - 1119 and iras 22223 + 4327 have been carried out .
we have also made a contemporary abundance analysis of the high galactic latitude supergiants bd+39@xmath0 4926 and hd 107369 .
the former is heavily depleted in refractories and estimated [ zn / h ] of @xmath10.7 dex most likely gives initial metallicity of the star . for hd 107369
the abundances of @xmath2 and fe - peak elements are similar to those of halo objects and moderate deficiency of s - process elements is seen . iras 07140 - 2321 despite being a short period binary with circumstellar shell does not exhibit selective depletion of refractory elements .
we have compiled the stellar parameters and abundances for post - agb stars with s - process enhancement , those showing significant depletion of condensable elements and those showing neither .
the compilation shows that the s - process enhanced group contains very small number of binaries , and observed [ @xmath2/fe ] are generally similar to thick disc values .
it is likely that they represent agb evolution of single stars .
the compilation of depleted group contains larger fraction of binaries and generally supports the hypothesis of dusty discs surrounding binary post - agb stars inferred via the shape of their sed and mid ir interferometry .
iras 07140 - 2321 and bd+39@xmath0 4926 are difficult to explain with this scenario and indicate the existence of additional parameter / condition needed to explain the depletion phenomenon .
however the conditions for discernible depletion , minimum....
And you have already written the first three sentences of the full article: considerable theoretical and observational interest has in recent years been focused on asymptotic giant branch ( agb ) stars but much remains mysterious about them .
the agb phase is enjoyed by low and intermediate mass stars ( approximate mass range 0.8 to 8m@xmath3 ) .
it is in this phase that a star experiences extensive internal nucleosynthesis whose fruits are dredged to the stellar surface * ( see herwig 2005)*. furthermore , mass - loss ensures that the products of nucleosynthesis are dispersed into the circumstellar and subsequently the interstellar environment ..
Please generate the next two sentences of the article | thus , agb stars are likely major contributors of li , c , n , f and @xmath4-process elements among others to galactic chemical evolution * ( romano et al
. 2010)*. observational validation of theoretical investigations of how agb stars achieve internal nucleosynthesis , dredge - up and mass - loss are generally hampered by the fact that the more evolved and more interesting of these stars have low temperature atmospheres and therefore spectra replete with dense and complex molecular * lines*. although these spectra have been analysed by a few stellar spectroscopists , the abundance studies are generally limited to very few elements and isotopic ratios . |
7,031 | Suppose that you have an abstract for a scientific paper: we define a 90% complete , volume - limited sample of 31 @xmath0 x - ray clusters and present a systematic analysis of public rosat pspc data on 22 of these objects .
our efforts are undertaken in support of the penn / ovro sze survey , and to this end we present predictions for the inverse compton optical depth towards all 22 of these clusters .
we have performed detailed monte carlo simulations to understand the effects of the cluster profile uncertainties on the sze predictions given the ovro 5.5-meter telescope beam and switching patterns .
we also present a similar analysis for the near - future acbar experiment . for most of the clusters in the sample
we find less than a 5% uncertainty in the sze predictions due to an imperfect knowledge of the profile .
a comparison of different cooling flow modeling strategies shows that our results are robust with respect to this .
the profile uncertainties are then one of the least significant components of our error budget for sze - based distance measurements . the density models which result from this analysis also yield baryonic masses and , under the assumption of hydrostatic equilibrium , total masses and baryon mass fractions .
our monte carlo profile analysis indicates that the baryon masses within @xmath1 mpc for these clusters are accurate to better than @xmath2 and unaffected by realistic pspc systematics . in the sample as a whole
, we find a mean gas mass fraction of @xmath3 internal to @xmath4 mpc .
this is in agreement with previous x - ray cluster analyses , which indicate an overabundance of baryons relative to the prediction of big bang nucleosynthesis for an @xmath5 universe .
our analysis of the x - ray spectra confirms a previous claim of an excess absorbing column density towards a478 , but we do not find evidence for anomalous column densities in the other 21 clusters .
we also find some indications of an excess of soft counts in the rosat pspc data .
a measurement of @xmath6 using these models and ovro sze....
And you have already written the first three sentences of the full article: the discovery @xcite that many galaxy clusters are also strong sources of x - rays opened a new window on cosmology which has proved fruitful for nearly three decades .
subsequent investigations ( e.g. , * ? ? ?
* ; * ? ? ?.
Please generate the next two sentences of the article | * ) determined that this emission originates in a hot ( @xmath7 ) thermal plasma with electron number densities of @xmath8 .
since the sound - crossing time for pressure waves in this plasma is less than the hubble time , the plasma can be assumed to accurately trace the cluster gravitational potential . |
7,032 | Suppose that you have an abstract for a scientific paper: in this work we investigate the theory for three different uni - directional population transfer schemes in trapped multilevel systems which can be utilized to cool molecular ions .
the approach we use exploits the laser - induced coupling between the internal and motional degrees of freedom so that the internal state of a molecule can be mapped onto the motion of that molecule in an external trapping potential . by sympathetically cooling the translational motion back into its ground state
the mapping process can be employed as part of a cooling scheme for molecular rotational levels .
this step is achieved through a common mode involving a laser - cooled atom trapped alongside the molecule . for the coherent mapping
we will focus on adiabatic passage techniques which may be expected to provide robust and efficient population transfers . by applying far - detuned chirped adiabatic rapid passage pulses we are able to achieve an efficiency of better than 98% for realistic parameters and including spontaneous emission . even though our main focus is on cooling molecular states ,
the analysis of the different adiabatic methods has general features which can be applied to atomic systems . .
And you have already written the first three sentences of the full article: the emerging field of cold molecules is a very vibrant topic in physics and physical chemistry .
the considerable interest in this topic is related to the properties of cold molecules and their many potential applications .
cold molecules have been identified as attractive systems for ultrahigh - resolution spectroscopy @xcite , quantum information processing @xcite , for developing new time standards and testing fundamental physical theories such as the time variation of physical constants @xcite , the existence of a dipole moment of the electron @xcite , and for the measurement of parity violation @xcite . in chemistry ,.
Please generate the next two sentences of the article | cold molecules are essential tools to explore quantum - mechanical effects in chemical reactions .
in contrast to atoms , molecules have a very complicated level structure that consists of vibrational and rotational states as well as electronic levels . |
7,033 | Suppose that you have an abstract for a scientific paper: schemes for optical - state truncation of two cavity modes are analyzed .
the systems , referred to as the nonlinear quantum scissors devices , comprise two coupled nonlinear oscillators ( kerr nonlinear coupler ) with one or two of them pumped by external classical fields .
it is shown that the quantum evolution of the pumped couplers can be closed in a two - qubit hilbert space spanned by vacuum and single - photon states only .
thus , the pumped couplers can behave as a two - qubit system .
analysis of time evolution of the quantum entanglement shows that bell states can be generated .
a possible implementation of the couplers is suggested in a pumped double - ring cavity with resonantly enhanced kerr nonlinearities in an electromagnetically - induced transparency scheme .
the fragility of the generated states and their entanglement due to the standard dissipation and phase damping are discussed by numerically solving two types of master equations . .
And you have already written the first three sentences of the full article: methods for preparation and manipulation of nonclassical states of light have become an important research area in quantum optics @xcite , especially in relation to possible optical implementations of quantum computers and systems for quantum communication and quantum cryptography @xcite . among various schemes for optical - qubit generation , the so - called _ quantum scissors _ device of pegg _ et al . _
@xcite produces a superposition of vacuum and single - photon states , @xmath0 , by optical - state truncation of an input single - mode coherent light .
quantum scissors device was studied in numerous papers ( see , e.g. , @xcite ) , and tested experimentally by babichev _.
Please generate the next two sentences of the article | _ @xcite and resch _ et al .
this simple scheme and its generalizations for truncation of an input optical state to a superposition of @xmath1 fock states ( the so - called qudits ) @xcite are based on linear optical elements , and thus referred to as the _ linear quantum scissors _ devices . |
7,034 | Suppose that you have an abstract for a scientific paper: we investigate the geometrical properties of static vacuum @xmath0-brane solutions of einstein gravity in @xmath1 dimensions , which have spherical symmetry of @xmath2 orthogonal to the @xmath0-directions and are invariant under the translation along them .
the solutions are characterized by mass density and @xmath0 number of tension densities .
the causal structure of the higher dimensional solutions is essentially the same as that of the five dimensional ones .
namely , a naked singularity appears for most solutions except for the schwarzschild black @xmath0-brane and the kaluza - klein bubble .
we show that some important geometric properties such as the area of @xmath2 and the total spatial volume are characterized only by the three parameters such as the mass density , the sum of tension densities and the sum of tension density squares rather than individual tension densities .
these geometric properties are analyzed in detail in this parameter space and are compared with those of 5-dimensional case . .
And you have already written the first three sentences of the full article: recently , the physical meaning of the two parameters in static vacuum hypercylindrical solutions in five dimensions @xcite was correctly interpreted in ref . @xcite . in the analogy of weak field solutions for a cylindrical matter source distributed along the fifth direction
uniformly , the author identified the two parameters with mass " and tension " densities .
it is also pointed out that the well - known schwarzschild black string solution corresponds to the case that the tension - to - mass ratio is exactly one half ..
Please generate the next two sentences of the article | this means that the schwarzschild black string , which was believed to be a family of solutions characterized by the mass density only , is indeed a special case of a wider class of solutions characterized by tension density as well .
note also that in @xmath3-dimensional spacetime , there is another class of stationary solutions which is characterized by the mass " and momentum " densities along the extra - directions @xcite . |
7,035 | Suppose that you have an abstract for a scientific paper: the nonlinear climbing sine map is a nonhyperbolic dynamical system exhibiting both normal and anomalous diffusion under variation of a control parameter .
we show that on a suitable coarse scale this map generates an oscillating parameter - dependent diffusion coefficient , similarly to hyperbolic maps , whose asymptotic functional form can be understood in terms of simple random walk approximations . on finer scales
we find fractal hierarchies of normal and anomalous diffusive regions as functions of the control parameter . by using a green - kubo formula for diffusion the origin of these different regions
is systematically traced back to strong dynamical correlations .
starting from the equations of motion of the map these correlations are formulated in terms of fractal generalized takagi functions obeying generalized de rham - type functional recursion relations .
we finally analyze the measure of the normal and anomalous diffusive regions in the parameter space showing that in both cases it is positive , and that for normal diffusion it increases by increasing the parameter value . deterministic diffusion , nonhyperbolic maps , fractal diffusion coefficient , anomalous diffusion , periodic windows 05.45.df , 05.10.-a , 05.45.ac , 05.60.-k .
And you have already written the first three sentences of the full article: low - dimensional time - discrete maps are among the most important models for exploring different aspects of chaos .
these systems display a very rich dynamical behavior but are still very amenable to straightforward computer simulations .
even more , in some cases rigorous analytical solutions are possible . after it was realized that diffusion processes can be generated by microscopic deterministic chaos in the equations of motion , time - discrete maps became useful tools in deterministic transport theory ..
Please generate the next two sentences of the article | the analysis of these simple models required to suitably combine nonequilibrium statistical mechanics with dynamical systems theory leading to a more profound understanding of transport in nonequilibrium situations @xcite . however , time - discrete maps provide not only a suitable starting point for studying normal diffusion but also for investigating the anomalous case @xcite .
moreover , there are certain classes of more realistic models which share specific properties of maps such as being low - dimensional and exhibiting certain periodicities . |
7,036 | Suppose that you have an abstract for a scientific paper: we relate disentanglement and decoherence rates in a pair of three - level atoms subjected to multi - local and collective pure dephasing noise acting in a preferred basis . the bipartite entanglement decay rate , as bounded from above by the negativity ,
is found to be greater than or equal to the dephasing - decoherence rates characterized by the decay of off - diagonal elements in the corresponding full density matrix describing the system or the reduced density matrix describing either qutrit , extending previous results for qubit pairs subject to such noise . .
And you have already written the first three sentences of the full article: quantum entanglement can be affected by a range of noise sources , both quantum and classical in nature .
noise can give rise to a loss of entanglement over a broad range of quantum states .
recently , the relationship between dephasing - decoherence and bipartite entanglement reduction under basis - specific classical noise has been studied in two - qubit systems @xcite and in pairs of qutrit systems @xcite ; this relationship has been studied in two - qubit systems under quantum dissipative vacuum noise as well @xcite ..
Please generate the next two sentences of the article | for example , it has been noted that initially entangled two - qubit systems can suffer `` entanglement sudden death , '' in which a two - qubit system may suddenly lose entanglement in a finite time , even though each qubit itself maintains its quantum - coherence@xcite . here , we present the first general analysis of the disentanglement and dephasing of two qutrits as realized in atoms with `` v''-type energy - level configuration under a classical pure dephasing noise model , at the multi - local and collective level .
we compare the timescales of disentanglement and dephasing - decoherence , the latter timescale specifically in the basis on which this noise acts as in previous studies . in sec . |
7,037 | Suppose that you have an abstract for a scientific paper: we analyze the localized phase of a general model of a directed polymer in the proximity of an interface that separates two solvents .
each monomer unit carries a charge , @xmath0 , that determines the type ( attractive or repulsive ) and the strength of its interaction with the solvents .
in addition , there is a polymer interface interaction and we want to model the case in which there are impurities @xmath1 , called again charges , at the interface .
the charges are distributed in an inhomogeneous fashion along the chain and at the interface : more precisely the model we consider is of quenched disorder type . + it is well known that such a model undergoes a localization / delocalization transition .
we focus on the localized phase , where the polymer sticks to the interface .
our new results include estimates on the exponential decay of correlations , the proof that the free energy is infinitely differentiable away from the transition and estimates on finite size corrections to the thermodynamic limit of the free energy per unit site .
other results we prove , instead , generalize earlier works that typically deal either with the case of copolymers near an homogeneous interface ( @xmath2 ) or with the case of disordered pinning , where the only polymer
environment interaction is at the interface ( @xmath3 ) .
moreover , with respect to most of the previous literature , we work with rather general distributions of charges ( we will assume only a suitable concentration inequality ) and we allow more freedom on the law of the underlying random walk .
+ + 2000 _ mathematics subject classification : 60k35 , 82b41 , 82b44 _
+ + _ keywords : directed polymers , copolymers , copolymers with adsorption , disordered pinning , localized phase _ .
And you have already written the first three sentences of the full article: polymers are repetitive chains of elementary blocks called monomers ( or monomer units ) .
copolymers are inhomogeneous polymers , in the sense that each monomer unit carries a charge , and the charge is distributed along the chain in a _ disordered _ way .
it is well known that when the medium surrounding the copolymer is made of two solvents , separated for example by an interface , and the solvents interact with the monomers according to the value of the charge , the typical behavior of the copolymer may differ substantially from the case in which the medium is homogeneous . on copolymers.
Please generate the next two sentences of the article | there is an extremely extended literature , given above all their practical relevance , see for example @xcite and @xcite and references therein .
moreover , for a realistic model of the interface , one should consider the possibility of the presence of impurities or fluctuations in the interface layer , as in @xcite . as an extreme , but very important example , one could consider also the case in which the interactions at the interface are essentially the only relevant ones , see @xcite . in order to be more concrete , |
7,038 | Suppose that you have an abstract for a scientific paper: spectral spatial fluctuations ( ssf ) of the cosmic microwave background radiation ( cmbr ) temperature are considered as a result of an interaction of primordial atoms and molecules with cmbr in proto - objects moving with peculiar velocities relative to the cmbr .
expected optimistic values of @xmath0 are @xmath1 for ssf caused by heh@xmath2 at z = 20 - 30 which are possible redshifts of early reionization scenario .
the bandwidth of the lines is 0.1 - 2% depending on the scale of proto - objects and redshifts . for the ssf search cmbr maps in different spectral channels
are to be observed and then processed by the difference method .
simulation of the experiment is made for msrt ( tuorla observatory , finland ) equipped with a @xmath3 beam cryo - microbolometer array with a chopping flat and frequency multiplexer providing up to 7 spectral channels in each beam ( 88 - 100 ghz ) .
expected @xmath4t / t limit in the experiment is 2@xmath510 @xmath6 with 6@xmath7 - 7@xmath7 angular and 2% frequency resolution .
simulation shows that ssf may be recognized in the angular power spectrum when s / n in single frequency cmbr maps is as small as 1.17 or even something less for white noise .
such an experiment gives us a possibility to set upper limit of ssf in mm band and prepare future ssf observations .
cosmic microwave background ( cmb),cosmology , molecules , radio telescope 98.80.@xmath8k,34.50.@xmath8s,95.85.bh .
And you have already written the first three sentences of the full article: observational effects caused by primordial molecules seem to be most promising in investigating dark ages epoch of the universe .
the basic properties of the molecules are discrete narrow energy levels and high efficiency of their interaction with cmbr .
this leads to forming ssf if proto - objects , containing these molecules , move with peculiar velocities v@xmath9 relative to cmbr ( dubrovich,1977,1982 , puy,1993 ) ..
Please generate the next two sentences of the article | we may consider ssf as manifestation of the proto - objects at high redshifts 300 @xmath10 10 as scattering of cmb photons by primordial molecules must leave imprints on the cmbr temperature distribution .
the most abundant chemical elements predicted by the pure big bang model are h , he , d , @xmath11he , li and their ions . |
7,039 | Suppose that you have an abstract for a scientific paper: by means of a systematic numerical analysis , we demonstrate that hexagonal lattices of parallel linearly - coupled waveguides , with the intrinsic cubic self - focusing nonlinearity , give rise to three species of stable semi - discrete complexes ( which are continuous in the longitudinal direction ) , with embedded vorticity @xmath0 : triangular modes with @xmath1 , hexagonal ones with @xmath2 , both centered around an empty central core , and compact triangles with @xmath1 , which do not not include the empty site .
collisions between stable triangular vortices are studied too .
these waveguiding lattices can be realized in optics and bec . .
And you have already written the first three sentences of the full article: lattice solitons are a topic of great interest to ongoing studies of nonlinear dynamics in photonic media and becs ( bose - einstein condensates ) @xcite .
these localized modes are produced by the interplay of the intrinsic nonlinearity of the medium with an effective periodic potential induced in it by permanent or virtual lattice patterns .
in fact , the lattice may itself be a nonlinear structure if it is induced by a spatially periodic modulation of the local nonlinearity @xcite . in the limit of a deep periodic potential.
Please generate the next two sentences of the article | , the fundamental models of lattice media reduce to various versions of the discrete nonlinear schrdinger ( dnls ) equation @xcite .
the realization of the one - dimensional ( 1d ) dnls model in arrayed optical waveguides was originally proposed in ref . |
7,040 | Suppose that you have an abstract for a scientific paper: we present infrared jhk photometry of the cataclysmic variable sdssj123813.73 - 033933.0 and analyze it along with optical spectroscopy , demonstrating that the binary system is most probably comprised of a massive white dwarf with @xmath0k and a brown dwarf of spectral type l4 .
the inferred system parameters suggest that this system may have evolved beyond the orbital period minimum and is a bounce - back system .
sdssj123813.73 - 033933.0 stands out among cvs by exhibiting the cyclical variability that called _
brightenings_. these are not related to specific orbital phases of the binary system and are fainter than dwarf novae outbursts , that usually occur on longer timescales .
this phenomenon has not been observed extensively and , thus , is poorly understood .
the new time - resolved , multi - longitude photometric observations of sdssj123813.73 - 033933.0 allowed us to observe two consecutive _ brightenings _ and to determine their recurrence time .
the period analysis of all observed _ brightenings _ during 2007 suggests a typical timescale that is close to a period of @xmath1 hours .
however , the _ brightenings _ modulation is not strictly periodic , possibly maintaining coherence only on timescales of several weeks . the characteristic variability with double orbital frequency that clearly shows up during _ brightenings
_ is also analyzed .
the doppler mapping of the system shows the permanent presence of a spiral arm pattern in the accretion disk .
a simple model is presented to demonstrate that spiral arms in the velocity map appear at the location and phase corresponding to the 2:1 resonance radius and constitute themselves as a double - humped light curves .
the long - term and short - term variability of this cv is discussed together with the spiral arm structure of an accretion disk in the context of observational effects taking place in bounce - back systems . .
And you have already written the first three sentences of the full article: the object catalogued as sdss j123813.73 - 033933.0 ( hereafter sdss1238 ) was identified with a faint ( @xmath2 mag ) short - period cataclysmic variable ( cv ) by @xcite .
the optical spectrum of sdss1238 shows a blue continuum with broad absorption features originating in the photosphere of a white dwarf surrounding double - peaked balmer emission lines , formed in a high inclination accretion disk .
the orbital period of the system is @xmath3 , based on spectroscopic data . the orbital period and the spectral features match those of wz - sge - type systems , but with this.
Please generate the next two sentences of the article | , similarities practically end .
a number of observed aspects of the system differ from the majority of short period cvs . |
7,041 | Suppose that you have an abstract for a scientific paper: we investigated the whispering gallery modes of cavities with a hexagonal cross - section .
we found two different modes , namely perturbed and quasi - wgms , of which the former exhibits the higher @xmath0 when the corner radius is large .
we studied the dependence of @xmath0 on the curvature radius of the polygonal cavities and found that the coupling between the two modes determines the @xmath0 of the cavity .
in addition we fabricated a cavity by employing laser heated pedestal growth and demonstrated a high @xmath0 . .
And you have already written the first three sentences of the full article: optical microcavities such as photonic crystal nanocavities @xcite , microring resonators @xcite , toroidal microcavities @xcite and crystalline whispering gallery mode ( wgm ) cavities @xcite are attractive platforms for studying the optical linear and nonlinear properties of light @xcite .
these cavities have been employed in various studies including work on slow light generation @xcite , an ultra - narrow linewidth laser @xcite , an optoelectronic oscillator @xcite , nonlinear switching @xcite , frequency - comb generation @xcite , opto - mechanics @xcite , frequency conversion @xcite , and nanoparticle sensing @xcite .
wgm cavities , which use internal reflection for light confinement , are particularly attractive because they can provide a very high quality factor ( @xmath0 ) ..
Please generate the next two sentences of the article | recent progress on the @xmath0 factor in such cavities has been noteworthy . in particular , cavities made of @xmath1 such as toroidal @xcite and bottle @xcite cavities exhibit a very high-@xmath0 exceeding @xmath2 because @xmath1 is a low - loss material and the laser reflow process is well established . on the other hand ,
wgm cavities made of crystal materials also exhibit an ultrahigh-@xmath0 , because their absorption loss is even lower than that of @xmath3 @xcite . |
7,042 | Suppose that you have an abstract for a scientific paper: we investigate double transitivity of galois groups in the classical schubert calculus on grassmannians .
we show that all schubert problems on grassmannians of 2- and 3-planes have doubly transitive galois groups , as do all schubert problems involving only special schubert conditions .
we use these results to give a new proof that schubert problems on grassmannians of 2-planes have galois groups that contain the alternating group .
we also investigate the galois group of every schubert problem on @xmath0 , finding that each galois group either contains the alternating group or is an imprimitive permutation group and therefore fails to be doubly transitive .
these imprimitive examples show that our results are the best possible general results on double transitivity of schubert problems . .
And you have already written the first three sentences of the full article: galois groups are not only symmetry groups of field extensions , they are also symmetry groups in enumerative geometry . this second point was made by jordan in 1870 @xcite who studied some classical problems in enumerative geometry , showing that several had galois groups which were not the full symmetric group , reflecting the intrinsic structure of these problems .
earlier , hermite gave a different connection to geometry , showing that the algebraic galois group coincided with a geometric monodromy group @xcite .
harris used this to study the galois group of several problems in enumerative geometry @xcite . for each he showed that their monodromy groups were the full symmetric groups on their sets of solutions and therefore the problem had no intrinsic structure ..
Please generate the next two sentences of the article | the schubert calculus is a well - understood family of problems in enumerative geometry that involve linear subspaces having prescribed positions with respect to other , fixed linear spaces .
it provides a laboratory for studying galois groups in enumerative geometry . |
7,043 | Suppose that you have an abstract for a scientific paper: many meson processes are related to the @xmath0 axial anomaly , present in the feynman graphs where fermion loops connect axial vertices with vector vertices .
however , the coupling of pseudoscalar mesons to quarks does not have to be formulated via axial vertices .
the pseudoscalar coupling is also possible , and this approach is especially natural on the level of the quark substructure of hadrons . in this paper
we point out the advantages of calculating these processes using ( instead of the anomalous graphs ) the feynman graphs where axial vertices are replaced by pseudoscalar vertices .
we elaborate especially the case of the processes related to the abelian axial anomaly of qed , but we speculate that it seems possible that effects of the non - abelian axial anomaly of qcd can be accounted for in an analogous way . .
And you have already written the first three sentences of the full article: numerous processes in meson physics are related to the adler - bell - jackiw ( abj ) axial anomaly @xcite appearing in the fermion loops connecting certain number of axial ( a ) and vector ( v ) vertices . concretely , in this paper we will deal with the processes related to the avv ( triangle " , fig . [
fig : triangle ] ) and vaaa ( box " , fig .
[ fig : box ] ) anomaly , exemplified by the famous @xmath1 and @xmath2 transitions . with two photons of momenta @xmath3 and @xmath4 ..
Please generate the next two sentences of the article | the quark - photon coupling is in general given by dressed vector vertices @xmath5 , which in the free limit reduce to @xmath6.,height=151 ] , studied by the pseudoscalar coupling method in , e.g. , refs .
there are six different contributing graphs , obtained from the above graph by the permutations of the vertices of the three different pions . |
7,044 | Suppose that you have an abstract for a scientific paper: the isothermal entropy change and the adiabatic temperature change are rigorously calculated for the exactly solved spin-1/2 fisher s super - exchange antiferromagnet in order to examine magnetocaloric properties of the model in a vicinity of the second - order phase transition .
it is shown that the large inverse magnetocaloric effect occurs around the temperature interval for any magnetic - field change @xmath0 .
the most pronounced inverse magnetocaloric effect can be found for the magnetic - field change , which coincides with the critical field of a zero - temperature phase transition from the antiferromagnetically ordered ground state to the paramagnetic one . .
And you have already written the first three sentences of the full article: the magnetocaloric effect ( mce ) , which is characterized by an isothermal change of the entropy or an adiabatic change of the temperature upon magnetic - field variation , enjoys a great scientific interest mainly because of its immense application potential @xcite . besides a conventional mce observed in regular ferromagnets or paramagnets ,
there may also be detected an inverse mce , namely , in ferrimagnetic or antiferromagnetic materials . in the former case
the system cools down when the magnetic field is removed adiabatically , while in the latter case it heats up ..
Please generate the next two sentences of the article | however , the mce has been so far rigorously studied only in one - dimensional spin systems ( see e.g. ref .
@xcite and references therein ) due to a lack of exactly solved spin models in higher dimensions accounting for a non - zero magnetic field . |
7,045 | Suppose that you have an abstract for a scientific paper: direct imaging observations of protoplanetary disks at near - infrared ( nir ) wavelengths have revealed structures of potentially planetary origin .
investigations of observational signatures from planet - induced features have so far focused on disks viewed face - on . combining 3d hydrodynamics and radiative transfer simulations , we study how the appearance of the spiral arms and the gap produced in a disk by a companion varies with inclination and
position angle in nir scattered light .
we compare the cases of a @xmath0 and a @xmath1 companion , and make predictions suitable for testing with gemini / gpi , vlt / naco / sphere , and subaru / hiciao / scexao .
we find that the two trailing arms produced by an external perturber can have a variety of morphologies in inclined systems they may appear as one trailing arm ; two trailing arms on the same side of the disk ; or two arms winding in opposite directions .
the disk ring outside a planetary gap may also mimic spiral arms when viewed at high inclinations .
we suggest potential explanations for the features observed in hh 30 , hd 141569 a , ak sco , hd 100546 , and ab aur .
we emphasize that inclined views of companion - induced features can not be converted into face - on views using simple and commonly practiced image deprojections . .
And you have already written the first three sentences of the full article: gas giant planets form in gaseous disks surrounding newly born stars .
as planets form in disks , their gravity perturbs the surrounding material and produces structures such as spiral density waves and gaps ( e.g. , * ? ? ?
these planet - induced structures are detectable in high angular resolution , direct imaging observations of disks at near - infrared ( nir ) wavelengths ( e.g. , * ? ? ?.
Please generate the next two sentences of the article | * ; * ? ? ?
* ; * ? ? ? |
7,046 | Suppose that you have an abstract for a scientific paper: a quantum pseudo - spin model with random spin sizes is introduced to study the effects of charging - energy disorder on the superconducting transition in granular superconducting materials .
charging - energy effects result from the small electrical capacitance of the grains when the coulomb charging energy is comparable to the josephson coupling energy . in the pseudo - spin model ,
randomness in the spin size is argued to arise from the inhomogeneous grain - size distribution . for a particular bimodal spin - size distribution ,
the model describes percolating granular superconductors .
a mean - field theory is developed to obtain the phase diagram as a function of temperature , average charging energy and disorder . and
granular superconductors , josephson - junction arrays , superconductor - insulator transition 74.81.-g , 74.25.dw , 74.40.+k , 64.70.tg .
And you have already written the first three sentences of the full article: quenched disorder is obiquitous in condensed - matter systems , sometimes determining entirely new physical properties and phenomena . for the theoretical explanation of many experimental findings ,
models of classical and quantum spin systems are employed and - typically - disorder is introduced through a spatial variation of the exchange couplings , of the direction of the axial anisotropies , and of the sign of the couplings .
theoretical and experimental studies of model and real physical systems with these kinds of disorder have lead to much new physics ..
Please generate the next two sentences of the article | much discussed have been the glassy phases in magnetic @xcite , and superconducting materials @xcite . in superconductors , specially with the advent of high-@xmath0 ceramic superconductors , the role of disorder has become central in the discussion of the physical properties of real materials @xcite .
many materials are naturally microstructured and granularity characterises the mesoscopic structures of most systems , leading to a phase diagram often displaying a superconductor - insulator transition at zero temperature due to the charging energy of the grains . |
7,047 | Suppose that you have an abstract for a scientific paper: the quantum efficiency in the transfer of an initial excitation in disordered finite networks , modeled by the @xmath0-body embedded gaussian ensembles of random matrices , is studied for bosons and fermions .
the influence of the presence or absence of time - reversal symmetry and centrosymmetry / centrohermiticity are addressed . for bosons and fermions ,
the best efficiencies of the realizations of the ensemble are dramatically enhanced when centrosymmetry ( centrohermiticity ) is imposed . for few bosons distributed in two single - particle levels
this permits perfect state transfer for almost all realizations when one - particle interactions are considered . for fermionic systems
the enhancement is found to be maximal for cases when all but one single particle levels are occupied . .
And you have already written the first three sentences of the full article: an important question on complex quantum systems , which remains open to a large extent , addresses the conditions to have robust efficient transport of excitations across a disordered finite network @xcite . whereas it is well known how to define a hamiltonian system where perfect transport is obtained @xcite , the fact that such system requires the precise specification of a large number of parameters makes it difficult to achieve in practice .
this is the sense of robustness above : statistical changes in the parameters should lead to small fluctuations that preserve good efficiencies , instead of large transmission fluctuations .
clearly , the number of control parameters should be as small as possible ..
Please generate the next two sentences of the article | inspired by ref .
@xcite , we study here the distribution of the transport efficiencies of an initial localized excitation in a disordered network of @xmath1 sites , which is modeled by random hamiltonian that includes many - body interactions , considering both fermions and bosons ; to the best of our knowledge , quantum efficiencies of this type of disordered networks have not been considered . in general , this question is of interest in a variety of fields , including understanding photosynthetic light - harvesting complexes @xcite , such as the fenna - matthews - olson ( fmo ) complex @xcite , or in quantum communication protocols across quantum spin chains @xcite . in either case |
7,048 | Suppose that you have an abstract for a scientific paper: the quantum monte carlo ( qmc ) method can yield the imaginary - time dependence of a correlation function @xmath0 of an operator @xmath1 .
the analytic continuation to real - time proceeds by means of a `` numerical inversion '' of these data to find the response function or spectral density @xmath2 corresponding to @xmath1 .
such a technique is very sensitive to the statistical errors in @xmath0 especially for large values of @xmath3 , when we are interested in the low - energy excitations . in this paper
, we find that if we use the flat histogram technique in the qmc method , in such a way to make the _ histogram of _ @xmath0
_ flat _ , the results of the analytic continuation for low - energy excitations improve using the same amount of computational time . to demonstrate the idea we select an exactly soluble version of the single - hole motion in the @xmath4 model and the diagrammatic monte carlo technique . .
And you have already written the first three sentences of the full article: quantum monte carlo simulation , an undeniably useful tool in addressing a number of issues in quantum many - body physics , can not be used to simulate real - time dynamics . by means of analytic continuation to euclidean time @xmath3 ( @xmath5 ) , however , the schrdinger equation turns into a diffusion equation , which can be simulated using random walks which explore the potential landscape by spending proportionately more `` time '' near the valleys of the potential and less `` time '' near the potential heights .
the same transformation into imaginary time turns the path integral representation of the evolution operator from an integral over paths of computationally `` nasty '' phase factors , a problem almost impossible to treat stochastically , into an integral over paths in imaginary time weighted by a real and positive `` boltzmann - like '' weight ; this weight is interpreted as a well - behaved probability for a particular path to contribute to the sum and this interpretation allows a straightforward stochastic treatment@xcite .
this transformation , by itself , is useful because it yields the interacting ground state and physical quantities related to the equilibrium statistical mechanical description of a quantum many - body system ..
Please generate the next two sentences of the article | however , if we are interested in obtaining information about the real - time dynamics and information about the excitations of the system , an `` inversion '' of this ill - defined transformation for the results of correlation functions @xmath0 of an operator @xmath6 representing a physical observable , namely , @xmath7 ( where @xmath8 is the imaginary - time ordering operator ) from the imaginary time @xmath3 back to real time @xmath9 is required .
the analytic continuation to real - time proceeds by means of a `` numerical inversion '' of the qmc data on @xmath0 to find the spectral function @xmath2 . |
7,049 | Suppose that you have an abstract for a scientific paper: to exactly answer which density region that some frequently used symmetry - energy - sensitive observables probe , for the first time , we make a study of decomposition of the sensitivity of some symmetry - energy - sensitive observables .
it is found that for the au+au reaction at incident beam energies of 200 and 400 mev / nucleon , frequently used symmetry - energy - sensitive observables mainly probe the density - dependent symmetry energy around 1.25@xmath0 ( for pionic observables ) or 1.5@xmath0 ( for nucleonic observables ) .
effects of the symmetry energy in the low - density region is in general small but observable .
the fact that the symmetry - energy - sensitive observables are not sensitive to the symmetry energy in the maximal baryon - density region increases the difficulty of studying nuclear symmetry energy at super - density . .
And you have already written the first three sentences of the full article: in the last 20 years , great progress has been made in the study of a new branch of nuclear physics , i.e , the isospin nuclear physics @xcite .
theoretical studies have shown that , within the parabolic approximation , the energy per particle in asymmetric nuclear matter can be approximately expressed as @xmath1 , where @xmath2 is the isospin asymmetry parameter and @xmath3 is the density - dependent nuclear symmetry energy .
the latter has been studied for decades due to its great importance in both nuclear physics and astrophysics @xcite ..
Please generate the next two sentences of the article | although significant progress has been made , the symmetry energy is still subject to uncertainties especially at high - density region @xcite .
nowadays , many sensitive observables have been identified as promising probes of the symmetry energy , such as the @xmath4 ratio @xcite , energetic photon as well as @xmath5 @xcite , the neutron to proton ratio @xmath6 @xcite , @xmath7 @xcite , the isospin fractionation @xcite and the neutron - proton differential flow @xcite . |
7,050 | Suppose that you have an abstract for a scientific paper: we describe the first results from two observational projects aimed at measuring the amount and spatial distribution of dark matter in distant early - type galaxies ( e / s0s ) and clusters of galaxies . at the galaxy scale
, the lenses structure and dynamics ( lsd ) survey is gathering kinematic data for distant ( up to @xmath0 ) e / s0s that are gravitational lenses . a joint lensing and dynamical analysis
constrains the fraction of dark matter within the einstein radius , the mass - to - light ratio of the stellar component , and the total slope of the mass density profile .
these properties and their evolution with redshift are briefly discussed in terms of the formation and evolution of e / s0 galaxies and measurement of the hubble constant from gravitational time delay systems . at the cluster scale after careful removal of the stellar component with a joint lensing and dynamical analysis
systems with giant radial arcs can be used to measure precisely the inner slope of the dark matter halo .
an hst search for radial arcs and the analysis of a first sample are briefly discussed in terms of the universal dark matter halos predicted by cdm simulations .
# 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: decades after the discovery of dark matter around spiral galaxies little is known about dark matter in early - type galaxies .
mass tracers at large radii ( such as stellar kinematics , kinematics of globular clusters and of planetary nebulae , and x - ray halos ) generally indicate that a constant mass - to - light ratio can not reproduce the observations , although there are typically large uncertainties and a wide variety of behavior is seen .
the main source of uncertainty in interpreting kinematic measures is that the derived mass profile depends on the assumed orbital structure ..
Please generate the next two sentences of the article | this is commonly referred to as the mass - anisotropy degeneracy .
the situation is even more uncertain outside the local universe , because traditional kinematic tracers at large radii are generally not feasible at cosmological distances . |
7,051 | Suppose that you have an abstract for a scientific paper: bosonsampling is a restricted model of quantum computation proposed recently , where a non - adaptive linear - optical network is used to solve a sampling problem that seems to be hard for classical computers .
here we show that , even if the linear - optical network has a constant number ( greater than four ) of beam splitter layers , the exact version of the bosonsampling problem is still classically hard , unless the polynomial hierarchy collapses to its third level .
this is based on similar result known for constant - depth quantum circuits and circuits of 2-local commuting gates ( iqp ) . .
And you have already written the first three sentences of the full article: recently , several restricted models of quantum computation have been investigated that seem to lie between classical and quantum , in terms of their computational complexity . while unlikely to be universal for quantum computation , these models seem to have some nontrivial computational power , as they were shown to perform tasks considered hard for classical computers . unlike factoring
, the tasks performed by these restricted models do not seem to be in np nor to be related to `` useful '' applications , making them less appealing from a practical point of view than the more standard applications of quantum computers , such as shor s factoring algorithm @xcite . on the other hand ,
it is conceivable that these models are easier to implement in experimental settings , since they do not require the full power of quantum computation , and thus provide good candidates for intermediate milestones for the field ..
Please generate the next two sentences of the article | examples of these models include the one clean qubit model and generalizations @xcite , quantum circuits of constant depth three or greater @xcite , circuits of commuting 2-local quantum gates , also known as iqp @xcite , non - adaptive measurement - based quantum computation , known as mbcc ( measurement - based classical computation ) @xcite , and non - adaptive linear optics , also known as bosonsampling @xcite .
however , even if these restricted models propose demonstrations closer to the reach of current technologies than universal quantum computers , there are still important technological challenges to overcome before we can provide compelling evidence that quantum systems can outperform classical computers . |
7,052 | Suppose that you have an abstract for a scientific paper: the shape and the inverse participation ratio ( ipr ) of local spectral density ( lsd ) are studied for a generic isolated system of coupled quantum states , the hamiltonian of which is represented by a band random matrix with the disordered leading diagonal .
we find for the matrices with arbitrary small band that the lack of ergodicity for lsd can be associated with an exponential increase in ipr with the ratio @xmath0 ( @xmath1 - the root of mean square for off - diagonal matrix elements , @xmath2 - the energy spacing between directly coupled basis states ) .
criterions specifying transition to localization and ergodicity for lsd are considered . .
And you have already written the first three sentences of the full article: the statistical properties of quantum system attract considerable attention in the broad field of modern physics ranging from nuclear , atomic and molecular physics to condensed matter and quantum computing . of a special interest
is the properties specifying the quantum chaos border for a system of many - body quantum states .
extensive investigations of many - body interacting systems such as nuclei , many - electron atoms , quantum dots , quantum spin glasses and quantum computer models @xcite have shown that the border is associated with a crossover of level spacing statistics from the poisson distribution to wigner - dyson one and with a transition to ergodic distribution for the eigenstate wavefunction over the large number of basis levels as in random matrix theory ( rmt ) @xcite . in a sense.
Please generate the next two sentences of the article | the interaction leads to dynamic thermalization without coupling to an external thermal bath .
according to @xcite this crossover takes place when the coupling matrix elements of the hamiltonian become comparable to the energy spacing between directly coupled states . |
7,053 | Suppose that you have an abstract for a scientific paper: a projected mass estimator and a maximum likelihood estimator are developed to best determine the mass of stellar clusters from proper motion data .
both methods effectively account and correct for errors in the velocities , and provide an unbiased and robust estimate of the cluster mass . using an extensive proper motion study of @xmath0 centauri by van leeuwen et al .
( 2000 ) , we estimate the mass of @xmath0 centauri using these two different methods to be @xmath1^{3}$ ] . within this modeling context , the statistical error is @xmath2 and the systematic error is @xmath3 .
[ firstpage ] stellar dynamics - celestial mechanics - galaxy : globular clusters : individual : ngc 5139 .
And you have already written the first three sentences of the full article: estimating accurate masses of self - gravitating systems , such as star clusters , is of central importance in astronomy .
most estimates of such masses have been based on radial velocities from a few tracers of the system .
however , the advent of the next generation telescopes , proper motion data will become more accurate and reliable within an observation time of a few years ..
Please generate the next two sentences of the article | proper motions at the milky way s center has already proven a boon ( e.g. @xcite ) .
combined with radial velocities , proper motions can provide us with 5 components of the 6-dimensional phase space of a large number of tracers . |
7,054 | Suppose that you have an abstract for a scientific paper: we describe the physics capabilities and status of the mipp experiment which is scheduled to enter its physics data taking period during december 2004-july 2005 .
we show some of the results obtained from the engineering run that concluded in august 2004 and point out the unique features of mipp that make it an ideal apparatus to study non - perturbative qcd properties . . .
And you have already written the first three sentences of the full article: the main injector particle production experiment ( fnal e-907 , mipp ) @xcite is situated in the meson center beamline at fermilab .
it received its approval @xcite in november 2001 and has installed both the experiment and a newly designed secondary beamline in the interim .
it received its first beams in march 2004 and concluded its engineering run in august 2004 ..
Please generate the next two sentences of the article | the physics data taking run of mipp is scheduled for the running period december 2004-july 2005 .
mipp is designed primarily as an experiment to measure and study in detail the dynamics associated with non - perturbative strong interactions . |
7,055 | Suppose that you have an abstract for a scientific paper: we introduce the concept of black shell , consisting on a massive thin spherical shell contracting toward its gravitational radius from the point of view of an external observer far from the shell , in order to effectively model the gravitational collapse . considering complementary description of entanglement entropy of a black shell and according to gibbons - hawking euclidean approach
, we calculate the bekenstein - hawking entropy retrieving horizon integral and discarding boundary at infinity .
+ key words : black hole entropy , entanglement entropy , black hole thermodynamics .
+ pacs numbers : 04.70.dy .
And you have already written the first three sentences of the full article: bekenstein - hawking entropy @xmath0 has been derived from different points of view @xcite .
but if it is considered thermal with a microscopic description , according to the statistical foundations of entropy , perhaps the most promising and appropriate formalism to explain @xmath0 is the entanglement entropy approach @xcite .
in particular , entanglement entropy of black shells is required , because the usual thermal entropies for black holes are divergent and geometric in nature @xcite . in the first part of this paper.
Please generate the next two sentences of the article | we complete the concept of black shell presented in @xcite .
thus , by simplicity we effectively model the significant features of the gravitational collapse , in terms of a massive thin spherical collapsing shell with respect to an external observer . in the second part of the text we consider euclidean approach for entropy of black shells , thinking in its complementary description of entanglement entropy . |
7,056 | Suppose that you have an abstract for a scientific paper: we present results for the low mass drell - yan production in proton - proton collisions at the lhc in the color dipole formalism .
the dy differential cross sections at @xmath0 tev as a function of dilepton rapidity , transverse momentum and invariant mass are discussed .
we have imposed kinematical cuts related to the low mass dy production investigated by atlas and lhcb collaborations . .
And you have already written the first three sentences of the full article: the cross sections for producing lepton pairs by drell - yan ( dy ) process have been proven to still fulfill the factorization property and are finite to first orders in perturbation theory at sufficiently large transverse momenta , @xmath1 . on the other hand , there is an extensive program of research treating the low @xmath1 region as the conventional factorization approaches give divergent results at @xmath2 ( see ref . @xcite and references therein ) .
in particular , in ref . @xcite it was shown that differential cross section in the region @xmath3 is driven by subprocesses initiated by incident gluons and therefore massive lepton - pair differential cross sections are useful sources of constraints on the gluon density .
that study using next - to - leading order qcd and @xmath1-resummation was generalized in ref ..
Please generate the next two sentences of the article | @xcite to polarized scattering and in ref .
@xcite to electroweak gauge boson production . |
7,057 | Suppose that you have an abstract for a scientific paper: we reconstruct @xmath0-ray opacity of the universe out to @xmath1 using an extensive library of observed galaxy luminosity function ( lf ) surveys extending to high redshifts .
we cover the whole range from uv to mid - ir ( 0.15 - 25 ) providing for the first time a robust empirical calculation of the @xmath2 optical depth out to several tev . here
, we use the same database as @xcite where the extragalactic background light was reconstructed from lfs out to 4.5 and was shown to recover observed galaxy counts to high accuracy .
we extend our earlier library of lfs to 25 such that it covers the energy range of pair production with @xmath0-rays ( 1 ) in the entire _
fermi_/lat energy range , and ( 2 ) at higher tev energies probed by ground - based cherenkov telescopes . in the absence of significant contributions to the cosmic diffuse background from unknown populations , such as the putative population iii era sources
, the universe appears to be largely transparent to @xmath0-rays at all _ fermi_/lat energies out to @xmath3 whereas becoming opaque to tev photons already at @xmath4 and reaching @xmath5 at @xmath6 .
comparison of the currently available _
fermi_/lat gamma - ray burst and blazar data shows that there is room for significant emissions originating in the first stars era . .
And you have already written the first three sentences of the full article: the extragalactic background light ( ebl ) supplies opacity for propagating high energy gev - tev photons via an electron - positron pair production ( @xmath7 ) @xcite . determining the transparency of the universe is of fundamental importance for a wide variety of current observatories such as the space - borne _ fermi_/lat instrument operating at energies @xmath8 gev to ground - based @xmath0-ray telescopes probing energies @xmath91 tev .
the distance at which the optical depth due to this interaction is @xmath10 defines a horizon of the observable universe at @xmath0-ray energies , and has been a subject of extensive efforts designed to model the build - up of ebl with time from the posited emission history of galaxy populations . in this letter
we show that , with observed galaxy populations over a wide range of wavelengths , one can uniquely reconstruct the optical depth of the universe at these energies out to redshifts @xmath11 ..
Please generate the next two sentences of the article | this empirical reconstruction relies exclusively on _ data _ from an extensive library of galaxy luminosity functions ( lfs ) encompassing 18 finely sampled wavelengths from uv to mid - ir ( 0.15 - 24 ) relevant for the pair - production opacity .
this methodology enables robust calculation of the @xmath0-ray opacity in the _ |
7,058 | Suppose that you have an abstract for a scientific paper: fermi observations of gev emission from grbs have suggested that the lorentz factor of some grbs is around a thousand or even higher . at the same time
the same fermi observations have shown an extended gev emission indicating that this higher energy emission might be a part of the afterglow and it does not come from the same region as the lower energy prompt emission .
if this interpretation is correct then we may have to reconsider the opacity limits on the lorentz factor which are based on a one - zone model .
we describe here a two - zone model in which the gev photons are emitted in a larger radius than the mev photons and we calculate the optical depth for pair creation of a gev photon passing the lower energy photons shell . we find that , as expected , the new two - zone limits on the lorentz factor are significantly lower . when applied to fermi bursts
the corresponding limits are lower by a factor of five compared to the one - zone model .
it is possible that both the mev and gev regions have relatively modest lorentz factors ( @xmath0 ) , which is significantly softer then one zone limit . .
And you have already written the first three sentences of the full article: highly relativistic motion , essential to overcome the compactness problem @xcite , is a basic ingredient of all grb models .
the value of the bulk lorentz factor , @xmath1 , of the relativistic outflow is of outmost interest .
it is essential for understanding the nature of the inner engine , the outflow and its acceleration and collimation mechanisms , the conditions at the emitting regions and the radiation mechanism ..
Please generate the next two sentences of the article | so far the most robust method to estimate @xmath1 was using the compactness .
the high energy photons set an upper limit on the optical depth for pair production . |
7,059 | Suppose that you have an abstract for a scientific paper: the focus of the present review is the production of the heaviest elements in nature via the r - process .
a correct understanding and modeling requires the knowledge of nuclear properties far from stability and a detailed prescription of the astrophysical environment .
experiments at cern / isolde have played a pioneering role in exploring the characteristics of nuclear structure in terms of masses and @xmath0-decay properties .
initial examinations paid attention to far unstable nuclei with magic neutron numbers related to r - process peaks , while present activities are centered on the evolution of shell effects with the distance from the valley of stability .
we first show in site - independent applications the effect of both types of nuclear properties on r - process abundances .
then , we explore the results of calculations related to two different ` realistic ' astrophysical sites , ( i ) the supernova neutrino wind and ( ii ) neutron star mergers .
we close with a list of remaining theoretical and experimental challenges needed to overcome for a full understanding of the nature of the r - process , and the role cern / isolde can play in this process .
nuclear astrophysics , r - process nucleosynthesis , isotope and isomer separation via hf splitting , laser ion source , nuclear structure , neutron - rich isotopes , ultra - metal - poor halo stars .
And you have already written the first three sentences of the full article: the astrophysical rapid neutron - capture process ( r - process ) has been recognized for a long time as the scenario responsible for the synthesis of approximately half of the nuclear species in nature , which are more massive than fe @xcite .
it requires environments with a high neutron density , where neutron captures are faster than @xmath0-decays , even for neutron - rich unstable nuclei up to 15 - 30 units from stability . only under such conditions it is possible that highly unstable nuclei are produced near the neutron drip - line via neutron captures , @xmath1-photodisintegrations , @xmath2-decays and @xmath0-delayed processes , leading also to the formation of the heaviest elements in nature like th , u , and pu .
far from stability , magic neutron numbers are encountered for smaller mass numbers a than in the valley of stability , which shifts the r - process abundance peaks in comparison to the s - process peaks ( which occur at neutron shell closures at the stability line due to small neutron capture cross sections ) . besides this basic understanding , the history of r - process research has been quite diverse in suggested scenarios ( for reviews see @xcite ) . starting with a seed distribution somewhere around a=50 - 80 before massive neutron - capture sets in.
Please generate the next two sentences of the article | , the operation of an r - process requires 10 to 150 neutrons per seed nucleus to form all heavier r - nuclei .
the question is which kind of environment can provide such a supply of neutrons to act before decaying with a 10 min half - life . |
7,060 | Suppose that you have an abstract for a scientific paper: we give new examples of simple finitely generated groups arising from actions of free abelian groups on the cantor sets .
as particular examples , we discuss groups of interval exchange transformations , and a group naturally associated with the penrose tilings .
many groups in this class are amenable . .
And you have already written the first three sentences of the full article: the motivation of this paper is to enrich the class of _ non - elementary amenable _ groups .
a group @xmath0 is amenable if there exists a finitely additive translation invariant probability measure on all subsets of @xmath0 .
this definition was given by john von neumann , @xcite , in a response to banach - tarski , and hausdorff paradoxes ..
Please generate the next two sentences of the article | he singled out the property of a group which forbids paradoxical actions .
the class of _ elementary amenable groups _ , denoted by @xmath1 , was introduced by mahlon day in @xcite , as the smallest class of groups that contain finite and abelian groups and is closed under taking subgroups , quotients , extensions and directed unions . |
7,061 | Suppose that you have an abstract for a scientific paper: we continue our study of ends of non - compact manifolds , with a focus on the inward tameness condition . for manifolds with compact boundary , inward tameness , by itself ,
has significant implications .
for example , such manifolds have stable homology at infinity in all dimensions .
we show that these manifolds have ` almost perfectly semistable ' fundamental group at each of their ends .
that observation leads to further analysis of the group theoretic conditions at infinity , and to the notion of a ` near pseudo - collar ' structure .
we obtain a complete characterization of @xmath0-manifolds ( @xmath1 ) admitting such a structure , thereby generalizing @xcite .
we also construct examples illustrating the necessity and usefulness of the new conditions introduced here .
variations on the notion of a perfect group , with corresponding versions of the quillen plus construction , form an underlying theme of this work . .
And you have already written the first three sentences of the full article: in @xcite , @xcite and @xcite we carried out a program to generalize l.c .
siebenmann s famous manifold collaring theorem @xcite in ways applicable to manifolds with non - stable fundamental group at infinity .
motivated by some important examples of finite - dimensional manifolds and a seminal paper by t.a ..
Please generate the next two sentences of the article | chapman and siebenmann @xcite on hilbert cube manifolds , we chose the following definitions .
a manifold @xmath2 with compact boundary is called a _ |
7,062 | Suppose that you have an abstract for a scientific paper: nonlinear control algorithm for a self - energizing electro - hydraulic brake is analytically designed .
the desired closed - loop system behavior is reached via a synthesized nonlinear controller .
shell nonlinear system , nonlinear control , algorithm , electro - hydraulic brake . .
And you have already written the first three sentences of the full article: -reinforcing brakes are a subject of intensive investigation during last years .
working principle of such brakes is to use the wheelset s inertia momentum of a vehicle as the source of power for braking .
one major advantage of self - reinforcing brakes is the energy consumption decrease which makes this research direction perspective . at present.
Please generate the next two sentences of the article | the development of a new brake concept of a self - energizing electro - hydraulic brake for a railway application is being carried out at the institute for fluid power drives and control ( ifas , rwth aachen university ) .
working principle of the braking system can be found in [ 69 ] . |
7,063 | Suppose that you have an abstract for a scientific paper: we have obtained optical long - slit spectroscopy of the nucleus of m32 using the space telescope imaging spectrograph aboard the _ hubble space telescope_. the stellar rotation velocity and velocity dispersion , as well as the full line - of - sight velocity distribution ( losvd ) , were determined as a function of position along the slit using two independent spectral deconvolution algorithms .
we see three clear kinematical signatures of the nuclear black hole : a sudden upturn , at @xmath0 from the center , in the stellar velocity dispersions ; a flat or rising rotation curve into the center ; and strong , non - gaussian wings on the central losvd .
the central velocity dispersion is @xmath1 ( gaussian fit ) or @xmath2 ( corrected for the wings ) .
both the velocity dispersion spike and the shape of the central losvd are consistent with the presence of a supermassive compact object in m32 with a mass in the range @xmath3 .
these data are a significant improvement on previous stellar kinematical data , making m32 the first galaxy for which the imprint of the black hole s gravitation on the stellar velocities has been observed with a resolution comparable to that of gas - dynamical studies .
# 1#23.6pt keywords : galaxies : elliptical and lenticular galaxies : structure galaxies : nuclei stellar dynamics .
And you have already written the first three sentences of the full article: the presence of a supermassive compact object , presumably a black hole , at the center of the dwarf elliptical galaxy m32 has been suspected for some time ( @xcite ) .
the evidence consists of rapid rotation of the stars near the center of m32 and a central peak in the stellar velocity dispersions ( @xcite ; @xcite ; @xcite ; @xcite ; @xcite ) .
the most recent study ( @xcite , 1998 ) used data from the faint object spectrograph ( fos ) on the _ hubble space telescope _ ( hst ) to infer the rotation and dispersion velocities with a spatial resolution of @xmath4 in the inner @xmath5 of m32 ..
Please generate the next two sentences of the article | the fos data revealed a sharper rise in the stellar velocity dispersions than had been observed from the ground ; however the velocity resolution of the fos is limited , making that instrument only marginally useful for the study of a low velocity dispersion system like m32 .
in fact , van der marel et al . ( |
7,064 | Suppose that you have an abstract for a scientific paper: here we address a fundamental issue in surface physics : the dynamics of adsorbed molecules .
we study this problem when the particle s desorption is characterized by a non markovian process , while the particle s adsorption and its motion in the bulk are governed by a markovian dynamics .
we study the diffusion of particles in a semi - infinite cubic lattice , and focus on the effective diffusion process at the interface @xmath0 .
we calculate analytically the conditional probability to find the particle on the @xmath1 plane as well as the surface dispersion as functions of time .
the comparison of these results with monte carlo simulations show an excellent agreement . .
And you have already written the first three sentences of the full article: the mechanism called _ bulk - mediated surface diffusion _ typically arises at interfaces separating a liquid bulk phase and a second phase which may be either solid , liquid , or gaseous .
whenever the adsorbed species is soluble in the liquid bulk , adsorption - desorption processes occur continuously .
these processes generate surface displacement because desorbed molecules undergo fickian diffusion in the liquid s bulk , and are latter re - adsorbed elsewhere ..
Please generate the next two sentences of the article | when this process is repeated many times , an effective diffusion results for the molecules on the surface .
the importance of bulk - surface exchange in relaxing homogeneous surface density perturbations is experimentally well established @xcite . |
7,065 | Suppose that you have an abstract for a scientific paper: dawson and murray - clay ( 2012 ) pointed out that the inner part of the cold population in the kuiper belt ( that with semi major axis @xmath0 au ) has orbital eccentricities significantly smaller than the limit imposed by stability constraints . here , we confirm their result by looking at the orbital distribution and stability properties in proper element space . we show that the observed distribution could have been produced by the slow sweeping of the 4/7 mean motion resonance with neptune that accompanied the end of neptune s migration process .
the orbital distribution of the hot kuiper belt is not significantly affected in this process , for the reasons discussed in the main text .
therefore , the peculiar eccentricity distribution of the inner cold population can not be unequivocally interpreted as evidence that the cold population formed in - situ and was only moderately excited in eccentricity ; it can simply be the signature of neptune s radial motion , starting from a moderately eccentric orbit .
we discuss how this agrees with a scenario of giant planet evolution following a dynamical instability and , possibly , with the radial transport of the cold population . .
And you have already written the first three sentences of the full article: the kuiper belt has a complex orbital structure and can be divided in multiple sub - populations ( see gladman et al . , 2008 for a review ) . among them
are the cold and the hot populations , which are defined as the collections of objects inwards of the 1/2 resonance with neptune ( @xmath1 au ) with , respectively , inclinations smaller or larger than 4 degrees .
the cold and hot populations have also distinct physical properties ( see morbidelli and brown , 2004 for a review ) ..
Please generate the next two sentences of the article | there is a quite general consensus that the hot population formed originally closer to the sun , was dynamically excited by the perturbations from the giant planets and finally was transported into the kuiper belt ( gomes , 2003 ; levison et al . , 2008 ) .
however , there is no consensus on the origin of the cold population . |
7,066 | Suppose that you have an abstract for a scientific paper: in monolayer mos@xmath0 optical transitions across the direct bandgap are governed by chiral selection rules , allowing optical valley initialization . in time
resolved photoluminescence ( pl ) experiments we find that both the polarization and emission dynamics do not change from 4k to 300k within our time resolution .
we measure a high polarization and show that under pulsed excitation the emission polarization significantly decreases with increasing laser power .
we find a fast exciton emission decay time on the order of 4ps . by compensating the
temperature induced change in bandgap energy with the excitation laser energy an emission polarization of 40% is recovered at 300k , close to the maximum emission polarization for this sample at 4k . .
And you have already written the first three sentences of the full article: * time resolved photoluminescence of a - exciton . * ( a ) laser pulse ( blue line ) and pl emission ( black line ) intensity at t = 4 k detected at maximum of a - exciton
pl e@xmath1 ev as a function of time .
inset : chiral optical selection rules in 1ml mos@xmath0 ( b ) t=4k , e@xmath2 ev , e@xmath1 ev . laser polarization @xmath3 . left axis : @xmath3 ( @xmath4 ) polarized pl emission intensity presented in black ( red ) as a function of time ..
Please generate the next two sentences of the article | right axis : circular polarisation degree during exciton emission ( blue hollow squares : excitation power p@xmath5 , green full squares:0.01 p@xmath6 ) , errors bars take into account uncertainty in time origin @xmath7 .
( c ) same as ( b ) , but for t=300k , e@xmath8 ev , e@xmath9 ev.,scaledwidth=45.0% ] transition metal dichalcogenides such as mos@xmath0 emerge as an exciting class of atomically flat , two - dimensional materials for electronics @xcite , optics @xcite and optoelectronics @xcite . |
7,067 | Suppose that you have an abstract for a scientific paper: by careful searching of synthetic and observed spectra in a sample of cool giant and supergiant stars , we have updated the continuum band - passes of near - infrared wing three filter system . this photometric system measures the strength of titanium oxide ( tio ) absorption in near - infrared ( nir ) at 719 nm .
we show that new reference continuum band - passes are essentially free from molecular absorptions and the updated tio - index defines the temperature variation in a sample of cool giants with less scatter .
a tio - index vs. effective temperature calibration is derived based on new continuum band - passes . .
And you have already written the first three sentences of the full article: among many absorption features in spectra of cool stars , tio molecular absorptions are be recognized as an indicator of basic stellar parameters mainly in two type of stars , cool pulsating giants and super giants and chromospheric active stars which tio absorption can be used as a starspot indicator @xcite .
the temperature sensitivity of tio bands at near - infrared is so pronounced that these bands have always been used as a primary indicator to divide m stars into their subtypes .
another interesting observed fact is that the tio absorption strength is independent of luminosity class , which is approximately the same for dwarf , giants and supergiants @xcite ..
Please generate the next two sentences of the article | @xcite defined an index by measuring the tio@xmath0 absorption band strength at @xmath1 = 886 nm in m giants , and calibrated it versus temperature by using the relation between spectral type and temperature given by ridgway @xcite .
as shown in figure 2 of ramsey , the depth of the tio band at 886 nm is a sensitive temperature indicator for giants in the range @xmath2 k. it is also somewhat useful in the range @xmath3 k. at @xmath4 k , the tio bands become too weak to be useful . |
7,068 | Suppose that you have an abstract for a scientific paper: bounded apollonian circle packings ( acp s ) are constructed by repeatedly inscribing circles into the triangular interstices of a configuration of four mutually tangent circles , one of which is internally tangent to the other three .
if the original four circles have integer curvature , all of the circles in the packing will have integer curvature as well . in @xcite
, sarnak proves that there are infinitely many circles of prime curvature and infinitely many pairs of tangent circles of prime curvature in a primitive integral acp . in this paper , we give a heuristic backed up by numerical data for the number of circles of prime curvature less than @xmath0 , and the number of kissing primes , " or _
pairs _ of circles of prime curvature less than @xmath0 in a primitive integral acp .
we also provide experimental evidence towards a local to global principle for the curvatures in a primitive integral acps . .
And you have already written the first three sentences of the full article: start with four mutually tangent circles , one of them internally tangent to the other three as in fig .
[ circles ] .
one can inscribe into each of the curvilinear triangles in this picture a unique circle ( the uniqueness follows from an old theorem of apollonius of perga circa 200 bc ) ..
Please generate the next two sentences of the article | if one continues inscribing the circles in this way the resulting picture is called an apollonian circle packing ( acp ) .
a key aspect of studying such packings is to consider the radii of the circles which come up in a given acp . however , since these radii become small very quickly , it is more convenient to study the _ curvatures _ of the circles , or the reciprocals of the radii |
7,069 | Suppose that you have an abstract for a scientific paper: we study the relative velocity of inertial particles suspended in turbulent flows and discuss implications for dust particle collisions in protoplanetary disks .
we simulate a weakly compressible turbulent flow , evolving 14 particle species with friction timescale , @xmath0 , covering the entire range of scales in the flow .
the particle stokes numbers , @xmath1 , measuring the ratio of @xmath0 to the kolmogorov timescale , are in the range @xmath2 . using simulation results ,
we show that the model by pan & padoan ( pp10 ) gives satisfactory predictions for the rms relative velocity between identical particles .
the probability distribution function ( pdf ) of the relative velocity is found to be highly non - gaussian .
the pdf tails are well described by a 4/3 stretched exponential function for particles with @xmath3 , where @xmath4 is the lagrangian correlation timescale , consistent with a prediction based on pp10 .
the pdf approaches gaussian only for very large particles with @xmath5 .
we split particle pairs at given distances into two types with low and high relative speeds , referred to as continuous and caustic types , respectively , and compute their contributions to the collision kernel .
although amplified by the effect of clustering , the continuous contribution vanishes in the limit of infinitesimal particle distance , where the caustic contribution dominates .
the caustic kernel per unit cross section rises rapidly as @xmath1 increases toward @xmath6 , reaches a maximum at @xmath7 , and decreases as @xmath8 for @xmath9 . .
And you have already written the first three sentences of the full article: the dynamics of particles of finite inertia suspended in turbulent flows is a fundamental problem with applications ranging from industrial processes ( e.g. spray combustion engines ) to geophysical flows ( e.g. , atmospheric clouds ) .
the interaction between turbulence and particles has been studied to understand rain initiation in warm terrestrial clouds ( e.g. , pinsky & khain 1997 ; falkovich , fouxon , & stepanov 2002 ; shaw 2003 ) , cloud evolution in the atmospheres of planets , cool stars and brown dwarfs ( e.g. , rossow 1978 ; pruppacher & klett 1997 ; freytag et al .
2010 ; helling et al ..
Please generate the next two sentences of the article | 2011 ) , collisions and growth of dust particles in protoplanetory disks ( e.g. , dullemond & dominik 2005 ; zsom et al . 2010 , 2011 ;
birnstiel et al . |
7,070 | Suppose that you have an abstract for a scientific paper: the huge spin precession frequency observed in recent experiments with spin - polarized beams of hot electrons shot through magnetized films is interpreted as being caused by zeeman coupling of the electron spins to the so - called _ weiss exchange field _ in the film .
a `` stern - gerlach experiment '' for electrons moving through an inhomogeneous exchange field is proposed .
the microscopic origin of exchange interactions and of large mean exchange fields , leading to different types of magnetic order , is elucidated .
a microscopic derivation of the equations of motion of the weiss exchange field is presented .
novel proofs of the existence of phase transitions in quantum @xmath0-models and antiferromagnets , based on an analysis of the statistical distribution of the exchange field , are outlined . .
And you have already written the first three sentences of the full article: effects of ferromagnetism have been known since antiquity . but a mathematical understanding of the microscopic origin of ferromagnetism has remained somewhat elusive , until today ! pauli paramagnetism , ferro- , ferri- and antiferromagnetism are quantum phenomena connected to the spin of electrons and to pauli s exclusion principle .
the theory of _ paramagnetism _ in ( free ) electron gases is quite straightforward , @xcite .
_ antiferromagnetism _ is relatively well understood : a mechanism for the generation of antiferromagnetic exchange interactions has been proposed by anderson @xcite , who discovered a close relationship between the half - filled hubbard model and the heisenberg antiferromagnet using perturbative methods ; ( see also @xcite for mathematically more compelling and more general variants of anderson s key observation ) ..
Please generate the next two sentences of the article | it has been proven rigorously by dyson , lieb and simon @xcite , using the method of infrared bounds previously discovered in @xcite , that the _ quantum heisenberg antiferromagnet _ with nearest - neighbour exchange couplings exhibits a phase transition accompanied by spontaneous symmetry breaking and the emergence of gapless spin waves , as the temperature is lowered , in _ three _ or _ more _ dimensions .
( the mermin - wagner theorem says that , in ( one and ) two dimensions , continuous symmetries can not be broken spontaneously in models with short - range interactions , @xcite . ) |
7,071 | Suppose that you have an abstract for a scientific paper: to assess the classification accuracy of a continuous diagnostic result , the receiver operating characteristic ( roc ) curve is commonly used in applications .
the partial area under the roc curve ( pauc ) is one of widely accepted summary measures due to its generality and ease of probability interpretation . in the field of life science , a direct extension of the pauc into the time - to - event setting
can be used to measure the usefulness of a biomarker for disease detection over time . without using a trapezoidal rule ,
we propose nonparametric estimators , which are easily computed and have closed - form expressions , for the time - dependent pauc .
the asymptotic gaussian processes of the estimators are established and the estimated variance - covariance functions are provided , which are essential in the construction of confidence intervals .
the finite sample performance of the proposed inference procedures are investigated through a series of simulations .
our method is further applied to evaluate the classification ability of cd4 cell counts on patient s survival time in the aids clinical trials group ( actg ) 175 study .
in addition , the inferences can be generalized to compare the time - dependent paucs between patients received the prior antiretroviral therapy and those without it .
= 0.3 in .
And you have already written the first three sentences of the full article: decision - making is an important issue in many fields such as signal detection , psychology , radiology , and medicine .
for example , preoperative diagnostic tests are medically necessary and implemented in clinical preventive medicine to determine those patients for whom surgery is beneficial . for the sake of cost - saving or performance improvement , new diagnostic tests are often introduced and the classification accuracies of them are evaluated and compared with the existing ones .
the roc curve , a plot of the true positive rate ( tpr ) versus the false positive rate ( fpr ) for each possible cut point , has been widely used for this purpose when the considered diagnostic tests are continuous ..
Please generate the next two sentences of the article | one advantage of the roc curve is that it describes the inherent classification capability of a biomarker without specifying a specific threshold .
moreover , the invariance characteristic of roc curve in measurement scale provides a suitable base to compare different biomarkers . generally , the more the curve moves toward the point @xmath0 , the better a biomarker performs . in many applications , the area under the roc curve ( auc ) , |
7,072 | Suppose that you have an abstract for a scientific paper: we present the essential experimental steps of our all - optical approach to prepare a double - degenerate fermi - fermi mixture of @xmath0li and @xmath1k atoms , which then serves as a starting point for molecule formation .
we first describe the optimized trap loading procedures , the internal - state preparation of the sample , and the combined evaporative and sympathetic cooling process .
we then discuss the preparation of the sample near an interspecies feshbach resonance , and we demonstrate the formation of heteronuclear molecules by a magnetic field ramp across the resonance . .
And you have already written the first three sentences of the full article: the groundbreaking achievements in experiments with ultracold fermi gases @xcite have opened up unprecedented possibilities to study new regimes of strongly interacting quantum matter .
ultracold gases represent well - controllable model systems for the exploration of many - body regimes in a way not possible in conventional condensed - matter systems @xcite .
a new frontier in the field is currently being explored in experiments on ultracold fermi - fermi mixtures of @xmath0li and @xmath1k atoms @xcite . because of the mass imbalance and the possibility to apply species - specific optical potentials , such systems promise manifold intriguing applications both in many - body physics @xcite and few - body physics @xcite . to prepare degenerate fermi gases ,.
Please generate the next two sentences of the article | all - optical approaches have proven to be simple and robust and they facilitate highly efficient evaporative cooling
. therefore they are routinely applied in many present experiments ; see ref . |
7,073 | Suppose that you have an abstract for a scientific paper: we integrated the orbital evolution of 30,000 jupiter - family comets , 1300 resonant asteroids , and 7000 asteroidal , trans - neptunian , and cometary dust particles . for initial orbital elements of bodies close to those of comets 2p , 10p , 44p , and 113p , a few objects got earth - crossing orbits with semi - major axes @xmath0@xmath12 au and moved in such orbits for more than 1 myr ( up to tens or even hundreds of myrs ) .
four objects ( from 2p and 10p runs ) even got inner - earth orbits ( with aphelion distance @[email protected] au ) and aten orbits for myrs .
our results show that the trans - neptunian belt can provide a significant portion of near - earth objects , or the number of trans - neptunian objects migrating inside the solar system can be smaller than it was earlier considered , or most of 1-km former trans - neptunian objects that had got near - earth object orbits for millions of years disintegrated into mini - comets and dust during a smaller part of their dynamical lifetimes .
the probability of a collision of an asteroidal or cometary particle during its lifetime with the earth was maximum at diameter @xmath3@xmath4100 @xmath5 m . at @xmath3@xmath110 @xmath5 m
such probability for trans - neptunian particles was less than that for asteroidal particles by less than an order of magnitude , so the fraction of trans - neptunian particles with such diameter near earth can be considerable . .
And you have already written the first three sentences of the full article: celestial bodies and dust particles migrate to near - earth space from different regions of the solar system ( from the main asteroid and edgeworth - kuiper belts , the oort and hills clouds , etc . ) . some scientists ( farinella et al .
1993 ; bottke et al .
2002 ) considered that most near - earth objects ( neos ) are asteroidal fragments , others ( wetherill 1988 ) supposed that half of neos are former short - period comets ..
Please generate the next two sentences of the article | we studied migration of small bodies and dust particles based on extensive integrations , considering more jupiter - crossing objects than before .
the interval of considered diameters of dust particles was wider than in previous publications . |
7,074 | Suppose that you have an abstract for a scientific paper: the internet - of - things ( iot ) is an emerging concept of network connectivity at anytime and anywhere for billions of everyday objects , which has recently attracted tremendous attentions from both the industry and academia .
the rapid growth of iot has been driven by recent advancements in consumer electronics , wireless network densification , 5 g communication technologies [ e.g. , millimeter wave and massive multiple - input and multiple - output ( mimo ) ] , and cloud - computing enabled big - data analytics .
one of the remaining key challenges for iot is the limited network lifetime due to massive iot devices being powered by batteries with finite capacities .
the low - power and low - complexity backscatter communications ( backcom ) has emerged to be a promising technology for tackling the challenge . in this article
, we present an overview of the active area by discussing basic principles , system and network architectures and relevant techniques .
last , we describe the iot applications for backcom and how the technology can solve the energy challenge for iot . .
And you have already written the first three sentences of the full article: the idea of _ internet - of - things _ ( iot ) originated from an internet - connected coke machine at carnegie mellon university in the 1980 s and took over in the late 1990 s with the vision of networking everyday objects so as to automate our societies and daily lives . in the past decades
, the iot has seen technological innovations in a wide range of applications such as smart city , smart home , and autonomous robots , vehicles and _ unmanned aerial vehicles _ ( uavs ) .
the iot is expected to comprise tens of billions of sensors in the near future among other types of nodes ..
Please generate the next two sentences of the article | the big - data collected via the sensors over iot is centralized and analyzed in the cloud to measure and regulate phenomena of common interest in the real world such as pollution , traffic congestion , and parking availability . empowered by cloud computing
, the iot technologies can penetrate many sectors of our society ranging from traffic control to business and foster breakthroughs in diversified fields ranging from physics to biology . |
7,075 | Suppose that you have an abstract for a scientific paper: according to the multiple point principle our universe is on the coexistence curve of two or more phases of the quantum vacuum .
the coexistence of different quantum vacua can be regulated by the exchange of the global fermionic charges between the vacua , such as baryonic , leptonic or family charge . if the coexistence is regulated by the baryonic charge , all the coexisting vacua exhibit the baryonic asymmetry . due to the exchange of the baryonic charge between the vacuum and matter which occurs above the electroweak transition , the baryonic asymmetry of the vacuum induces the baryonic asymmetry of matter in our standard - model phase of the quantum vacuum .
the present baryonic asymmetry of the universe indicates that the characteristic energy scale which regulates the equilibrium coexistence of different phases of quantum vacua is about @xmath0 gev . .
And you have already written the first three sentences of the full article: dealing with quantum vacuum whose ` microscopic ' physics is still unknown the high - energy , general - relativity and condensed - matter communities use different experience developed in working in each of those fields @xcite . in condensed matter there is a rather general class of fermionic systems , where the relativistic quantum field theory gradually emerges at low energy and where the momentum - space topology is responsible for the mass protection for fermions , so that masses of all the fermions are much smaller than the natural energy scale provided by the microscopic ( trans - planckian ) physics @xcite .
since the vacuum of the standard model belongs to the same universality class of quantum vacua , this condensed - matter example provides us with some criteria for selection of the particle physics theories : the theory which incorporates the standard model must be consistent with its condensed - matter analog .
here we apply such criteria to the multiple point principle ( mpp ) @xcite . according to mpp.
Please generate the next two sentences of the article | , nature chooses the parameters of the standard model such that two or several phases of the quantum vacua have the same energy density .
these phases coexist in our universe in the same manner as different phases of quantum liquids , such as superfluid phases a and b of @xmath1he or mixtures of @xmath1he and @xmath2he liquids . using mpp nielsen and |
7,076 | Suppose that you have an abstract for a scientific paper: some ob stars show variable non - thermal radio emission .
the non - thermal emission is due to synchrotron radiation that is emitted by electrons accelerated to high energies .
the electron acceleration occurs at strong shocks created by the collision of radiatively - driven stellar winds in binary systems . here
we present results of our modelling of two colliding wind systems : cyg ob2 no .
8a and cyg ob2 no .
9 . .
And you have already written the first three sentences of the full article: , title="fig:",width=192 ] , title="fig:",width=192 ] during recent years many ob stars have been discovered to be binary systems .
non - thermal radio emission is observed to be produced by some of these binary stars .
the non - thermal emissivity is thought to be due to synchrotron emission radiated by relativistic electrons ..
Please generate the next two sentences of the article | the electrons are accelerated up to high energies by strong shocks produced by the collision between the two radiatively driven stellar winds ( ( * ? ? ?
* eichler & usov 1993 ) ) . |
7,077 | Suppose that you have an abstract for a scientific paper: a paperclip can float on water .
drops of mercury refuse to spread on a surface .
these capillary phenomena are macroscopic manifestations of molecular interactions , and can be explained in terms of surface tension . for students ,
the concept of surface tension is quite challenging since the microscopic intuition is often in conflict with the common macroscopic interpretations . in this paper
we address a number of conceptual questions that are often encountered when teaching capillarity . by answering these questions
we provide a perspective that reconciles the macroscopic viewpoints , from thermodynamics or fluid mechanics , and the microscopic perspective from statistical physics . .
And you have already written the first three sentences of the full article: capillarity is one of the most interesting subjects to teach in condensed matter physics , as its detailed understanding involves three otherwise separated domains : macroscopic thermodynamics@xcite , fluid mechanics and statistical physics@xcite .
the microscopic origin of surface tension lies in the intermolecular interactions and thermal effects@xcite , while macroscopically it can be seen as a force acting along the interface or an energy per unit surface . in the present article
we discuss the link between these three aspects of capillarity , on the basis of simple academic examples ..
Please generate the next two sentences of the article | we first discuss the standard problems faced by students and many researchers in the understanding of surface tension .
we will see that the difficulty of understanding surface tension forces is often caused by the improper or incomplete definition of a system on which the forces act . |
7,078 | Suppose that you have an abstract for a scientific paper: a comprehensive survey is given of the thermoballistic approach to charge carrier transport in semiconductors .
this semiclassical approach bridges the gap between the drift - diffusion and ballistic ( `` thermionic '' ) models of carrier transport , whose validity is limited to the range of very small and very large values , respectively , of the carrier mean free path .
the physical concept underlying the thermoballistic approach , while incorporating basic features of the drift - diffusion and ballistic descriptions , constitutes a novel , unifying scheme .
it is based on the introduction of `` ballistic configurations '' defined by a random partitioning of the length of a semiconducting sample into ballistic transport intervals .
the points linking adjacent ballistic intervals are assumed to be points of local thermodynamic equilibrium characterized by a local chemical potential .
carriers thermally emitted at any such point are ballistically transmitted across either interval , while at the same time carriers transmitted from the equilibrium points next to it are `` absorbed '' at that point , i.e. , they are assumed to be instantaneously equilibrated there . during their transmission ,
the carriers face , in general , potential energy barriers arising from internal and external electrostatic potentials in the sample .
the lengths of the ballistic intervals are stochastic variables , with associated probabilities given by the probabilities for carriers to traverse an interval without collisions with the scattering centers randomly distributed over the sample .
these probabilities are controlled by the carrier mean free path , whose magnitude is arbitrary . by averaging the ballistic carrier currents over all ballistic configurations ,
a position - dependent thermoballistic current is derived , which is the key element of the thermoballistic concept and forms the point of departure for the calculation of various transport properties .
the present article starts out with a....
And you have already written the first three sentences of the full article: the phenomenon of electric conduction in metals and semiconductors has been a prominent research topic ever since the early days of solid - state physics .
the idea that electric currents flowing inside solid materials are effected by the transport of `` small '' charged particles ( `` charge carriers '' ) was first conceived by weber.@xcite following the discovery of the electron by thomson,@xcite weber s idea quickly found its concrete expression in attempts to understand electric ( as well as thermal ) conduction in solids as a manifestation of electron transport .
the basic concept for a theoretical treatment of conduction in terms of the motion of individual carriers was outlined by riecke.@xcite relying to some extent on this concept , drude@xcite formulated his celebrated transport model , which subsequently was refined by lorentz.@xcite in drude s model , the atomistic picture of matter and the kinetic theory of gases are combined to describe conduction in terms of a homogeneous gas of non - interacting , mobile charge carriers in thermodynamic equilibrium , which are assumed to move against a background of spatially fixed , heavy atoms . when an external electric field is applied , the interplay of field - induced acceleration and subsequent thermalizing collisions with the heavy atoms gives rise to a `` drift current '' of the carriers ..
Please generate the next two sentences of the article | the magnitude of this current is determined by the `` mean free path '' , i.e. , the average distance the carriers travel between two collisions . for the drift
current to be a valid concept , the mean free path must be very small as compared with typical dimensions of the sample . |
7,079 | Suppose that you have an abstract for a scientific paper: in contrary to other 1d momentum - conserving lattices such as the fermi - pasta - ulam @xmath0 ( fpu-@xmath0 ) lattice , the 1d coupled rotator lattice is a notable exception which conserves total momentum while exhibits normal heat conduction behavior .
the temperature behavior of the thermal conductivities of 1d coupled rotator lattice had been studied in previous works trying to reveal the underlying physical mechanism for normal heat conduction .
however , two different temperature behaviors of thermal conductivities have been claimed for the same coupled rotator lattice .
these different temperature behaviors also intrigue the debate whether there is a phase transition of thermal conductivities as the function of temperature . in this work
, we will revisit the temperature dependent thermal conductivities for the 1d coupled rotator lattice .
we find that the temperature dependence follows a power law behavior which is different with the previously found temperature behaviors .
our results also support the claim that there is no phase transition for 1d coupled rotator lattice .
we also give some discussion about the similarity of diffusion behaviors between the 1d coupled rotator lattice and the single kicked rotator also called the chirikov standard map . .
And you have already written the first three sentences of the full article: the exploration of underlying mechanism for anomalous and normal heat conduction in low dimensional systems represents a huge challenge in the area of statistical physics @xcite . after enormous efforts for more than one decade from numerical simulations@xcite , theoretical predictions@xcite and experimental observations@xcite
, there is still no consensus for the exact physical mechanism causing anomalous heat conduction .
it is believed that momentum conservation plays an important role in determining the actual heat conduction behavior . in general ,.
Please generate the next two sentences of the article | 1d non - integrable lattices with momentum conserving property should have anomalous heat conduction where the thermal conductivity @xmath1 diverges with the lattice size @xmath2 as @xmath3 where @xmath4 @xcite .
however , the 1d coupled rotator lattice is a well known exception . |
7,080 | Suppose that you have an abstract for a scientific paper: we present new _ very large array _
h i spectral line , archival _ sloan digital sky survey _ , and archival _ spitzer space telescope _
imaging of eight star - forming blue compact dwarf galaxies that were selected to be optically compact ( optical radii < 1 kpc ) .
these systems have faint blue absolute magnitudes ( m@xmath017 ) , ongoing star formation ( based on emission - line selection by the h@xmath1 or [ ] lines ) , and are nearby ( mean velocity @xmath2 3315 kms@xmath3 @xmath4 45 mpc ) .
one galaxy in the sample , adbs 113845 + 2008 , is found to have an h i halo that extends 58 r - band scale lengths from its stellar body .
in contrast , the rest of the sample galaxies have h i radii to optical - scale - length ratios ranging from 9.3 to 26 .
the size of the h i disk in the `` giant disk '' dwarf galaxy adbs 113845 + 2008 appears to be unusual as compared to similarly compact stellar populations . .
And you have already written the first three sentences of the full article: blue compact dwarf galaxies ( hereafter , bcds ) have emerged as a particularly intriguing subset of dwarf galaxies that have been studied in the local universe ( [email protected] ) . since the early studies and characterizations by @xcite and @xcite , many investigations have classified bcds as systems that harbor spatially and temporally concentrated ongoing star formation in a low - mass galaxy potential well .
while definitions in the literature vary , bcds are instrinsically faint systems ( m@xmath617 ) that exhibit ongoing star formation over the bulk of an otherwise physically compact stellar population .
detailed studies of individual , nearby bcds have provided important insights into their physical properties and into the mechanisms that initiate and govern their star formation ..
Please generate the next two sentences of the article | @xcite found that five compact dwarf galaxies that are currently experiencing strong bursts of star formation exhibit central h i surface densities that are significantly higher than those of dwarf irregular ( dirr ) galaxies .
similarly , some well - studied bcds harbor very high column density neutral hydrogen gas in the regions of active star formation ( e.g. , n@xmath7 @xmath4 2.4@xmath810@xmath9 @xmath10 in izw18 ; see brown etal . |
7,081 | Suppose that you have an abstract for a scientific paper: we consider a random knockout tournament among players @xmath0 , in which each match involves two players .
the match format is specified by the number of matches played in each round , where the constitution of the matches in a round is random .
supposing that there are numbers @xmath1 such that a match between @xmath2 and @xmath3 will be won by @xmath2 with probability @xmath4 , we obtain a lower bound on the tournament win probability for the best player , as well as upper and lower bounds for all the players .
we also obtain additional bounds by considering the best and worst formats for player @xmath5 in the special case @xmath6 * random knockout tournaments * * ilan adler * + department of industrial engineering and operations research + university of california , berkeley + @xmath7 + * yang cao * + department of industrial and systems engineering + university of southern california + @xmath7 + * richard karp * + computer science department + university of california , berkeley + @xmath7 + * erol pekoz * + school of business + boston university + @xmath7 + * sheldon m. ross * + department of industrial and systems engineering @xmath7 + university of southern california @xmath8 [email protected] + [email protected] + [email protected] + [email protected] + [email protected] @xmath8 .
And you have already written the first three sentences of the full article: we consider a tournament among players @xmath0 , in which each match involves two players . the tournament is assumed to be of knockout type in that the losers of matches are eliminated and do not move on to the next round , and the tournament continues until all but one player is eliminated , with that player being declared the winner of the tournament .
the match format is specified by the set of positive integers @xmath9 with the interpretation that there are a total of @xmath10 rounds , with round @xmath2 consisting of @xmath11 matches , @xmath12 because @xmath13 players have been eliminated by the end of round @xmath14 , we must have that @xmath15 we suppose that the constitution of the matches in a round is totally random . that is , for instance ,
the @xmath16 players that play in round @xmath5 are randomly chosen from all @xmath17 players and then randomly arranged into @xmath18 match pairs ..
Please generate the next two sentences of the article | the winners of these @xmath18 matches , along with the @xmath19 players that did not play a match in round @xmath5 then move to round @xmath20 , and so on .
we suppose that the players have respective values @xmath1 , and that a match involving players @xmath2 and @xmath3 is won by player @xmath2 with probability @xmath21 we let @xmath22 be the probability that player @xmath2 wins the tournament , @xmath23 in section 3 we derive a lower bound on the probability that the strongest player ( e.g. , the one with the largest @xmath24 ) wins the tournament , and an upper bound on the probability that the weakest player wins the tournament . in section 4 we derive upper and lower bounds on the win probabilities @xmath25 and also show that if @xmath26 then @xmath27 in section 5 , we consider the special case where @xmath28 and show that when @xmath29 the best format for the strongest player is the so - called _ balanced format _ that has @xmath30 matches in the first round and then has all remaining players competing in each subsequent round . |
7,082 | Suppose that you have an abstract for a scientific paper: ( 1,0)400 + + @xmath0 the famous twin paradox of the special theory o__f _ _ relativity by einstein ( 1905 ) is revisited and revised .
this paradox is not a paradox in the true sense of a paradox but a reflection of a misunderstanding of the problem and the principle o__f _ _ relativity .
the currently accepted solution to this takes into account the accelerations and deceleration of the traveling twin thus introducing an asymmetry that solves the paradox .
we argue here that , with the acceleration and deceleration neglected , the problem is asymmetric hence leading to the same conclusion that the traveling twin will age less than the stay at home .
we introduce a symmetric twin paradox whose solution can not be found within the currently accepted provinces of the str if one adopts the currently accepted philosophy of the str namely that it is impossible for an inertial observer to determine their state of motion . to resolve this
, we present ( in our modest view ) a simple and convincing argument that leads us to conclude that it must be possible for an inertial observer to determine their own state of motion . with this
, we are able to solve the symmetric twin paradox .
the fact that it is possible for an inertial observer to determine their state of motion brings us back to the long rejected idea of an all pervading and permeating medium the aether , namely the lorentz luminiferous aether .
an experiment capable of validating or invalidating this claim is suggested .
+ + * keywords : * absolute motion , aether , asymmetry , symmetry , principle _ of _ relativity , relative motion . + ( 1,0)400 * jules henri poincar * ( 1854 - 1912 ) .
And you have already written the first three sentences of the full article: the philosophy derived from the principle o__f _ _ relativity , according to which the laws o__f _ _ physical phenomena must be the same for a `` stationary '' inertial observer as for one that is in uniform relative motion with the `` stationary '' inertial observer , states that there exists no means by which any inertial observer can determine whether or not they are in motion .
this philosophy introduces some uncomfortable inconsistencies that have made some critics of the str to spend a considerable amount of their time ( such as professor herbert dingle who spent about thirty years , see e.g. mccausland 2008 ) arguing that these inconsistencies rendered the str obsolete .
the str has never failed any experimental test to which has been subjected to , and this has lead to the mainstream scientific community to ignore any such criticism ..
Please generate the next two sentences of the article | this philosophy that there exists no means mechanical or optical by which any inertial observer can determine whether or not they are in motion rests its weight on the michelson - mosley experiment ( mm - exp ) ( michelson 1881 , 1887 ) .
the mm - exp is an experiment that was designed to measure the speed of the earth in the hypothetical aether . |
7,083 | Suppose that you have an abstract for a scientific paper: in this work we relate the well - known no - go theorem that two non - orthogonal ( mixed ) quantum states can not be perfectly discriminated , to the general principle in physics , the no - signalling condition .
in fact , the minimum error in discrimination between two quantum states is derived from the no - signalling condition . .
And you have already written the first three sentences of the full article: two non - orthogonal quantum states can not be discriminated with certainty , while the discrimination error can be made smaller as their copies are provided .
this leads to one of the well - known no - go theorems , that quantum states can not be copied with certainty @xcite , although approximate quantum cloning is possible with the use of quantum operations and ancillary quantum systems @xcite .
interestingly , the impossibility of perfect quantum cloning can be connected to the no - signalling principle in physics , which dictates that information can not be sent faster than light . as a consequence , quantum communication that makes use of ( non - local ) quantum correlations.
Please generate the next two sentences of the article | can not be performed faster than light .
in fact , the relation between the no - cloning theorem and the no - signalling constraint has been established in both qualitative and quantitative terms . |
7,084 | Suppose that you have an abstract for a scientific paper: we consider two approaches to balanced truncation of stochastic linear systems , which follow from different generalizations of the reachability gramian of deterministic systems . both preserve mean - square asymptotic stability , but
only the second leads to a stochastic @xmath0-type bound for the approximation error of the truncated system .
generalized lyapunov equation , model order reduction , balanced truncation , stochastic linear system , asymptotic mean square stability 15a24 , 93a15 , 93b36 , 93b40 , 93d05 , 93e15 , .
And you have already written the first three sentences of the full article: optimization and ( feedback ) control of dynamical systems is often computationally infeasible for high dimensional plant models .
therefore , one tries to reduce the order of the system , so that the input - output mapping is still computable with sufficient accuracy , but at considerably smaller cost than for the original system , @xcite . to guarantee the desired accuracy , computable error bounds are required .
moreover , system properties which are relevant in the context of control system design like asymptotic stability need to be preserved ..
Please generate the next two sentences of the article | it has long been known that for linear time - invariant ( lti ) systems the method of balanced truncation preserves asymptotic stability and provides an error bound for the @xmath1-induced input - output norm , that is the @xmath0-norm of the associated transfer function , see @xcite .
when considering model order reduction of more general system classes , it is natural to try to extend this approach . |
7,085 | Suppose that you have an abstract for a scientific paper: we show that the renormalizable @xmath0 yang mills coupled to matter and the higgs field fits all the experimentally observed differential cross sections known in nature .
this extended standard model reproduces the experimental gravitational differential cross sections without resorting to the graviton field and instead by exchanging @xmath1 gauge fields . by construction ,
each so(4 ) generator in quantum gravitodynamics does not commute with the dirac gamma matrices .
this produces additional interactions absent to non - abelian gauge fields in the standard model .
the contributions from these new terms yield differential cross sections consistent with the newtonian and post newtonian interactions derived from general relativity .
dimensional analysis of the lagrangian shows that all its terms have total dimensionality four or less and therefore that all physical quantities in the theory renormalize by finite amounts .
these properties make qgd the only renormalizable 4-dimensional theory describing gravitational interactions . .
And you have already written the first three sentences of the full article: the structure and success of general relativity have lead us to the believe that the spin-2 graviton field mediates quantum gravitational interactions ; but to date this believe has eluded experimental detection . furthermore , the quantum limit of general relativity fails to renormalize properly forcing us to further believe that general relativity comes from a classical projection of a 10 dimensional string .
on the other hand , we know that the geometrical object that describes the geodesics in general relativity is the connection and not the metric which enters that construction only after arbitrarily imposing the metric compatibility constraint
. then , we can in practice construct a quantum theory of gravity where the fundamental field is the connection as in@xcite or a similar object as we do here ..
Please generate the next two sentences of the article | nothing but experimental observation constrains these possibilities .
therefore , we should not force the graviton upon ourselves and instead focus on matching the proposed model s differential cross sections to experimental evidence ; more so , when we must yet detect the particle mediating gravitational interactions . here |
7,086 | Suppose that you have an abstract for a scientific paper: polymers adopt extended coil and compact globule states according to the balance between entropy and interaction energies .
the transition of a polymer between an extended coil state and compact globule state can be induced by changing thermodynamic force such as temperature to alter the energy / entropy balance .
previously , this transition was theoretically studied by taking into account the excluded - volume interaction between monomers of a polymer chain using the partition function . for binary mixtures of a long polymer and short polymers ,
the coil - globule transition can be induced by changing the concentration of the shorter polymers . here
we investigate the transition caused by short polymers by generalizing the partition function of the long polymer to include the excluded - volume effect of short polymers .
the coil - globule transition is studied as a function of the concentration of mixed polymers by systematically varying flory s @xmath0-parameters .
we show that the transition is caused by the interplay between the excluded - volume interaction and the dispersion state of short polymers in the solvent .
we also reveal that the same results can be obtained by combining the mixing entropy and elastic energy if the volume of a long polymer is properly defined . .
And you have already written the first three sentences of the full article: a single polymer molecule can transition between elongated coil and compact globule states upon changing the temperature , ph of salts or addition of other polymer molecules . in general , the extended ( coil ) state of a long polymer
is stabilized when the interaction between the polymer segment and solvent is favorable , typically occurring in good solvents .
@xcite in contrast , the contracted ( globule ) state of a long polymer is stabilized when the interaction between the polymer segments is favorable , which occurs in poor solvents . by varying the solvent quality.
Please generate the next two sentences of the article | , the coil - globule transition of a polymer can be induced .
transitions between coil and globule states can also be induced by adding solutes that can be regarded as another solvent . |
7,087 | Suppose that you have an abstract for a scientific paper: kinetic theories constitute one of the most promising tools to decipher the characteristic spatio - temporal dynamics in systems of actively propelled particles . in this context
, the boltzmann equation plays a pivotal role , since it provides a natural translation between a particle - level description of the system s dynamics and the corresponding hydrodynamic fields . yet
, the intricate mathematical structure of the boltzmann equation substantially limits the progress toward a full understanding of this equation by solely analytical means . here , we propose a general framework to numerically solve the boltzmann equation for self - propelled particle systems in two spatial dimensions and with arbitrary boundary conditions .
we discuss potential applications of this numerical framework to active matter systems , and use the algorithm to give a detailed analysis to a model system of self - propelled particles with polar interactions . in accordance with previous studies , we find that spatially homogeneous isotropic and broken symmetry states populate two distinct regions in parameter space , which are separated by a narrow region of spatially inhomogeneous , density - segregated moving patterns .
we find clear evidence that these three regions in parameter space are connected by first order phase transitions , and that the transition between the spatially homogeneous isotropic and polar ordered phases bears striking similarities to liquid - gas phase transitions in equilibrium systems . within the density segregated parameter regime
, we find a novel stable limit - cycle solution of the boltzmann equation , which consists of parallel lanes of polar clusters moving in opposite directions , so as to render the overall symmetry of the system s ordered state nematic , despite purely polar interactions on the level of single particles . .
And you have already written the first three sentences of the full article: developing a deeper understanding of active matter @xcite has been the major focus of a considerable amount of theoretical work over the last decades @xcite . in recent years
, kinetic theory has gained considerable popularity to assess the ordering behavior in systems of actively propelled particles @xcite . in this context , the boltzmann equation provides a particularly compelling approach to active matter systems .
apart from its inherent limitations , which are largely due the assumptions of binary particle interactions and molecular chaos ( cf . refs ..
Please generate the next two sentences of the article | @xcite ) , the following advantages of this framework are manifest : ( i ) the structure of the boltzmann equation , relating convection and collision processes on the level of the one - particle distribution function , is ideally suited to explicitly implement a microscopic picture of particle dynamics .
( ii ) due to its mesoscopic character , the boltzmann equation provides an immediate connection to the system s hydrodynamic variables , which naturally arise in the form of the various moments of the one - particle distribution function . |
7,088 | Suppose that you have an abstract for a scientific paper: we analyze the time evolution of quantum entanglement in a model consisting of two two - level atoms interacting with a two - mode electromagnetic field for a variety of initial states and interatomic separations .
we study two specific atomic separations which give rise to symmetric atom - field couplings . for general atomic distances
we consider a subset of initial states analytically , and then treat the more general situation numerically .
we examine a variety of qualitative features such as entanglement sudden death , dynamical generation , protection , and transfer between subsystems .
our analysis shows a stark contrast in features of entanglement between the two special coupling schemes often considered ; further , these features are uncharacteristic of those arising for general distances , due to the high degree of symmetry present in the special cases .
the variety of behaviors in these two - mode cases suggest the importance of considering atomic separation carefully for any model where two atoms interact with a common field .
# 1|#1 # 1#1| # 1 # 1 # 1#2^#1#2 .
And you have already written the first three sentences of the full article: quantum entanglement has been extensively studied , both due to its fundamental significance in quantum theory @xcite and its utility as a resource for quantum communication and quantum information processing @xcite .
atomic physics offers a domain with sufficient control of the system and isolation from noise that it has been possible to perform precision experiments on quantum entanglement @xcite , and , therefore , it is also a productive target for theoretical study of the issue as well .
one of the simplest scenarios for theoretical studies of the dynamics of entanglement between atoms is that of two atoms which are isolated from one another and interact with different electromagnetic fields . studying this sort of model led to the discovery of the entanglement sudden death ( sd ) phenomenon @xcite , in which entanglement decays to zero in a finite time rather than asymptotically ..
Please generate the next two sentences of the article | sd has garnered significant interest because it is both unintuitive and potentially undesirable .
an alternative simple model for atom - field interaction in which to study entanglement dynamics is the model studied by dicke @xcite and tavis and cummings @xcite , where one assumes all atoms are grouped in a sample whose size is small compared to the resonant wavelength ( resulting in identical coupling to every atom ) . |
7,089 | Suppose that you have an abstract for a scientific paper: suppose @xmath0 is an arithmetic locally symmetric space of noncompact type ( with the natural metric induced by the killing form of the isometry group of @xmath1 ) , and let @xmath2 be a point on the visual boundary of @xmath1 .
t.hattori showed that if each horoball based at @xmath2 intersects every @xmath3-orbit in @xmath1 , then @xmath2 is not on the boundary of any @xmath4-split flat in @xmath1 .
we prove the converse .
( this was conjectured by w.h.rehn in some special cases . )
furthermore , we prove an analogous result when @xmath3 is a nonarithmetic lattice . .
And you have already written the first three sentences of the full article: [ horolimdefn ] let @xmath0 be a locally symmetric space of noncompact type ( with universal cover @xmath1 ) , and let @xmath5 .
a point @xmath2 on the visual boundary of @xmath1 is a _ horospherical limit point _ for @xmath3 if every horoball based at @xmath2 intersects the orbit @xmath6 .
( see [ cgammahorolimdefn ] for an alternate characterization which makes it clear that this notion is independent of the choice of the basepoint @xmath7 . ).
Please generate the next two sentences of the article | our main theorem characterizes the horospherical limit points for any finite - volume locally symmetric space @xmath0 of noncompact type .
the result is slightly easier to state if we assume that the lattice @xmath3 is arithmetic . |
7,090 | Suppose that you have an abstract for a scientific paper: we investigate the use of spiral arm pitch angles as a probe of disk galaxy mass profiles .
we confirm our previous result that spiral arm pitch angles ( p ) are well - correlated with the rate of shear ( s ) in disk galaxy rotation curves , by using a much larger sample ( 51 galaxies ) than used previously ( 17 galaxies ) .
we use this correlation to argue that imaging data alone can provide a powerful probe of galactic mass distributions out to large lookback times .
in contrast to previous work , we show that observed spiral arm pitch angles are similar when measured in the optical ( at 0.4 @xmath0 m ) and the near - infrared ( at 2.1 @xmath0 m ) with a mean difference of @xmath1 .
this is then used to strengthen the known correlation between p and s using @xmath2 band images .
we then use two example galaxies to demonstrate how an inferred shear rate coupled with a bulge - disk decomposition model and a tully - fisher derived velocity normalization can be used to place constraints on a galaxy s baryon fraction and dark matter halo profile .
we show that eso 582-g12 , a galaxy with a high shear rate ( slightly declining rotation curve ) at @xmath3 kpc , favors an adiabatically contracted halo , with high initial nfw concentration ( @xmath4 ) and a high fraction of halo baryons in the form of stars ( @xmath5% ) .
in contrast , ic 2522 has a low shear rate ( rising rotation curve ) at @xmath3 kpc and favors non - adiabatically contracted models with low nfw concentrations ( @xmath6 ) and a low stellar baryon fraction @xmath7% . .
And you have already written the first three sentences of the full article: the correlation found between spiral arm pitch angle and rotation curve shear rate ( seigar , block & puerari 2004 ; seigar et al .
2005 ) suggests that there is a link between the tightness of spiral structure and the central mass concentration in spiral galaxies .
the shear rate , @xmath8 , a dimensionless quantity , can be measured directly from rotation curves and is defined as follows , @xmath9 where a is the first oort constant , @xmath10 is the angular velocity and @xmath11 is the velocity at a radius @xmath12 ..
Please generate the next two sentences of the article | the shear rate depends upon the shape of the rotation curve . for a rotation curve that remains flat
@xmath13 , for a falling rotation curve @xmath14 and for a continually rising rotation curve @xmath15 . |
7,091 | Suppose that you have an abstract for a scientific paper: we have studied the afterglow of the gamma - ray burst ( grb ) of february 18 , 2006 .
this is a nearby long grb , with a very low peak energy , and is therefore classified as an x - ray flash ( xrf ) .
xrf060218 is clearly associated with a supernova dubbed sn2006aj .
we present early spectra for sn2006aj as well as optical lightcurves reaching out to 50 days past explosion .
our optical lightcurves define the rise times , the lightcurve shapes and the absolute magnitudes in the @xmath0 , @xmath1 and @xmath2 bands , and we compare these data with data for other relevant supernovae .
sn2006aj evolved quite fast , somewhat similarly to sn2002ap , but not as fast as sn1994i .
our spectra show the evolution of the supernova over the peak , when the @xmath0-band portion of the spectrum rapidly fades due to extensive line blanketing .
we compare to similar spectra of very energetic type ic supernovae .
our first spectra are earlier than spectra for any other grb - sn .
the spectrum taken 12 days after burst in the rest frame is similar to somewhat later spectra of both sn1998bw and sn2003dh , implying a rapid early evolution .
this is consistent with the fast lightcurve . from the narrow emission lines from the host galaxy we derive a redshift of @xmath3 .
this makes xrf060218 the second closest gamma - ray burst detected .
the flux of these emission lines indicate a high - excitation state , and a modest metallicity and star formation rate of the host galaxy . .
And you have already written the first three sentences of the full article: the last few years have settled the debate about the origin of long gamma - ray bursts ( grbs ) .
the hint provided by grb980425 and sn1998bw @xcite was finally taken when the spectroscopic follow - up of the afterglow of grb030329 revealed the unambiguous signatures of a very energetic supernova
sn 2003dh @xcite . soon thereafter , another clear - cut sn1998bw look - alike emerged in the afterglow of grb031203 @xcite . while the swift satellite @xcite has been very successful in finding grbs over a large redshift range ( e.g. , * ? ? ?.
Please generate the next two sentences of the article | * ) , the wait for the next spectacular case of a nearby grb - supernova has lasted more than two years .
grb060218 was detected by the bat instrument on - board the swift satellite @xcite on february 18.149 2006 ut . |
7,092 | Suppose that you have an abstract for a scientific paper: we consider the holographic dark energy ( hde ) model in the framework of dgp braneworld with granda - oliveros infrared ( ir ) cutoff , @xmath0 . with this choice for ir cutoff
, we are able to derive evolution of the cosmological parameters such as the equation of state and the deceleration parameters , @xmath1 and @xmath2 , as the functions of the redshift parameter @xmath3 . as far as we know
, most previous models of hde presented in the literatures , do not gives analytically @xmath4 and @xmath5 .
we plot the evolution of these parameters versus @xmath3 and discuss that the results are compatible with the recent observations . with suitably choosing the parameters , this model can exhibit a transition from deceleration to the acceleration around @xmath6 .
then , we suggest a correspondence between the quintessence and tachyon scalar fields and hde in the framework of dgp braneworld .
this correspondence allows us to reconstruct the evolution of the scalar fields and the scalar potentials .
we also investigate stability of the presented model by calculating the squared sound speed , @xmath7 , whose sign determines the stability of the model .
our study shows that @xmath7 could be positive provided the parameters of the model are chosen suitably .
in particular , for @xmath8 , @xmath9 , and @xmath10 , @xmath11 , we have @xmath12 during the history of the universe , and so the stable dark energy dominated universe can be achieved .
this is in contrast to the hde in standard cosmology , which is unstable against background perturbations and so can not lead to a stable dark energy dominated universe . .
And you have already written the first three sentences of the full article: a complementary astrophysical data from type ia supernova , large scale structure ( lss ) and cosmic microwave background ( cmb ) indicate that our universe is currently undergoing a phase of accelerating @xcite .
a component which is responsible for this accelerated expansion is usually dubbed `` dark energy '' ( de ) . the simplest candidate for de
is the cosmological constant @xcite which is located in the center both from theoretical and observational evidences ..
Please generate the next two sentences of the article | however , there are different alternative theories for the dynamical de scenarios which have been proposed to interpret the accelerating universe
. one of these models , which has arisen a lot of enthusiasm recently , is hde . |
7,093 | Suppose that you have an abstract for a scientific paper: we study spin @xmath0 hadronic states in quenched lattice qcd to search for a possible @xmath1 pentaquark resonance .
simulations are carried out on @xmath2 , @xmath3 , @xmath4 and @xmath5 lattices at @xmath6=5.7 at the quenched level with the standard plaquette gauge action and the wilson quark action .
we adopt a dirichlet boundary condition in the time direction for the quark to circumvent the possible contaminations due to the ( anti)periodic boundary condition for the quark field , which are peculiar to the pentaquark . by diagonalizing the @xmath7 correlation matrices constructed from two independent operators with the quantum numbers @xmath8 ,
we successfully obtain the energies of the lowest state and the 2nd - lowest state in this channel .
the analysis of the volume dependence of the energies and spectral weight factors indicates that a resonance state is likely to exist slightly above the nk threshold in @xmath9 channel . .
And you have already written the first three sentences of the full article: after the discovery @xcite of @xmath10 followed by the other experiments @xcite , identifying the properties of the particle is one of the central problems in hadron physics . while the isospin of @xmath11 is likely to be zero @xcite , the spin and the parity and the origin of its tiny width still remain open questions @xcite . in spite of many theoretical studies on @xmath11 @xcite ,
the nature of this exotic particle , including the very existence of the particle , is still controversial . among theoretical approaches ,
the lattice qcd calculation is considered as one of the most reliable _ ab initio _.
Please generate the next two sentences of the article | methods for studying the properties of hadronic states , which has been very successful in reproducing the non - exotic hadron mass spectra @xcite . up to now , several lattice qcd studies have been reported , which aim to look for pentaquarks in various different ways . however , the conclusions are unfortunately contradictory with each other . on one hand , the authors in refs .
@xcite conclude that the parity of @xmath11 is likely to be negative , while in ref . |
7,094 | Suppose that you have an abstract for a scientific paper: in this note we describe the theory of functional asynchronous networks and one of the main results , the modularization of dynamics theorem , which for a large class of functional asynchronous networks gives a factorization of dynamics in terms of constituent subnetworks . for these networks
we can give a complete description of the network function in terms of the function of the events comprising the network and thereby answer a question originally raised by alon in the context of biological networks . .
And you have already written the first three sentences of the full article: kastan & alon @xcite identify and describe the configurations of relatively simple and small subnetworks that occur more frequently in biological networks than would be the case if the network were random .
they refer to these subnetworks as _
network motifs_. later , in his 2007 book on systems biology @xcite , alon makes the following comment _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ `` ideally , we would like to understand the dynamics of the entire network based on the dynamics of the individual building blocks . '' _.
Please generate the next two sentences of the article | ( alon @xcite . ) _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ the underlying premise behind this comment is that a modular , or engineering , approach to network dynamics is feasible .
identify building blocks , connect together to form networks and then describe dynamical properties of the resulting network in terms of the dynamics of its components . |
7,095 | Suppose that you have an abstract for a scientific paper: we consider exit problems for general lvy processes , where the first passage over a threshold is detected either immediately or at an epoch of an independent homogeneous poisson process .
it is shown that the two corresponding one - sided problems are related through a surprisingly simple identity .
moreover , we identify a simple link between two - sided exit problems with one continuous and one poisson exit . finally , poisson exit of a reflected process is connected to the continuous exit of a process reflected at poisson epochs , and a link between some parisian type exit problems is established . with the appropriate perspective , the proofs of all these relations turn out to be quite elementary . for
spectrally one - sided lvy processes this approach enables alternative proofs for a number of previously established identities , providing additional insight . .
And you have already written the first three sentences of the full article: let @xmath0 be a real - valued lvy process , and let @xmath1 be the epochs of an independent poisson process with intensity @xmath2 ; add @xmath3 .
the probability law corresponding to @xmath4 started at @xmath5 will be denoted by @xmath6 ( with @xmath7 denoting the expectation ) . when @xmath5 is not mentioned
explicitly we assume that @xmath8 and write simply @xmath9 and @xmath10 ..
Please generate the next two sentences of the article | define @xmath11 which we interpret as the first passage times under continuous and poisson observations , respectively .
observe that @xmath12 and , moreover , @xmath13 converges in probability to @xmath14 as @xmath15 ( the same is true for @xmath16 and @xmath17 ) . |
7,096 | Suppose that you have an abstract for a scientific paper: we have developed gpu versions for two major high - performance - computing ( hpc ) applications originating from two different scientific domains .
gene @xcite is a plasma microturbulence code which is employed for simulations of nuclear fusion plasmas .
vertex @xcite is a neutrino - radiation hydrodynamics code for `` first principles''-simulations of core - collapse supernova explosions @xcite .
the codes are considered state of the art in their respective scientific domains , both concerning their scientific scope and functionality as well as the achievable compute performance , in particular parallel scalability on all relevant hpc platforms .
gene and vertex were ported by us to hpc cluster architectures with two nvidia _ kepler _ gpus mounted in each node in addition to two intel xeon cpus of the _ sandy bridge _ family .
on such platforms we achieve up to twofold gains in the overall application performance in the sense of a reduction of the time to solution for a given setup with respect to a pure cpu cluster .
the paper describes our basic porting strategies and benchmarking methodology , and details the main algorithmic and technical challenges we faced on the new , heterogeneous architecture . , and gpu , hpc application , gene , vertex .
And you have already written the first three sentences of the full article: with gpu hardware and the corresponding software environments becoming mature , compute clusters with gpu - accelerated nodes establish as a new , powerful platform for high - performance computing ( hpc ) .
mainly motivated by the expected boost for application performance ( i.e. reducing `` time to solution '' ) and also by energy - efficiency considerations ( i.e. reducing `` energy to solution '' ) , major research organizations and providers of hpc resources have already deployed an appreciable amount of gpu - accelerated resources worldwide @xcite .
moreover , gpu - like architectures are expected to play a major role in the upcoming exascale era @xcite ..
Please generate the next two sentences of the article | it is well known , however , in the community , that the new hardware architecture together with the apparently disruptive programming models pose substantial challenges to scientific application developers ( e.g. @xcite ) .
while selected algorithms and applications have in fact been demonstrated to keep up with the shiny performance promises of gpus , in some cases even at the very large scale ( e.g. @xcite ) , it remains to be seen whether a broader class of scientific applications can take advantage of gpu - accelerated systems with reasonable programming effort and in a sustainable way . |
7,097 | Suppose that you have an abstract for a scientific paper: we discuss and generalize multi - particle entanglement based on statistical correlations using ursell - mayer type of cluster coefficients .
cluster coefficients are used to distinguish different , independent entangled systems as well as those which are connected through local unitary transformations .
we propose a genuinely and maximally entangled five - particle state for efficient information processing .
the physical realization of entangled states and information processing protocols are analyzed using quantum gates and circuit diagrams .
we show that direct as well as controlled communication can be achieved using the state proposed here , with certainty in the case of teleportation and with a high degree of optimity in the case of dense coding . for controlled dense coding the amount of information transferred from the sender to the receiver is always a maximum irrespective of the measurement basis used by the controller . .
And you have already written the first three sentences of the full article: quantum entanglement is a key resource for quantum information processing ( qip ) protocols [ 1 - 4 ] .
information processing involving multi - particle states requires entangled channels which can process the information from one remote location to another with reliability .
experimental realization of multi - particle systems and the detection of all orthogonal basis states forming a complete set of entangled states remains a challenge [ 5 - 9 ] , nevertheless , efficient theoretical construction and characterization of different multi - particle entangled channels for analyzing different information protocols is an important precursor to successful design of experiments ..
Please generate the next two sentences of the article | quantum teleportation involving many particles has been studied theoretically using different multi - particle entangled systems [ 10 - 22 ] .
many experiments have also been performed which provide partial experimental support to this concept [ 23 - 28 ] . |
7,098 | Suppose that you have an abstract for a scientific paper: we study the effect of zeeman magnetic field in the superconducting phase with two component order parameter scenario , such as , @xmath0 , where @xmath1 .
this scenario is equivalent to applying magnetic field parrllel to @xmath2 planes . in a weak magnetic field , which does not cause much change to the predominant @xmath3-wave ,
supresses the minor @xmath4 component leading to pure @xmath3-wave phase .
this observation is in contrary to the effect of magnetic field applied in the @xmath5-direction to the @xmath2 planes which is believed to induce a minor component @xmath4 to @xmath3-wave superconductors .
we also show that the response of such superconductors to a weak zeeman magnetic field can be quite different depending on the phase @xmath6 of the minor component ( @xmath4 ) .
epsf 2 .
And you have already written the first three sentences of the full article: although the nature of the superconducting pair wave function in high -@xmath7 cuprates is not yet known strong evidences of a major @xmath8 symmetry exists @xcite .
experiments sensitive to the internal phase structure of the pair wave function reported a sign reversal of the order parameter supporting @xmath3 wave symmetry @xcite .
most recently from various experiments and theory it appears that the pairing symmetry of these family could be a mixed one like @xmath0 where @xmath4 could be something in the @xmath9 wave family or @xmath10 ..
Please generate the next two sentences of the article | there were early questions from tunneling experiments regarding the pure d - wave symmetry@xcite as the data supports an admixture of d and s - wave components due to orthorhombicity in ybco@xcite .
possibility of a minor but finite @xmath11 symmetry alongwith the predominant @xmath12 has also been suggested@xcite in connection with magnetic defects or small fractions of a flux quantum @xmath13 in ybco powders . |
7,099 | Suppose that you have an abstract for a scientific paper: a two - component model is developed consisting of a discrete loop of cardiac cells that circulates action potentials as well as a pacing mechanism .
physiological properties of cells such as restitutions of refractoriness and of conduction velocity are given via experimentally measured functions .
the dynamics of circulating pulses and their interactions with the pacer are regulated by two threshold relations .
patterns of spontaneous initiations and terminations of reentry ( sitr ) generated by this system are studied through numerical simulations and analytical observations .
these patterns can be regular or irregular ; causes of irregularities are identified as the threshold bistability of reentrant circulation ( t - bistability ) and in some cases , also phase - resetting interactions with the pacer . * complex patterns of spontaneous initiation and termination * * of reentrant circulation in a loop of cardiac tissue * h. sedaghat@xmath0 , m.a .
wood@xmath1 , j.w .
cain@xmath0 , c.k .
cheng@xmath2 c.m .
baumgarten@xmath3 , d.m .
chan@xmath0 @xmath0department of mathematics and the center for the study of biological complexity ; @xmath1department of internal medicine - cardiology and the pauley heart center ; @xmath2department of computer science and the center for the study of biological complexity ; @xmath3department of physiology and the pauley heart center ; virginia commonwealth university , richmond , virginia , 23284 - 2014 , usa * keywords * reentry ; loop ; pacer ; thresholds ; bistability ; difference equations .
And you have already written the first three sentences of the full article: ventricular arrhythmia is the leading cause of cardiac arrest and sudden death .
clinical observations and implantable cardioverter defibrillators have accumulated a substantial amount of data on the occurrences of ventricular arrhythmia in patients [ 1 , 36 , 37 , 38 , 52 , 59 - 61 ] .
temporal patterns of initiations and terminations of ventricular arrhythmia tend to exhibit substantial variations across different time scales , and their occurrences do not correlate decisively with medication , exertion , stress , lifestyles and similar factors ..
Please generate the next two sentences of the article | arrhythmia events are not random ; they show circadian patterns [ 36 , 60 ] and also tend to occur in clusters . however , the detection times between consecutive events and clusters are spread out over time [ 37 , 52 , 59 ] , making it difficult to understand their causes and make predictions about their occurrences . unlike the circadian patterns ,
these clusterings or their patterns of occurrences are not affected by the long - term administration of antiarrhythmic drugs [ 59 ] . in spite of the abundant data in existence , |
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