id
int64 0
203k
| input
stringlengths 66
4.29k
| output
stringlengths 0
3.83k
|
|---|---|---|
5,500 | Suppose that you have an abstract for a scientific paper: we present a detailed review of scaling behavior in the magnetically underdoped cuprate superconductors ( hole dopings less than @xmath0 ) and show that it reflects the presence of two coupled components throughout this doping regime : a non - landau fermi liquid and a spin liquid whose behavior maps onto the theoretical monte carlo calculations of the 2d heisenberg model of localized cu spins for most of its temperature domain .
we use this mapping to extract the doping dependence of the strength , @xmath1 of the spin liquid component and the effective interaction , @xmath2 between the remnant localized spins that compose it ; we find both decrease linearly with x as the doping level increases .
we discuss the physical origin of pseudogap behavior and conclude that it is consistent with scenarios in which the both the large energy gaps found in the normal state and their subsequent superconductivity are brought about by the coupling between the fermi liquid quasiparticles and the spin liquid excitations , and that differences in this coupling between the 1 - 2 - 3 and 2 - 1 - 4 materials can explain the measured differences in their superconducting transition temperatures and other properties .
_ advances in physics : _ + * universal behavior and the * + * two - component character of magnetically * + * underdoped cuprate superconductors * + victor barzykin@xmath3 and david
pines@xmath4 + @xmath3 national high magnetic field laboratory , florida state university , tallahassee , fl 32310 , usa + @xmath4 department of physics and institute for complex adaptive matter , university of california , davis , ca 95616 , usa .
And you have already written the first three sentences of the full article: explaining the anomalous normal state properties of the so - called pseudogap regime of the underdoped cuprate superconductors is widely regarded as an essential step toward understanding the basic physics of these materials and unlocking the mechanism of their superconductivity@xcite .
perhaps the most striking aspect of these is the universal , or scaling , behavior , first identified in measurements of their temperature - dependent uniform magnetic susceptibility@xcite , and since found in knight shift , transport , and entropy measurements . in the present article we present a detailed review of scaling behavior in the underdoped cuprates that extends previous analyses of its manifestations in both static and low frequency dynamic behavior as well as that seen in inelastic neutron scattering ( ins ) experiments .
our review updates our earlier analysis@xcite and the results presented in norman _ _ et al.__@xcite , and complements the recent review of gap behavior presented in hfner _ _.
Please generate the next two sentences of the article | et al.__@xcite .
we find that from zero hole doping until planar doping levels of @xmath5 are reached , the scaling behavior seen by probes of magnetic behavior reflects the presence of a spin liquid whose behavior maps onto the theoretical monte carlo calculations of the 2d heisenberg model of localized @xmath6 spins@xcite for most of its temperature domain . |
5,501 | Suppose that you have an abstract for a scientific paper: the @xmath0-jet invariant mass spectrum produced in the reaction @xmath1 has been studied at a center - of - mass energy of 300 gev .
the data were collected using the zeus detector operating at the hera collider , and correspond to an integrated luminosity of @xmath2 pb@xmath3 .
the observed mass spectrum is in good agreement with standard model expectations up to an @xmath0-jet mass of @xmath4 gev . above this mass ,
some excess is seen .
the angular distribution of these events is typical of high-@xmath5 neutral current events and does not give convincing evidence for the presence of a narrow scalar or vector state .
limits are presented on the product of cross section and branching ratio for such a state and are interpreted as limits on leptoquark or r - parity - violating squark production .
specific leptoquark types are ruled out at @xmath6% confidence level for coupling strength @xmath7 for masses between @xmath8 and @xmath9 gev .
-1.5 cm -0.3 cm -0.3 cm 16.cm 0.cm 0.3 cm plus0.05 cm minus0.05 cm desy
00 - 023 + february 2000 + -1.cm -0.3 cm -0.3
cm 16.cm 0.cm 0.3 cm plus0.05 cm minus0.05 cm the zeus collaboration j. breitweg , s. chekanov , m. derrick , d. krakauer , s. magill , b. musgrave , a. pellegrino , j. repond , r. stanek , r. yoshida + _ argonne national laboratory , argonne , il , usa _ @xmath10 m.c.k .
mattingly + _ andrews university , berrien springs , mi , usa _
g. abbiendi , f. anselmo , p. antonioli , g. bari , m. basile , l. bellagamba , d. boscherini@xmath11 , a. bruni , g. bruni , g. cara romeo , g. castellini@xmath12 , l. cifarelli@xmath13 , f. cindolo , a. contin , n. coppola , m. corradi , s. de pasquale , p. giusti , g. iacobucci , g. laurenti , g. levi , a. margotti , t. massam , r. nania , f. palmonari , a. pesci , a. polini , g. sartorelli , y. zamora garcia@xmath14 , a. zichichi + _ university and infn bologna , bologna , italy _
@xmath15 c. amelung , a. bornheim , i. brock....
And you have already written the first three sentences of the full article: the @xmath0-jet mass spectrum in @xmath67 scattering has been investigated with the zeus detector at hera .
an excess of events relative to standard model expectations has previously been reported by the h1 @xcite and zeus @xcite collaborations in neutral current deep inelastic scattering at high @xmath68 and high @xmath5 .
these events contain high - mass @xmath0-jet final states ..
Please generate the next two sentences of the article | several models have been discussed @xcite as possible sources of these events , including leptoquark production @xcite and r - parity - violating squark production @xcite .
this paper presents an analysis of zeus data specifically aimed at searching for high mass states decaying to @xmath0-jet . |
5,502 | Suppose that you have an abstract for a scientific paper: this paper presents a new framework for manifold learning based on a sequence of principal polynomials that capture the possibly nonlinear nature of the data . the proposed principal polynomial analysis ( ppa )
generalizes pca by modeling the directions of maximal variance by means of curves , instead of straight lines .
contrarily to previous approaches , ppa reduces to performing simple univariate regressions , which makes it computationally feasible and robust .
moreover , ppa shows a number of interesting analytical properties .
_ first _ , ppa is a volume - preserving map , which in turn guarantees the existence of the inverse .
_ second _ , such an inverse can be obtained in closed form .
invertibility is an important advantage over other learning methods , because it permits to understand the identified features in the input domain where the data has physical meaning .
moreover , it allows to evaluate the performance of dimensionality reduction in sensible ( input - domain ) units .
volume preservation also allows an easy computation of information theoretic quantities , such as the reduction in multi - information after the transform .
_ third _ , the analytical nature of ppa leads to a clear geometrical interpretation of the manifold : it allows the computation of frenet - serret frames ( local features ) and of generalized curvatures at any point of the space . and _ fourth _
, the analytical jacobian allows the computation of the metric induced by the data , thus generalizing the mahalanobis distance .
these properties are demonstrated theoretically and illustrated experimentally .
the performance of ppa is evaluated in dimensionality and redundancy reduction , in both synthetic and real datasets from the uci repository . .
And you have already written the first three sentences of the full article: principal component analysis ( pca ) , also known as the karhunen - love transform or the hotelling transform , is a well - known method in machine learning , signal processing and statistics @xcite .
pca essentially builds an orthogonal transform to convert a set of observations of possibly correlated variables into a set of linearly uncorrelated variables .
pca has been used for manifold description and dimensionality reduction in a wide range of applications because of its simplicity , energy compaction , intuitive interpretation , and invertibility ..
Please generate the next two sentences of the article | nevertheless , pca is hampered by data exhibiting nonlinear relations . in this paper , we present a nonlinear generalization of pca that , unlike other alternatives , keeps all the above mentioned appealing properties of pca . in recent years
, several dimensionality reduction methods have been proposed to deal with manifolds that can not be linearly described ( see @xcite for a comprehensive review ) : the approaches proposed range from local methods @xcite , to kernel - based and spectral decompositions @xcite , neural networks @xcite , and projection pursuit methods @xcite . however , despite the advantages of nonlinear methods , classical pca still remains the most widely used dimensionality reduction technique in real applications . |
5,503 | Suppose that you have an abstract for a scientific paper: as the luminosity of an accreting black hole drops to a few percent of eddington , the spectrum switches from the familiar soft state to a hard state that is well - described by a distended and tenuous advection - dominated accretion flow ( adaf ) .
an adaf is a poor radiator , and the ion temperature can approach @xmath0 k near the center , although the electrons are cooler , with their temperature typically capped at @xmath1 k. the foundational papers predicted that the large thermal energy in an adaf would drive strong winds and jets , as later observed and also confirmed in computer simulations . of chief interest , however , is the accreting gas that races inward .
it carries the bulk of the accretion energy as stored thermal energy , which vanishes without a trace as the gas passes through the hole s event horizon .
one thus expects black holes in the adaf regime to be unusually faint .
indeed , this is confirmed by a comparison of accreting stellar - mass black holes and neutron stars , which reside in very similar transient x - ray binary systems .
the black holes are on average observed to be fainter by a factor of @xmath2 .
the natural explanation is that a neutron star must radiate the advected thermal energy from its surface , whereas a black hole can hide the energy behind its event horizon .
the case for an event horizon in sagittarius a@xmath3 , which is immune to caveats on jet outflows and is furthermore independent of the adaf model , is especially compelling .
these two lines of evidence for event horizons are impervious to counterarguments that invoke strong gravity or exotic stars . , .
And you have already written the first three sentences of the full article: the foundations of our present understanding of _ advection - dominated accretion _ were laid out in a series of papers by narayan & yi ( 1994 , 1995a , b , hereafter ny94 , ny95a , ny95b ) , abramowicz et al .
( 1995 ) and chen et al .
( 1995 ) , although some ideas were anticipated much earlier by ichimaru ( 1977 ) ..
Please generate the next two sentences of the article | the specific abbreviation adaf , which stands for _ advection - dominated accretion flow _ , was introduced by lasota(1996 ) and has become standard in the field .
we review here the application of adafs to accreting black holes ( bhs ) , and in 4 we also consider their application to accreting neutron stars . |
5,504 | Suppose that you have an abstract for a scientific paper: we study numerically the geometric entanglement in the laughlin wave function , which is of great importance in condensed matter physics .
the slater determinant having the largest overlap with the laughlin wave function is constructed by an iterative algorithm .
the logarithm of the overlap , which is a geometric quantity , is then taken as a geometric measure of entanglement .
it is found that the geometric entanglement is a linear function of the number of electrons to a good extent .
this is especially the case for the lowest laughlin wave function , namely the one with filling factor of @xmath0 .
surprisingly , the linear behavior extends well down to the smallest possible value of the electron number , namely , @xmath1 .
the constant term does not agree with the expected topological entropy . .
And you have already written the first three sentences of the full article: the laughlin wave function @xcite is a paradigm as a variational wave function @xcite .
its construction is simple , yet its implication is rich . it not only explains the most robust fractional quantum hall effects @xcite , but also embodies many exotic notions like fractionally charged excitations , fractional statistics , and composite - fermions / bosons @xcite .
its simplicity and fertileness make it very intriguing , and significant efforts have been dedicated to its nature @xcite . besides the conventional way of studying correlation functions , a more recent approach is studying the entanglement in the wave function @xcite . in ref ..
Please generate the next two sentences of the article | @xcite , bipartite entanglement entropy in the laughlin wave function has been studied both analytically and numerically .
a noteworthy result is that , by studying the scaling behavior of the entanglement entropy , the topological entropy corresponding to the so - called `` total quantum dimension '' @xcite is extracted , confirming the fact that the laughlin wave function is a topologically ordered state . |
5,505 | Suppose that you have an abstract for a scientific paper: in order to study whether the inter - band nesting can favor superconductivity arising from electron - electron repulsion in a three - dimensional system , we have looked at the repulsive hubbard model on a stack of honeycomb ( i.e. , non - bravais ) lattices with the flex method , partly motivated by the superconductivity observed in mgb@xmath0 . by systematically changing the shape of fermi surface with varied band filling @xmath1 and the third - direction hopping , we have found that the pair scattering across the two - bands is indeed found to give rise to gap functions that change sign across the bands and behave as an s- or d - wave within each band .
this implies ( a ) the electron repulsion can assist _ gapful _ pairing when a phonon - mechanism pairing exists , and ( b ) the electron repulsion alone , when strong enough , can give rise to a d - wave - like pairing , which should be , for a group - theoretic reason , a time - reversal broken d@xmath2id with _ point nodes _ in the gap . 2 .
And you have already written the first three sentences of the full article: recent discovery of the superconductivity in mgb@xmath0@xcite with relatively high transition temperature ( @xmath3k ) has invoked renewed interests in @xmath4-bonded materials .
electronically , the system is a @xmath5 electron system on layered honeycomb lattice , which immediately reminds us of graphite intercalation compounds ( gic ) such as lic@xmath6@xcite or kc@xmath7@xcite .
while the gic is considered to be a conventional superconductor with @xmath8k , mgb@xmath0 has an unusually high @xmath9 for @xmath4-bonded materials ( with a recent exception of c@xmath10-fet structure@xcite ) ..
Please generate the next two sentences of the article | recently , choi _
et al._@xcite have used an ab - initio pseudopotential density functional theory to solve eliashberg s equation numerically , and have reproduced @xmath11k , isotope - effect exponent @xmath12@xcite , and have obtained a gapful bcs pairing , which is consistent with experimental results such as specific heat@xcite , tunneling and photoemission spectra@xcite , penetration depth@xcite , and the raman spectra@xcite . thus gic and |
5,506 | Suppose that you have an abstract for a scientific paper: the properties of neutron stars are investigated within the relativistic central variational method by using a realistic nucleon - nucleon ( @xmath0 ) interaction .
the strong repulsion of realistic @xmath0 interactions at short distances is treated by a jastrow central correlation function , whose form is completely determined through minimization of the total energy of the nuclear many - body system .
the relativistic hartree - fock wave functions are chosen as the trial wave function . in this framework ,
the equation of state of the neutron star matter in @xmath1 equilibrium is obtained self - consistently .
we further determine the properties of neutron stars via the tolman - oppenheimer - volkoff equation using bonn a , b , and c potentials .
the maximum masses of neutron stars with these realistic potentials are around @xmath2 and their corresponding radii are around @xmath3 km .
these results are in accordance with the calculations of the relativistic brueckner - hartree - fock theory with the same potentials .
furthermore , we also find that the splitting of proton - neutron effective masses will be reversed at high density in the neutron star matter , which are caused by the contribution of short - range correlation on kinetic energy . .
And you have already written the first three sentences of the full article: the first neutron star was discovered by bell and hewish in 1967 . since then
, the neutron star has spawned the topics of research in numerous studies in astronomy and nuclear physics .
a neutron star can be treated as a huge nucleus composed of neutrons , protons , and leptons @xcite ..
Please generate the next two sentences of the article | the properties of neutron stars , like mass and radii , can be precisely measured with the gradual development of astronomical observation technology .
this development has promoted theoretical studies on the nuclear many - body theory @xcite , especially on the properties of nuclear matter at high densities , where high density refers to densities above 3 times the nuclear saturation density in the core of a neutron star . in the tolman - oppenheimer - volkoff ( tov ) equation @xcite , which is derived by solving the einstein equations for a spherically symmetric and time invariant system , |
5,507 | Suppose that you have an abstract for a scientific paper: an algebraic method is introduced for an analytical solution of the eigenvalue problem of the tavis - cummings ( tc ) hamiltonian , based on polynomially deformed _
su(2 ) _ , i.e. @xmath0 , algebras . in this method
the eigenvalue problem is solved in terms of a specific perturbation theory , developed here up to third order .
generalization to the @xmath1-atom case of the rabi frequency and dressed states is also provided .
a remarkable enhancement of spontaneous emission of @xmath1 atoms in a resonator is found to result from collective effects . .
And you have already written the first three sentences of the full article: we consider here the collective behavior of the system of @xmath2 two - level atoms coupled to a single mode of the electromagnetic field in a resonator .
the useful form for the atom - field interaction was proposed in the rotating wave approximation ( rwa ) by tavis and cummings @xcite . in their model
@xmath1 identical two - level atoms interact via dipole coupling with a single - mode quantized radiation field at resonance , so that the hamiltonian is given by @xmath3 here @xmath4 is a frequency of the electromagnetic field and @xmath5 is the level splitting of the two - level atoms ..
Please generate the next two sentences of the article | the operators @xmath6 are collective spin variables of @xmath1 two - level atoms .
these operators are defined as @xmath7 where @xmath8 s are pauli matrices . |
5,508 | Suppose that you have an abstract for a scientific paper: after summarizing neutrino oscillation results i discuss high and low - scale seesaw mechanisms , with or without supersymmetry , as well as recent attempts to understand the pattern of neutrino mixing from flavor symmetries .
i also mention the possibility of intrinsic supersymmetric neutrino masses in the context of broken r parity models , showing how this leads to clear tests at the lhc .
address= ahep group , instituto de fsica corpuscular , c.s.i.c .
universitat de valncia + edificio de institutos de paterna , apartado 22085 , e46071 valncia , spain + .
And you have already written the first three sentences of the full article: we now have uncontroversial evidence for neutrino flavor conversion coming from `` celestial '' ( solar and atmospheric ) as well as `` laboratory '' studies with reactor and accelerator neutrinos @xcite .
oscillations constitute the only viable explanation of the data and provide the first sign of physics beyond the standard model ( sm ) .
the basic concept in terms of which to describe them is the lepton mixing matrix , the leptonic analogue of the quark mixing matrix . in its simplest @xmath0 unitary form.
Please generate the next two sentences of the article | it is given as @xcite @xmath1 where each @xmath2 is characterized by an angle and a corresponding cp phase .
present experiments are insensitive to cp violation , hence we set all three phases to zero . in this |
5,509 | Suppose that you have an abstract for a scientific paper: in a protoplanetary disk , a combination of thermal and non - thermal desorption processes regulate where volatiles are liberated from icy grain mantles into the gas phase .
non - thermal desorption should result in volatile - enriched gas in disk - regions where complete freeze - out is otherwise expected .
we present alma observations of the disk around the young star i m lup in 1.4 mm continuum , c@xmath0o 21 , h@xmath1co@xmath2 32 and dco@xmath2 32 emission at @xmath305 resolution .
the images of these dust and gas tracers are clearly resolved . the dco@xmath2 line exhibits a striking pair of concentric rings of emission that peak at radii of @xmath306 and 2 ( @xmath390 and 300au , respectively ) .
based on disk chemistry model comparison , the inner dco@xmath2 ring is associated with the balance of co freeze - out and thermal desorption due to a radial decrease in disk temperature . the outer dco@xmath2 ring is explained by non - thermal desorption of co ice in the low - column - density outer disk , repopulating the disk midplane with cold co gas .
the co gas then reacts with abundant h@xmath4d@xmath2 to form the observed dco@xmath2 outer ring .
these observations demonstrate that spatially resolved dco@xmath2 emission can be used to trace otherwise hidden cold gas reservoirs in the outmost disk regions , opening a new window onto their chemistry and kinematics . .
And you have already written the first three sentences of the full article: planets form through the assembly of refractory dust , volatile ice , and gas in disks around young stars .
the spatial distribution of volatile abundances helps determine the compositions of nascent planets that form at different disk radii .
the separation of these volatiles into their gas and ice phases is set by the balance of adsorption ( freeze - out " of gas onto solids ) , and desorption back to the gas phase ..
Please generate the next two sentences of the article | desorption results from both thermal and non - thermal processes that can be active in different regions of protoplanetary disks .
the thermal desorption ( sublimation ) rate for a volatile is set by its energy barrier for ice desorption in concert with the grain temperature . |
5,510 | Suppose that you have an abstract for a scientific paper: using results of pitowsky and gupta , we show in a direct , elementary fashion that , in the case of three spins , bell s inequalities indeed provide a representation of the tetrahedron of all spin correlation matrices as intersection of half - spaces . + + mathematics subject classification[2010]:52b12,62h20,81p40 .
And you have already written the first three sentences of the full article: the non - local character of quantum correlations is manifested by the violation of bell s inequality @xcite , and , more generally , of the so - called chsh inequality @xcite .
the experimental violation of these inequalities @xcite constitutes by now an important part of modern scientific culture .
this property and its relation to entanglement has in fact become one of the cornerstones of quantum information theory , see e.g. @xcite ..
Please generate the next two sentences of the article | the relation between bell s inequalities and convex geometry is also well - known : it has been studied somewhat independently in the mathematical physics literature @xcite , ( * ? ? ? * appendix a ) , @xcite , @xcite and in the statistics literature @xcite . in particular , bell s inequalities are known to be related to the representation of a polytope as intersection of halfspaces .
nevertheless , the problem of finding a minimal set of bell - like inequalities is in general still open as it relates to the hard problem of finding all the facets of a polytope @xcite . the purpose of this note is to show that , in the simple but important original case of @xmath0 spin random variables , the fact that bell s inequalities provide a facets representation of the polytope of all spin correlation matrices can be proven in a direct , straightforward way using the available description of the extreme points @xcite . |
5,511 | Suppose that you have an abstract for a scientific paper: we investigate the young stellar population in and near the cometary globule orii-2 .
the analysis is based on deep nordic optical telescope @xmath0-band and h@xmath1 images , jcmt scuba 450 and 850 images combined with near - infrared 2mass photometry and mid - infrared archival _
spitzer _
images obtained with the irac ( 3.6 , 4.5 , 5.8 and 8 ) , and mips ( 24 and 70 ) instruments .
we identify a total of 125 sources within the 5@xmath25 region imaged by irac . of these sources 87
are detected in the @xmath0-band image and 51 are detected in the 2mass survey .
the detailed physical properties of the sources are explored using a combination of near / mid - infrared color - color diagrams , greybody fitting of seds and an online sed fitting tool that uses a library of 2d radiation transfer based accretion models of young stellar objects with disks .
orii-2 shows clear evidence of triggered star formation with four young low luminosity pre - main sequence stars embedded in the globule .
at least two , possibly as many as four , additional low - mass pms objects , were discovered in the field which are probably part of the young @xmath3 orionis cluster . among the pms stars which have formed in the globule
, mir-54 is a young , deeply embedded class 0/i object , mir-51 and 52 are young class ii sources , while mir-89 is a more evolved , heavily extincted class ii object with its apparent colors mimicking a class 0/i object .
the class 0/i object mir-54 coincides with a previously known iras source and is a strong sub - millimeter source .
it is most likely the source for the molecular outflow and the large parsec scale herbig - haro flow .
however the nearby class ii source , mir-52 , which is strong a h@xmath1 emission line star , also appears to drive an outflow approximately aligned with the outflow from mir-54 , and because of the proximity of the two outflows , either star could contribute .
mir-89 appears to excite a low excitation hh object , hh 992 , discovered for the....
And you have already written the first three sentences of the full article: cometary globules are believed to be molecular cloud condensations , which are so dense that they are not disrupted when an region expands into the molecular cloud(s ) surrounding it .
such globules are always bright rimmed and often have a cometary or tear shaped form , because the stellar wind and ionizing radiation from the central o stars ablate away the low density gas on the side facing the o stars and sweep away dust towards the tail .
cometary globules are thought to form from `` elephant trunks '' @xcite , although for compact cores surrounded by low density gas this phase can be quite short ..
Please generate the next two sentences of the article | the rosette nebula is a good example of an region , which shows an abundance of both cometary globules and elephant trunk structures @xcite .
although elephant trunks and cometary globules have been known for a long time , the fact that these sites may be forming stars was realized only in the last few decades . the first clear confirmation that stars form in cometary globules was a result of the identification of bernes 135 in the cometary globule cg1 , one of the large cometary globules in the gum nebula , as a pre - main - sequence ( pms ) star @xcite . |
5,512 | Suppose that you have an abstract for a scientific paper: we have attempted to analyse all the available data taken by xmm - newton as it slews between targets .
this slew survey , the resultant source catalogue and the analysis procedures used are described in an accompanying paper . in this letter
we present the initial science results from the survey . to date , detailed source - searching has been performed in three x - ray bands ( soft , hard and total ) in the epic - pn 0.2@xmath012kev band over @xmath16300 sq.degrees ( @xmath115% of the sky ) , and of order 4000 x - ray sources have been detected ( @xmath155% of which have ids ) .
a great variety of sources are seen , including agn , galaxies , clusters and groups , active stars , snrs , low- and high - mass xrbs and white dwarfs .
in particular , as this survey constitutes the deepest ever hard - band 2@xmath012kev all - sky survey , a large number of hard sources are detected .
furthermore , the great sensitivity and low - background of the epic - pn camera are especially suited to emission from extended sources , and interesting spatial structure is observed in many supernova remnants and clusters of galaxies .
the instrument is very adept at mapping large areas of the x - ray sky .
also , as the slew survey is well matched to the rosat all - sky survey , long - term variability studies are possible , and a number of extremely variable x - ray sources , some possibly due to the tidal disruption of stars by central supermassive black holes , have been discovered . .
And you have already written the first three sentences of the full article: xmm - newton ( jansen 2001 ) , with the huge collecting area of its mirrors and the high quantum efficiency of its epic detectors ( strder 2001 , turner 2001 ) , is the most sensitive x - ray observatory ever flown .
this is strikingly evident during slew exposures which , while yielding only at most around 15 seconds of on - source observing time , actually constitute a hard - band 2 - 10 kev survey with a limiting flux sensitivity of @xmath2erg @xmath3 s@xmath4 .
this is 5@xmath010 times deeper than all other all - sky surveys ..
Please generate the next two sentences of the article | the soft - band 0.2 - 2 kev survey ( limiting flux sensitivity @xmath5erg @xmath3 s@xmath4 ) is comparable with the rosat pspc all - sky survey ( rass ) , offering long - term variability studies .
with the release of the first source catalogue ( xmmsl1 , released in may 2006 ) into the xmm x - ray science archive - ` http://xmm.vilspa.esa.es/ ` ` external / xmm_data_acc / xsa / index.shtml ` , we are able here to show selected highlights seen so far . |
5,513 | Suppose that you have an abstract for a scientific paper: a lower bound for the ground state energy of a one particle relativistic hamiltonian - sometimes called no - pair operator - is provided . .
And you have already written the first three sentences of the full article: the multi - particle analogon of the operator @xmath0 is often used to describe relativistic effects in atoms and molecules , see , e.g. , @xcite . here
@xmath1 is the free dirac operator @xmath2 and @xmath3 with @xmath4 is the projection operator on the electron subspace of the free dirac operator in momentum space .
the underlying hilbert space of @xmath5 is the space of square integrable four spinors @xmath6 with @xmath7 ..
Please generate the next two sentences of the article | the operator @xmath5 was introduced for the two particle case by brown and ravenhall @xcite ( see also @xcite ) to cure the continuum dissolution of the two particle dirac operator with coulomb interaction : since the dirac operator is unbounded form below the two particle dirac operator has the whole real line as spectrum , the eigenvalues of the one particle operator `` dissolve '' .
@xmath5 is called no - pair operator or in the description of meson models ( usually with different potentials ) `` reduced salpeter operator '' @xcite . recently , |
5,514 | Suppose that you have an abstract for a scientific paper: recommender systems daily influence our decisions on the internet .
while considerable attention has been given to issues such as recommendation accuracy and user privacy , the long - term mutual feedback between a recommender system and the decisions of its users has been neglected so far .
we propose here a model of network evolution which allows us to study the complex dynamics induced by this feedback , including the hysteresis effect which is typical for systems with non - linear dynamics . despite the popular belief that recommendation helps users to discover new things , we find that the long - term use of recommendation can contribute to the rise of extremely popular items and thus ultimately narrow the user choice .
these results are supported by measurements of the time evolution of item popularity inequality in real systems .
we show that this adverse effect of recommendation can be tamed by sacrificing part of short - term recommendation accuracy . .
And you have already written the first three sentences of the full article: even if we do not notice it , our life on the internet is influenced by recommendations .
popular web sites such as amazon , netflix and youtube attempt to facilitate our navigation by suggesting us new possibly relevant items and thus increase our satisfaction and their profits @xcite . employed recommendation algorithms range from simple variants of `` buyers who choose item a also choose item b '' @xcite in amazon to more sophisticated techniques such as the singular value decomposition @xcite . even though many users still act independently of any automated assistance , the use of recommendation is on a rise .
for example , the dvd rental company netflix estimated that 75@xmath0 of the rental choices of their users come from some form of recommendation @xcite ..
Please generate the next two sentences of the article | the rationale behind recommendation is to match the right customers with the right products .
this task is particularly important and difficult for less popular items for which user patterns can not be easily identified . |
5,515 | Suppose that you have an abstract for a scientific paper: we study gauge coupling unification and various phenomenological issues , such as baryon number conservation , the @xmath0 problem and neutrino anomalies , within susy 5d orbifold models .
the 5d mssm on an @xmath1 orbifold with minimal field content does not lead to low scale unification , while some of its extensions can give unification near the multi tev scale . within the orbifold @xmath2 gut , low scale unification
can not be realized due to full @xmath2 multiplets participating in the renormalization above the compactification scale . as alternative examples ,
we construct 5d @xmath3 susy pati - salam @xmath4 and flipped @xmath5 guts [ both maximal subgroups of @xmath6 on an @xmath7 orbifold .
new examples of low scale unifications within @xmath8 are presented . for @xmath9
the unification scale is shown to be necessarily close to @xmath10 gev .
the possible influence of brane couplings on the gauge coupling unification is also outlined . for the resolution of the various phenomenological problems extensions with a discrete @xmath11 symmetry turn out to be very effective . * gauge coupling unification and phenomenology + of selected orbifold 5d @xmath3 susy models * filipe paccetti correia@xmath12 , michael g. schmidt@xmath12 , zurab tavartkiladze@xmath13 @xmath14_institut fr theoretische physik , universitt heidelberg , philosophenweg 16 , + d-69120 heidelberg , germany + @xmath15 institute of physics , georgian academy of sciences , tbilisi 380077 , georgia + _ .
And you have already written the first three sentences of the full article: the standard model of elementary particle physics ( sm ) gives an excellent explanation of all existing experimental data . however , there are quite strong theoretical motivations to believe that the sm is an effective theory of a more fundamental theory and that the gauge couplings of @xmath16 have a common origin .
the construction of grand unified theories ( guts ) @xcite , which unify @xmath17 gauge interactions in a single non abelian group [ @xmath2 , @xmath18 , @xmath19 etc ] , give an elegant explanation of charge quantization and also unify quark - lepton families .
the idea of gut got a great support from the fact that the three gauge couplings measured at that early times were indeed unifying at energies near @xmath20 gev @xcite ..
Please generate the next two sentences of the article | progress in measuring the strong gauge coupling and also the weak mixing angle @xmath21 with higher accuracy has ruled out the minimal @xmath2 gut [ and also minimal @xmath18 without intermediate scale ] from the viewpoint of coupling unification @xcite , @xcite .
however , the minimal supersymmetric extension of the standard model ( mssm ) and also the minimal susy @xmath2 gut @xcite(which except for gut threshold corrections both have the same pattern of running of couplings below @xmath22 ) were giving values for the @xmath23 coupling @xcite-@xcite well within the experimental limits at that time . indeed |
5,516 | Suppose that you have an abstract for a scientific paper: in this letter , the radial velocity variability of the chemically peculiar star @xmath0 ursae majoris ( @xmath0 uma ) from the sharp cores of the hydrogen lines is investigated .
this study is based on the elodie archival data obtained at different phases of the rotational cycle .
the star exhibits low - amplitude radial velocity variations with a period of @xmath1 = 5.0887 d. the best keplerian solution yields an eccentricity @xmath2 = 0.503 and a minimum mass @xmath314.7@xmath4 on the hypothesis that the rotational axis of @xmath0 uma is perpendicular to the orbital plane .
this result indicate that the companion is the brown - dwarf with the projected semi - amplitude variation of the radial velocity @xmath5 = 135.9 km @xmath6 and the sine of inclination times semi - major axis @xmath7@xmath8(i ) = 0.055 au .
[ firstpage ] binaries : spectroscopic stars : chemically peculiar stars : individual : @xmath0 ursae majoris . .
And you have already written the first three sentences of the full article: epsilon ursae majoris ( @xmath0 uma , hd 112185 , hr 4905 ) is the brightest ( @xmath9 = 1.77 mag ) chemically peculiar ( cp ) star and has been extensively studied during the last century .
@xcite established a period of 5.@xmath100887 d from variations in the intensity of the ca ii k line and also noticed a periodic splitting of some lines .
@xcite subsequently reported doubling of lines of cr ii , fe ii , v ii and other elements at certain phases ..
Please generate the next two sentences of the article | since the overall widths of the double lines are the same and not all lines double , they ruled out the orbital motion and instead suggested that the phenomenon is related to rotation of the star .
@xcite measured a double wave light variation with the same 5.@xmath100887 period . |
5,517 | Suppose that you have an abstract for a scientific paper: we show that crystals with the properties of crystalline cohomology of ordinary calabi - yau threefolds in characteristic @xmath0 , exhibit a remarkable similarity with the well known structure on the cohomology of complex calabi - yau threefolds near a boundary point of the moduli space with maximal unipotent local monodromy
. in particular , there are canonical coordinates and an analogue of the prepotential of the yukawa coupling .
moreover in formulas ( [ eq : qprops ] ) and ( [ eq : yukinteger ] ) we show @xmath1-adic analogues of the integrality properties for the canonical coordinates and the prepotential of the yukawa coupling , which have been observed in the examples of mirror symmetry . .
And you have already written the first three sentences of the full article: calabi - yau manifolds of dimensions @xmath2 and @xmath3 , i.e. elliptic curves and k3-surfaces , have a long and successful tradition in geometry and number theory . in the 1980 s , in connection with developments in string theory , calabi - yau manifolds of dimension @xmath4 moved to the forefront . emphasis has been on their complex and symplectic geometry , and in particular on the variation of the hodge structure for calabi - yau threefolds near the so - called large complex structure limit .
this is the first of a series of papers in which we want to describe certain aspects of the arithmetic geometry of families of ordinary calabi - yau threefolds and analogies with complex calabi - yau threefolds near the large complex structure limit .
more specifically , this paper discusses the associated crystals , i.e. modules with an integrable connection , like the gauss - manin connection on the cohomology of a family of calabi - yau threefolds ..
Please generate the next two sentences of the article | crystals which originate from geometry come with a hodge filtration , which is not preserved by the connection but instead satisfies griffiths transversality .
crystals which originate from geometry in characteristic @xmath1 additionally carry an action of frobenius operators behaving in an appropriate way with respect to the connection and the hodge filtration : they are divisible hodge @xmath5-crystals . for so - called divisible _ |
5,518 | Suppose that you have an abstract for a scientific paper: organic haze plays a key role in many planetary processes ranging from influencing the radiation budget of an atmosphere to serving as a source of prebiotic molecules on the surface .
numerous experiments have investigated the aerosols produced by exposing mixtures of n@xmath0/ch@xmath1 to a variety of energy sources .
however , many n@xmath0/ch@xmath1 atmospheres in both our solar system and extrasolar planetary systems also contain co. we have conducted a series of atmosphere simulation experiments to investigate the effect of co on formation and particle size of planetary haze analogues for a range of co mixing ratios using two different energy sources , spark discharge and uv .
we find that co strongly affects both number density and particle size of the aerosols produced in our experiments and indicates that co may play an important , previously unexplored , role in aerosol chemistry in planetary atmospheres . .
And you have already written the first three sentences of the full article: atmospheric hazes , present in a range of solar system and extrasolar planetary atmospheres , play an important role in physical and chemical processes occurring in the atmosphere and for terrestrial planets , on the surface .
haze particles affect the radiative balance of an atmosphere , may serve as condensation nuclei for clouds and rain , play a role in fluvial and aeolian processes @xcite , and affect the elemental budget of an atmosphere and surface .
the effect on haze particles on the temperature structure of an atmosphere has implications for the habitability of a planet and an organic haze , such as seen in the atmosphere of saturn s moon titan , may potentially serve as the building blocks of life @xcite ..
Please generate the next two sentences of the article | while haze formation in n@xmath0/ch@xmath1 atmospheres has been extensively studied for decades in the laboratory through the production of titan aerosol analogues or `` tholins '' ( see @xcite ) , the effect of other atmospheric constituents on the formation of haze in planetary atmospheres has not been well studied .
carbon monoxide ( co ) is particularly interesting because it might serve as a source of oxygen for incorporation into photochemical aerosols affecting both their radiative and chemical properties and it is found in numerous atmospheres throughout the universe . |
5,519 | Suppose that you have an abstract for a scientific paper: eigenstates of bose particles with repulsive contact interactions in one - dimensional space with periodic boundary conditions can be found with the help of the bethe ansatz .
the type ii excitation spectrum identified by e. h. lieb , reproduces the dispersion relation of dark solitons in the mean - field approach .
the corresponding eigenstates possess translational symmetry which can be broken in measurements of positions of particles .
we analyze emergence of single and double solitons in the course of the measurements and investigate dynamics of the system . in the weak interaction limit , the system follows the mean - field prediction for a short period of time .
long time evolution reveals many - body effects that are related to an increasing uncertainty of soliton positions . in the strong interaction regime particles
behave like impenetrable bosons .
then , the probability densities in the configuration space become identical to the probabilities of non - interacting fermions but the wave - functions themselves remember the original bose statistics .
especially , the phase flips that are key signatures of the solitons in the weak interaction limit , can be observed in the time evolution of the strongly interacting bosons . .
And you have already written the first three sentences of the full article: solitons are solutions of non - linear wave equations that maintain their shape during time evolution .
they appear in different phenomena investigated in the fields of non - linear optics , ultra - cold atomic gases and in many other physical systems .
both in the optics and atomic gases bright and dark solitons have been observed experimentally @xcite ..
Please generate the next two sentences of the article | the former corresponds to a localized pulse propagating without a change of shape through an optical self - focusing kerr medium or to a localized matter - wave packet formed by attractively interacting atoms @xcite .
dark solitons are related to dark holes on continuous - wave background that can be created in a self - defocusing kerr medium or in repulsively interacting massive particles @xcite . in the areas of non - linear optics and ultra - cold atomic gases , the non - linear wave equations are results of the approximation that assumes occupation of single modes by a large number of photons or atoms |
5,520 | Suppose that you have an abstract for a scientific paper: we obtain the maximum entropy distribution for an asset from call and digital option prices . a rigorous mathematical proof of its existence and exponential form is given , which can also be applied to legitimise a formal derivation by buchen and kelly @xcite .
we give a simple and robust algorithm for our method and compare our results to theirs .
we present numerical results which show that our approach implies very realistic volatility surfaces even when calibrating only to at - the - money options .
finally , we apply our approach to options on the s&p 500 index .
* keywords : * entropy @xmath0 information theory @xmath0 @xmath1-divergence @xmath0 asset distribution @xmath0 option pricing @xmath0 volatility smile * mathematics subject classification ( 2000 ) : * 91b24 @xmath0 91b28 @xmath0 91b70 @xmath0 94a17 * jel : * c16 @xmath0 c63 @xmath0 g13 .
And you have already written the first three sentences of the full article: the recent market turbulence caused by the credit crunch has exposed in a drastic way the consequences of overconfidence in financial modelling assumptions .
typically , a financial model , such as the famous black - scholes model , will assume that the price of an asset follows a given stochastic process whose parameters need to be calibrated to market prices .
if a model becomes an accepted standard and most market participants adopt it , problems can occur when assumptions that hold under normal market conditions are also expected to hold under abnormal ones ..
Please generate the next two sentences of the article | an example is the stock market crash of @xmath2 , where the volatilities used for pricing at - the - money options were also used for pricing far out - of - the - money put options . as the market headed downwards , it turned out that the true hedging cost for somebody who had sold such puts was far greater than the received premium .
another good example is described in the recent paper @xcite , where the authors demonstrate for cdos and cdo@xmath3s what can happen to asset prices when model parameters that are hard to observe or estimate with sufficient accuracy are put to a true stress test . |
5,521 | Suppose that you have an abstract for a scientific paper: predictions for lhc physics are given for a two - higgs - doublet model having four generalized cp symmetries . in this _ maximally - cp - symmetric model _
( mcpm ) the first fermion family is , at tree level , uncoupled to the higgs fields and thus massless . the second and third fermion families have a very symmetric coupling to the higgs fields .
but through the electroweak symmetry breaking a large mass hierarchy is generated between these fermion families .
thus , the fermion mass spectrum of the model presents a rough approximation to what is observed in nature . in the mcpm the couplings of the higgs bosons to the fermions are completely fixed .
this allows us to present clear predictions for the production at the lhc and for the decays of the physical higgs bosons . as salient feature
we find rather large cross sections for higgs - boson production via drell yan type processes . in this paper
we present a short outline of the model and extend a former study by the predictions at lhc for a center - of - mass energy of 7 tev . .
And you have already written the first three sentences of the full article: extending the standard model ( sm ) higgs sector to two higgs doublets , @xmath0 gives the two - higgs - doublet model ( thdm ) .
there , the potential may contain many more terms than in the sm ; see e.g. @xcite .
the most general thdm higgs potential can be written @xcite @xmath1 + [ \lambda_6 ( \varphi_1^\dagger \varphi_2 ) + \lambda_6^ * ( \varphi_2^\dagger \varphi_1 ) ] ( \varphi_1^\dagger \varphi_1 ) + [ \lambda_7 ( \varphi_1^\dagger \varphi_2 ) + \lambda_7^ * ( \varphi_2^\dagger \varphi_1 ) ] ( \varphi_2^\dagger \varphi_2)\;,\end{gathered}\ ] ] with @xmath2 , @xmath3 , @xmath4 real and @xmath5 , @xmath6 complex ..
Please generate the next two sentences of the article | many properties of thdms turn out to have a simple geometric meaning if we introduce gauge invariant bilinears @xcite , @xmath7 in terms of these bilinears @xmath8 , @xmath9 , the higgs potential reads @xmath10 with parameters @xmath11 , @xmath12 , 3-component vectors @xmath13 , @xmath14 and a @xmath15 matrix @xmath16 , all real .
the standard cp transformation of the higgs - doublet fields is defined by @xmath17 in terms of the bilinears , this standard cp transformation is @xcite @xmath18 where @xmath19 , corresponding in @xmath20 space to a reflection on the 13 plane . generalised cp transformations ( gcps ) are by @xcite @xmath21 with @xmath22 an arbitrary unitary @xmath23 matrix . in terms of the bilinears |
5,522 | Suppose that you have an abstract for a scientific paper: ensemble averaging experiments may conceal many fundamental molecular interactions . to overcome that
, a high - throughput detection of single molecules or colloidal nanodots is crucial for biomedical , nanoelectronic , and solid - state applications .
one - dimensional ( 1d ) discrete flow of nanoscale objects is an efficient approach in this direction .
the development of simple and cost - effective nanofluidic devices is a critical step to realise 1d flow .
this letter presents a nanofabrication technique using shadow - angle - electron - beam - deposition for a high - throughput preparation of parallel nanofluidic channels . these were used to flow and detect small fragments of dna , carbon - nanodots , and organic fluorophores .
the 1d molecular mass transport was performed using electro - osmotic flow .
the 1d flow behaviour was analysed using two - focus fluorescence correlation spectroscopy ( 2ffcs ) .
a range of flow velocities of single molecules was achieved from 15 @xmath0 m/s to 290 @xmath0 m/s .
the transitions of single molecules or nanodots through the two foci were quantitatively analysed using confocal scanning fluorescence microscopy , correlative photon detection , and burst size distribution analysis .
the results suggest an efficient nanofabrication technique is developed to prepare nanofluidic devices .
this first demonstration of high - throughput nanochannel fabrication process and using 2ffcs - based single molecule flow detection should have potential impact on ultra - sensitive biomedical diagnostics and studying biomolecular interactions as well as nanomaterials . .
And you have already written the first three sentences of the full article: due to brownian motion , it is impossible to keep a molecule within the detection volume for an extended period of time .
the study of nanofluidics became popular to circumvent this problem with wide scientific applications @xcite . with the advancement of nanotechnologies , nanofluidic devices comprising arrays of nanochannels with diameters
less than hundred nanometres have become significant for bioanalytical diagnostics applications , such as dna optical mapping @xcite , single virus and nanoparticle detection @xcite ..
Please generate the next two sentences of the article | nanochannels are useful tools allowing systematic studies of entities from single molecule to viruses over long periods of time .
it can induce 1d fluidic confinement by suppressing the thermal motions in two directions . |
5,523 | Suppose that you have an abstract for a scientific paper: we investigate the clustering properties of a dynamical dark energy component . in a cosmic mix of a pressureless fluid and a light scalar field ,
we follow the linear evolution of spherical matter perturbations .
we find that the scalar field tends to form underdensities in response to the gravitationally collapsing matter .
we thoroughly investigate these voids for a variety of initial conditions , explain the physics behind their formation and consider possible observational implications .
detection of dark energy voids will clearly rule out the cosmological constant as the main source of the present acceleration . .
And you have already written the first three sentences of the full article: direct @xcite and indirect @xcite evidence of the present acceleration of the universe is accumulating .
nonetheless , the source of the accelerated expansion is as elusive as ever . in the context of general relativity
, one needs to hypothesize a dark energy source with negative pressure to accommodate the acceleration ..
Please generate the next two sentences of the article | alternative ideas include various modifications to gravity .
little is known about the dark energy except that its pressure is negative , and that it accounts for about @xmath0 of the critical density of the universe . whether the dark energy is the cosmological constant or a dynamically evolving source of energy is a fundamental unanswered question . |
5,524 | Suppose that you have an abstract for a scientific paper: more than 30 years ago , the feasibility of detecting magnetic resonance in the faraday - rotation noise spectrum of transmitted light has been demonstrated experimentally .
however , practical applications of this experimental approach have emerged only recently thanks , in particular , to a number of crucial technical ements .
this method has now become a popular and efficient tool for studying magnetic resonance and spin dynamics in atomic and solid - state paramagnets . in this paper
, we present a review of research in the field of spin noise spectroscopy including its physical basis , its evolution since its first experimental demonstration , and its recent experimental advances .
main attention is paid to the specific capabilities of this technique that render it unique compared to other methods of magnetic and optical spectroscopy . the paper is primarily intended for the experimentalists who may wish to use this novel optical technique . .
And you have already written the first three sentences of the full article: in the photonics and information science of recent years , much attention is paid to the spin - based , rather than charge - based , electronic systems .
this area of research , nowadays referred to as spintronics , treats spin as a carrier of quantum information and is considered as a highly promising pathway to new information technologies @xcite .
this tendency has arisen a great interest to dynamic properties of spin - systems both in equilibrium and under different kind of perturbations capable of controlling spin state of the system ..
Please generate the next two sentences of the article | the new technique - spin noise spectroscopy , developed in the last decade , refers to the experimental methods intended for studying spin - systems under conditions of thermal equilibrium .
the term spin noise spectroscopy ( sns ) signifies experimental technique that implies spectral investigations of spontaneous fluctuations of spin - system magnetization ( spin polarization ) . until recently , |
5,525 | Suppose that you have an abstract for a scientific paper: we propose new physical processes based on the axial vector anomaly and described by the wess - zumino - witten term that couples the photon , @xmath0-boson , and the @xmath1-meson .
the interaction takes the form of a pseudo - chern - simons term , @xmath2 .
this term induces neutrino - photon interactions at finite baryon density via the coupling of the @xmath0-boson to neutrinos .
these interactions may be detectable in various laboratory and astrophysical arenas .
the new interactions may account for the miniboone excess .
they also produce a competitive contribution to neutron star cooling at temperatures @xmath3 . these processes and related axion photon interactions at finite baryon density appear to be relevant in many astrophysical regimes . .
And you have already written the first three sentences of the full article: the axial vector anomaly plays a fundamental role in the structure of the standard model and describes many physical processes , including the classic decay @xmath4 @xcite .
one can summarize the traditional current algebra manipulations used to treat anomalous processes by an effective action .
this is a functional , @xmath5 , of a chiral field of the pseudoscalar mesons , @xmath6 , and background gauge fields @xmath7 , @xmath8 , coupled to left- and right - handed chiral currents ..
Please generate the next two sentences of the article | it generates ( consistent ) anomalies under local gauge transformations and is known as the wess - zumino - witten ( wzw ) term @xcite .
the wzw term has been developed into a phenomenologically useful form by kaymakcalan , rajeev and schechter ( krs ) @xcite following witten s pioneering work . |
5,526 | Suppose that you have an abstract for a scientific paper: we combine a pair of independent weyl fermions to compose a dirac fermion on the four - dimensional euclidean lattice .
the obtained dirac operator is antihermitian and does not reproduce anomaly under the usual chiral transformation . to simulate the correct chiral anomaly ,
we modify the chiral transformation .
we also show that chiral gauge theories can be constructed nonperturbatively with exact gauge invariance .
the formulation is based on a doubler - free lattice derivative , which is a simple matrix defined as a discrete fourier transform of momentum with antiperiodic boundary conditions .
long - range fermion hopping interactions are truncated using the lanczos factor . #
10= 0=0 1= 1=1 0>1 # 1 / .
And you have already written the first three sentences of the full article: in the continuum euclidean path - integral , chiral anomaly comes from jacobian of the fermion measure @xcite .
the point is that @xmath0 of the transformed fermion measure gives nonzero contribution because of the infinite degrees of freedom . on the other hand ,
lattice field theory is a framework to simulate the continuum theory with a finite number of lattice sites ..
Please generate the next two sentences of the article | chiral anomaly can not be reproduced on the finite lattice in the same way as the continuum theory .
we should definitely distinguish finite and infinite lattice formulations and concentrate on reproducing chiral anomaly based on the finite lattice for practical numerical studies . |
5,527 | Suppose that you have an abstract for a scientific paper: we study a question of density of lipschitz mappings in the sobolev class of mappings from a closed manifold into a singular space .
the main result of the paper , theorem [ main ] , shows that if we change the metric in the target space to a bi - lipschitz equivalent one , than the property of the density of lipschitz mappings may be lost .
other main results in the paper are theorems [ one ] , [ dens ] , [ subaru ] , [ smooth ] . .
And you have already written the first three sentences of the full article: sobolev spaces have been playing a major role in the study of nonlinear partial differential equations and calculus of variations for more than seven decades now .
variational approach to mappings between manifolds leads in a natural way to the notion of sobolev mappings between manifolds @xmath0 . here
the symbol @xmath1 stands for the sobolev space of @xmath2 integrable mappings with @xmath2 integrable first order derivatives ..
Please generate the next two sentences of the article | this class of mappings was considered for the first time as early as in 1948 by morrey @xcite in his celebrated paper on regularity of minimizing harmonic mappings from two dimensional surfaces into manifolds . while it is a well known theorem of meyers and serrin that smooth functions are dense in the sobolev space @xmath3 , where @xmath4 is a riemannian manifold , similar question , raised by eells and lemaire , @xcite , about density of smooth mappings in the class of sobolev mappings between manifolds
is no longer obvious . |
5,528 | Suppose that you have an abstract for a scientific paper: a large fraction of white dwarfs ( wds ) may host planets in their habitable zones .
these planets may provide our best chance to detect bio - markers on a transiting exoplanet , thanks to the diminished contrast ratio between the earth - sized wd and its earth - sized planets .
the james webb space telescope is capable of obtaining the first spectroscopic measurements of such planets , yet there are no known planets around wds . here
we propose to take advantage of the unique capability of the kepler spacecraft in the 2-wheels mode to perform a transit survey that is capable of identifying the first planets in the habitable zone ( @xmath0 4 - 30 h ) of a wd .
we propose to obtain kepler time - series photometry of @xmath1 wds in the sloan digital sky survey imaging area to search for planets in the habitable zone .
thanks to the large field of view of kepler , for the first time in history , a large number of wds can be observed at the same time , which is essential for discovering transits .
our proposed survey requires a total of 200 days of observing time , and will find up to 100 planets in the wd habitable zone .
this survey will maintain kepler s spirit of searching for habitable earths , but near new hosts .
with few - day observations and minute - cadences per field , it will also open up a completely unexplored discovery space .
in addition to planets , this survey is sensitive to pulsating wds , as well as eclipsing short period stellar and substellar companions .
these have important implications for constraining the double wd merger rate and their contribution to type ia supernovae and the gravitational wave foreground . given the relatively low number density of our targets ,
this program can be combined with other projects that would benefit from high cadence and ` many - fields ' observations with kepler , e.g. a transit survey of a magnitude - limited , complete sample of nearby m dwarfs or asteroseismology of variable stars ( e.g. rr lyrae ) in the same fields . .
And you have already written the first three sentences of the full article: transiting exoplanets provide invaluable information on planetary physics , their formation , and evolution .
the search for planets in the habitable zone has so far focused on solar - type stars and m dwarfs .
however , transiting planets in the habitable zone around white dwarfs ( wds ) may be common and they may provide our best chance to detect biomarkers on an exoplanet in the near future @xcite ..
Please generate the next two sentences of the article | wds are as common as sun - like stars , and they provide an energy source for planets for billions of years .
typical wds have @xmath2 , and @xmath3 , so a planet must orbit at @xmath40.01 au to be at a temperature for liquid water to exist on its surface . |
5,529 | Suppose that you have an abstract for a scientific paper: in this paper a reduced set of the partial differential wave equations valid in the conversion layer close to o - mode cutoff surface and accounting for the magnetic field 2d inhomogeneity with no restriction to an angle between the toroidal direction and the magnetic field direction is derived .
an integral representation of a solution to the derived set of equation is given .
for the particular case of small angle between o mode cut - off surface and x mode cut - off surface an explicit expressions for both the electric field components and the conversion coefficients are obtained and its properties are considered in details . .
And you have already written the first three sentences of the full article: nowadays the electron bernstein waves ( ebws ) having no density cut - offs and effectively damped even at high electron cyclotron harmonics are considered as the most promising candidate to provide an auxiliary heating and current drive in a dense plasma of a spherical tokamaks and stellarators @xcite .
the ebw could be excited via direct conversion of x mode to bernstein mode in a vicinity of the upper hybrid resonance ( uhr ) or via so - called o - x - b scheme .
the efficiency of last scheme , as it was demonstrated theoretically @xcite in the frame of 1d slab model , is determined by the efficiency of o to x mode conversion , which can reach 100 percent value at the certain parallel refractive index being constant in slab geometry . due to , in a real spherical tokamak s configurations , where the poloidal inhomogeneity of the magnetic field is important , both the parallel refractive index is no longer constant and the components of the dielectric tensor are functions of two co - ordinates , an analysis of the full - wave equations in the frame of 2d model is important ..
Please generate the next two sentences of the article | the first attempt to consider 2d model of ox conversion has been undertaken a couple of years ago @xcite . the main conclusion provided by author of @xcite concerning the absence of the o mode reflection from the o - mode cut - off surface seems to be quite doubtful and lacks support from the last two papers devoted to this topic @xcite .
unfortunately , the ox mode conversion in @xcite has been considered in the frame of the oversimplified model ignoring as it does both the poloidal magnetic field and , as result , varying of the parallel refractive index on the magnetic surface . |
5,530 | Suppose that you have an abstract for a scientific paper: in complex systems , crucial parameters are often subject to unpredictable changes in time .
climate , biological evolution and networks provide numerous examples for such non stationarities . in many cases , improved statistical models are urgently called for . in a general setting , we study systems of correlated quantities to which we refer as amplitudes .
we are interested in the case of non stationarity , _
i.e. _ , seemingly random covariances .
we present a general method to derive the distribution of the covariances from the distribution of the amplitudes . to ensure analytical tractability
, we construct a properly deformed wishart ensemble of random matrices .
we apply our method to financial returns where the wealth of data allows us to carry out statistically significant tests .
the ensemble that we find is characterized by an algebraic distribution which improves the understanding of large events . .
And you have already written the first three sentences of the full article: in electroencephalography ( eeg ) electrical currents are recorded at different positions on the scalp to measure the brain activity .
the correlations between the time series of these currents strongly depend on the overall state of the brain . during an epileptic seizure ,
for example , the correlations are much stronger than in normal periods @xcite . this time dependence of the correlations is the kind of non stationarity that we wish to address ..
Please generate the next two sentences of the article | non stationarities are also seen when wave packets travel through disordered systems . even if the disorder is static , the correlations between the wave intensities measured at different positions versus time will change , when the direction or the composition of the wave packet is altered @xcite .
finance provides another important example for this type of non stationarity . |
5,531 | Suppose that you have an abstract for a scientific paper: the pressure induced bcc to hcp transition in fe has been investigated via ab - initio electronic structure calculations .
it is found by the disordered local moment ( dlm ) calculations that the temperature induced spin fluctuations result in the decrease of the energy of burgers type lattice distortions and softening of the transverse @xmath0-point @xmath1 phonon mode with @xmath2 $ ] polarization . as a consequence ,
spin disorder in an system leads to the increase of the amplitude of atomic displacements .
on the other hand , the exchange coupling parameters obtained in our calculations strongly decrease at large amplitude of lattice distortions .
this results in a mutual interrelation of structural and magnetic degrees of freedom leading to the instability of the bcc structure under pressure at finite temperature . .
And you have already written the first three sentences of the full article: since many years considerable effort has been made to investigate the problem of nucleation and growth of a new phase upon martensitic transformation . despite these attempts , there is no clear understanding so far of the atomic scale mechanism of the bcc - hcp reconstructive transformation occurring even in non - magnetic materials . in the case of
fe - considered here - there are convincing arguments , both from theoretical and experimental side , that magnetism plays a crucial role for the stability of bcc structure , making the problem more complicated @xcite .
the bcc - hcp transformation observed in non - magnetic materials has been extensively discussed in the literature @xcite ..
Please generate the next two sentences of the article | the corresponding mechanism suggested by burgers @xcite consists in two types of simultaneous distortions ( see appendix , fig .
[ fig_burgers ] ): |
5,532 | Suppose that you have an abstract for a scientific paper: a generic approach for compiling any classical block compression algorithm into a quantum block compression algorithm is presented . using this technique , compression asymptoticaly approaching the von neumann entropy of a qubit source
can be achieved .
the automatically compiled algorithms are competitive ( in time and space complexity ) with hand constructed quantum block compression algorithms . .
And you have already written the first three sentences of the full article: we are concerned with quantum compression , which is best understood in the context of quantum information theory .
informally , the schumacher coding theorem @xcite states that a qubit source can be compressed to its von neumann entropy with high fidelity .
this statement is strongly analogous to the shannon coding theorem for classical information theory which states that a bit source can be compressed to its shannon entropy with high probability ..
Please generate the next two sentences of the article | quantum compression is therefore concerned with algorithms for achieving compression near to the von neumann entropy of a qubit source in a reasonable amount of time and space .
the main result of this paper is a compilation algorithm which takes as input any family of classical block compression ( and decompression ) algorithm as well as a description of the quantum source . |
5,533 | Suppose that you have an abstract for a scientific paper: different representations of an effective , covariant theory of the hadronic interaction are examined . for this purpose
we have introduced nucleon - meson vertices parametrized in terms of scalar combinations of hadronic fields , extending the conceptual frame of the density dependent hadronic field theory .
nuclear matter properties at zero temperature are examined in the mean field approximation , including the equation of state , the landau parameters , and collective modes .
the treatment of isospin channels in terms of qcd sum rules inputs is outlined . .
And you have already written the first three sentences of the full article: a generalized concept in present theoretical physics is that description of all physical phenomena should be derivable from first principles in a unified way .
however , the bridge towards concrete applications requires elaborated procedures and judicious arguments .
this is the case of quantum chromodynamics ( qcd ) , which is the accepted theoretical model for the strong interactions . despite the fact that it is perturbative in the high energy regime , the fundamental state of matter corresponds to the opposite limit , where confinement and the breakdown of symmetries make it mathematically intractable ..
Please generate the next two sentences of the article | different effective models , such as nambu- jona lasinio , skyrme , bag - like , and chiral perturbation theory attempts to translate the main features of qcd into the hadronic phase . on the other hand , lattice simulations and qcd sum - rules share this aim , although using different methods .
+ qcd sum - rules is a ingenious procedure to reveal the foundations of certain hadronic properties . |
5,534 | Suppose that you have an abstract for a scientific paper: the minimum description length ( mdl ) principle in supervised learning is studied .
one of the most important theories for the mdl principle is barron and cover s theory ( bc theory ) , which gives a mathematical justification of the mdl principle .
the original bc theory , however , can be applied to supervised learning only approximately and limitedly . though barron et al .
recently succeeded in removing a similar approximation in case of unsupervised learning , their idea can not be essentially applied to supervised learning in general . to overcome this issue , an extension of bc theory to supervised learning
is proposed .
the derived risk bound has several advantages inherited from the original bc theory .
first , the risk bound holds for finite sample size .
second , it requires remarkably few assumptions .
third , the risk bound has a form of redundancy of the two - stage code for the mdl procedure .
hence , the proposed extension gives a mathematical justification of the mdl principle to supervised learning like the original bc theory .
as an important example of application , new risk and ( probabilistic ) regret bounds of lasso with random design are derived .
the derived risk bound holds for any finite sample size @xmath0 and feature number @xmath1 even if @xmath2 without boundedness of features in contrast to the past work .
behavior of the regret bound is investigated by numerical simulations .
we believe that this is the first extension of bc theory to general supervised learning with random design without approximation .
lasso , risk bound , random design , mdl principle .
And you have already written the first three sentences of the full article: there have been various techniques to evaluate performance of machine learning methods theoretically .
taking lasso @xcite as an example , lasso has been analyzed by nonparametric statistics @xcite , empirical process @xcite , statistical physics @xcite and so on . in general ,
most of these techniques require either asymptotic assumption ( sample number @xmath0 and/or feature number @xmath1 go to infinity ) or various technical assumptions like boundedness of features or moment conditions ..
Please generate the next two sentences of the article | some of them are much restrictive for practical use . in this paper
, we try to develop another way for performance evaluation of machine learning methods with as few assumptions as possible . |
5,535 | Suppose that you have an abstract for a scientific paper: our recent estimates of galaxy counts and the luminosity density in the near - infrared @xcite indicated that the local universe may be under - dense on radial scales of several hundred megaparsecs .
such a large - scale local under - density could introduce significant biases in the measurement and interpretation of cosmological observables , such as the inferred effects of dark energy on the rate of expansion . in @xcite , we measured the @xmath0band luminosity density as a function of distance from us to test for such a local under - density .
we made this measurement over the redshift range @xmath1 ( radial distances @xmath2 @xmath3 mpc ) .
we found that the shape of the @xmath0band luminosity function is relatively constant as a function of distance and environment .
we derive a local ( @xmath4 @xmath3 mpc ) @xmath0band luminosity density that agrees well with previously published studies . at @xmath5 ,
we measure an increasing luminosity density that by @xmath6 rises to a value of @xmath7 times higher than that measured locally .
this implies that the stellar mass density follows a similar trend . assuming that the underlying dark matter distribution is traced by this luminous matter
, this suggests that the local mass density may be lower than the global mass density of the universe at an amplitude and on a scale that is sufficient to introduce significant biases into the measurement of basic cosmological observables .
at least one study has shown that an under - density of roughly this amplitude and scale could resolve the apparent tension between direct local measurements of the hubble constant and those inferred by planck team .
other theoretical studies have concluded that such an under - density could account for what looks like an accelerating expansion , even when no dark energy is present . .
And you have already written the first three sentences of the full article: the assumption that the universe is homogeneous on large scales is a fundamental pillar of our current concordance cosmology .
however , it is well known that very large - scale inhomogeneity exists in the form of sheets , voids , and filaments of matter . as structure formation proceeds ,
gravity acts to pile more matter onto the over - dense regions , and simultaneously evacuate the under - dense regions ..
Please generate the next two sentences of the article | models have shown that this phenomenon implies that cosmological observables measured by an observer will vary significantly depending on where that observer is located with respect to these large - scale structures .
in two previous papers @xcite , we investigated large - scale inhomogeneity in the local universe . |
5,536 | Suppose that you have an abstract for a scientific paper: in this paper , we investigate the accretion on the reissner - nordstrm anti - de - sitter black hole with global monopole charge . we discuss the general solutions of accretion using the isothermal and polytropic equations of state for steady state ,
spherically symmetric , non - rotating accretion on the black hole . in the case of isothermal flow , we consider some specific fluids and derive their solutions at the sonic point as well .
however , in case of polytropic fluid we calculate the general expressions only , as there exists no global ( bondi ) solutions for polytropic test fluids .
in addition to this , the effect of fluid on the mass accretion rate are also studied . moreover
, the large monopole parameter @xmath0 greatly suppresses the maximum accretion rate .
+ * keywords * : accretion ; black hole ; cosmological constant ; global monopole charge . .
And you have already written the first three sentences of the full article: in astrophysics , the accretion of fluids or matter onto compact objects such as neutron stars or black holes , is an interesting physical process as it describes a scenario which is most likely to explain the high energy output from the active galactic nuclei and quasars .
accretion is the process of capturing the matter by a gravitating object towards its center which leads to increase the mass and angular momentum of the accreting body .
the stars and planets are formed by the process of accretion in dust clouds ..
Please generate the next two sentences of the article | the existence of supermassive black holes at the center of galaxies suggests that such black holes could have been gradually developed through the accretion process .
an accretion disk is developed when dust and gases rotate around a compact object and accumulate into a disk . |
5,537 | Suppose that you have an abstract for a scientific paper: we link the study of positive quantum maps , block positive operators , and entanglement witnesses with problems related to multivariate polynomials . for instance , we show how indecomposable block positive operators relate to biquadratic forms that are not sums of squares .
although the general problem of describing the set of positive maps remains open , in some particular cases we solve the corresponding polynomial inequalities and obtain explicit conditions for positivity .
= 2 mm .
And you have already written the first three sentences of the full article: the set of positive maps acting on a finite dimensional hilbert space is a long - standing subject of mathematical interest . in spite of many efforts ( see @xcite and references therein ) ,
the structure of this set in spaces of arbitrary dimension is still not well understood .
of particular interest are positive maps , which are not completely positive @xcite ..
Please generate the next two sentences of the article | the theorem of jamiokowski implies @xcite that any such map can be represented by an operator , acting on a bi - partite hilbert space , which is not positive , but is block - positive .
non completely positive maps recently attracted a considerable attention of the physics community @xcite . |
5,538 | Suppose that you have an abstract for a scientific paper: human agents happen to judge that a conjunction of two terms is more probable than one of the terms , in contradiction with the rules of classical probabilities this is the conjunction fallacy .
one of the most discussed accounts of this fallacy is currently the quantum - like explanation , which relies on models exploiting the mathematics of quantum mechanics .
the aim of this paper is to investigate the empirical adequacy of major quantum - like models which represent beliefs with quantum states .
we first argue that they can be tested in three different ways , in a question order effect configuration which is different from the traditional conjunction fallacy experiment .
we then carry out our proposed experiment , with varied methodologies from experimental economics .
the experimental results we get are at odds with the predictions of the quantum - like models .
this strongly suggests that this quantum - like account of the conjunction fallacy fails .
future possible research paths are discussed . .
And you have already written the first three sentences of the full article: conjunction fallacy was first empirically documented by tversky and kahneman ( 1982 , 1983 ) through a now renowned experiment in which subjects are presented with a description of someone called linda " : _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ linda is 31 years old , single , outspoken , and very bright .
she majored in philosophy . as a student , she was deeply concerned with issues of discrimination and social justice , and also participated in anti - nuclear demonstrations . " _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
then , subjects are shown a list of 8 possible outcomes describing her present employment and activities , and are asked to rank the propositions by representativeness or probability ..
Please generate the next two sentences of the article | two items were specifically tested : * linda is a bank teller " , * linda is a bank teller and is active in the feminist movement " .
empirical results show that most people judge ( 2 ) more probable than ( 1 ) . in the framework of classical probabilities , this is a fallacy the conjunction fallacy , since a conjunction can not be more probable than one of its components . |
5,539 | Suppose that you have an abstract for a scientific paper: when a composite of nonlinear particles suspended in a host medium is subjected to a sinusoidal electric field , the electrical response in the composite will generally consist of alternating current ( ac ) fields at frequencies of higher - order harmonics .
the situation becomes more interesting when the suspended particles are graded , with a spatial variation in the dielectric properties .
the local electric field inside the graded particles can be calculated by the differential effective dipole approximation , which agrees very well with a first - principles approach . in this work ,
a nonlinear differential effective dipole approximation and a perturbation expansion method have been employed to investigate the effect of gradation on the nonlinear ac responses of these composites .
the results showed that the fundamental and third - harmonic ac responses are sensitive to the dielectric - constant and/or nonlinear - susceptibility gradation profiles within the particles .
thus , by measuring the ac responses of the graded composites , it is possible to perform a real - time monitoring of the fabrication process of the gradation profiles within the graded particles . *
pacs number(s ) : * 77.84.lf , 77.22.ej , 42.65.-k , 42.79.ry .
And you have already written the first three sentences of the full article: graded materials with spatial gradients in their structure @xcite are abundant in nature , which have received much attention as one of the advanced inhomogeneous composite materials in diverse engineering applications @xcite .
these materials can be made to realize quite different physical properties from the homogeneous materials , and thus , to some extent , more useful and interesting . for graded materials , the traditional theories @xcite for homogeneous materials do not work any longer .
recently , we presented a first - principles approach @xcite and a differential effective dipole approximation ( deda ) @xcite , to investigate the dielectric properties of the graded materials . to our interest ,.
Please generate the next two sentences of the article | the two methods have been demonstrated in excellent agreement between each other @xcite . in the case of graded materials , the problem will become more complicated by the presence of nonlinearity inside them .
fortunately , for deriving the equivalent nonlinear susceptibility of graded particles , we have succeeded in putting forth a nonlinear differential effective dipole approximation ( ndeda ) @xcite . |
5,540 | Suppose that you have an abstract for a scientific paper: recent results on spectroscopy with special focus on searches for pentaquarks are presented from the h1 and zeus collaborations .
cross sections of observed states and upper limits on the production cross section of unobserved states are extracted in order to enable comparison between experiments .
measurements of the inclusive photoproduction of the neutral mesons @xmath0 , @xmath1 , @xmath2 and @xmath3 in @xmath4 interactions at hera at an average @xmath5 collision energy of @xmath6 gev are also presented . .
And you have already written the first three sentences of the full article: recently , some experiments have reported narrow signals in the vicinity of 1530 mev in the @xmath7 and @xmath8 invariant mass spectra which are consistent with the exotic pentaquark baryon state @xmath9 with quark content @xmath10 @xcite , while other experiments have searched for this state with negative results . the possible existence
a charm pentaquark has also been discussed , with renewed theoretical interest in calculating their expected properties @xcite following the observation of strange pentaquarks .
the results of pentaquark searches by the h1 and the zeus collaboration are presented in this report ..
Please generate the next two sentences of the article | the analyses are based on data samples with an integrated luminosity of 75 pb@xmath11 and 126 pb@xmath11 taken by the h1 and the zeus collaborations in the years 1994 - 2000 when hera collided electrons or positrons with 27.6 gev and protons with 820 or 920 gev .
understanding the process whereby quarks and gluons convert to colourless hadrons is one of the outstanding problems in particle physics . |
5,541 | Suppose that you have an abstract for a scientific paper: we present _ spitzer _ space telescope irac and mips observations toward a sample of nine high - mass star forming regions at a distance of around 2 kpc . based on irac and mips 24 @xmath0 m photometric results and 2mass _ jhks _ data
, we carry out a census of young stellar objects ( ysos ) in a @xmath1 field toward each region . toward seven out of the nine regions ,
we detect parsec sized clusters with around 20 ysos surrounded by a more extended and sparse distribution of young stars and protostars . for the other two regions , iras 20126 + 4104 and iras 22172 + 5549 ,
the former has the lowest number of ysos in the sample and shows no obvious cluster , and the latter appears to be part of a larger , potentially more evolved cluster .
the deep irac imaging reveals at least twelve outflows in eight out of the nine regions , with nine outflows prominent in the 4.5 @xmath0 m band most probably attributed to shocked h@xmath2 emission , two outflows dominated by scattered light in the 3.6 and 4.5 @xmath0 m bands , and one outflow standing out from its hydrocarbon emission in the 8.0 @xmath0 m band . in comparison with previous ground - based observations ,
our irac observations reveal new outflow structures in five regions .
the dramatically different morphologies of detected outflows can be tentatively interpreted in terms of possible evolution of massive outflows .
the driving sources of these outflows are deeply embedded in dense dusty cores revealed by previous millimeter interferometric observations .
we detect infrared counterparts of these dusty cores in the irac or mips 24 @xmath0 m bands .
reflection nebulae dominated by the emission from uv heated hydrocarbons in the @xmath3 m band can be found in most regions and they may imply the presence of young b stars . .
And you have already written the first three sentences of the full article: it is well know that high - mass stars form in dense clusters @xcite .
the research on embedded young clusters around young intermediate- to high - mass stars has advanced significantly via near - infrared surveys ( e.g. , * ? ? ?
* ; * ? ? ?.
Please generate the next two sentences of the article | * ; * ? ? ?
the _ spitzer _ |
5,542 | Suppose that you have an abstract for a scientific paper: the internet structure is extremely complex .
the positive - feedback preference ( pfp ) model is a recently introduced internet topology generator .
the model uses two generic algorithms to replicate the evolution dynamics observed on the internet historic data .
the phenomenological model was originally designed to match only two topology properties of the internet , i.e. the rich - club connectivity and the exact form of degree distribution . whereas numerical evaluation has shown that the pfp model accurately reproduces a large set of other nontrivial characteristics as well .
this paper aims to investigate why and how this generative model captures so many diverse properties of the internet . based on comprehensive simulation results , the paper presents a detailed analysis on the exact origin of each of the topology properties produced by the model .
this work reveals how network evolution mechanisms control the obtained topology properties and it also provides insights on correlations between various structural characteristics of complex networks . .
And you have already written the first three sentences of the full article: it is vital to obtain a good description of a network topology because structure fundamentally affects function @xcite .
the internet contains millions of routers , which are grouped into thousands of subnetworks , called _ autonomous systems _ ( as ) , which are then glued into a global network by the border gateway protocol .
effective engineering of the internet is predicated on a detailed understanding of issues such as the large - scale structure of its underlying physical topology , the manner in which it evolves over time , and the way in which its constituent components contribute to its overall function @xcite ..
Please generate the next two sentences of the article | the recently introduced positive - feedback preference ( pfp ) model @xcite is an internet as - level topology generator .
the model uses two evolution mechanisms , namely the interactive growth and the positive - feedback preference . |
5,543 | Suppose that you have an abstract for a scientific paper: given a piecewise linear ( pl ) function @xmath0 defined on an open subset of @xmath1 , one may construct by elementary means a unique polyhedron with multiplicities @xmath2 in the cotangent bundle @xmath3 representing the graph of the differential of @xmath0 . restricting to dimension 2 ,
we show that any smooth function @xmath4 may be approximated by a sequence @xmath5 of pl functions such that the areas of the @xmath6 are locally dominated by the area of the graph of @xmath7 times a universal constant . .
And you have already written the first three sentences of the full article: in approximating smooth submanifolds by polyhedra , it is well known that pathologies may occur if the triangles of the polyhedra become too thin .
for example , the famous schwartz lantern " ( cf .
@xcite , section 3.1.3 ) shows that the areas of a sequence of polyhedra @xmath8 approximating a surface @xmath9 may fail to converge unless the ratio of the area of a general constituent triangle to the square of its diameter is bounded away from zero . on the other hand , if this .
Please generate the next two sentences of the article | fatness " condition is imposed then the sequence enjoys convergence not only to first order ( i.e. convergence of areas ) , but also to second order in the sense that certain curvature integrals ( or , more precisely , their polyhedral analogues ) for the @xmath8 converge weakly to the corresponding integrals for @xmath9 ( @xcite ) .
the key observation is that the corresponding _ absolute _ curvature integrals of the @xmath8 remain bounded in the course of the approximation process |
5,544 | Suppose that you have an abstract for a scientific paper: the stability of an einstein static universe in the dgp braneworld scenario is studied in this letter .
two separate branches denoted by @xmath0 of the dgp model are analyzed .
assuming the existence of a perfect fluid with a constant equation of state , @xmath1 , in the universe , we find that , for the branch with @xmath2 , there is no a stable einstein static solution , while , for the case with @xmath3 , the einstein static universe exists and it is stable when @xmath4 .
thus , the universe can stay at this stable state past - eternally and may undergo a series of infinite , non - singular oscillations .
therefore , the big bang singularity problem in the standard cosmological model can be resolved . .
And you have already written the first three sentences of the full article: although most of the problems in the standard cosmological model can be resolved by the inflation theory , the resolution of the existence of a big bang singularity in the early universe is still elusive . based upon the string / m - theory , the pre - big bang @xcite and ekpyrotic / cyclic @xcite scenarios
have been proposed to address the issue .
recently , ellis et al proposed , in the context of general relativity , a new scenario , called an emergent universe @xcite to avoid this singularity . in this scenario ,.
Please generate the next two sentences of the article | the space curvature is positive , which is supported by the recent observation from wmap7 @xcite where it was found that a closed universe is favored at the @xmath5 confidence level , and the universe stays , past - eternally , in an einstein static state and then evolves to a subsequent inflationary phase .
so , in an emergent theory , the universe originates from an einstein static state rather than from a big bang singularity . however , the einstein static universe in the classical general relativity is unstable , which means that it is extremely difficult for the universe to remain in such an initial static state in a long time due to the existence of perturbations , such as the quantum fluctuations . |
5,545 | Suppose that you have an abstract for a scientific paper: we present a discussion on the effects of convection on the @xmath0 colours of a and f stars . the mixing - length theory used in atlas9
is compared to the turbulent convection theory of canuto & mazzitelli ( 1991 , 1992 ) .
comparison with fundamental stars reveals that colours calculated using the canuto & mazzitelli convection theory are generally in better agreement than those obtained using mixing - length theory . .
And you have already written the first three sentences of the full article: the colours calculated for stars later than mid a - type are affected by treatment of convection .
small systematic errors were found in the colours calculated using atlas6 ( kurucz , 1979 ) , which could be due to convection or missing opacity in the models ( relyea & kurucz , 1978 ) .
recent improvements in opacity in atlas9 models ( kurucz , 1991 ) ought to ensure that opacity is now a less dominant source of the discrepancies ..
Please generate the next two sentences of the article | this leaves convection as a possible source of the discrepancies .
we have compared mixing length theory ( see castelli et al . , 1997 ) with the turbulent convection model of canuto & mazzitelli ( 1991 , 1992 ) . |
5,546 | Suppose that you have an abstract for a scientific paper: in this article , we study parameter - dependent systems of reaction - diffusion equations on the sphere , which are equivariant under the group @xmath0 of all rigid rotations on a sphere .
two main types of spatial - temporal patterns that can appear in such systems are rotating waves ( equilibrium in a co - rotating frame ) and modulated rotating waves ( periodic solution in a co - rotating frame ) . the transition from rotating waves to modulated rotating waves on spherical domains
is explained via a supercritical hopf bifurcation from a rotating wave , @xmath0-symmetry and finite - dimensional equivariant center manifold reduction .
the baker - campbell - haussdorff formula in the lie algebra @xmath1 is used to get reduced differential equations on @xmath1 , a formula for a primary frequency vector , as well as a formula for the periodic part associated to any modulated rotating wave obtained by a supercritical hopf bifurcation from a rotating wave . as a consequence , there are three types of motions for the tips of these modulated rotating waves . in the resonant case ( with two parameters ) , we obtain that the primary frequency vectors of a branch of these modulated rotating waves are generically orthogonal to the frequency vector of the initial rotating wave undergoing hopf bifurcation . + _ _ equivariant center manifold , rotating wave , modulated rotating wave , hopf bifurcation .
And you have already written the first three sentences of the full article: the main motivation of this article is the presence of spiral waves in excitable media , especially in cardiac tissue .
spiral waves arise as stable spatio - temporal patterns in various chemical , physical systems and biological systems , as well as numerical simulations of reaction - diffusion systems on excitable media with various geometries .
excitable media are extended non - equilibrium systems having a uniform rest state that is linearly stable but susceptible to finite perturbations ..
Please generate the next two sentences of the article | spiral waves have been observed experimentally , for instance , in catalysis of platinum surfaces @xcite , belousov - zhabotinsky chemical reactions @xcite , rayleigh - bernard convection @xcite , slime - mould cells @xcite and the most important , cardiac tissue @xcite .
numerical simulations of the spiral waves have been done by @xcite , for example . |
5,547 | Suppose that you have an abstract for a scientific paper: we study analytically the late time statistics of the number of particles in a growing tree model introduced by aldous and shields . in this model
, a cluster grows in continuous time on a binary cayley tree , starting from the root , by absorbing new particles at the empty perimeter sites at a rate proportional to @xmath0 where @xmath1 is a positive parameter and @xmath2 is the distance of the perimeter site from the root . for @xmath3
, this model corresponds to random binary search trees and for @xmath4 it corresponds to digital search trees in computer science . by introducing a backward fokker - planck approach
, we calculate the mean and the variance of the number of particles at large times and show that the variance undergoes a ` phase transition ' at a critical value @xmath5 . while for @xmath6 the variance is proportional to the mean and the distribution is normal , for @xmath7 the variance is anomalously large and the distribution is non - gaussian due to the appearance of extreme fluctuations .
the model is generalized to one where growth occurs on a tree with @xmath8 branches and , in this more general case , we show that the critical point occurs at @xmath9 . * keywords : * search trees , growth models , phase transitions .
And you have already written the first three sentences of the full article: growing clusters are ubiquitous in nature and they exhibit fascinating structures and patterns .
examples range from natural fractals , such as snowflakes and soots , to artificial structures such as networks , for example the internet and social networks .
various growth models have been studied extensively by physicists over the last three decades @xcite . in these models growth.
Please generate the next two sentences of the article | starts from a single seed site and proceeds via absorbing new particles into the cluster according to certain specified rules .
different growth rules give rise to different growth models , examples being the eden model @xcite , invasion percolation @xcite , diffusion limited aggregation @xcite and the growing network models @xcite which have recently received much attention . |
5,548 | Suppose that you have an abstract for a scientific paper: the usual development of the continuous time random walk ( ctrw ) assumes that jumps and time intervals are a two - dimensional set of independent and identically distributed random variables . in this paper
we address the theoretical setting of non - independent ctrw s where consecutive jumps and/or time intervals are correlated .
an exact solution to the problem is obtained for the special but relevant case in which the correlation solely depends on the signs of consecutive jumps . even in this simple case some interesting features arise such as transitions from unimodal to bimodal distributions due to correlation .
we also develop the necessary analytical techniques and approximations to handle more general situations that can appear in practice . .
And you have already written the first three sentences of the full article: for more than four decades , since their introduction in 1965 by montroll and weiss @xcite , continuous time random walks ( ctrw s ) have been applied to virtually any field in which one wishes to provide a dynamical description on the microstructure of a given random system .
a huge number of examples and applications can be found in the literature , of which we only cite a handful : transport in disordered media @xcite , random networks @xcite , self - organized criticality @xcite , electron tunneling @xcite , earthquake modeling @xcite , hydrology @xcite , time - series analysis @xcite and finance @xcite .
the ctrw generalizes the ordinary random walk since in the latter the steps of the random walker are made at equal intervals of time , while in the ctrw the interval between steps is a continuous random variable . in this sense ctrw.
Please generate the next two sentences of the article | is related to several other extensions of random walks in continuous time , like semi - markov processes or markov renewal processes @xcite , although the seeds of this idea can be traced back to the 1920 s with the pure birth poisson process @xcite .
a great number of developments of the ctrw are based on the assumption that the magnitude of the steps ( or jumps ) and the time intervals between them ( also called sojourns ) are a two - dimensional set of independent and identically distributed random variables . while in many cases this is a convenient assumption which allows for simple developments , there are some other cases in which independent walks are clearly insufficient to explain some aspects of the physical reality , and correlations between consecutive step sizes and/or waiting times must be considered . |
5,549 | Suppose that you have an abstract for a scientific paper: we investigate the time - evolution and steady states of the stochastic susceptible - infected - recovered - susceptible ( sirs ) epidemic model on one- and two- dimensional lattices .
we compare the behavior of this system , obtained from computer simulations , with those obtained from the mean - field approximation ( mfa ) and pair - approximation ( pa ) .
the former ( latter ) approximates higher order moments in terms of first ( second ) order ones .
we find that the pa gives consistently better results than the mfa . in one dimension
the improvement is even qualitative . .
And you have already written the first three sentences of the full article: the mathematical modeling of the spread of epidemics is a subject of continuing theoretical and practical interest @xcite .
this is enhanced by the fact that the same or similar models are used for describing other phenomena such as plant and animal dispersal , and successional dynamics in ecology @xcite .
the level of description provided by a model can be purely macroscopic and deterministic or individual and stochastic @xcite . in the first case one.
Please generate the next two sentences of the article | uses ( partial- ) differential equations to describe the time evolution of different subpopulations ; e.g. , susceptible , infectious and recovered . in the second case one typically uses stochastic dynamics on a lattice ( or more general graphs ) where the variables at each node represent the state of an individual or a small spatial region .
the time evolution of these variables is stochastic , e.g. , an infected individual at site @xmath0 has a certain probability per unit time ( rate ) @xmath1 to infect a susceptible individual at a neighboring site @xmath2 . |
5,550 | Suppose that you have an abstract for a scientific paper: swag ( `` survey of water and ammonia in the galactic center '' ) is a multi - line interferometric survey toward the center of the milky way conducted with the australia telescope compact array .
the survey region spans the entire @xmath0400pc central molecular zone and comprises @xmath042 spectral lines at pc spatial and sub - km / s spectral resolution .
in addition , we deeply map continuum intensity , spectral index , and polarization at the frequencies where synchrotron , free - free , and thermal dust sources emit .
the observed spectral lines include many transitions of ammonia , which we use to construct maps of molecular gas temperature , opacity and gas formation temperature ( see poster by nico krieger et al . , this volume ) .
water masers pinpoint the sites of active star formation and other lines are good tracers for density , radiation field , shocks , and ionization .
this extremely rich survey forms a perfect basis to construct maps of the physical parameters of the gas in this extreme environment . .
And you have already written the first three sentences of the full article: the galactic center , being the closest galactic nucleus at a distance of only 8.5kpc , contains @xmath1% of the entire galactic molecular gas within a @xmath0500pc region known as the central molecular zone ( cmz ; e.g. morris et al .
1996 ; oka et al . 1998 ; jones et al .
this gas is subject to a unique and extreme environment that is dominated by shocks from cloud - cloud collisions , large fluxes of uv photons and cosmic rays , turbulence , as well as strong magnetic and tidal fields ..
Please generate the next two sentences of the article | these conditions are reflected in extreme physical parameters : large temperatures , densities , dispersions , and ionization fractions of the gas , and in a peculiar chemistry that is enhanced in abundances of complex molecules .
similar conditions are also found in high - z galaxies at cosmic times when the bulk of stars were created ( e.g. kruijssen & longmore 2013 ) . to understand the astrophysics of star formation processes in this environment |
5,551 | Suppose that you have an abstract for a scientific paper: it is well known that the classical gauss sum , normalized by the square - root number of terms , takes only finitely many values .
if one restricts the range of summation to a subinterval , a much richer structure emerges .
we prove a limit law for the value distribution of such incomplete gauss sums .
the limit distribution is given by the distribution of a certain family of periodic functions .
our results complement oskolkov s pointwise bounds for incomplete gauss sums as well as the limit theorems for quadratic weyl sums ( theta sums ) due to jurkat and van horne and the second author . .
And you have already written the first three sentences of the full article: the present paper investigates the asymptotic distribution of the incomplete gauss sum @xmath0 where @xmath1 , @xmath2 , and @xmath3 ; the weight function @xmath4 is periodic with period one .
the case @xmath5 corresponds to the classical gauss sum .
the main example of an incomplete gauss sum in the literature is the case when @xmath4 is the characteristic function of a subinterval of the unit interval @xcite ..
Please generate the next two sentences of the article | it is natural to assume that @xmath6 and @xmath7 are coprime , i.e , @xmath8 . here
@xmath9 is the multiplicative group of integers mod @xmath7 . |
5,552 | Suppose that you have an abstract for a scientific paper: we investigate the role of the electroweak corrections to the scattering cross section of standard model fermions with gravity .
we use both an approach of scattering off an external potential , where the gravitational field is treated as a classical background generated by a heavy source , and the usual interaction based on the one - graviton - exchange . in the potential appoach
we consider the fields both of a localized and of a distributed gravitational source of spherical symmetry and uniform density , separating the cases of interactions taking place both in the inner and external regions of the source .
this allows to make a distinction between interactions involving neutrinos and dark matter particles with a realistic gravity source , which cover the inner region , and the rest of the standard model fermions .
the role of the gravitationally induced flavour - changing transitions , as well as the flavour diagonal ones , are investigated in the limit of both large and small momentum transfers , deriving the structure of the corresponding hamiltonian . * fermion scattering in a gravitational background : * electroweak corrections and flavour transitions _ @xmath0dipartimento di matematica e fisica `` ennio de giorgi '' , universit del salento and + infn - lecce , via arnesano , 73100 lecce , italy
_ + .
And you have already written the first three sentences of the full article: radiative corrections to the graviton / matter vertex have been investigated since the 70 s by berends and gastmans @xcite in the qed case , who quantified the impact of these corrections to the bending of photons and fermions in an external localized gravitational field .
these results were based on the study of 3-point functions ( gravitational form factors ) with two fermions ( @xmath1 ) or two photons ( @xmath2 ) in external gravity , and one insertion of the energy momentum tensor ( emt ) @xmath3 of the matter fields . the very small size of these corrections , which affect the angles of deflection , combined with the experimental difficulty to improve on their direct measurements , call into question the possibility of using these effects as a possible test of general relativity .
perhaps , it is for this reason that the study of the electroweak corrections to the bending angles have not drawn any attention on these processes until the analysis of @xcite and , more recently , of @xcite , which concern the fermion / graviton vertex . in the photon case.
Please generate the next two sentences of the article | , the @xmath2 vertex in qed has been re - investigated in the analysis of the conformal anomaly action in @xcite , later extended to the electroweak case in @xcite . in the @xmath4 case
, the study has been separated into the flavour - changing @xcite and flavour diagonal sectors @xcite , the first of the two playing a significant role in the analysis of possible flavour transitions in the presence of a scalar component in the external gravitational field , as pointed out in @xcite . |
5,553 | Suppose that you have an abstract for a scientific paper: we have studied the quasi - free dissociation of quarkonia through a complex potential which is obtained by correcting both the perturbative and nonperturbative terms of the @xmath0 potential at t=0 through the dielectric function in real - time formalism .
the presence of confining nonperturbative term even above the transition temperature makes the real - part of the potential more stronger and thus makes the quarkonia more bound and also enhances the ( magnitude ) imaginary - part which , in turn contributes more to the thermal width , compared to the medium - contribution of the perturbative term alone .
these cumulative observations result the quarkonia to dissociate at higher temperatures .
finally we extend our calculation to a medium , exhibiting local momentum anisotropy , by calculating the leading anisotropic corrections to the propagators in keldysh representation .
the presence of anisotropy makes the real - part of the potential stronger but the imaginary - part is weakened slightly .
however , since the medium corrections to the imaginary - part is a small perturbation to the vacuum part , overall the anisotropy makes the dissociation temperatures higher , compared to isotropic medium . 0.1 in 0.1 in lata thakur , uttam kakade and binoy krishna patra + 0.01 in pacs : 12.39.-x,11.10.st,12.38.mh,12.39.pn : quantum chromodynamics , debye mass , momentum anisotropy , string tension , dielectric permittivity , quark - gluon plasma , heavy quark potential , decay width . .
And you have already written the first three sentences of the full article: the study of the heavy quarkonium states at finite temperature got impetus after the proposal by matsui and satz @xcite where the dissociation of quarkonium due to the color screening in the deconfined medium signals the formation of quark gluon plasma ( qgp ) @xcite .
the assumption behind the proposal is that the medium effects can be envisaged through a temperature - dependent heavy quark potentials and have been studied over the decades either phenomenologically or through lattice based free - energy calculations @xcite . in recent years
there have been important theoretical developments in heavy quarkonium physics where a sequence of effective field theories ( eft ) @xcite are derived by exploiting the hierarchy of different scales of heavy quark bound state : @xmath1 , due to its large quark mass ( @xmath2 ) ..
Please generate the next two sentences of the article | for example , the heavy quark system can be described by non - relativistic quantum chromodynamics ( nrqcd ) obtained from qcd by integrating out the mass . to describe the bound state of two quarks
, one can further integrate out the typical momentum exchange ( @xmath3 ) between the bound quarks @xcite and leads to potential non - relativistic qcd ( pnrqcd ) which describes a bound state by a two point function satisfying the schrdinger equation through the potentials as the matching coefficients of the lagrangian . |
5,554 | Suppose that you have an abstract for a scientific paper: in the last years several theoretical papers discussed if time can be an emergent propertiy deriving from quantum correlations . here , to provide an insight into how this phenomenon can occur , we present an experiment that illustrates page and wootters mechanism of `` static '' time , and gambini et al .
subsequent refinements . a static , entangled state between a clock system and the rest of the universe is perceived as evolving by internal observers that test the correlations between the two subsystems .
we implement this mechanism using an entangled state of the polarization of two photons , one of which is used as a clock to gauge the evolution of the second : an `` internal '' observer that becomes correlated with the clock photon sees the other system evolve , while an `` external '' observer that only observes global properties of the two photons can prove it is static .
.45 the `` problem of time '' @xcite in essence stems from the fact that a canonical quantization of general relativity yields the wheeler - de witt equation @xcite predicting a static state of the universe , contrary to obvious everyday evidence .
a solution was proposed by page and wootters @xcite : thanks to quantum entanglement , a static system may describe an evolving `` universe '' from the point of view of the internal observers .
energy - entanglement between a `` clock '' system and the rest of the universe can yield a stationary state for an ( hypothetical ) external observer that is able to test the entanglement vs. abstract coordinate time .
the same state will be , instead , evolving for internal observers that test the correlations between the clock and the rest @xcite .
thus , time would be an emergent property of subsystems of the universe deriving from their entangled nature : an extremely elegant but controversial idea @xcite .
here we want to demystify it by showing experimentally that it can be naturally embedded into ( small ) subsystems of the universe , where page and wootters....
And you have already written the first three sentences of the full article: we thank a. ashtekar for making us aware of ref . @xcite .
we acknowledge the compagnia di san paolo for partial support.e.v.moreva acknowledges the support from the dynasty foundation and russian foundation for basic research ( project 13 - 02 - 01170-d ) a. augustinus hipponensis , _ confessiones _ , xi , 14 ( 400 ) .
kuchar , in `` proceedings of the 4th canadian conference on general relativity and relativistic astrophysics '' ed ..
Please generate the next two sentences of the article | g. kunstatter , d. vincent and j. williams ( world scientific , singapore 1992 ) . c.j .
isham , in `` integrable systems , quantum groups and quantum field theories '' ed . |
5,555 | Suppose that you have an abstract for a scientific paper: we compute the reionization histories of hydrogen and helium due to the ionizing radiation fields produced by stars and quasars .
for the quasars we use a model based on halo - merger rates that reproduces all known properties of the quasar luminosity function at high redshifts .
the less constrained properties of the ionizing radiation produced by stars are modeled with two free parameters : ( i ) a transition redshift , @xmath0 , above which the stellar population is dominated by massive , zero - metallicity stars and below which it is dominated by a scalo mass function ; ( ii ) the product of the escape fraction of stellar ionizing photons from their host galaxies and the star - formation efficiency , @xmath1 .
we constrain the allowed range of these free parameters at high redshifts based on the lack of the hi gunn - peterson trough at @xmath2 and the upper limit on the total intergalactic optical depth for electron scattering , @xmath3 , from recent cosmic microwave background ( cmb ) experiments .
we find that quasars ionize helium by a redshift @xmath4 , but can not reionize hydrogen by themselves before @xmath5 . a major fraction of the allowed combinations of @xmath1 and @xmath6 lead to an early peak in the ionized fraction due to metal - free stars at high redshifts .
this sometimes results in two reionization epochs , namely an early hii or heiii overlap phase followed by recombination and a second overlap phase .
even if early overlap is not achieved , the peak in the visibility function for scattering of the cmb often coincides with the early ionization phase rather than with the actual reionization epoch .
consequently , @xmath7 does not correspond directly to the reionization redshift .
we generically find values of @xmath8 , that should be detectable by the map satellite . .
And you have already written the first three sentences of the full article: following cosmological recombination at a redshift @xmath9 , the baryonic gas filling up the universe became predominantly neutral . given that this gas is known to be mostly ionized today
, one arrives at two of the major questions in current extragalactic astronomy : _ (
i ) when were the cosmic hydrogen and helium re - ionized ? _ and _ ( ii ) which sources dominated this reionization process ? _ the answers to both questions are likely to be different for hydrogen and helium ( see review by barkana & loeb 2001 ) ..
Please generate the next two sentences of the article | recent observations provide preliminary answers to the first question .
the absorption spectra of sdss quasars at @xmath5 indicate that the neutral fraction of hydrogen increases significantly at @xmath10 ( becker et al . |
5,556 | Suppose that you have an abstract for a scientific paper: the appearance of the radion field , which is associated with the spin-0 metric fluctuations combined in some manner with the scalar stabilizing field , and of the radion , the corresponding lowest kaluza - klein ( kk ) mode , is a generic prediction of stabilized brane world models . in such models
the radion plays the role of the dilaton , and its mass may be somewhat smaller than that of all the kk modes of other particles propagating in the multidimensional bulk . due to its origin , the radion couples to the trace of the energy - momentum tensor of the standard model , the interaction lagrangian of the radion and the standard model fermions being similar to that of the sm higgs - fermion interactions except for additional terms , which come into play only in the case of off - shell fermions . in the present paper
it is shown that all the contributions to perturbative amplitudes of physical processes due to these additional terms are canceled out for both massless and massive off - shell fermions .
thus the additional fermion - radion terms in the interaction lagrangian do not alter any production and decay properties of the radion compared to those of the higgs boson .
* higgs - radion similarity in production processes involving off - shell fermions + * e. boos@xmath0 , s. keizerov@xmath0 , e. rahmetov@xmath1 , k. svirina@xmath2 + + _ @xmath1skobeltsyn institute of nuclear physics , lomonosov moscow state university _ + _ leninskie gory , 119991 , moscow , russia _ + _ @xmath3faculty of physics , lomonosov moscow state university , leninskie gory _
+ _ 119991 , moscow , russia _ .
And you have already written the first three sentences of the full article: there are few generic predictions in brane world models as possible extensions of the standard model ( sm ) .
the fields propagating in the multidimensional bulk manifest themselves as kk towers of states on the brane , where we are supposed to live .
these kk tower of states are an example of such generic predictions ..
Please generate the next two sentences of the article | another phenomenon of this kind is the presence of a new scalar field ( or fields ) on `` our '' brane ( tev - brane ) associated with spin-0 fluctuations of the metric component corresponding to extra space dimension .
the size of the extra space dimension should be stabilized in order to get a physically meaningful picture . |
5,557 | Suppose that you have an abstract for a scientific paper: we study the equivariantly perturbed mirror landau - ginzburg model of @xmath0 .
we show that the eynard - orantin recursion on this model encodes all genus all descendants equivariant gromov - witten invariants of @xmath0 .
the non - equivariant limit of this result is the norbury - scott conjecture @xcite , while by taking large radius limit we recover the bouchard - mario conjecture on simple hurwitz numbers @xcite . .
And you have already written the first three sentences of the full article: the equivariant gromov - witten theory of @xmath0 has been studied extensively . in @xcite ,
okounkov - pandharipande completely solved the equivariant gromov - witten theory of the projective line and established a gw / h correspondence between the stationary sector of gromov - witten theory of @xmath0 and hurwitz theory . in @xcite , givental derived a quantization formula for all genus descendant potential of the equivariant gromov - witten theory of @xmath0 ( and more generally , @xmath1 ) . in the non - equivariant limit , these results imply the virasoro conjecture of @xmath0 .
the norbury - scott conjecture @xcite relates ( non - equivariant ) gromov - witten invariants of @xmath0 to eynard - orantin invariants @xcite of the affine plane curve @xmath2 . in @xcite , p. dunin - barkowski ,.
Please generate the next two sentences of the article | n. orantin , s. shadrin , and l. spitz relate the eynard - orantin topological recursion to the givental formula for the ancestor formal gromov - witten potential , and prove the norbury - scott conjecture using their main result and givental s quantization formula for all genus descendant potential of the ( non - equivariant ) gromov - witten theory of @xmath0 .
it is natural to ask if the norbury - scott conjecture can be extended to the equivariant setting , such that the original conjecture can be recovered in the non - equivariant limit . |
5,558 | Suppose that you have an abstract for a scientific paper: massively parallel desktop computing capabilities now well within the reach of individual academics modify the environment for posterior simulation in fundamental and potentially quite advantageous ways . but to fully exploit these benefits algorithms that conform to parallel computing environments are needed .
sequential monte carlo comes very close to this ideal whereas other approaches like markov chain monte carlo do not .
this paper presents a sequential posterior simulator well suited to this computing environment .
the simulator makes fewer analytical and programming demands on investigators , and is faster , more reliable and more complete than conventional posterior simulators .
the paper extends existing sequential monte carlo methods and theory to provide a thorough and practical foundation for sequential posterior simulation that is well suited to massively parallel computing environments .
it provides detailed recommendations on implementation , yielding an algorithm that requires only code for simulation from the prior and evaluation of prior and data densities and works well in a variety of applications representative of serious empirical work in economics and finance .
the algorithm is robust to pathological posterior distributions , generates accurate marginal likelihood approximations , and provides estimates of numerical standard error and relative numerical efficiency intrinsically .
the paper concludes with an application that illustrates the potential of these simulators for applied bayesian inference .
keywords : graphics processing unit ; particle filter ; posterior simulation ; sequential monte carlo ; single instruction multiple data jel classification : primary , c11 ; secondary , c630 . .
And you have already written the first three sentences of the full article: bayesian approaches have inherent advantages in solving inference and decision problems , but practical applications pose challenges for computation . as these challenges have been met bayesian approaches have proliferated and contributed to the solution of applied problems .
mcgrayne ( 2011 ) has recently conveyed these facts to a wide audience .
the evolution of bayesian computation over the past half - century has conformed with exponential increases in speed and decreases in the cost of computing ..
Please generate the next two sentences of the article | the influence of computational considerations on algorithms , models , and the way that substantive problems are formulated for statistical inference can be subtle but is hard to over - state .
successful and innovative basic and applied research recognizes the characteristics of the tools of implementation from the outset and tailors approaches to those tools . |
5,559 | Suppose that you have an abstract for a scientific paper: diffraction is important when nearby substellar objects gravitationally lens distant stars .
if the wavelength of the observation is comparable to the schwarzschild radius of lensing object , diffraction leaves an observable imprint on the lensing signature .
the ska may have sufficient sensitivity to detect the typical sources , giant stars in the bulge .
the diffractive signatures in a lensing event break the degeneracies between the mass of the lens , its distance and proper motion . .
And you have already written the first three sentences of the full article: as light passes an object , it diffracts around it and spreads out by an angle @xmath0 , so if the angle that the object subtends , @xmath1 , is less than this , the object `` disappears '' .
furthermore , if the object has mass , light that passes close - by is delayed by travelling through its potential well . the figure of merit for whether diffraction is important in gravitational lensing is @xmath2 where @xmath3 is the schwarzschild radius of the lens . for values of @xmath4
much less than unity , diffraction dominates and the peak magnification is greatly diminished , for large values of @xmath4 the diffraction fringes are closely spaced , so either the finite size of the source or the finite bandwidth of the observations can easily smear them out yielding the magnification that one expects from geometric optics ..
Please generate the next two sentences of the article | the path length from the star at @xmath5 to the telescope through the point @xmath6 in the lens plane is @xmath7 the magnification of the star is related to the sum of all the phases from the light taking various paths , @xmath8 the schwarzschild radius of the earth is about one centimeter . beyond @xmath9 au
lensing dominates over occultation |
5,560 | Suppose that you have an abstract for a scientific paper: we consider stochastic electro - mechanical dynamics of an overdamped power system in the vicinity of the saddle - node bifurcation associated with the loss of global stability such as voltage collapse or phase angle instability .
fluctuations of the system state vector are driven by random variations of loads and intermittent renewable generation . in the vicinity of collapse
the power system experiences so - called phenomenon of critical slowing - down characterized by slowing and simultaneous amplification of the system state vector fluctuations . in generic case of a co - dimension 1 bifurcation corresponding to the threshold of instability it is possible to extract a single mode of the system state vector responsible for this phenomenon .
we characterize stochastic fluctuations of the system state vector using the formal perturbative expansion over the lowest ( real ) eigenvalue of the system power flow jacobian and verify the resulting expressions for correlation functions of the state vector by direct numerical simulations .
we conclude that the onset of critical slowing - down is a good marker of approach to the threshold of global instability .
it can be straightforwardly detected from the analysis of single - node autostructure and autocorrelation functions of system state variables and thus does not require full observability of the grid . .
And you have already written the first three sentences of the full article: most of the us national power grid has ultimately been shaped and built during the quick urbanization period of the beginning of 20@xmath0 century .
increasing power demand continues to put enormous strain on the infrastructure of the aging grid , forcing utilities to maximally utilize its existing resources . as a consequence ,
many parts of the grid often operate in nearly critical regimes with significantly increased probability of large scale failures @xcite . in the modern world.
Please generate the next two sentences of the article | it becomes crucially important to be able to read the state of the pre - critical smart grid in a timely and precise manner , to effectively control parameters of smart grids operating in pre - critical regimes minimizing the probability of their large scale failures .
unfortunately , commonly used used power system state estimation and control algorithms , working extremely well for stable operating regimes , become less efficient ( see for example @xcite ) when the operating point of the grid is close to the threshold of instability . as we shall discuss below |
5,561 | Suppose that you have an abstract for a scientific paper: we show how to differentiate the minimal supersymmetric extension of the standard model from black hole events at the large hadron collider .
black holes are simulated with the ` catfish ` generator .
supersymmetry simulations use a combination of ` pythia ` and ` isajet ` .
our study , based on event shape variables , visible and missing momenta , and analysis of dilepton events , demonstrates that supersymmetry and black hole events at the lhc can be easily discriminated . .
And you have already written the first three sentences of the full article: at cern s large hadron collider ( lhc ) @xcite protons will soon collide at an astonishing 800 million times per second to provide experimental evidence for the higgs @xcite , supersymmetry ( susy ) @xcite or extra dimensions @xcite .
susy is widely considered to be one of the best candidates for physics beyond the standard model ( sm ) .
it provides an explanation for the higgs mass problem , a candidate for cold dark matter , and unification of low energy gauge couplings by introducing superpartners to sm fields ( see ref ..
Please generate the next two sentences of the article | @xcite and references therein ) .
an alternative to susy is given by phenomenological extra - dimensional models such as large extra dimensions ( leds ) @xcite , warped braneworlds @xcite or universal extra dimensions @xcite . |
5,562 | Suppose that you have an abstract for a scientific paper: the success of density functional theory for the description of the adsorption of atoms on surfaces is well established , and based on recent calculations using gradient corrections , it has been shown that it also describes well the dissociative adsorption of molecules at surfaces admittedly however , the data base for reactions at surfaces is still somewhat small . in the present paper the power of density functional theory calculations
is demonstrated by investigations for two different adsorption systems , namely , one with a strongly electropositive adsorbate [ na on al(111 ) ] and one with a strongly electronegative adsorbate [ o on ru(0001 ) ] . in each case , new hitherto not expected adsorbate phases have been predicted by the theory : for na on al(111 ) the stability of a `` four - layer '' surface alloy was identified while for o on ru(0001 ) it was predicted that the formation of a @xmath0-o adlayer should be possible which implies that the apparent saturation coverage of @xmath1 is due to kinetic hindering . .
And you have already written the first three sentences of the full article: it is of great interest to have an accurate theoretical framework for the description of the interaction and reaction of particles at surfaces
. calculations of this nature would give insight and understanding into the varied and complex processes that take place between atoms , molecules , and solid surfaces .
in relation to this , information concerning atomic and electronic structure , energy barriers , site specificity , bond formation and scission , and the identification of reaction pathways could be obtained . indeed , experimentally , a strong motivation for chemisorption studies with well - defined single crystal surfaces is the prospect of gaining deeper insight into the elementary steps governing heterogeneously catalyzed reactions ..
Please generate the next two sentences of the article | obviously a proper theoretical description of such processes at surfaces with accurate predictive power is of enormous technological importance , particularly for example , in the field of catalysis . in this respect ,
density functional theory is emerging as a very promising approach for describing these phenomena which involve the breaking and formation of chemical bonds , as for example , in the cases of dissociative adsorption , associative desorption , and chemical reactions . |
5,563 | Suppose that you have an abstract for a scientific paper: ballistic transport properties in a two dimensional electron gas are studied numerically , where magnetic fields are perpendicular to the plane of two dimensional electron systems and periodically modulated both in @xmath0 and @xmath1 directions .
we show that there are three types of trajectories of classical electron motions in this system ; chaotic , pinned and runaway trajectories .
it is found that the runaway trajectories can explain the peaks of magnetoresistance as a function of external magnetic fields , which is believed to be related to the commensurability effect between the classical cyclotron diameter and the period of magnetic modulation . the similarity with and difference from the results in the antidot lattice
are discussed . .
And you have already written the first three sentences of the full article: high mobility two dimensional electron gases formed in gaas / algaas heterostructures allow ballistic motion of electrons over distances of several @xmath2 m at low temperatures@xcite .
ballistic system is realized at low temperatures , low electron densities and low impurity concentrations .
such samples are used in many experiments to study various novel transport properties in low dimensional mesoscopic semiconductors , and a lot of interesting phenomena have been discovered ..
Please generate the next two sentences of the article | one of such mesoscopic systems is a two dimensional electron gas ( 2deg ) in a periodic antidot array . when the sample s typical geometrical scale , such as the distance between antidots , is larger than the fermi wave length , the dynamics of a wave packet approaches the classical limit .
semi - classical model explains some experimental results in this system , such as the quenching of the hall resistance in low fields@xcite , and the oscillatory field - dependence of the magnetoresistance in an antidot array @xcite . in the latter , |
5,564 | Suppose that you have an abstract for a scientific paper: context : worldwide interest in the recent eclipse of @xmath0 aurigae resulted in the generation of several extensive data sets , including those related to high resolution spectroscopic monitoring .
this lead to the discovery , among other things , of the existence of a mass transfer stream , seen notably during third contact . + aims : we explored spectroscopic facets of the mass transfer stream during third contact , using high resolution spectra obtained with the arces and triplespec instruments at apache point observatory .
+ methods : one hundred and sixteen epochs of data between 2009 and 2012 were obtained , and equivalent widths and line velocities measured , selected according to reports of these being high versus low eccentricity disk lines .
these datasets also enable greater detail to be measured of the mid - eclipse enhancement of the he i 10830 line , and the discovery of the p cygni shape of the pa-@xmath1 line at third contact .
+ analysis : we found evidence of higher speed material , associated with the mass transfer stream , persisting between third and fourth eclipse contacts .
we visualize the disk and stream interaction using shape software , and use cloudy software to estimate that the source of the enhanced he i 10830 absorption arises from a region with log n = 10 ( @xmath2 ) and temperature of 20,000 k consistent with a mid - b type central star .
+ results and next steps : van rensbergen binary star evolutionary models are somewhat consistent with the current binary parameters for the case of a 9 plus 8 solar mass initial binary , evolving into a 2.3 and 14.11 solar mass end product after 35 myr .
prior to the next eclipse , it is possible to make predictions which suggest that continued monitoring will help resolve standing questions about this binary . .
And you have already written the first three sentences of the full article: the exceptional binary star , @xmath0 aurigae exhibits two year - long eclipses every 27.1 years .
the eclipse of the f supergiant primary star is now understood to be caused by an opaque disk hiding a companion star ( see stencel , 2012 and references therein ) . an international effort to monitor all aspects of
the 2009 - 2011 eclipse resulted in substantial archives of new data , including those involving high resolution spectroscopic monitoring , e.g. strassmeier et al ..
Please generate the next two sentences of the article | ( 2014 ) and others . here
we report on sampling of the high resolution spectroscopic archive generated during 2009 - 2011 eclipse , by the arces instrument at apache point observatory ( wang et al . |
5,565 | Suppose that you have an abstract for a scientific paper: _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ a block spin renormalization group approach is proposed for the dynamical triangulation formulation of quantum gravity in arbitrary dimensions .
renormalization group flow diagrams are presented for the three - dimensional and four - dimensional theories near their respective transitions .
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ .25 in pacs numbers : 04.60.+n , 05.70.jk , 11.10.gh .25 in = 10000 = 10000 .
And you have already written the first three sentences of the full article: there are currently many different avenues to a theory of quantum gravity .
this paper focuses on the formulation provided by dynamical triangulations .
extensive work has been done in two dimensions and a significant body of work has also examined three and four dimensions @xcite ..
Please generate the next two sentences of the article | dynamical triangulations are similar to the formulation of regge in that the manifold is broken up into simplexes and the curvature is identified with a deficit angle about a subsimplex with dimensionality two less than that of the manifold .
the formulations differ in their treatment of the functional integral over all possible metrics . in the regge approach , this is provided by varying the link lengths on a fixed lattice . in the dynamical triangulation approach , |
5,566 | Suppose that you have an abstract for a scientific paper: we assume a community whose members adopt one of two opinions .
each member appears as an inflexible , or as a non - contrarian or contrarian floater .
an inflexible adheres to its opinion , whereas a floater may change into a floater of the alternative opinion .
the occurrence of this change is governed by the local majority rule : members meet in groups of a fixed size , and a floater changes provided its opinion has the minority in its group .
a non - contrarian floater keeps the opinion it adopts under the local majority rule , whereas a contrarian floater adopts the alternative opinion .
we determine the dynamics generated by repeated opinion changes , and study its dependence on the densities of inflexibles and the frequencies of contrarians among the floaters .
we restrict ourselves to groups of size at most 3 .
20 pt * two opinions dynamics generated by inflexibles and non - contrarian and contrarian floaters * + + f. jacobs + + _ section theoretical biology + institute of biology + leiden university + kaiserstraat 63 + nl-2311 gp leiden + the netherlands + + e - mail address : [email protected]_ + + s. galam
+ + _ centre de recherche en epistmologie applique ( crea ) + ecole polytechnique + 1 rue descartes + 75005 paris + france + + e - mail address : [email protected]_ + + author for correspondence : f. jacobs + + * running title : * two opinions dynamics + + * acknowledgement * f. jacobs appreciates the support of the research underlying this paper by cost grant cost - stsm - p10 - 01215 .
* keywords : * sociomathematics , sociophysics , opinions dynamics , local majority rule , contrarian behaviour , floating behaviour + + * note concerning the current version of the text : due to the large sizes of some figures , the accompanying captions to these figures do not fit together with the figures on the same page . therefore , these captions are placed in the main text , instead of in the sequence of figures at the end of the....
And you have already written the first three sentences of the full article: within the growing field of sociophysics ( see @xcite for the defining paper , and @xcite-@xcite for an impression of the recent state of the art ) , two- and three states galam opinion models and their modifications ( @xcite , @xcite ) play a guiding role in analyzing the process of opinion spreading in communities .
these models are centered around the _ local majority rule _ ( l.m.r . ) , which is applied either in a deterministic or a probabilistic way . in the basic _ deterministic _ case , supporters of the ( two or three ) opinions present in a community are randomly distributed over all possible groups of a fixed size . within each group
the members adopt the opinion that has the majority in that group , after which all group members are recollected again . in case.
Please generate the next two sentences of the article | there is no majority in a group , its members stick to their own opinion ( i.e. , _ neutral _ treatment ; the _ probabilistic _ treatment in case of a tie assigns opinions to the group members according to a certain probability distribution ) .
repeated application of this principle generates what is called _ randomly localized dynamics with a local majority rule _ |
5,567 | Suppose that you have an abstract for a scientific paper: the aim of this paper is to investigate how the correlation properties of a stationary markovian stochastic processes affect the first passage time distribution .
first passage time issues are a classical topic in stochastic processes research .
they also have relevant applications , for example , in many fields of finance such as the assessment of the default risk for firms assets .
by using some explicit examples , in this paper we will show that the tail of the first passage time distribution crucially depends on the correlation properties of the process and it is independent from its stationary distribution .
when the process includes an infinite set of time - scales bounded from above , the fptd shows tails modulated by some exponential decay . in the case when the process is power - law correlated the fptd shows power - law tails @xmath0 and therefore the moments @xmath1 of the fptd are finite only when @xmath2 .
we will also show that such power - law behaviour is not merely due to the fact that the process includes an infinite and unbounded set of time - scales .
rather , the time - scale must enter the fptd with weights that must be distributed according to a power - law for large time - scales values .
finally , we will give a general result connecting the fptd of an additive stochastic processes @xmath3 to the fptd of a generic process @xmath4 related by a coordinate transformation @xmath5 to the first one . .
And you have already written the first three sentences of the full article: stochastic processes are used to model a great variety of systems in disciplines as disparate as physics @xcite , genomics @xcite , finance @xcite , climatology @xcite and social sciences @xcite . here
we will devote our attention to the special class of markovian stochastic processes that are also stationary and that can be described by a fokker - planck ( fp ) equation @xcite .
such processes are fully determined by the knowledge of their probability density function ( pdf ) @xmath6 and their conditional transition probability @xmath7 ..
Please generate the next two sentences of the article | the simplest stationary markovian stochastic process is the ornstein - uhlenbeck ( ou ) one that is characterized by an exponential autocorrelation function @xmath8 where @xmath9 is referred to as the time - scale of the process . for a general stationary markovian additive process
the methodology of eigenfunction expansion @xcite allows us to write the autocovariance function as the infinite weighted sum of exponential functions @xmath10 each characterized by a time - scale @xmath11 , where the @xmath12 values are the eigenvalues of the fp operator . by analogy with respect to the ou process , for an additive stationary markovian process |
5,568 | Suppose that you have an abstract for a scientific paper: edge detection is a classic problem in the field of image processing , which lays foundations for other tasks such as image segmentation .
conventionally , this operation is performed using gradient operators such as the roberts or sobel operator , which can discover local changes in intensity levels .
these operators , however , perform poorly on low contrast images . in this paper
, we propose an edge detector architecture for color images based on fuzzy theory and the sobel operator .
first , the r , g and b channels are extracted from an image and enhanced using fuzzy methods , in order to suppress noise and improve the contrast between the background and the objects .
the sobel operator is then applied to each of the channels , which are finally combined into an edge map of the origin image .
experimental results obtained through an fpga - based implementation have proved the proposed method effective .
image edge detection , fuzzy systems , sobel operator , hardware implementation , memristors . .
And you have already written the first three sentences of the full article: detection plays a fundamental role in the field of image processing .
an _ edge _ is a collection of connected pixels where the intensity level changes abruptly.@xcite edges are especially important for image recognition and analysis since they can capture local features and provide useful information .
so far , techniques for edge detection have been studied extensively ..
Please generate the next two sentences of the article | edges can usually be found in parts of an image where transition occurs , either between different objects , different regions , or between objects and the background . in this view , gradients are effective descriptors of edges .
consequently , various gradient - based edge detectors were proposed during the 1960s , including the robert operators , robinson operators , prewitt operators , and sobel operators , first suggested by irwin sobel and gary feldman@xcite . a more accurate detector known as the _ canny detector _ was later proposed by j. canny , which smooths the input image with a gaussian filter and applies non - maxima suppression for optimal results.@xcite for digital images |
5,569 | Suppose that you have an abstract for a scientific paper: widely studied quasiparticle models for quark gluon plasma is revisited here to understand the statistical mechanics and thermodynamics of the system .
we investigate the statistical mechanics and thermodynamics inconsistencies involved in these models and their consequences in the observables .
quasiparticle model is a phenomenological model with few parameters and by adjusting them all models fit the results of lattice gauge simulation of gluon plasma @xcite .
however , after fixing 2 of the 3 parameters of the model by physical arguments , only one quasiparticle model , which is consistent with both statistical mechanics and thermodynamics , fits the bielefeld lattice data @xcite .
the same model also fits the recent lattice results of wuppertal - budapest group @xcite , which deals with precision su(3 ) thermodynamics for a large temperature range , reasonably well .
.75 cm * pacs
nos :* 12.38.mh , 05.30jp , 12.39.mk , 12.38.gc , 05.70.ce + * keywords :* equation of state , gluon plasma , quasiparticle model . .
And you have already written the first three sentences of the full article: quark gluon plasma ( qgp ) is a non - ideal system and hence the formulation of statistical mechanics ( sm)and thermodynamics ( td ) is a challenging one .
sm and td of ideal system is straight forward , but the equilibrium studies of non - ideal system is still underdeveloped because of the difficulties due to mutual interaction among the constituents . of course , there are theories like classical and quantum mayer cluster expansion @xcite , but they are not fully successful for qgp because of the strong interaction @xcite .
mayer s cluster expansion is valid for weakly coupled system , whereas qgp seems to be strongly coupled @xcite ..
Please generate the next two sentences of the article | therefore , one goes for phenomenological models like strongly coupled quark gluon plasma @xcite , quasi - particle models @xcite , etc . with few fitting parameters .
model results are fitted with the results of the simulation of lattice gauge theory ( lgt ) for qgp @xcite . here |
5,570 | Suppose that you have an abstract for a scientific paper: a supergiants are objects in transition from the blue to the red ( and vice versa ) in the uppermost hrd .
they are the intrinsically brightest `` normal '' stars at visual light with absolute visual magnitudes up to -9 .
they are ideal to study young stellar populations in galaxies beyond the local group to determine chemical composition and evolution , interstellar extinction , reddening laws and distances .
we discuss most recent results on the quantitative spectral analysis of such objects in galaxies beyond the local group based on medium and low resolution spectra obtained with the eso vlt and keck .
we describe the analysis method including the determination of metallicity and metallicity gradients . a new method to measure accurate extragalactic distances based on the stellar gravities and effective temperatures
is presented , the flux weighted gravity - luminosity relationship ( fglr ) .
the fglr is a purely spectroscopic method , which overcomes the untertainties introduced by interstellar extinction and variations of metallicity , which plague all photometric stellar distance determination methods .
we discuss the perspectives of future work using the giant ground - based telescopes of the next generation such as the tmt , the gmt and the e - elt . .
And you have already written the first three sentences of the full article: it has long been the dream of stellar astronomers to study individual stellar objects in distant galaxies to obtain detailed spectroscopic information about the star formation history and chemodynamical evolution of galaxies and to determine accurate distances based on the determination of stellar parameters and interstellar reddening and extinction . at the first glance
, one might think that the most massive and , therefore , most luminous stars with masses higher than 50 @xmath0 are ideal for this purpose .
however , because of their very strong stellar winds and mass - loss these objects keep very hot atmospheric temperatures throughout their life and , thus , waste most of their precious photons in the extreme ultraviolet ..
Please generate the next two sentences of the article | as we all know , most of these uv photons are killed by dust absorption in the star forming regions , where these stars are born , and the few which make it to the earth can only be observed with tiny uv telescopes in space such as the hst or fuse and are not accessible to the giant telescopes on the ground .
thus , one learns quickly that the most promising objects for such studies are massive stars in a mass range between 15 to 40 @xmath0 in the short - lived evolutionary phase , when they leave the hydrogen main - sequence and cross the hrd in a few thousand years as blue supergiants of late b and early a spectral type . because of the strongly reduced absolute value of bolometric correction when evolving towards smaller temperature these objects increase their brightness in visual light and become the optically brightest `` normal '' stars in the universe with absolute visual magnitudes up to @xmath1 rivaling with the integrated light brightness of globular clusters and dwarf spheroidal galaxies . |
5,571 | Suppose that you have an abstract for a scientific paper: the study of @xmath0-ray emission from galactic sources such as supernova remnants ( snr ) may provide key insights into their potential role as accelerators of cosmic rays up to the knee ( @xmath1 ev ) .
the veritas observatory is sensitive to galactic and extragalactic @xmath0-ray sources in the 100 gev to 30 tev energy range .
we report here on veritas observations of the vicinity of the cocoon of freshly accelerated cosmic rays reported by fermi , which lies between potential accelerators in the cygnus ob2 association and the @xmath0-cygni snr . a particular focus is placed on the source ver j2019 + 407 in @xmath0-cygni . .
And you have already written the first three sentences of the full article: veritas , located at the fred lawrence whipple observatory near tucson , arizona , is an array of four 12-meter imaging atmospheric cherenkov telescopes .
each telescope has a pixelated camera comprised of 499 photomultiplier tubes with a @xmath2 field of view . designed to detect photons of astrophysical origin between 100 gev and 30 tev , veritas detects and images the secondary cherenkov light produced when gamma rays and cosmic rays initiate particle cascades in the upper atmosphere .
stereoscopic reconstruction of events using multiple telescopes allows for single - photon angular resolution of better than @xmath3 and energy resolution on the order of 15 - 25% . in its current configuration.
Please generate the next two sentences of the article | , veritas can detect a source with @xmath4 of the crab nebula flux in less than 30 hours .
the instrument has been operating in full array mode since 2007 . |
5,572 | Suppose that you have an abstract for a scientific paper: observations suggest that many , if not all , post agb systems evolve through an aspherical outflow phase .
such outflows require a sufficient engine rotational energy which binaries can provide . via common envelope evolution
, binaries can directly eject equatorial outflows or produce poloidal outflows from magnetized accretion disks around the primary or secondary .
we discuss how accretion driven magnetohydrodynamic outflow models all make similar predictions for the outflow power and speed and we distinguish between the launch vs. propagation regimes of such outflows .
we suggest that the high velocity bipolar outflows observed in planetary nebulae ( pne ) and the lower velocity but higher power bipolar outflows observed in pre - pne ( ppne ) are kinematically consistent with time dependent accretion onto a white dwarf ( wd ) within a depleting envelope .
since the wd primary core is always present in all post - agb systems , accretion onto this core is potentially common .
previous work has focused on core accretion from sub - stellar companions , but low mass stellar companions may be more important , and further work is needed . .
And you have already written the first three sentences of the full article: understanding the origin of asymmetric outflows in pne and ppne requires feedback between observers , specific object modelers , and paradigm - seeking , order of magnitude theorists . here
we behave as the latter .
generally , ppne exhibit a combination of a fast bipolar outflow embedded within a slow spherically symmetric wind from the agb star @xcite ..
Please generate the next two sentences of the article | presently , the data do not rule out all ppne having gone through a strongly asymmetric outflow and all pne having gone through an asymmetric pne phase .
the symmetry of pne would then correlate with age and the evolution from the ppne to pne could reflect a time evolution of the same physical mechanism that produces asymmetry on small scales but leads to a a nearly spherical structure on large scale as supersonic motions damp . while agb stars produce spherically symmetric outflows , ppne asymmetry arises within @xmath0 yr @xcite . for ppne @xcite , each fast wind has a typical age @xmath1yr , speed @xmath2km / s , mass @xmath3 , outflow rate , @xmath4 , momentum @xmath5 , and mechanical luminosity @xmath6 ( can be as high as @xmath7erg / s ) . |
5,573 | Suppose that you have an abstract for a scientific paper: the differential cross section for @xmath0-deuteron compton scattering from a tensor polarized deuteron is computed in an effective field theory .
the first non - vanishing contributions to this differential cross section are the interference terms between the leading electric coupling diagrams and the subleading single potential pion exchange diagrams or the subleading magnetic moment coupling diagrams . at 90@xmath1 photon scattering angle
, only the pion term contributes at this order to the tensor polarized differential cross section .
this provides a clean way to study the photon pion dynamics in the two nucleon sector .
the effect is measurable for photon energies between 40 and 80 mev provided the uncertainty in the measured cross sections are @xmath2 .
# 1#1 # 1#1 # 1| # 1| # 1#2 # 11.5ex-16.5mu # 1 # 1#2#3#4#1 * # 2 * , # 3 ( # 4 ) .
And you have already written the first three sentences of the full article: @xmath3-deuteron compton scattering probes the structure of the deuteron and provides necessary information that may allow the extraction of neutron properties , such as neutron electric and magnetic polarizabilities .
the differential cross section of unpolarized @xmath3-deuteron compton scattering has been measured at incident photon energies of 49 mev and 69 mev with 10% uncertainty @xcite .
theoretical calculations based on potential models and taking the nucleon polarizabilities as inputs find reasonably good agreement with data @xcite but are not sufficient to give tight constraints on the nucleon polarizabilities . in comparison to potential model calculations ,.
Please generate the next two sentences of the article | a model independent , parameter free and analytic computation of unpolarized @xmath3-deuteron compton scattering based on a recently developed nucleon - nucleon effective field theory @xcite was presented in @xcite .
contributions up to next - to - leading order ( nlo ) in the effective field theory expansion including diagrams contributing to the nucleon polarizabilities give excellent agreement with the data at 49 mev and reasonable agreement with the data at 69 mev . at this order ( nlo ) |
5,574 | Suppose that you have an abstract for a scientific paper: the paper analyses the ground antenna echo using microwave frequency detector and high speed sampling technology and a new method detecting buried objects in time domain near - field is presented .
the method detecting particular reflection echo frequency of microwave pulse via digital signal processing is to reduce the false alarm rate .
simulation results show that this method has advantages of easy identification and high precision . *
key words * : near - field measurement ; mine detection ; fdtd ; microwave frequency detector ; high - speed sampling .
And you have already written the first three sentences of the full article: recently , the accuracy of buried - objects detection system is increasing important which decided personal safety in mine affected areas .
few technology is employed in the real world to detect land mines because of high false alarm rate [ 1 ] . since mine detection requires low false alarm rate , improving the precision of detection system
should be studied ..
Please generate the next two sentences of the article | many research works have been reported in the control of false alarm rate .
angular correlation function [ 2 ] and a statistical approach method [ 3 ] are employed to detect buried objects . |
5,575 | Suppose that you have an abstract for a scientific paper: we consider whether stellar collisions can explain the observed depletion of red giants in the galactic center .
we model the stellar population with two different imfs : 1 ) the miller - scalo and 2 ) a much flatter imf . in the former case ,
low - mass main - sequence stars dominate the population , and collisions are unable to remove red giants out to 0.4pc although brighter red giants much closer in may be depleted via collisions with stellar - mass black holes . for a much flatter imf ,
the stellar population is dominated by compact remnants ( _ i.e. _ black holes , white dwarfs and neutron stars ) .
the most common collisions are then those between main - sequence stars and compact remnants .
such encounters are likely to destroy the main - sequence stars and thus prevent their evolution into red giants . in this way
, the red - giant population could be depleted out to 0.4pc matching observations .
if this is the case , it implies the galactic center contains a much larger population of stellar - mass black holes than would be expected from a regular imf .
this may in turn have implications for the formation and growth of the central supermassive black hole . .
And you have already written the first three sentences of the full article: the milky way contains a supermassive black hole at its very center , sagittarius a * , whose mass is @xmath0m@xmath1 ( e.g. * ? ? ?
a dense stellar cluster surrounds this black hole , with a central density at least comparable to that seen in the cores of the densest globular clusters .
at least one , and possibly two , discs containing young stars at distances between @xmath2 and @xmath3pc from the black hole are also seen @xcite ..
Please generate the next two sentences of the article | the latter stellar population is thought to have an unusually flat imf @xcite .
it has long been known that the central 0.2pc or so of the galactic center is deficient in bright red giants @xcite . |
5,576 | Suppose that you have an abstract for a scientific paper: we employ qcd sum rules to calculate the coupling constant g@xmath0 by studying the three point @xmath1-correlation function .
our results is consistent with the value of this coupling constant obtained using vector meson dominance of the electromagnetic current and the experimental @xmath2-photoproduction data . .
And you have already written the first three sentences of the full article: the existence of the scalar - isoscalar @xmath3 meson as a broad @xmath4 resonance has long been controversial . recently , an increasing number of theoretical and experimental analyzes point toward the existence of this important meson @xcite .
most of these analyzes find a @xmath3-pole position near 500-i250 mev @xcite .
a direct experimental evidence seems to emerge from the d@xmath5 decay channel observed by the fermilab e791 collaboration , where @xmath3 meson is seen as a clear dominant peak with m@xmath6=478 mev and @xmath7=324 mev @xcite ..
Please generate the next two sentences of the article | since @xmath3 meson is a relevant hadronic degree of freedom , it must be incorporated into the analysis of hadronic processes .
although at sufficiently high energies and low momentum transfers electromagnetic production of vector mesons on nucleon targets has been explained by pomeron exchange models , at low energies near threshold scalar and pseudoscalar meson exchange mechanisms become important @xcite . in particular , |
5,577 | Suppose that you have an abstract for a scientific paper: this paper introduces an information - based model for the pricing of storable commodities such as crude oil and natural gas .
the model makes use of the concept of market information about future supply and demand as a basis for valuation .
physical ownership of a commodity is regarded as providing a stream of `` convenience dividends '' equivalent to a continuous cash flow .
the market filtration is assumed to be generated jointly by ( i ) current and past levels of the dividend rate , and ( ii ) partial information concerning the future of the dividend flow .
the price of a commodity is given by the expectation of the totality of the discounted risk - adjusted future convenience dividend , conditional on the information provided by the market filtration .
in the situation where the dividend rate is modelled by an ornstein - uhlenbeck process , the prices of options on commodities can be derived in closed form , both in the case when underlying is the spot price , and in the case when underlying is a futures price .
the approach presented can be applied to other assets that can yield potentially negative effective cash flows , such as real estate , factories , refineries , mines , and power generating plants .
+ * keywords * : commodity markets ; commodity derivatives ; crude oil ; natural gas ; convenience yield ; information - based asset pricing ; market microstructure . .
And you have already written the first three sentences of the full article: in the extensive literature devoted to the pricing and risk management of commodity derivatives , most investigations take as a starting point the specification of a price process for the commodity . the outcome of chance in the market in which the commodity is traded is usually modelled by a fixed probability space equipped with the filtration generated by a brownian motion of one or more dimensions , and it is typically assumed that the commodity price can be modelled as an ito process adapted to this filtration .
such an approach to the pricing of commodities and related derivatives is in line with the standard " modelling framework for asset pricing , within which much of modern financial engineering has been carried out .
a fundamental methodological issue arising in the standard framework is that the market filtration is fixed in an essentially _ ad hoc _ way , and that no indication is provided concerning the nature of the information it purports to convey , or why it is relevant to the price ..
Please generate the next two sentences of the article | the information is in practice typically no more than that of the price movements themselves , so it can hardly be claimed in any useful way that the price movements are taking place `` in response '' to `` shocks '' associated with the arrival of information .
one knows , however , that in real markets , information concerning the possible future cash flows and other benefits or obligations linked to the physical possession of an asset can be crucial in the determination of trading decisions , even in situations where such information is of an imperfect nature . |
5,578 | Suppose that you have an abstract for a scientific paper: the projective degrees of strict partitions of @xmath0 were computed for all @xmath1 and the partitions with maximal projective degree were found for each @xmath0 . it was observed that maximizing partitions for successive values of @xmath0 `` lie close to each other '' in a certain sense . conjecturing that this holds for larger values of @xmath0 ,
the partitions of maximal degree were computed for all @xmath2 .
the results are consistent with a recent conjecture on the limiting shape of the strict partition of maximal projective degree . .
And you have already written the first three sentences of the full article: let @xmath3 be a partition of @xmath0 , denoted as usual by @xmath4 .
let @xmath5 denote the number of standard tableaux of shape @xmath6 .
@xmath5 is also the number of paths in the young graph @xmath7 from the root @xmath8 to @xmath6 , and it is also the degree of the irreducible character @xmath9 of the symmetric group @xmath10 ..
Please generate the next two sentences of the article | a partition @xmath11 is said to be _ strict _ if @xmath12 for some @xmath13 . in that case
we write @xmath14 . |
5,579 | Suppose that you have an abstract for a scientific paper: we review the theory and present status of the proton spin problem with emphasis on the transition between current quarks and constituent quarks in qcd .
150 mm 239 mm -11 mm 6 mm 0 cm [ cols= " < " , ] 12 mm * constituent quarks and @xmath0 * + * steven d. bass * + _ max planck institut fr kernphysik , postfach 103 980 , + d-69029 heidelberg , germany _ + _
institut fr theoretische physik , + physik department , technische universitt mnchen , + d-85747 garching , germany _ + 10 mm = 6truemm .
And you have already written the first three sentences of the full article: polarised deep inelastic scattering experiments at cern @xcite , desy @xcite and slac @xcite have revealed an apparent two ( or more ) standard deviations violation of ozi in the flavour - singlet axial charge @xmath1 which is extracted from the first moment of @xmath0 ( the nucleon s first spin dependent structure function ) .
this discovery has inspired much theoretical and experimental effort to understand the internal spin structure of the nucleon . in this article
we review the theory and present status of the proton spin problem in qcd ..
Please generate the next two sentences of the article | we start with a simple sum - rule for the spin of the proton ( @xmath2 ) in terms of the angular momentum of its quark and gluonic constituents : @xmath3 here , @xmath4 and @xmath5 are the quark and gluonic intrinsic spin contributions to the nucleon s spin and @xmath6 is the orbital contribution .
one would like to understand the spin decomposition , eq.(1 ) , both in terms of the fundamental qcd quarks and gluons and also in terms of the constituent quark quasi - particles of low - energy qcd . in deep inelastic processes the internal structure of the nucleon |
5,580 | Suppose that you have an abstract for a scientific paper: given a matrix , the seriation problem consists in permuting its rows in such way that all its columns have the same shape , for example , they are monotone increasing .
we propose a statistical approach to this problem where the matrix of interest is observed with noise and study the corresponding minimax rate of estimation of the matrices .
specifically , when the columns are either unimodal or monotone , we show that the least squares estimator is optimal up to logarithmic factors and adapts to matrices with a certain natural structure .
finally , we propose a computationally efficient estimator in the monotonic case and study its performance both theoretically and experimentally .
our work is at the intersection of shape constrained estimation and recent work that involves permutation learning , such as graph denoising and ranking .
, statistical seriation , permutation learning , minimax estimation , adaptation , shape constraints , matrix estimation . .
And you have already written the first three sentences of the full article: the _ consecutive 1 s problem _ ( ) @xcite is defined as follows . given a binary matrix @xmath0 the goal is to permute its rows in such a way that the resulting matrix enjoys the _ consecutive 1 s property _ : each of its columns is a vector @xmath1 where @xmath2 if and only if @xmath3 for two integers @xmath4 between @xmath5 and @xmath6 .
this problem has its roots in archeology and especially _ sequence dating _ where the goal is to recover the chronological order of sepultures based on artifacts found in these sepultures where the entry @xmath7 of matrix @xmath0 indicates the presence of artifact @xmath8 in sepulture @xmath9 . in his seminal work , egyptologist flinders petrie @xcite formulated the hypothesis that two sepultures should be close in the time domain if they present similar sets of artifacts .
already in the noiseless case , this problem presents an interesting algorithmic challenge and is reducible to the famous travelling salesman problem @xcite as observed by statistician david kendall @xcite who employed early tools from multidimensional scaling as a heuristic to solve it.
Please generate the next two sentences of the article | . belongs to a more general class of so - called _ seriation _ problems that consist in optimizing various criteria over the discrete set of permutations .
while such problems are hard in general , it can be shown that a subset of the these problems , including , can be solve efficiently using spectral method @xcite or convex optimization @xcite . |
5,581 | Suppose that you have an abstract for a scientific paper: we study static spherically symmetric gravitating dyon solutions and dyonic black holes in einstein - yang - mills - higgs theory .
the gravitating dyon solutions share many features with the gravitating monopole solutions . in particular ,
gravitating dyon solutions and dyonic black holes exist only up to a maximal coupling constant , and beside the fundamental dyon solutions there are excited dyon solutions .
= 6.125truein = 8.125truein preprint hep - th/9807169 .
And you have already written the first three sentences of the full article: su(2 ) einstein - yang - mills - higgs ( eymh ) theory , with the higgs field in the adjoint representation , possesses globally regular gravitating magnetic monopole solutions and corresponding magnetically charged black hole solutions @xcite . for small gravitational constant ,
the gravitating fundamental monopole solution smoothly emerges from the corresponding flat space solution , the t hooft - polyakov monopole @xcite . with increasing gravitational constant ,
the mass of the gravitating fundamental monopole solution decreases , and it ceases to exist beyond a maximal value of the gravitational constant . the corresponding magnetically charged eymh black hole solutions represent counterexamples to the `` no - hair '' conjecture ..
Please generate the next two sentences of the article | distinct from embedded reissner - nordstrm ( rn ) black holes with unit magnetic charge , they emerge from the globally regular magnetic monopole solutions when a finite regular event horizon is imposed .
consequently , they have been characterized as `` black holes within magnetic monopoles '' @xcite . |
5,582 | Suppose that you have an abstract for a scientific paper: turbulence is the most common state of astrophysical flows . in typical astrophysical fluids ,
turbulence is accompanied by strong magnetic fields , which has a large impact on the dynamics of the turbulent cascade .
recently , there has been a significant breakthrough on the theory of magnetohydrodynamic ( mhd ) turbulence . for the first time we have a scaling model that is supported by both observations and numerical simulations .
we review recent progress in studies of both incompressible and compressible turbulence .
we compare iroshnikov - kraichnan and goldreich - sridhar models , and discuss scalings of alfvn , slow , and fast waves .
we discuss the implications of this new insight into mhd turbulence for cosmic ray transport . .
And you have already written the first three sentences of the full article: most astrophysical systems , e.g. accretion disks , stellar winds , the interstellar medium ( ism ) and intercluster medium are turbulent with an embedded magnetic field that influences almost all of their properties .
this turbulence which spans from km to many kpc ( see discussion in armstrong , rickett , & spangler 1995 ; scalo 1987 ; lazarian , pogosyan , & esquivel 2002 ) holds the key to many astrophysical processes . for instance , propagation of cosmic rays and their acceleration is strongly affected by mhd turbulence .
recent research has shown that a substantial part of the earlier results in the field require revision ..
Please generate the next two sentences of the article | earlier research used ad hoc models of mhd turbulence and this entailed erroneous conclusions .
before we start a discussion of mhd turbulence let us recall some basic properties of the hydrodynamic turbulence . |
5,583 | Suppose that you have an abstract for a scientific paper: electroweak precision observables allow stringent tests of the standard model at the quantum level and imply interesting bounds on the mass of the higgs boson through higher - order loop effects .
very significant constraints come especially from the determination of the mass of the @xmath0 boson and from the effective leptonic weak mixing angle .
after shortly reviewing the status of theoretical computations of the @xmath0 mass , the new calculation of two - loop corrections with closed fermion loops to the effective leptonic weak mixing angle is discussed in detail .
the phenomenological implications of the new result are analyzed including an estimate of remaining uncertainties . .
And you have already written the first three sentences of the full article: in recent years , the standard model of electroweak interactions has been confirmed experimentally with outstanding success .
not only was almost all the particle content discovered at accelerator experiments , but their properties and interactions have been measured with high precision , in agreement with the model prediction . the only missing piece is the higgs boson , which is responsible for electroweak symmetry breaking .
however , even today we can obtain meaningful constraints on the higgs boson mass from electroweak precision measurements . due to the impressive accuracy of some of these experimental results ,.
Please generate the next two sentences of the article | they are sensitive to electroweak radiative corrections at the next - to - leading ( nlo ) and sometimes next - to - next - to - leading ( nnlo ) level , and thus depend on the impact of the higgs boson entering in the loops .
two of the most important quantities in this respect are the mass of the @xmath0 boson , @xmath1 and the sine of the leptonic effective weak mixing angle @xmath2 . |
5,584 | Suppose that you have an abstract for a scientific paper: quantum state tomography aims to determine the state of a quantum system as represented by a density matrix .
it is a fundamental task in modern scientific studies involving quantum systems . in this paper , we study estimation of high - dimensional density matrices based on pauli measurements . in particular , under appropriate notion of sparsity , we establish the minimax optimal rates of convergence for estimation of the density matrix under both the spectral and frobenius norm losses ; and show how these rates can be achieved by a common thresholding approach .
numerical performance of the proposed estimator is also investigated .
./style / arxiv - general.cfg , , , .
And you have already written the first three sentences of the full article: for a range of scientific studies including quantum computation , quantum information and quantum simulation , an important task is to learn and engineer quantum systems [ @xcite , @xcite ( @xcite , @xcite ) , @xcite , @xcite,@xcite , @xcite , and wang ( @xcite , @xcite ) ] .
a quantum system is described by its state characterized by a density matrix , which is a positive semidefinite hermitian matrix with unit trace . determining a quantum state , often referred to as quantum state tomography , is an important but difficult task [ @xcite , @xcite , @xcite , @xcite , @xcite , @xcite , @xcite , and @xcite ] .
it is often inferred by performing measurements on a large number of identically prepared quantum systems ..
Please generate the next two sentences of the article | more specifically , we describe a quantum spin system by the @xmath0-dimensional complex space @xmath1 and its quantum state by a complex matrix on @xmath1 .
when measuring the quantum system by performing measurements on some observables which can be represented by hermitian matrices , we obtain the measurement outcomes for each observable , where the measurements take values at random from all eigenvalues of the observable , with the probability of observing a particular eigenvalue equal to the trace of the product of the density matrix and the projection matrix onto the eigenspace corresponding to the eigenvalue . to handle the up and down states of particles in a quantum spin system , a common approach is to employ the well - known pauli matrices as observables to perform measurements and obtain the so - called pauli measurements [ @xcite , @xcite , @xcite , @xcite , @xcite , and wang ( @xcite , @xcite ) ] . |
5,585 | Suppose that you have an abstract for a scientific paper: we prove a seifert - van kampen theorem for legendrian submanifolds and exact lagrangian cobordisms , and use it to calculate the change in the dga caused by critical legendrian ambient surgery .
* keywords : * symplectic , legendrian , reeb chords , exact lagrangian cobordism , gradient flow tree , contact homology * ams subject code : * 53d12 , 53d42 .
And you have already written the first three sentences of the full article: let @xmath0 be an @xmath1-dimensional manifold , and let @xmath2 be a hyperplane distribution .
we say the pair @xmath3 is a * contact manifold * if @xmath4 is maximally non - integrable .
the primary example of a contact manifold we will use is the * one - jet manifold of @xmath5 * , @xmath6 , where @xmath7 , @xmath8 is the coordinate of @xmath9 and @xmath10 is the pullback to @xmath11 of the tautological one - form of @xmath12 ..
Please generate the next two sentences of the article | let @xmath13 ; we say an @xmath14-dimensional submanifold @xmath15 is * legendrian * if @xmath16 .
this is equivalent to : @xmath17 we define the * lagrangian projection * @xmath18 , * front projection * @xmath19 , and * base projection * @xmath20 to be the projections : @xmath21@xmath22@xmath23 let @xmath24 be a @xmath25-dimensional manifold , and let @xmath26 be a two - form on @xmath24 . |
5,586 | Suppose that you have an abstract for a scientific paper: we study hybrid mesons from the clover and improved gauge actions at @xmath0 on the anisotropic @xmath1 lattice using our pc cluster .
we estimate the mass of @xmath2 light quark hybrid as well as the mass of the charmonium hybrid .
the improvement of both quark and gluonic actions , first applied to the hybrid mesons , is shown to be more efficient in reducing the lattice spacing and finite volume errors . .
And you have already written the first three sentences of the full article: lattice qcd is the ideal approach not only for computing @xmath3 meson spectrum , but also for hybrids and glueballs .
however , the lattice technique is not free of systematic errors .
the wilson gauge and quark actions suffer from significant lattice spacing errors , which are smaller only at very large @xmath4 , and very large lattice volume is required to get rid of finite size effects ..
Please generate the next two sentences of the article | there have been several quenched lattice calculations of hybrid meson masses , part of them are listed in tab .
[ tab6 ] . in ref . |
5,587 | Suppose that you have an abstract for a scientific paper: we review the signal , and the @xmath0 background , for higgs production by the exclusive double - diffractive process , @xmath1 , and its subsequent @xmath2 decay , at the lhc .
we discuss the production of higgs bosons in both the sm and mssm .
we show how the predicted rates may be checked at the tevatron by observing the exclusive double - diffractive production of dijets , or @xmath3 or @xmath4 mesons , or @xmath5 pairs . .
And you have already written the first three sentences of the full article: the identification of the higgs boson(s ) is one of the main goals of the large hadron collider ( lhc ) being built at cern .
there are expectations that there exists a ` light ' higgs boson with mass @xmath6 gev . in this mass range
, its detection at the lhc will be challenging ..
Please generate the next two sentences of the article | there is no obvious perfect detection process , but rather a range of possibilities , none of which is compelling on its own . _
either _ large signals are accompanied by a huge background , _ or _ the processes have comparable signal and background rates for which the number of higgs events is rather small . here |
5,588 | Suppose that you have an abstract for a scientific paper: to date , the quasar 1556 + 3517 is the only radio loud broad absorption line qso ( balqso ; becker et al . 1997 ) .
this prompted narrow band filter imaging observations in the range 415 @xmath0 with the iso satellite .
the source is clearly detected in all filters and appears point - like and isolated at the resolution of iso .
the overall spectral energy distribution ( sed ) in @xmath1 peaks at a rest wavelength @xmath2 and is reddened by 1.6 visual magnitudes . correction for reddening brings 1556 + 3517 within 1.3 sigma from the @xmath3 dividing line between radio - loud and radio - quiet sources .
the mid - ir luminosity integrated over the 1.86 @xmath0 rest wavelength range is @xmath4 ( @xmath5 ) , which requires at least @xmath6 of dust and @xmath7 of associated gas .
it is unlikely that such a large mass stems from the bal wind itself . .
And you have already written the first three sentences of the full article: broad absorption lines ( bal ) quasars constitute about @xmath8 10 % of the overall quasar population .
observationally , they are characterized by very broad ( @xmath9 at zero intensity ) and blue shifted absorption lines mostly from highly ionized species such as nv@xmath101240 , civ@xmath101550 , .
approximately 10 % of the balqso display in addition absorption lines from low ionisation species such as siii , mgii and aliii ( weymann et al ..
Please generate the next two sentences of the article | these are the so - called low ionisation balqso , or lo - bal .
balqso in general are also heavily absorbed in the x - rays ( green & mathur 1996 ) though it is not clear that the hot and highly ionized gas needed to produce the ionization edges seen in the kev range is the same as that which produces the uv and optical absorption troughs . |
5,589 | Suppose that you have an abstract for a scientific paper: following an approach developed by paczyski & stanek , we derive a distance to the large magellanic cloud ( lmc ) by comparing red clump stars from the _ hipparcos _ catalog with the red clump stars observed in two fields in the lmc that were selected from the ongoing photometric survey of the magellanic clouds to lie in low extinction regions .
the use of red clump stars allows a single step determination of the distance modulus to the lmc , @xmath0mag ( statistical plus systematic error ) , and the corresponding distance , @xmath1 .
this measurement is in excellent agreement with the recent determination by udalski et al .
, also based on the red clump stars , but is @xmath2mag smaller than the generally accepted value of @xmath3mag .
we discuss possible reasons for this discrepancy and how it can be resolved . .
And you have already written the first three sentences of the full article: the generally accepted distance modulus to the large magellanic cloud ( lmc ) is @xmath4mag ( for recent discussion see westerlund 1997 , madore & freedman 1998 ) . however , there is a long standing @xmath5mag discrepancy between the `` long '' distance determined using cepheids ( e.g. laney & stobie 1994 ) and the `` short '' distance determined using rr lyr stars ( e.g. walker 1992 , layden et al .
a similar discrepancy is present in the distance to the lmc derived with the supernova sn1987a ( @xmath6mag , gould & uza 1998 ; @xmath7mag , panagia et al . 1997 ) .
recently udalski et al . (.
Please generate the next two sentences of the article | 1998 ) used red clump stars observed in the lmc by the ogle 2 project ( udalski et al .
1997 ) and obtained a value of @xmath8mag ( statistical plus systematic error ) . |
5,590 | Suppose that you have an abstract for a scientific paper: x - ray observations of galaxy clusters have detected numerous x - ray cavities , evolved from the interaction of agn jets with the intracluster medium ( icm ) and providing compelling evidence for the importance of jet - mode agn feedback . here
we argue for the physical importance of the cavity shape , which we characterize with two geometric parameters : radial elongation @xmath0 and top wideness @xmath1 .
we study the cavity shape with 16 hydrodynamic jet simulations in two representative clusters , and find that the shapes of young cavities are mainly determined by various jet properties .
our simulations successfully reproduce two observed types of young cavities elongated along either the jet ( @xmath2 ; type - ii ) or perpendicular ( @xmath3 ; type - i ) direction .
bottom - wide type - i cavities are produced by very light internally - subsonic jets , while top - wide type - ii cavities are produced by heavier , internally - supersonic jets , which may also produce center - wide cavities with @xmath4 if the jets are only slightly supersonic .
bottom - wide type - ii cavities can be produced by very light jets with very long durations and cylindrical cavities are produced by very light internally - supersonic jets .
while not appreciably affecting the shapes of young cavities , viscosity significantly affects the long - term cavity evolution , suppressing both interface instabilities and the formation of torus - like morphology .
we encourage observers to study the shapes of young and old x - ray cavities separately , the former probing the properties of agn jets and the latter potentially probing the icm viscosity level . .
And you have already written the first three sentences of the full article: it is widely accepted that mechanical feedback from active galactic nuclei ( agns ) plays a key role in the evolution of galaxy clusters , suppressing cooling flows and the associated fast growth of central galaxies ( e.g. , @xcite ; @xcite ) .
one of the most compelling evidences comes from mounting detections of surface brightness depressions in x - ray images of galaxy clusters , often referred as x - ray cavities " or agn bubbles " .
many cavities are associated with radio jets and spatially coincident with radio lobes ( e.g. , @xcite ; @xcite ; @xcite ; @xcite ) , confirming the common note that they are evolved from the interaction of agn jets with the intracluster medium ( icm ) ..
Please generate the next two sentences of the article | taking the agn jet origin for x - ray cavities , they are widely used to estimate the energetics of mechanical agn feedback . while travelling through the icm , the radio jets displace and
do @xmath5 work on the surrounding hot gas , producing x - ray cavities . |
5,591 | Suppose that you have an abstract for a scientific paper: we discuss the status of atomic physics in strong field .
we focus on the problem of electron - positron lines observed in heavy - ion collisions and on qed effects , calculated in strong coulomb fields , especially delbrck - scattering .
we discuss the similarities and differences between these effects and channeling respectively beamstrahlung .
we investigated the prospects for photon - channeling , calculated channeling from first principles on the basis of the dirac equation , and determined the rate for electron - positron pair production in the collision of two high - energy particle pulses . in this contribution
i would like to put the channeling phenomenon in a larger context , namely the physics of strong electromagnetic fields , a subject extensively investigated in frankfurt since many years .
the common technical feature of the many different effects investigated under this label is that the interaction of ( usually ) electrons with the electromagnetic fields of the problem can not be treated in perturbation theory , but has to be taken into account exactly @xcite .
+ to illustrate the diversity of this field i would like to address very shortly three topic , namely the status of the electron - positron coincidences observed at gsi for quite a number of years , some problems of qed in heavy atoms , and our contribution to the understanding of channeling and beamstrahlung . .
And you have already written the first three sentences of the full article: in the collision of two heavy ions one can generate for a very short time an atomic system with an effective charge which is the sum of the charges of the colliding nuclei .
this is possible because electrons with a wavelength of 1/@xmath0 fm can not resolve structures far below this scale . for the short time
such a collision takes an electron becomes very strongly bound ..
Please generate the next two sentences of the article | its binding energy can actually exceed twice its rest mass .
this happens if the combined atomic charge is larger than roughly 173 , depending on the amount of shielding by the other electrons . |
5,592 | Suppose that you have an abstract for a scientific paper: the paper discusses the optimal configuration of one or more ring lasers to be used for measuring the general relativistic effects of the rotation of the earth , as manifested on the surface of the planet .
the analysis is focused on devices having their normal vector lying in the meridian plane .
the crucial role of the evaluation of the angles is evidenced .
special attention is paid to the orientation at the maximum signal , minimizing the sensitivity to the orientation uncertainty .
the use of rings at different latitudes is mentioned and the problem of the non - sfericity of the earth is commented . .
And you have already written the first three sentences of the full article: ring lasers ( rl ) are top sensitivity devices able to measure absolute rotations .
the principle of operation of a ring laser is based on the sagnac effect @xcite .
rls are very reliable instruments , with large bandwidth and very high duty cycle ..
Please generate the next two sentences of the article | the most advanced rls are indeed used for accurate metrology in geophysics ( rotational seismology ) , and in geodesy for monitoring the fast variations of the earth rotation rate . for a laboratory on earth ,
the signal of a rl is proportional to the instantaneous s , much smaller than the typical times of other time depending phenomena in the lab and on the planet altogether . ] |
5,593 | Suppose that you have an abstract for a scientific paper: all complex hadamard matrices in dimensions two to five are known .
we use this fact to derive all inequivalent sets of mutually unbiased ( mu ) bases in low dimensions .
we find a three - parameter family of triples of mu bases in dimension four and two inequivalent classes of mu triples in dimension five .
we confirm that the complete sets of @xmath0 mu bases are unique ( up to equivalence ) in dimensions below six , using only elementary arguments for @xmath1 less than five . .
And you have already written the first three sentences of the full article: position and momentum of a _ classical _ non - relativistic particle are intimately linked since the momentum variable generates spatial translations .
mathematically , this important relation is embodied in the structure of the galilei group .
it turns out to be even more fundamental for a _ quantum mechanical _ particle , where it takes the form of the commutation relation of its position and momentum operators ..
Please generate the next two sentences of the article | the associated heisenberg - weyl group of phase - space translations continues to be relevant for quantum systems with only a _
finite _ number of orthogonal states , providing a basis of the space @xmath2 . for each dimension |
5,594 | Suppose that you have an abstract for a scientific paper: coin flipping is a cryptographic primitive in which two spatially separated players , who in principle do not trust each other , wish to establish a common random bit .
if we limit ourselves to classical communication , this task requires either assumptions on the computational power of the players or it requires them to send messages to each other with sufficient simultaneity to force their complete independence . without such assumptions , all classical protocols are so that one dishonest player has complete control over the outcome .
if we use quantum communication , on the other hand , protocols have been introduced that limit the maximal bias that dishonest players can produce .
however , those protocols would be very difficult to implement in practice because they are susceptible to realistic losses on the quantum channel between the players or in their quantum memory and measurement apparatus . in this paper
, we introduce a novel quantum protocol and we prove that it is completely impervious to loss .
the protocol is _ fair _ in the sense that either player has the same probability of success in cheating attempts at biasing the outcome of the coin flip
. we also give explicit and optimal cheating strategies for both players . .
And you have already written the first three sentences of the full article: coin flipping by telephone was first introduced with these words by manuel blum in 1981 : `` alice and bob [ ] have just divorced , live in different cities , want to decide who gets the car '' @xcite .
they agree that the best thing to do is to flip a coin , but neither of them trusts the other and they are unable to agree on a mutually trusted third party to do the flip for them .
more generally , coin - flipping protocols ( also known as `` coin - tossing '' ) can be used whenever two players need to pick a random bit even though it could be to the advantage of one of them ( or perhaps both ) to choose , or at least bias , the outcome of the protocol ..
Please generate the next two sentences of the article | the original coin - flipping protocol introduced by blum is _ asynchronous _ in the sense that it consists of a sequence of rounds in which the two players alternate in sending messages to each other .
the security of blum s protocol depends on the assumed difficulty of factoring large numbers . |
5,595 | Suppose that you have an abstract for a scientific paper: eleven candidate damped absorption systems were identified in twenty - seven spectra of the quasars from the apm z 4 survey covering the redshift range @xmath0 ( 8 with @xmath1 ) .
high resolution echelle spectra ( 0.8 fwhm ) have been obtained for three quasars , including two of the highest redshift objects in the survey .
two damped systems have confirmed hi column densities of @xmath2 10@xmath3 atoms @xmath4 , with a third falling just below this threshold .
we have discovered the highest redshift damped absorber known at [email protected] in qso br1202@xmath60725 .
the apm qsos provide a substantial increase in the redshift path available for damped surveys for z@xmath73 .
we combine this high redshift sample with other quasar samples covering the redshift range 0.008 @xmath8 z @xmath8 4.7 to study the redshift evolution and the column density distribution function for absorbers with log @xmath9 . in the column density distribution @xmath10
we find evidence for breaks in the power law , flattening for @xmath1121 and steepening for @xmath12@xmath13 .
the breaks are more pronounced at higher redshift . the column density distribution function for the data with log
@xmath220.3 is better fit with the form @xmath14 with log @xmath15 , @xmath16 , and @xmath17 .
we have studied the evolution of the number density per unit redshift of the damped systems by fitting the sample with the customary power law @xmath18 . for a population with no intrinsic evolution in the product of the absorption cross - section and comoving spatial number density
this will give @xmath19 ( @xmath20 ) or @xmath21 ( @xmath22 ) .
the best maximum likelihood fit for a single power law is @xmath23 and @xmath24 , consistent with no intrinsic evolution even though the value of @xmath25 is also consistent with that found for the lyman limit systems where evolution is detected at a significant level .
however , redshift evolution is evident in the higher column density systems with an apparent decline in @xmath26 for....
And you have already written the first three sentences of the full article: this paper is the third of a series presenting results from studies of the qsos discovered in the apm survey for z 4 quasars .
a study of the evolution of lyman limit absorption systems over the redshift range 0.04 @xmath28 z @xmath28 4.7 was presented in storrie - lombardi ( 1994 ) [ paper i ] . the intermediate resolution ( 5 )
qso spectra and the survey for high redshift damped absorbers are presented in storrie - lombardi ( 1996 ) [ paper ii ] ..
Please generate the next two sentences of the article | the evolution of the cosmological mass density of neutral gas at high redshift and the implications for galaxy formation theories are discussed in storrie - lombardi , mcmahon & irwin ( 1996 ) [ paper iv ] . in separate papers we will describe the intrinsic properties of the qsos and studies of the forest clouds at high redshift . a high resolution study of the forest region in a redshift @xmath29 qso has been completed by williger ( 1994 )
. how and when galaxies formed are questions at the forefront of work in observational cosmology . |
5,596 | Suppose that you have an abstract for a scientific paper: the pressure - induced structural phase transition in the intermediate - valence compound ceni has been investigated by x - ray and neutron powder diffraction techniques . for the first time
it is shown that the structure of the pressure - induced ceni phase ( phases ) can be described in terms of the @xmath0 space group .
equations of state for ceni on both sides of the phase transition are derived and an approximate @xmath1 phase diagram is suggested for @xmath2 gpa and @xmath3 k. the observed @xmath4 structural transition is analyzed using density functional theory ( dft ) calculations , which successfully reproduce the ground state volume , the phase transition pressure , and the volume collapse associated with the phase transition . .
And you have already written the first three sentences of the full article: the 4@xmath5-metals , and their alloys and intermetallic compounds exhibit rich pressure - temperature - composition phase diagrams . often , transitions between different phases are accompanied by a dramatic change in the material properties , including abrupt volume variation , and in particular the extent to which the @xmath5 electron localization changes under such phase transitions is of great scientific interest .
the transition between localized and itinerant behaviour is at the forefront of physics of strongly correlated systems .
such a transition occurs in the 5@xmath5 electron shell of the pure actinide metals - the 5@xmath5 electrons behave in a localized fashion in the heavy actinides but in a more delocalized manner in the light actinides - centering near pu and am ..
Please generate the next two sentences of the article | a quantitative and conclusive understanding of this phenomenon is still missing.@xcite in the lanthanide series , where the 4@xmath5 orbitals are spatially less extended than the 5@xmath5 orbitals in the actinides , localized - itinerant transitions occur at the beginning ( around ce ) , in the middle ( sm , eu ) and at the end ( yb ) . application of high pressure leads to a 4@xmath5 delocalization and , in some cases , to structural phase transformations accompanied by a volume discontinuity .
the most famous example is cerium , which exhibits the isostructural @xmath6 volume - collapse phase transition upon either cooling or application of external pressure . |
5,597 | Suppose that you have an abstract for a scientific paper: the lateral casimir force , which arises between aligned sinusoidally corrugated surfaces of a sphere and a plate , was measured for the case of a small corrugation period beyond the applicability region of the proximity force approximation .
the increased amplitudes of the corrugations on both the sphere and the plate allowed observation of an asymmetry of the lateral casimir force , i.e. , deviation of its profile from a perfect sine function .
the dependences of the lateral force on the phase shift between the corrugations on both test bodies were measured at different separations in two sets of measurements with different amplitudes of corrugations on the sphere .
the maximum magnitude of the lateral force as a function of separation was also measured in two successive experiments .
all measurement data were compared with the theoretical approach using the proximity force approximation and with the exact theory based on rayleigh expansions with no fitting parameters . in both cases real material properties of the test bodies and nonzero temperature
were taken into account .
the data were found to be in a good agreement with the exact theory but deviate significantly from the predictions of the proximity force approximation approach .
this provides the quantitative confirmation for the observation of diffraction - type effects that are disregarded within the pfa approach .
possible applications of the phenomenon of the lateral casimir force in nanotechnology for the operation of micromachines are discussed . .
And you have already written the first three sentences of the full article: the casimir effect @xcite is presently well known due to the many potential applications in both fundamental physics and nanotechnology .
the casimir force is an extension of the van der waals interaction to larger separations between macroscopic bodies where the relativistic retardation of the electromagnetic interaction becomes important due to the finite speed of light .
the casimir effect originates from the existence of zero - point and thermal oscillations in restricted quantization volumes ..
Please generate the next two sentences of the article | the results of extensive experimental and theoretical studies on the role of the casimir force in configurations with idealized boundary surfaces ( infinitely thin , with ideal - metal boundary conditions etc . ) and also between surfaces of real material bodies with account of roughness , nonzero skin depth and nonzero temperature are presented in ref .
@xcite ( see also earlier books and reviews @xcite ) . |
5,598 | Suppose that you have an abstract for a scientific paper: we show that a gas - to - liquid phase transition at zero temperature may occur in a coherent gas of bosons in the presence of competing nonlinear effects .
this situation can take place both in atomic systems like bose - einstein condensates in alkalii gases with two and three - body interactions of opposite signs , as well as in laser beams which propagate through optical media with kerr ( focusing ) and higher order ( defocusing ) nonlinear responses .
the liquefaction process takes place in absence of any quantum effect and can be formulated in the frame of a mean field theory , in terms of the minimization of a thermodynamic potential .
we also show numerically that the effect of linear gain and three - body recombination also provides a rich dynamics with the emergence of self - organization behaviour . .
And you have already written the first three sentences of the full article: paraxial propagation of linearly polarized laser beams through transparent optical media with intensity dependent refractive index is mathematically equivalent to the free evolution of the wavefunction order parameter used in the mean - field description of a two - dimensional gas of @xmath0 interacting atoms in a bose - einstein condensate ( bec ) at temperature @xmath1 @xcite .
both systems can be modeled by identical nonlinear schrdinger equations@xcite . for photons in the laser beam
, the @xmath2 component of the nonlinear optical susceptibility plays the same role as n - body interactions between atoms in the cloud and the propagation constant can be identified with a chemical potential for the light distribution ..
Please generate the next two sentences of the article | as all the photons in a coherent wave are equal , the laser beam can be treated on equal foot as any system of @xmath0 identical interacting bosons at zero temperature@xcite .
the previous point of view , which takes into account the equivalence between laser beams and becs of ultracold atoms , has led to an interesting suggestion made by chiao@xcite , who recently proposed to verify the superfluidity of coherent light , in analogy with degenerate quantum atomic gases . |
5,599 | Suppose that you have an abstract for a scientific paper: we have performed a systematic study of the phase transition in the pure compact u(1 ) lattice gauge theory in the extended coupling parameter space ( @xmath0 ) on toroidal and spherical lattices .
the observation of a non - zero latent heat in both topologies for all investigated @xmath1 $ ] , together with an exponent @xmath2 when large enough lattices are considered , lead us to conclude that the phase transition is first order . for negative @xmath3 ,
our results point to an increasingly weak first order transition as @xmath3 is made more negative .
_ departamento de fsica terica , facultad de ciencias , + universidad de zaragoza , 50009 zaragoza , spain + e - mail : isabel , tarancon , [email protected]_ + .
And you have already written the first three sentences of the full article: in this work the 4@xmath4 pure compact u(1 ) gauge theory is revisited . this model , being the prototype of gauge abelian interaction , has received a lot of attention through the years , since it constitutes a preliminary step in approaching qed . however , the questions related with the mechanisms driving the transition and with the order of the phase transition itself , have turned out to be a more controversial issue than one might expect from its apparent simplicity . through this section
we shall summarize the main results obtained up to date .
the 4@xmath4 pure compact u(1 ) theory is known to undergo a phase transition between a region in which the photons are confined ( strong coupling ) and another region in which they carry a coulomb potential ( weak coupling ) ..
Please generate the next two sentences of the article | the theory can be discretized in the lattice using the wilson action @xmath5 \ . \label{sw}\ ] ] most of the work has been done on the hypercubic lattice with periodic boundary conditions , namely on the hypertorus . on this topology
the pioneer studies ( see eg . |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.