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6,500 | Suppose that you have an abstract for a scientific paper: we study a two - component model for gelation consisting of @xmath0-functional monomers ( the gel ) and inert particles ( the solvent ) .
after equilibration as a simple liquid , the gel particles are gradually crosslinked to each other until the desired number of crosslinks has been attained . at a critical crosslink density the largest gel cluster percolates and an amorphous solid forms .
this percolation process is different from ordinary lattice or continuum percolation of a single species in the sense that the critical exponents are new .
as the crosslink density @xmath1 approaches its critical value @xmath2 , the shear viscosity diverges : @xmath3 with @xmath4 a nonuniversal concentration - dependent exponent . .
And you have already written the first three sentences of the full article: it is generally accepted that percolation is an essential aspect of gelation or vulcanization it is doubtful that even in a highly entangled melt of long polymers a nonzero value of the static shear modulus could exist in the absence of an infinite connected network .
however , percolation has usually been studied in rather special limits .
site and bond percolation of a single species on regular lattices are very well characterized and off - lattice percolation seems to present no new features @xcite , at least insofar as critical behavior is concerned ..
Please generate the next two sentences of the article | more closely related to real gels are the so - called correlated percolation models where the distribution of crosslinks is drawn from a boltzmann distribution appropriate for a nearest neighbor lattice gas @xcite .
except at special points in the phase diagram these models are also in the universality class of the simple percolation problem . in our previous work on transport properties near the gel point @xcite , |
6,501 | Suppose that you have an abstract for a scientific paper: working with tree graphs is always easier than with loopy ones and spanning trees are the closest tree - like structures to a given graph .
we find a correspondence between the solutions of random k - satisfiability problem and those of spanning trees in the associated factor graph .
we introduce a modified survey propagation algorithm which returns null edges of the factor graph and helps us to find satisfiable spanning trees .
this allows us to study organization of satisfiable spanning trees in the space spanned by spanning trees . .
And you have already written the first three sentences of the full article: understanding the nature of complexity in np - hard optimization problems is an important goal in the study of complex systems @xcite .
most of optimization problems are indeed a constraint satisfaction problem and satisfiability problem is a prototype of such problems @xcite . in a satisfiability problem one looks for a configuration of logical variables that satisfies a number of logical constraints ( clauses ) .
a clause is in turn disjunction of a few logical variables . in random k - satisfiability ( k - sat ).
Please generate the next two sentences of the article | problem a clause involves @xmath0 randomly selected variables each negated with a given probability . increasing the number of clauses per variables , these problems display a phase transition from satisfiable to unsatisfiable phase @xcite .
it is around this sat - unsat transition that the typical complexity of the problem raises rapidly . |
6,502 | Suppose that you have an abstract for a scientific paper: we experimentally demonstrate optical trapping of @xmath0 atoms using a two - color evanescent field around an optical nanofiber . in our trapping geometry , a blue - detuned traveling wave
whose polarization is nearly parallel to the polarization of a red - detuned standing wave produces significant vector light shifts that lead to broadening of the absorption profile of a near - resonant beam at the trapping site .
a model that includes scalar , vector , and tensor light shifts of the probe transition @xmath1-@xmath2 from the trapping beams , weighted by the temperature - dependent position of the atoms in the trap , qualitatively describes the observed asymmetric profile and explains differences with previous experiments that used cs atoms .
the model provides a consistent way to extract the number of atoms in the trap . .
And you have already written the first three sentences of the full article: the small mode volume of evanescent field atom traps engenders strong atom - light interactions without the need for a cavity @xcite .
the recent demonstrations of trapping @xmath3cs with an optical nanofiber ( onf ) @xcite - and a state - insensitive variant @xcite mark an important experimental realization of these systems .
their high optical depth ( @xmath4 ) allows for efficient dispersive readout @xcite and strong nonlinear interactions , and they could potentially realize collective effects such as superradiance @xcite . the success of onf traps has inspired a growing effort to trap atoms in the evanescent field of nanophotonic waveguides @xcite ..
Please generate the next two sentences of the article | this regime of strong coupling opens the door to the study of long - range interactions and the formation of so - called atomic mirrors @xcite , the observation of self - crystallization @xcite , or the generation of a sub - poissonian atom number distribution @xcite .
furthermore , low loss onfs @xcite have been proposed as one of steps toward the realization of a hybrid quantum system coupling photons to atoms to superconducting circuit elements @xcite . |
6,503 | Suppose that you have an abstract for a scientific paper: we analyse catalogues of galaxies from the sloan digital sky survey ( sdss ) and find a weak but significant assembly - type bias , where old galaxies have a higher clustering amplitude at scales @xmath0 1 @xmath1 than young galaxies of equal magnitude . when using the definition of age based on the luminosity - weighted stellar age , the difference increases from @xmath2 to @xmath3 sdss galaxies , from a 25 per cent to a 45 per cent effect .
in contrast , when using the definition based on the @xmath4 index , the clustering amplitude at large scales shows a weaker signal - to - noise for the assembly bias detection . in semi - analytic galaxies
the difference in clustering , using the stellar age and luminosity , is similar at distances beyond 3 @xmath1 , but they overpredict the assembly bias found in sdss galaxies at smaller scales .
we then adapt the model presented by lacerna & padilla ( paper i ) to redefine the overdensity peak height , that traces the assembly bias such that galaxies in equal density peaks show the same clustering regardless of their age , but this time using observational features .
the proxy of peak height for observational data consists in the luminosity inside cylinders of different radii centred in each galaxy .
this radius is parameterized as a funcion of stellar age and magnitude @xmath5 .
the best - fitting set of parameters that make the assembly bias practically absent for both simulated and real galaxies are similar ( @xmath6 , @xmath7 and @xmath8 , @xmath7 , respectively ) . by estimating a weighted average for the values in the range of @xmath9 for semi - analytic and sdss galaxies
, it is obtained that the set of best - fitting parameters for the radius of the cylinder is @xmath10 , @xmath11 .
the idea behind the parametrization is not to minimize the bias , but it is to use this method to understand the physical features that produce the assembly bias effect . even though in this case we consider neighbour galaxies in cylinders in contrast to using a....
And you have already written the first three sentences of the full article: in the current hierarchical clustering models , galaxies form by gas cooling inside virialized cold dark matter haloes in a way that makes their properties depend only on the halo mass in which they form .
recently , results from @xmath12-body simulations have shown that the halo clustering at large - scales depends on the halo formation history in addition to the halo mass @xcite .
this effect , that is not expected from the excursion set theory , was termed `` assembly bias '' ..
Please generate the next two sentences of the article | for example , gao et al .
( 2005 ) found that low - mass haloes which were assembled at high redshifts are more strongly correlated than those of the same mass that assembled more recently . |
6,504 | Suppose that you have an abstract for a scientific paper: we investigate the pulsational properties of pre main - sequence ( pms ) stars by means of linear and nonlinear calculations .
the equilibrium models were taken from models evolved from the protostellar birthline to the zams for masses in the range 1 to 4 m@xmath0 .
the nonlinear analysis allows us to define the instability strip of pms stars in the hr diagram .
these models are used to constrain the internal structure of young stars and to test evolutionary models .
we compare our results with observations of the best case of a pulsating young star , hr 5999 , and we also identify possible candidates for pulsational variability among known herbig ae / be stars which are located within or close to the instability strip boundaries .
= cmbx10 scaled = cmbx10 scaled1 # 1;#2;#3;#4 # 1 , # 2 , # 3 , # 4 .
# 1;#2 * # 1 * : _ # 2 _ # 1@xmath1 # 1@xmath2 # 1equation ( [ # 1 ] ) # 1equation ( [ # 1 ] ) # 1 ( [ # 1 ] ) # 110^#1 # 1n _ # 1 # 1k_#1 .
And you have already written the first three sentences of the full article: young stars are characterized by a large degree of activity .
winds , jets and outflows are manifestations of the interaction of the stars with the circumstellar environment in which they are embedded .
similarly , both t tauri and herbig ae / be stars show photometric and spectroscopic variability on time scales of minutes to years , indicating that photospheric activity begins in the earliest phases of stellar evolution , prior to the arrival on the main sequence ( ms ) . in many cases ,.
Please generate the next two sentences of the article | strong and rapid line variability has been detected with periods close to the star rotation period , interpreted as due to the rotational modulation of spots on the stellar surface or of fast and slow streams in the stellar wind ( e.g. gahm et al .
1995 ; catala et al . |
6,505 | Suppose that you have an abstract for a scientific paper: we present measurements of the production of stable light nuclei for mass number @xmath0 , of strongly decaying states @xmath1 and @xmath2 and of the the hypernucleus @xmath3 .
we also examine trends in the production of these multibaryon states as a function of kinematic variables and properties of the states including strangeness content . .
And you have already written the first three sentences of the full article: experiment e864 at brookhaven has a quite comprehensive set of measurements which addresses the topic of coalescence of multibaryon states in heavy - ion collisions at ags energies .
these include measurements of stable light nuclei from mass number @xmath4=1 ( including the first measurement of neutrons in an ags au+pb or similar system ) up to @xmath4=7 .
in addition , we have measured production of the strongly decaying states @xmath1 and @xmath2 and the hypernucleus @xmath3 . with this set of measurements we can systematically examine the dependences of production of coalesced states on kinematic variables and collision centrality as well as on the mass number , spin , isospin , and strangeness content of the state ..
Please generate the next two sentences of the article | only for the lighter states ( @xmath5 ) do we currently have sufficient statistics to study the kinematic and centrality dependences of production . in figure [
fig : temp_vs_mass ] we display inverse slope parameters for protons , deuterons , and @xmath6 nuclei as a function of mass number . |
6,506 | Suppose that you have an abstract for a scientific paper: atca hi and radio continuum observations of the peculiar southern galaxy ic 2554 and its surroundings reveal typical signatures of an interacting galaxy group .
we detected a large hi cloud between ic 2554 and the elliptical galaxy ngc 3136b .
the gas dynamics in ic 2554 itself , which is sometimes described as a colliding pair , are surprisingly regular , whereas ngc 3136b was not detected . the hi cloud , which emerges from ic 2554 as a large arc - shaped plume , has a size of @xmath0 kpc , larger than that of ic 2554 .
the total hi mass of the ic 2554 system is @xmath1 m@xmath2 , a third of which resides in the hi cloud .
it is possible that tidal interaction between ic 2554 and ngc 3136b caused this spectacular hi cloud , but the possibility of ic 2554 being a merger remnant is also discussed .
we also detected hi gas in the nearby galaxies eso 092-g009 and rkk 1959 as well as an associated hi cloud , atca j10066710 .
together they have an hi mass of @xmath3 m@xmath2 .
another new hi source , atca j10076659 , with an hi mass of only @xmath4 m@xmath2 was detected roughly between ic 2554 and eso 092-g009 and corresponds to a face - on low surface brightness dwarf galaxy .
star formation is evident only in the galaxy ic 2554 with a rate of @xmath54 m@xmath2yr@xmath6 .
galaxies : individual ( ic 2554 , ngc 3136b , eso 092-g009 , rkk 1959 ) galaxies : interactions .
And you have already written the first three sentences of the full article: ic 2554 is a southern galaxy with a peculiar optical appearance .
it is also known as se 72/1 ( srsic 1974 ) , eso 092-ig012 , and iras 100756647 .
1 shows a deep optical image of ic 2554 ( laustsen , madsen & west 1987 ) revealing many bright knots as well as a network of dust lanes intersecting the main body of the galaxy ..
Please generate the next two sentences of the article | the optical extent of ic 2554 is 325 ( see table 1 ) .
its irregular and asymmetric appearance has prompted the division into multiple components , roughly aligned north - south . |
6,507 | Suppose that you have an abstract for a scientific paper: flux is an important source of uncertainties for a reactor neutrino experiment .
it is determined from thermal power measurements , reactor core simulation , and knowledge of neutrino spectra of fuel isotopes .
past reactor neutrino experiments have determined the flux to ( 2 - 3)% precision .
precision measurements of mixing angle @xmath0 by reactor neutrino experiments in the coming years will use near - far detector configurations .
most uncertainties from reactor will be canceled out .
understanding of the correlation of uncertainties is required for @xmath0 experiments .
precise determination of reactor neutrino flux will also improve the sensitivity of the non - proliferation monitoring and future reactor experiments .
we will discuss the flux calculation and recent progresses .
neutrino flux , reactor , fission rate .
And you have already written the first three sentences of the full article: reactor neutrino experiments have played a critical role in the history of neutrinos . among them , savannah river experiment @xcite by reines and cowan in 1956 observed the first neutrino .
chooz @xcite determined the most stringent upper limit of the last unknown neutrino mixing angle @xmath1 in 1998 .
kamland @xcite observed the first reactor neutrino disappearance in 2003 ..
Please generate the next two sentences of the article | flux is an important source of uncertainties for a reactor neutrino experiment .
it is determined from thermal power measurements , reactor core simulation , and knowledge of neutrino spectra of fuel isotopes . |
6,508 | Suppose that you have an abstract for a scientific paper: we outline a framework for understanding the x - ray spectra of high mass accretion rate stellar black holes based on x - ray data from rxte and asca .
three spectral regimes can be separated out by the behaviour of the observed disk luminosity and temperature .
the well established `` standard regime '' is seen when the disk dominates the spectrum , where only a small fraction of the luminosity is emitted in the power law tail .
these spectra generally satisfy the standard relation expected for thermal emission from a constant area , namely that the disk bolometric luminosity , @xmath0 , is proportional to its maximum temperature , @xmath1
. however , at higher luminosities this starts to change to @xmath2 .
this `` apparently standard regime '' is still dominated by the disk emission , but this difference luminosity - temperature relation and subtle changes in spectral shape may show that another cooling process is required in addition to radiative cooling . at intermediate luminosities
there is an anomalous regime ( or weak very high state ) where the disk temperature and luminosity are less clearly related .
these spectra are characterized by the presence of a much stronger comptonized tail indicating high energy electrons .
when observed disk emission is corrected for the the effects of comptonisation then these points lie back on the standard relation .
the growth of this comptonising corona is also clearly linked to the quasi - periodic oscillations , as these are observed preferentially in the anomalous regime .
this presented picture was found to explain the spectral behavior of both black hole binaries in our galaxy and lmc .
spectral evolution of several bright ulxs observed with asca were also successfully explained in the same picture . , black holes ; accretion disk . .
And you have already written the first three sentences of the full article: in a close binary consisting of a stellar - mass black hole and a mass donating normal star , the accreting matter releases its gravitational energy as x - ray radiation . in fig . [
fig : cygx1 ] , we show two typical x - ray spectra of cyg x-1 , the best studied black hole binary , showing its two distinct spectral states . in the low / hard state ,
its spectrum is approximately a power - law , with an exponential cut - off near @xmath3 kev ..
Please generate the next two sentences of the article | by contrast , the high / soft state is characterized by dominant soft emission below 10 kev , accompanied by a hard power - law tail extending to 500 kev and beyond .
as described , e.g. , by makishima et al . |
6,509 | Suppose that you have an abstract for a scientific paper: we investigate the berezin integral of non - compactly supported quantities . in the framework of supermanifolds with corners ,
we give a general , explicit and coordinate - free repesentation of the boundary terms introduced by an arbitrary change of variables . as a corollary ,
a general stokes s theorem is derived here , the boundary integral contains transversal derivatives of arbitrarily high order .
keywords : berezin integral , stokes s theorem , change of variables , non - compact supermanifold , boundary term , manifold with corners .
msc ( 2010 ) : 58c50 , 58a50 ( primary ) ; 58c35 ( secondary ) . .
And you have already written the first three sentences of the full article: supermanifolds were introduced by berezin , leites and konstant in the 1970s as a mathematical framework for the quantum theory of commuting and anticommuting fields .
a remarkable contribution was berezin s definition of his integral , in ref .
@xcite , predating the definition of supermanifolds by several years , and providing at the time sufficient indication that a reasonable supersymmetric analysis should exist . despite its utility ,.
Please generate the next two sentences of the article | the integral suffers from a fundamental pathology : only the integral of _ compactly supported _ quantities is well - defined in a coordinate independent form
changes of variables introduce , in general , so - called _ boundary terms_. this can be seen as a major obstacle in the development of global superanalysis . |
6,510 | Suppose that you have an abstract for a scientific paper: let @xmath0 be a finite subgroup in @xmath1 , and @xmath2 the corresponding affine dynkin diagram . in this paper
, we review the relation between the categories of @xmath0-equivariant sheaves on @xmath3 and @xmath4 , where @xmath5 is an orientation of @xmath2 , constructing an explicit equivalence of corresponding derived categories . .
And you have already written the first three sentences of the full article: let @xmath6 be a finite subgroup . according to mckay correspondence , such a subgroup gives rise to a graph @xmath2 which turns out to be an affine dynkin diagram of ade type .
let @xmath7 be the corresponding affine lie algebra .
there are several approaches allowing one to construct @xmath7 from @xmath0 : 1 ..
Please generate the next two sentences of the article | there is a geometric construction , due to nakajima and lusztig , of @xmath7 and its representations in terms of the quiver varieties associated to graph @xmath2 .
these varieties are closely related to the moduli spaces of instantons on the resolution of singularities @xmath8 . |
6,511 | Suppose that you have an abstract for a scientific paper: two operators for quantum gravity , angle and quasilocal energy , are briefly reviewed .
the requirements to model semi - classical angles are discussed . to model semi - classical angles
it is shown that the internal spins of the vertex must be very large , @xmath0 . .
And you have already written the first three sentences of the full article: spin net gravity is based on the quantization of gravity using connection variables .
( for a review , see ref .
@xcite . ) searching for the eigenspace for geometric observables , rovelli and smolin introduced new states @xcite which echoed an older , combinatorial definition of spacetime advocated by penrose @xcite . using penrose s original name.
Please generate the next two sentences of the article | the new states were named `` spin networks '' .
these were later shown to be a basis @xcite for the kinematic or 3-geometry states of quantum gravity . but |
6,512 | Suppose that you have an abstract for a scientific paper: outflows are common in many astrophysical systems which contain black holes and neutron stars .
difference between stellar outflows and outflows from these systems is that the outflows in these systems have to form out of the inflowing material only .
the inflowing material can form a hot and dense cloud surrounding the compact object either because of centrifugal barrier or a denser barrier due to pair plasma or pre - heating effects .
this barrier behaves like a stellar surface as far as the mass loss is concerned .
we estimate the outflow rate from such considerations .
these estimated rates roughly match with the rates in real observations as well as those obtained from numerical experiments .
= cmmi10 scaled1 = cmmi10 = cmmi7 = cmmib10 scaled1 = cmmib10 = cmmib10 scaled 833 = cmbsy10 scaled1 = cmbsy10 = cmbsy10 scaled 833 1 = 1 = 1 = 9 = 9 = 9 = 10 = 10 = 10 = submitted : 24th july , 1997 ; revised :
6th november , 1998 .
comparison with begelman and blandford work on cauldron model is added . .
And you have already written the first three sentences of the full article: cosmic radio jets are believed to be originated from the centers of active galaxies which harbor black holes ( e.g. , chakrabarti 1996a , hereafter c96a ) . even in so called ` micro - quasars ' , such as grs 1915 + 105 which are believed to have stellar mass black holes ( mirabel & rodriguez , 1994 )
, the outflows are common .
the well collimated outflows in ss 433 is well known for almost two decades ( margon , 1984 ) ..
Please generate the next two sentences of the article | similarly , systems with neutron stars also show outflows as is believed to be the case in x - ray bursters ( e.g. titarchuk , 1994 ) .
there are large number of works in the literature which attempt to explain the origin of these outflows . |
6,513 | Suppose that you have an abstract for a scientific paper: fermi coordinates are the natural generalization of inertial cartesian coordinates to accelerated systems and gravitational fields .
we study the motion of ultrarelativistic particles and light rays in fermi coordinates and investigate inertial and tidal effects beyond the critical speed @xmath0 .
in particular , we discuss the black - hole tidal acceleration mechanism for ultrarelativistic particles in connection with a possible origin for high - energy cosmic rays . .
And you have already written the first three sentences of the full article: physically meaningful interpretation of the measurement of relative motion from the point of view of an accelerated observer in a gravitational field requires the introduction of a special coordinate system ( i.e. fermi coordinates ) along the worldline of the observer . in this coordinate system ,
the equations of relative motion reveal tidal and inertial effects for ultrarelativistic motion ( with speed exceeding the critical value @xmath0 ) that are contrary to newtonian expectations .
while there are general treatments of inertial and tidal effects in fermi coordinates @xcite and the special case of ultrarelativistic motion of particles has been discussed in our recent papers @xcite , the purpose of this work is to present a more systematic and complete description of motion beyond the critical speed @xmath0 . to this end.
Please generate the next two sentences of the article | , the equations of motion in fermi coordinates are discussed in section [ s0 ] and inertial effects are considered in sections [ s2 ] , [ s3 ] and appendix a. section [ s4 ] is devoted to tidal effects .
a summary and brief discussion of our results is contained in section [ s5 ] . |
6,514 | Suppose that you have an abstract for a scientific paper: v407 vul ( rx j1914.4 + 2456 ) is a candidate double - degenerate binary with a putative 1.756 mhz ( 9.5 min ) orbital frequency . in a previous timing study using archival rosat and asca data we reported evidence for an increase of this frequency at a rate consistent with expectations for gravitational radiation from a detached ultracompact binary system .
here we report the results of new _
chandra _
timing observations which confirm the previous indications of spin - up of the x - ray frequency , and provide much tighter constraints on the frequency derivative , @xmath0 .
we obtained with _
chandra _ a total of 90 ksec of exposure in two epochs separated in time by 11.5 months .
the total time span of the archival rosat , asca and new _
chandra _
data is now @xmath1 years .
this more than doubles the interval spanned by the rosat and asca data alone , providing much greater sensitivity to a frequency derivative . with the addition of the chandra data an increasing frequency is unavoidable , and the mean
@xmath0 is @xmath2 hz s@xmath3 .
although a long - term spin - up trend is confirmed , there is excess variance in the phase timing residuals , perhaps indicative of shorter timescale torque fluctuations or phase instability associated with the source of the x - ray flux .
power spectral searches for periods longward of the 9.5 minute period do not find any significant modulations , however , the sensitivity of searches in this frequency range are somewhat compromised by the dithering of the chandra attitude .
the observed spin - up is of a magnitude consistent with that expected from gravitational radiation decay , however , the factor of @xmath4 variations in flux combined with the timing noise could conceivably result from accretion - induced spin - up of a white dwarf . continued monitoring to explore correlations of torque with x - ray flux could provide a further test of this hypothesis . .
And you have already written the first three sentences of the full article: ultracompact binary systems could provide a promising means to observe directly the influence of gravitational radiation on orbital evolution .
moreover , such systems would be ideal sources for detection with spaced based gravitational radiation observatories ( such as the planned nasa / esa lisa mission ) , opening up the possibility for detailed studies of compact interacting binaries . in recent years a pair of candidate ultracompact systems ; v407 vul ( also known as rx j1914.4 + 2456 ) and rx j0806 + 1527 ( hereafter j0806 ) have been proposed .
these objects were first discovered by rosat ( motch et al ..
Please generate the next two sentences of the article | 1996 ; israel et al . 1999 ; beuermann et al .
1999 ) , and initially were suggested to be members of a `` soft '' class of intermediate polars ( ips ) , with the x - ray periods of 569 and 321 s , respectively , representing the putative spin periods of the accreting white dwarfs . since |
6,515 | Suppose that you have an abstract for a scientific paper: probing the magnetism of the upper solar chromosphere requires measuring and modeling the scattering polarization produced by anisotropic radiation pumping in uv spectral lines .
here we apply porta ( a novel radiative transfer code ) to investigate the hydrogen ly@xmath0 line in a 3d model of the solar atmosphere resulting from a state of the art mhd simulation . at full spatial resolution
the linear polarization signals are very significant all over the solar disk , with a large fraction of the field of view showing line - center amplitudes well above the 1% level . via the hanle effect
the line - center polarization signals are sensitive to the magnetic field of the model s transition region , even when its mean field strength is only 15 g. the breaking of the axial symmetry of the radiation field produces significant forward - scattering polarization in ly@xmath0 , without the need of an inclined magnetic field .
interestingly , the hanle effect tends to decrease such forward - scattering polarization signals in most of the points of the field of view . when the spatial resolution is degraded , the line - center polarization of ly@xmath0 drops below the 1% level , reaching values similar to those previously found in 1d semi - empirical models ( i.e. , up to about 0.5% ) .
the center to limb variation of the spatially - averaged polarization signals is qualitatively similar to that found in 1d models , with the largest line - center amplitudes at @xmath1 ( @xmath2 being the heliocentric angle ) .
these results are important , both for designing the needed space - based instrumentation and for a reliable interpretation of future observations of the ly@xmath0 polarization . .
And you have already written the first three sentences of the full article: [ cols="^,^ " , ] for the forward - scattering case of a disk - center observation as a function of the spatial resolution @xmath3 ( in arcseconds ) of a square @xmath4 element .
the dotted lines indicate the resolution for which the average polarization signal is reduced by a factor @xmath5 with respect to the full - resolution case .
, width=302 ] the 3d model atmosphere considered in this paper is a snapshot of a radiation mhd simulation performed with the _ bifrost _ code @xcite taking into account non - equilibrium hydrogen ionization ( see details in * ? ? ?.
Please generate the next two sentences of the article | we used snapshot 385 of the simulation en024048-hion " , which is the same simulation recently made publicly available through the interface region imaging spectrograph project ( iris ; * ? ? ?
* ) at the hinode science data center europe ( http://sdc.uio.no ; see iris technical note 33 ) . |
6,516 | Suppose that you have an abstract for a scientific paper: the chirped - pulse interaction in the adiabatic coupling regime induces cyclic permutations of the energy states of a three - level system in the @xmath0-type configuration , which process is known as the three - level chirped rapid adiabatic passage .
here we show that a spectral hole in a chirped pulse can turn on and off one of the two adiabatic crossing points of this process , reducing the system to an effective two - level system .
the given hybrid adiabatic - nonadiabatic transition results in selective excitation of the three - level system , controlled by the laser intensity and spectral position of the hole as well as the sign of the chirp parameter .
experiments are performed with shaped femtosecond laser pulses and the three lowest energy - levels ( 5s@xmath1 , 5p@xmath1 , and 5p@xmath2 ) of atomic rubidium ( @xmath3rb ) , of which the result shows good agreement with the theoretically analyzed dynamics .
the result indicates that our method , being combined with the ordinary chirped - rap , implements an adiabatic transitions between the two excited states .
furthermore the laser intensity - dependent control may have applications including selective excitations of atoms or ions arranged in space when being used in conjunction with laser beam profile programming . .
And you have already written the first three sentences of the full article: adiabatic control of a quantum system through its adiabatic evolution path allows robust manipulation and high - fidelity state - preparation @xcite . gradually being recognized as an important requirement in quantum information processing @xcite , it has been under active investigation in recent years @xcite .
the best known examples of the adiabatic control methods are the rapid adiabatic passage ( rap ) @xcite and the stimulated raman adiabatic passage ( stirap ) @xcite . in rap ,
an excitation pulse with a monotonic frequency sweep induces a state vector to follow a population - inversion path in hilbert space traced by an adiabatic state . in stirap ,.
Please generate the next two sentences of the article | a pair of excitation pulses separated in time creates a population - trapping state of a three - level system and the state evolution through the subsequent adiabatic path ensures 100% population transfer from the initial state to the final state without populating the intermediate state .
both of these methods have been widely applied to various quantum systems including atom optics @xcite , nmr @xcite , cavity quantum electrodynamics @xcite , superconducting qubits @xcite , and quantum dots @xcite . |
6,517 | Suppose that you have an abstract for a scientific paper: observations with the extreme ultraviolet explorer ( euve ) satellite have shown that the inner region of the virgo cluster ( centered in m87 galaxy ) has a strong extreme ultraviolet ( euv ) emission ( up to @xmath0 ) in excess to the low - energy tail expected from the hot , diffuse intracluster medium ( icm ) .
detailed observations of large scale radio emission and upper limits for hard , non - thermal x - ray emission in the @xmath1 kev energy band have been also reported . here
we show that all available observations can be accounted for by the existence of two electron populations ( indicated as i and ii ) in the m87 galaxy .
the mildly relativistic population i is responsible for the euv excess emission via ic scattering of cbr and starlight photons .
population ii electrons ( with higher energy ) are instead responsible for the radio emission through synchrotron mechanism .
the same electrons also give rise to hard non - thermal x - ray emission ( via ic scattering of cbr photons ) , but the resulting power is always below the upper bounds placed by present observations .
the non - negligible energy budget of the two electron populations with respect to that associated with thermal electrons indicates that the m87 galaxy is not today in a quiescent ( relaxed ) phase .
nuclear activity and merging processes could have made available this energy budget that today is released in the form of relativistic electrons . .
And you have already written the first three sentences of the full article: observations with the euve satellite ( bowyer & malina @xcite ) have provided evidence that a number of clusters of galaxies produce intense euv emission , substantially in excess of the low - energy tail expected from the x - ray emission by the hot , diffuse icm at temperature of a few kev .
euv excesses have been reported for virgo ( lieu et al .
@xcite ) , coma ( lieu et al ..
Please generate the next two sentences of the article | @xcite ) , a1795 ( mittaz , lieu & lockman @xcite ) , a2199 galaxy clusters ( lieu , bonamente & mittaz @xcite ) , a4038 ( bowyer , lieu & mittaz @xcite ) and a4059 ( durret et al .
@xcite ) . however , although there is no doubt about the detection of the euv excess emission for virgo and coma clusters , considerable controversy still exists for the other clusters since euve results are affected by the variation of the telescope sensitivity over the field of view and depend also on subtraction of background signals that do not come from the cluster ( see berghfer & bowyer @xcite and durret et al . |
6,518 | Suppose that you have an abstract for a scientific paper: we present the discovery of the first l - type subdwarf , 2mass j05325346 + 8246465 .
this object exhibits enhanced collision - induced h@xmath0 absorption , resulting in blue nir colors ( @xmath1 ) .
in addition , strong hydride bands in the red optical and nir , weak tio absorption , and an optical / j - band spectral morphology similar to the l7 denis 0205@xmath21159ab imply a cool , metal - deficient atmosphere .
we find that 2mass 0532 + 8246 has both a high proper motion , @xmath3 = 2@xmath460@xmath50@xmath415 yr@xmath6 , and a substantial radial velocity , @xmath7 km s@xmath6 , and its probable proximity to the sun ( d = 1030 pc ) is consistent with halo membership . comparison to subsolar - metallicity evolutionary models strongly suggests that 2mass 0532 + 8246 is substellar , with a mass of 0.077 @xmath8 m @xmath8 0.085 m@xmath9 for ages 1015 gyr and metallicities @xmath10 @xmath11 .
the discovery of this object clearly indicates that star formation occurred below the hydrogen burning mass limit at early times , consistent with prior results indicating a flat or slightly rising mass function for the lowest - mass stellar subdwarfs .
furthermore , 2mass 0532 + 8246 serves as a prototype for a new spectral class of subdwarfs , additional examples of which could be found in nir proper motion surveys . .
And you have already written the first three sentences of the full article: subdwarfs are metal - deficient stars , classically defined as lying below the stellar main - sequence in optical color - magnitude diagrams @xcite .
these objects are in fact not subluminous but rather hotter ( i.e. , bluer in optical colors ) than equivalent mass main - sequence dwarfs , a consequence of their reduced metal opacity @xcite .
cool subdwarfs ( spectral types sdk and sdm ) are typically found to have halo kinematics ( @xmath12 km s@xmath6 ; gizis 1997 ) , and these objects are presumably relics of the early galaxy , with ages of 1015 gyr ..
Please generate the next two sentences of the article | because low mass subdwarfs have lifetimes far in excess of the age of the galaxy , they are important tracers of galactic chemical history , and are representatives of the first generations of star formation . all of the coolest subdwarfs ( [ fe / h ] @xmath130.3 ) and extreme subdwarfs ( [ fe / h ] @xmath140.5 ; gizis 1997 ) currently known have been identified in optical proper motion surveys , most notably luyten s half - second catalog ( * ? ? ?
* lhs ) and two - tenths catalog @xcite , the apm proper motion survey @xcite , and the galactic plane survey of @xcite . |
6,519 | Suppose that you have an abstract for a scientific paper: we propose a novel approach for pixel classification in hyperspectral images , leveraging on both the spatial and spectral information in the data .
the introduced method relies on a recently proposed framework for learning on distributions by representing them with mean elements in reproducing kernel hilbert spaces ( rkhs ) and formulating a classification algorithm therein .
in particular , we associate each pixel to an empirical distribution of its neighbouring pixels , a judicious representation of which in an rkhs , in conjunction with the spectral information contained in the pixel itself , give a new explicit set of features that can be fed into a suite of standard classification techniques
we opt for a well established framework of support vector machines ( svm ) .
furthermore , the computational complexity is reduced via random fourier features formalism .
we study the consistency and the convergence rates of the proposed method and the experiments demonstrate strong performance on hyperspectral data with gains in comparison to the state - of - the - art results .
+ * keywords : * hyperspectral images , pixelwise classification , kernel methods .
[ theorem]theorem 3 [ theorem]theorem 1 [ theorem]definition [ theorem]proposition [ 1][proof]*#1 . * ' '' '' .
And you have already written the first three sentences of the full article: hyperspectral images consist of very high - dimensional pixel observations that allow reconstruction of the spectral profiles of objects imaged thanks to the acquisition of several hundred narrow spectral bands .
the supervised classification of these pixels is a challenging task , which commonly arises in remote sensing imaging @xcite .
structure of the hyperspectral imagery is seldom studied in a comprehensive manner , with most approaches focusing either on spatial information building on tools available for normal imagery or with a focus on spectral information without a principled way to make use of both ..
Please generate the next two sentences of the article | we propose a novel approach to classification based on kernel embeddings of distributions which utilizes both the spatial and spectral information in the data . while aimed at hyperspectral imaging , the method we propose is general and can be applied to other types of data .
kernel methods and support vector machines have been employed in the hyperspectral imaging in @xcite the pixel data is lifted into a potentially infinite - dimensional feature space , called reproducing kernel hilbert space ( rkhs ) , where linear separating hyperplanes are sought . |
6,520 | Suppose that you have an abstract for a scientific paper: we present a new irac , spitzer irac images of the hh 34 outflow .
these are the first images that detect both the knots along the southern jet and the northern counterjet ( the counterjet knots were only detected previously in a long slit spectrum ) .
this result removes the problem of the apparent coexistence of a large scale symmetry ( at distances of up to @xmath0 pc ) and a complete lack of symmetry close to the source ( at distances of @xmath1 cm ) for this outflow .
we present a quantitative evaluation of the newly found symmetry between the hh 34 jet and counterjet , and show that the observed degree of symmetry implies that the jet production region has a characteristic size @xmath2 au .
this is the strongest constraint yet derived for the size of the region in which hh jets are produced . .
And you have already written the first three sentences of the full article: hh 34 is one of the hh objects in herbig s catalogue ( herbig 1974 ) .
it jumped into the limelight with the paper of reipurth et al .
( 1986 ) , who showed that the hh object ( hh 34s ) had a bow shaped morphology , and a jet - like association of aligned knots ( pointing towards the apex of the bow shock ) ..
Please generate the next two sentences of the article | later observations showed the existence of a northern counterpart to hh 34s ( hh34n ) and of a series of bipolar bow shock pairs at larger distances from the outflow source ( bally & devine 1994 ; eislffel & mundt 1997 ; devine et al .
there is a wealth of observations of this outflow , including images , spectrophotometry , radial velocity and proper motion measurements at optical ( see , e. g. , heathcote & reipurth 1992 ; eislffel & mundt 1992 ; morse et al . |
6,521 | Suppose that you have an abstract for a scientific paper: in this paper a general description for the hubbard model with nearest - neighbor transfer integral @xmath0 and on - site repulsion @xmath1 on a square lattice with @xmath2 sites is introduced .
it refers to three types of elementary objects whose occupancy configurations generate the state representations of the model extended global @xmath3 symmetry recently found in ref . @xcite .
such objects emerge from a suitable electron - rotated - electron unitary transformation .
it is such that rotated - electron single and double occupancy are good quantum numbers for @xmath4 .
the advantage of the description is that it accounts for the new found hidden @xmath5 symmetry in @xmath6/z_2 ^ 2 $ ] beyond the well - known @xmath7/z_2 $ ] model ( partial ) global symmetry .
specifically , the hidden @xmath5 symmetry state representations store full information on the positions of the spins of the rotated - electron singly occupied sites relative to the remaining sites . profiting from that complementary information , for the whole @xmath8 interaction range independent spin state representations
are naturally generated in terms of spin-@xmath9 spinon occupancy configurations in a spin effective lattice .
for all states such an effective lattice has as many sites as spinons .
this allows the extension to intermediate @xmath10 values of the usual large-@xmath10 descriptions of the spin degrees of freedom of the electrons that singly occupy sites , now in terms of the spins of the singly - occupied sites rotated electrons .
the operator description introduced in this paper brings about a more suitable scenario for handling the effects of hole doping . within it
such effects are accounted for in terms of the residual interactions of the elementary objects whose occupancy configurations generate the state representations of the charge hidden @xmath5 symmetry and spin @xmath11 symmetry , respectively .
this problem is investigated elsewhere .
the most interesting physical information revealed by the....
And you have already written the first three sentences of the full article: the hubbard model on a bipartite lattice is the simplest realistic toy model for description of the electronic correlation effects in general many - electron problems with short - range interaction on such a lattice .
the model involves two effective parameters : the in - plane nearest - neighbor transfer integral @xmath0 and the effective on - site repulsion @xmath1 . despite
that it is among the mostly studied models in condensed matter and ultra - cold atom physics , except for the one - dimensional ( 1d ) bipartite lattice @xcite there is no exact solution and few controlled approximations exist for finite @xmath10 values ..
Please generate the next two sentences of the article | one of the few exact results for the model on a general bipartite lattice is that the ground state of the repulsive half - filled hubbard model is for finite number of lattice sites and spin density @xmath12 a spin singlet @xcite .
a method to achieve further useful information about the hubbard model on a bipartite lattice such as the square lattice @xcite , honeycomb lattice @xcite , or cubic lattice @xcite involves the use of suitable systems of ultra - cold fermionic atoms . |
6,522 | Suppose that you have an abstract for a scientific paper: we study the distance - redshift relation in a universe filled with point particles , and discuss what the universe looks like when we make the number of particles @xmath0 very large , while fixing the averaged mass density . using the raychaudhuri equation and a simple analysis of the probability of strong lensing effects ,
we show that the statistical nature of the amplification is independent of @xmath0 , and clarify the appearance of the point particle universe . 0h_0 @ @.2326ex # 1^to-1.4@-@@ + gravinational lens effect + norimasa sugiura , + _ department of physics , kyoto university , sakyo - ku , kyoto 606 - 8502 , japan _ .
And you have already written the first three sentences of the full article: over the last several decades , a great deal of interest has been paid on the ( cumulative ) gravitational lensing effect on distant sources due to inhomogeneites in the matter distribution of the universe .
this problem has been studied using various methods @xcite . in some cases ,
the lens objects can be treated as point particles ..
Please generate the next two sentences of the article | the point particles may be galaxies for cosmological lenses , or stars for microlensing events . while surveying these papers , one question arises to us out of purely theoretical interst : what happens when we bring the number of particles @xmath0 very large , while fixing the mass density ? does it look like a friedman
lematre(fl ) universe , or a completely different universe ? in this article , we discuss what the universe looks like when we take the large @xmath0 limit of a universe filled with point particles by studying the distance - redshift relation . |
6,523 | Suppose that you have an abstract for a scientific paper: the atomic and magnetic structures of ( cu@xmath0)lanb@xmath1o@xmath2 ( @xmath0=cl and br ) are investigated using the density - functional calculations . among several dozens of examined structures , an orthorhombic distorted @xmath3 structure , in which the displacement pattern of @xmath0 halogens resembles the model conjectured previously based on the empirical information is identified as the most stable one .
the displacements of @xmath0 halogens , together with those of cu ions , result in the formation of @xmath0-cu-@xmath0-cu-@xmath0 zigzag chains in the two materials .
detailed analyses of the atomic structures predict that ( cu@xmath0)lanb@xmath1o@xmath2 crystallizes in the space group @xmath4 .
the nearest - neighbor interactions within the zigzag chains are determined to be antiferromagnetic ( afm ) for ( cucl)lanb@xmath1o@xmath2 but ferromagnetic ( fm ) for ( cubr)lanb@xmath1o@xmath2 . on the other hand , the first two neighboring interactions between the cu cations from adjacent chains are found to be afm and fm respectively for both compounds .
the magnitudes of all these in - plane exchange couplings in ( cubr)lanb@xmath1o@xmath2 are evaluated to be about three times those in ( cucl)lanb@xmath1o@xmath2 . in addition , a sizable afm inter - plane interaction is found between the cu ions separated by two nbo@xmath5 octahedra .
the fourth - neighbor interactions are also discussed .
the present study strongly suggests the necessity to go beyond the square @xmath6 model in order to correctly account for the magnetic property of ( cu@xmath7lanb@xmath1o@xmath2 . +
pacs : 71.15.mb , 75.45.+j + .
And you have already written the first three sentences of the full article: low - dimensional quantum spin systems with frustrated interactions have drawn considerable attention for several decades @xcite .
in particular , the square - lattice @xmath8 frustrated heisenberg magnets with first - neighbor exchange constant @xmath9 and second - neighbor constant @xmath10 are increasingly interesting due to their unusual ground states and quantum phenomena @xcite-@xcite . based on the @xmath6 model studies , there exist several phases as a function of @xmath11 . when @xmath9 dominates or @xmath10 is ferromagnetic ( fm ) , the system is either nel antiferromagnetic ( nafm ) or fm depending on the sign of @xmath9 ( refs .
when @xmath10 is antiferromagnetic ( afm ) and dominates , there appears the so - called columnar afm ( cafm ) order @xcite with antiferromagnetically coupled fm chains ..
Please generate the next two sentences of the article | the cafm and fm , or cafm and nafm ordered phases are separated by the intermediate quantum - disordered phases , the nature of which is not yet fully resolved @xcite .
the recent discoveries of quasi - two - dimensional materials are realizations to test the validity of the @xmath6 model . |
6,524 | Suppose that you have an abstract for a scientific paper: we consider the cauchy problem for a @xmath0 strictly hyperbolic system of balance laws @xmath1 each characteristic field being genuinely nonlinear or linearly degenerate . assuming that the @xmath2 norm of @xmath3 and @xmath4 are small enough
, we prove the existence and uniqueness of global entropy solutions of bounded total variation extending the result in @xcite to unbounded ( in @xmath5 ) sources .
furthermore , we apply this result to the fluid flow in a pipe with discontinuous cross sectional area , showing existence and uniqueness of the underlying semigroup . _
2000 mathematics subject classification : _
35l65 , 35l45 , 35l60 .
_ keywords : _ hyperbolic balance laws , unbounded sources , pipes with discontinuous cross sections . .
And you have already written the first three sentences of the full article: the recent literature offers several results on the properties of gas flows on networks . for instance , in @xcite the well posedness is established for the gas flow at a junction of @xmath6 pipes with constant diameters .
the equations governing the gas flow in a pipe with a smooth varying cross section @xmath7 are given by ( see for instance @xcite ) : @xmath8 the well posedness of this system is covered in @xcite where an attractive unified approach to the existence and uniqueness theory for quasilinear strictly hyperbolic systems of balance laws is proposed .
the case of discontinuous cross sections is considered in the literature inserting a junction with suitable coupling conditions at the junction , see for example @xcite ..
Please generate the next two sentences of the article | one way to obtain coupling conditions at the point of discontinuity of the cross section @xmath9 is to take the limit of a sequence of lipschitz continuous cross sections @xmath10 converging to @xmath9 in @xmath11 ( for a different approach see for instance @xcite ) .
unfortunately the results in @xcite require @xmath5 bounds on the source term and well posedness is proved on a domain depending on this @xmath5 bound . since in the previous equations the source term contains the derivative of the cross sectional area one can not hope to take the limit @xmath12 . indeed |
6,525 | Suppose that you have an abstract for a scientific paper: the structure of ne , na , mg , al , si , p and s nuclei near the neutron drip - line region is investigated in the frame - work of relativistic mean field theory and non - relativistic skyrme hartree - fock formalism . the recently discovered nuclei @xmath0 mg and @xmath1al , which are beyond the drip - line predicted by various mass formulae
are located within these models .
we find many largely deformed neutron - rich nuclei , whose structures are analyzed . from the structure anatomy , we find that at large deformation , low @xmath2 orbits of opposite parities ( e.g. @xmath3 and @xmath4 ) occur close to each other in energy . .
And you have already written the first three sentences of the full article: the structure of light nuclei near the neutron drip - line is one of the interesting topic for a good number of exotic phenomena .
nuclei in this region are quite different in collectivity and clustering features than the stable counterpart in the nuclear chart . for example , the neutron magic property is lost for n = 8 in @xmath5be @xcite and n = 20 in @xmath6 mg @xcite .
the unexpectedly large reaction cross - section for @xmath7c gives the indication of neutron halo structure @xcite ..
Please generate the next two sentences of the article | the discovery of large collectivity of @xmath8 mg by iwasaki et al .
@xcite is another example of such exotic properties . |
6,526 | Suppose that you have an abstract for a scientific paper: since their introduction by furstenberg @xcite , joinings have proved a very powerful tool in ergodic theory .
we present here some aspects of the use of joinings in the study of measurable dynamical systems , emphasizing on * the links between the existence of a non trivial common factor and the existence of a joining which is not the product measure , * how joinings can be employed to provide elegant proofs of classical results , * how joinings are involved in important questions of ergodic theory , such as pointwise convergence or rohlin s multiple mixing problem . .
And you have already written the first three sentences of the full article: we call here a _ dynamical system _ any quadruple of the form @xmath0 , where @xmath1 is a lebesgue space ( or equivalently a standard borel space equipped with a probability measure @xmath2 ) and @xmath3 an automorphism of @xmath1 : @xmath3 is a one - to - one measurable transformation of @xmath4 satisfying , for any measurable subset @xmath5 of @xmath4 , @xmath6 throughout this text , we will often use simply the symbol @xmath3 to designate the dynamical system @xmath0 .
we will also often need a second dynamical system @xmath7 , which will stand for the quadruple @xmath8 such dynamical systems , which are the objects of interest in measurable ergodic theory , can be considered from a rather probabilistic viewpoint by studying _
stationary processes_. indeed , any measurable map @xmath9 gives rise to a stationary process @xmath10 defined by @xmath11 ..
Please generate the next two sentences of the article | ( the set @xmath12 in which @xmath13 takes its values could be any standard borel space ; most of the time , it will be a finite or countable alphabet . )
conversely , to any @xmath12-valued stationary process @xmath10 , we can associate in a canonical way a dynamical system : take @xmath14 , the sample space of the whole process , equipped with its borel @xmath15-algebra @xmath16 and the law @xmath17 of the process . since @xmath13 is stationary , @xmath18 is invariant by the shift @xmath19 : @xmath20 where @xmath21 . in the dynamical system @xmath0 , the stationary process @xmath22 |
6,527 | Suppose that you have an abstract for a scientific paper: monte carlo simulations of the two - dimensional @xmath0 model are performed in a square geometry with free and mixed fixed - free boundary conditions . using a schwarz - christoffel conformal mapping
, we deduce the exponent @xmath1 of the order parameter correlation function and its surface equivalent @xmath2 at the kosterlitz - thouless transition temperature .
the well known value @xmath3 is easily recovered even with systems of relatively small sizes , since the shape effects are encoded in the conformal mapping .
the exponent associated to the surface correlations is similarly obtained @xmath4 .
epsf # 1#2#3#4#5#1 , # 2 * # 3 * ( # 5 ) # 4 .
And you have already written the first three sentences of the full article: 2 the two - dimensional classical @xmath0 model exhibits a non standard behaviour . long - range order of spins with continuous symmetries is indeed forbidden according to the mermin - wagner theorem @xcite , and thus there is no spontaneous magnetisation at finite temperature .
the transition is governed by unbinding of topological defects .
the low - temperature regime was investigated by berezinskii @xcite and the mechanism of unbinding of vortices was studied by kosterlitz and thouless @xcite using renormalization group methods . for reviews , see e.g. refs ..
Please generate the next two sentences of the article | @xcite .
the notations are specified below : we consider a @xmath5 @xmath0-model on a square lattice with two - components spin variables @xmath6 located at the sites @xmath7 of a lattice @xmath8 of linear extent @xmath9 . |
6,528 | Suppose that you have an abstract for a scientific paper: we propose an inverse scattering scheme of recovering a polyhedral obstacle in @xmath0 , @xmath1 , by only a few high - frequency acoustic backscattering measurements .
the obstacle could be sound - soft or sound - hard .
it is shown that the modulus of the far - field pattern in the backscattering aperture possesses a certain local maximum behavior , from which one can determine the exterior normal directions of the front sides / faces . then by using the phaseless backscattering data corresponding to a few incident plane waves with suitably chosen incident directions , one can determine the exterior unit normal vector of each side / face of the obstacle . after the determination of the exterior unit normals , the recovery is reduced to a finite - dimensional problem of determining a location point of the obstacle and the distance of each side
/ face away from the location point . for the latter reconstruction , we need make use of the far - field data with phases .
numerical experiments are also presented to illustrate the effectiveness of the proposed scheme . * keywords*. inverse scattering , polyhedral obstacle , backscattering , phaseless * mathematics subject classification ( 2010 ) * : 78a46 , 35q60 . .
And you have already written the first three sentences of the full article: this work concerns the inverse scattering problem of recovering an impenetrable obstacle by the corresponding acoustic wave detection .
the problem has its physical origin in radar / sonar , geophical exploration , non - destructive testing and medical imaging ( cf .
@xcite ) . let @xmath2 be a bounded lipschitz domain in @xmath0 , @xmath1 , such that @xmath3 is connected ..
Please generate the next two sentences of the article | @xmath2 represents an impenetrable obstacle located in the space and it is assumed to be unknown / inaccessible . in order to identify @xmath2 , one sends a time - harmonic detecting plane wave of the form @xmath4 which is an entire solution to the helmholtz equation @xmath5 in @xmath0 .
the presence of the obstacle @xmath2 interrupts the propagation of the plane wave , leading to the so - called scattered wave field @xmath6 , which exists only in the exterior of the obstacle . |
6,529 | Suppose that you have an abstract for a scientific paper: we stress that the observed pattern of flavor mixings can be partly interpreted by the quark mass hierarchy without the assumption of specific quark mass matrices .
the quantitatively proper relations between the kobayashi - maskawa matrix elements and quark mass ratios , such as @xmath0 \ ; , \ ] ] are obtainable from a simple _ ansatz _ of flavor permutation symmetry breaking at the weak scale .
we prescribe the same _ ansatz _ at the supersymmetric grand unified theory scale , and find that its all low - energy consequences on flavor mixings and @xmath1 violation are in good agreement with current experimental data .
= 17.1 cm = 24.71 cm = -15.mm = -11 mm plus 1pt minus 1pt * dpnu-96 - 39 + august 1996 * * implications of the quark mass hierarchy on flavor mixings * zhi - zhong xing _ department of physics , nagoya university , chikusa - ku , nagoya 464 - 01 , japan _
pacs number(s ) : 12.15.ff , 11.30.hv , 11.30.pb , 12.10.dm .
And you have already written the first three sentences of the full article: the discovery of the top quark at fermilab fulfilled the three - family quark picture in the standard electroweak model .
up to now , some knowledge on the mass spectra of @xmath2 and @xmath3 quarks has been accumulated through both experimental and theoretical ( or phenomenological ) attempts @xcite .
the ratios of quark mass eigenvalues are obtainable after one renormalizes them to a common reference scale , e.g. , @xmath4 gev or @xmath5 ..
Please generate the next two sentences of the article | there exists a clear mass hierarchy in each quark sector : @xmath6 in comparison , the masses of three charged leptons manifest a similar hierarchical pattern @xcite .
quark mass eigenstates are related to quark weak ( flavor ) eigenstates by the kobayashi - maskawa ( km ) matrix @xmath7 @xcite , which provides a quite natural description of flavor mixings and @xmath1 violation in the standard model . to date , many experimental constraints on the magnitudes of the km matrix elements have been achieved . |
6,530 | Suppose that you have an abstract for a scientific paper: the indefinite increase of temperature predicted by the solar wind expansion in the direction parallel to the interplanetary magnetic field is already notorious for not being confirmed by the observations . in hot and
dilute plasmas from space particle - particle collisions are not efficient in constraining large deviations from isotropy , but the resulting firehose instability provides in this case plausible limitations for the temperature anisotropy of the thermal ( core ) populations of both the electron and proton species .
the present paper takes into discussion the suprathermal ( halo ) electrons , which are ubiquitous in the solar wind .
less dense but hotter than the core , suprathermals may be highly anisotropic and susceptible to the firehose instability .
the main features of the instability are here derived from a first - order theory for conditions specific to the suprathermal electrons in the solar wind and terrestrial magnetospheres . unveiled here
, new regimes of the electron firehose instability may be exclusively controlled by the suprathermals .
the instability is found to be systematically stimulated by the suprathermal electrons , with thresholds that approach the limits of the temperature anisotropy reported by the observations .
these results represent new and valuable evidences for the implication of the firehose instability in the relaxation of the temperature anisotropy in space plasmas .
[ firstpage ] sun : solar wind electrons temperature anisotropy electromagnetic instabilities methods : analytical ; observational .
And you have already written the first three sentences of the full article: in collision - poor plasmas from space large deviations from thermodynamic equilibrium can not be relaxed by the particle - particle ( coulomb ) collisions , but can presumably be constrained by the resulting kinetic instabilities .
thus , if the solar wind expands adiabatically the cgl invariants conserve @xcite leading to an indefinite increase of temperature in the direction parallel to the inteplanetary magnetic field , i.e. , @xmath0 .
however , the in - situ measurements do not confirm such an increase of their parallel temperature with heliocentric distance , but indicate bounds of the temperature anisotropy of plasma particles @xcite . because collisions are not efficient , the most invoked mechanism that can limit the increase of parallel temperature is the firehose instability @xcite ..
Please generate the next two sentences of the article | the firehose instability driven by the anisotropic electrons with @xmath1 , also known as the electron firehose instability ( efhi ) , is particularly important as it can mediate a resonant transfer of ( free ) energy from electrons to protons @xcite .
this energy transfer from small to large scales is facilitated by the quasi - parallel efh modes , which are left - handed ( lh ) circularly polarized and have characteristic frequencies and growth rates in the range of the proton cyclotron frequency . |
6,531 | Suppose that you have an abstract for a scientific paper: the planned laser interferometer space antenna ( lisa ) is expected to detect gravitational wave signals from @xmath0 extreme - mass - ratio inspirals ( emris ) of stellar - mass compact objects into massive black holes .
the long duration and large parameter space of emri signals makes data analysis for these signals a challenging problem .
one approach to emri data analysis is to use time - frequency methods .
this consists of two steps : ( i ) searching for tracks from emri sources in a time - frequency spectrogram , and ( ii ) extracting parameter estimates from the tracks . in this paper
we discuss the results of applying these techniques to the latest round of the mock lisa data challenge , round 1b .
this analysis included three new techniques not used in previous analyses : ( i ) a new chirp - based algorithm for track search for track detection ; ( ii ) estimation of the inclination of the source to the line of sight ; ( iii ) a metropolis - hastings monte carlo over the parameter space in order to find the best fit to the tracks . .
And you have already written the first three sentences of the full article: the extreme - mass - ratio inspirals ( emris ) of compact objects ( white dwarfs , neutron stars or stellar - mass black holes ) with mass @xmath1 into massive black holes with mass @xmath2 can serve as excellent probes of strong - field general relativity ( see @xcite and references therein for details ) .
the detection of gravitational waves from emris is one of the main targets for the planned gravitational - wave detector lisa ( laser interferometer space antenna ) @xcite .
astrophysical uncertainties mean that rate predictions are somewhat uncertain , but tens to thousands of emris may be observed over the duration of the lisa mission @xcite ..
Please generate the next two sentences of the article | detection of emris is not an easy task , however .
the expected gravitational wave ( gw ) signals from emris will be buried in instrumental noise and a foreground of galactic white - dwarf binaries . |
6,532 | Suppose that you have an abstract for a scientific paper: to examine a recently proposed hypothesis that silicon nanoparticles are the source of extended red emission ( ere ) in the interstellar medium , we performed a detailed modeling of the mean galactic extinction in the presence of silicon nanoparticles .
for this goal we used the appropriate optical constants of nanosized si , essentially different from those of bulk si due to quantum confinement .
it was found that a dust mixture of silicon nanoparticles , bare graphite grains , silicate core - organic refractory mantle grains and three - layer silicate - water ice - organic refractory grains works well in explaining the extinction and , in addition , results in the acceptable fractions of uv / visible photons absorbed by silicon nanoparticles : 0.0710.081 . since these fractions barely agree with the fraction of uv / visible photons needed to excite the observed ere , we conclude that the intrinsic photon conversion efficiency of the photoluminescence by silicon nanoparticles must be near 100% , if they are the source of the ere . .
And you have already written the first three sentences of the full article: recently , extended red emission ( ere ) has been detected in the diffuse galactic background and in high - galactic latitude cirrus clouds with surprisingly high intensities ( gordon , witt , & friedmann 1998 ; @xcite ) .
this emission , appearing in the 500800 nm spectral range as an unstructured broad feature , is attributed to photoluminescence by some component of interstellar grains .
the correlation between the ere r - band intensity and -column density of ( [email protected])10@xmath1 ergs s@xmath2 @xmath2 sr@xmath2 h atom@xmath2 ( @xcite ) implies that , at a minimum , ( 10@xmath03)% of all uv / visible photons in the diffuse interstellar radiation field are absorbed by the ere producing grains , if each absorption results in the emission of an ere photon ..
Please generate the next two sentences of the article | this requires that the ere - grains make a significant contribution to the interstellar extinction in the uv / visible range , which further implies that they must consist of cosmically abundant elemental constituents in a form that permits extremely high efficiency photoluminescence . after a review of possible ere - grain candidates , witt , gordon , & furton ( 1998 ) and ledoux et al .
( 1998 ) independently proposed that silicon nanoparticles ( snps ) might be the source of ere in the interstellar medium in as far as they produce photoluminescence spectra closely matching those observed in ere sources and match the constraints regarding the required quantum efficiency and elemental abundance . |
6,533 | Suppose that you have an abstract for a scientific paper: we present a quantitative morphological analysis of 187 galaxies in a region covering the central 0.28 square degrees of the coma cluster . structural parameters from the best - fitting srsic @xmath0 bulge plus , where appropriate , exponential disc model , are tabulated here .
this sample is complete down to a magnitude of @xmath1=17 mag . by examining the edwards et al .
( 2002 ) compilation of galaxy redshifts in the direction of coma , we find that 163 of the 187 galaxies are coma cluster members , and the rest are foreground and background objects .
for the coma cluster members , we have studied differences in the structural and kinematic properties between early- and late - type galaxies , and between the dwarf and giant galaxies .
analysis of the elliptical galaxies reveals correlations among the structural parameters similar to those previously found in the virgo and fornax clusters . comparing the structural properties of the coma cluster disc galaxies with disc galaxies in the field , we find evidence for an environmental dependence : the scale lengths of the disc galaxies in coma are 30% smaller .
a kinematical analysis shows marginal differences between the velocity distributions of ellipticals with srsic index @xmath2 ( dwarfs ) and those with @xmath3 ( giants ) ; the dwarf galaxies having a greater ( cluster ) velocity dispersion .
finally , our analysis of all 421 background galaxies in the catalog of edwards et al . reveals a non - uniform distribution in redshift with contrasts in density @xmath4 , characterized by a void extending from @xmath5 to @xmath6 km s@xmath7 , and two dense and extended structures centred at @xmath6 and @xmath8 km s@xmath7 . .
And you have already written the first three sentences of the full article: the properties of galaxies can vary depending on whether they reside in dense galaxy clusters or the field .
the most remarkable example of this is the morphology density relation ( dressler 1980 ) in which the proportion of elliptical galaxies increases toward the cores of rich clusters .
the morphology of galaxies in clusters has been based , mostly , on a visual classification scheme ..
Please generate the next two sentences of the article | however , visual classification is only the first step in the characterization and description of galaxies .
it is necessary to conduct a quantitative morphological analysis of galaxies in clusters to answer basic questions like : are the properties of spiral galaxy discs , such as their scale - lengths , affected by the enviroment ? |
6,534 | Suppose that you have an abstract for a scientific paper: the ckm matrix describing quark mixing with three generations can be parameterized by three mixing angles and one cp violating phase . in most of the parameterizations ,
the cp violating phase chosen is not a directly measurable quantity and is parametrization dependent . in this work ,
we propose to use experimentally measurable cp violating quantities , @xmath0 , @xmath1 or @xmath2 in the unitarity triangle as the phase in the ckm matrix , and construct explicit @xmath0 , @xmath1 and @xmath2 parameterizations .
approximate wolfenstein - like expressions are also suggested . .
And you have already written the first three sentences of the full article: the mixing between different quarks is described by an unitary matrix in the charged current interaction of w - boson in the mass eigen - state of quarks , the cabibbo @xcite - kobayashi - maskawa @xcite(ckm ) matrix @xmath3 , defined by @xmath4 where @xmath5 , @xmath6 . for n - generations
, @xmath7 is an @xmath8 unitary matrix . with three generations , one can write @xmath9 a commonly used parametrization for mixing matrix with three generations of quark is given by @xcite , @xmath10 where @xmath11 and @xmath12 with @xmath13 being angles rotating in flavor space and @xmath14 is the cp violating phase .
we refer this as the pdg parametrization ..
Please generate the next two sentences of the article | there are a lot of experimental data on the mixing pattern of quarks .
fitting available data , the mixing angles and cp violating phase are determined to be @xcite @xmath15 from the above , we obtain the magnitude of the matrix elements as @xmath16 the angles can be viewed as rotations in flavor spaces . but both the angles and the phase in the ckm matrix are not directly measurable quantities . |
6,535 | Suppose that you have an abstract for a scientific paper: supersinglets @xmath0 are states of total spin zero of @xmath1 particles of @xmath2 levels .
some applications of the @xmath3 and @xmath4 states are described .
the @xmath3 states can be used to solve three problems which have no classical solution : the `` @xmath1 strangers , '' `` secret sharing , '' and `` liar detection '' problems . the @xmath4 ( with @xmath1 even )
states can be used to encode qubits in decoherence - free subspaces . .
And you have already written the first three sentences of the full article: quantum information has changed not only the way we understand quantum mechanics ; it has also changed the way we use quantum mechanics in our dealings with the real world . for years
, the research on quantum mechanics has focused on pointing out how different quantum mechanics was from classical physics .
the next step has been to realize that quantum mechanics can be used to solve problems unsolvable by any other means . however , although quantum states are powerful tools , they are very fragile for most real - life applications . therefore , the challenge is twofold : on one hand , to find out new applications .
Please generate the next two sentences of the article | problems without classical solutions that can be solved with the aid of quantum states ; on the other , to find out how to protect quantum states methods that allow us to use quantum states for practical purposes . in this paper
i review some results regarding a particular family of quantum states . |
6,536 | Suppose that you have an abstract for a scientific paper: electron scattering off an anderson impurity immersed in the bulk of a 3d topological insulator is studied in the strong coupling regime , where the temperature @xmath0 is lower than the kondo temperature @xmath1 .
the system displays either a self - screened kondo effect , or a kondo effect with so(3 ) or so(4 ) dynamical symmetries .
low temperature kondo scattering for systems with so(3 ) symmetry displays the behavior of a singular fermi liquid , an elusive property that so far has been observed only in tunneling experiments .
this is demonstrated through the singular behavior as @xmath2 of the specific heat , magnetic susceptibility and impurity resistivity , that are calculated using well known ( slightly adapted ) conformal field theory techniques .
quite generally , the low temperature dependence of some of these observables displays a remarkable distinction between the so(n=3,4 ) kondo effect , compared with the standard su(2 ) one . .
And you have already written the first three sentences of the full article: in this work we continue our study of a system composed of an anderson impurity @xmath3 immersed in a 3d topological insulator ( 3dti ) with an inverted - mexican - hat " band dispersion around the @xmath4-point @xcite . for
the sake of self - consistency let us very briefly recapitulate the peculiar feature of the pertinent system : due to the special band structure , the ensuing kondo effect ( ke ) is profoundly distinct from its metallic analog in normal metals , because in addition to the original anderson impurity @xmath3 , there is an in - gap bound state ( henceforth denoted as an @xmath5 impurity ) , that is formed as a result of potential scattering@xcite .
the @xmath3 and @xmath5 impurities form a composite quantum impurity " ( cqi ) that turns the pertinent kondo physics much richer ..
Please generate the next two sentences of the article | the reason for that is as follows : when isolated , the cqi can host two electrons that are found in singlet or triplet states with corresponding energies @xmath6 and @xmath7 . due to hybridization of the localized electrons in the cqi with the band electrons ,
the levels @xmath6 and @xmath7 are renormalized with decreasing bandwidth _ albeit with different rates _ @xcite . as a result , |
6,537 | Suppose that you have an abstract for a scientific paper: in this paper we investigate a solution of the dirac equation for a spin-@xmath0 particle in a scalar potential well with full spherical symmetry .
the energy eigenvalues for the quark particle in @xmath1 states ( with @xmath2 ) and @xmath3 states ( with @xmath4 ) are calculated .
we also study the continuous dirac wave function for a quark in such a potential , which is not necessarily infinite .
our results , at infinite limit , are in good agreement with the mit bag model .
we make some remarks about the sharpness value of the wave function on the wall .
this model , for finite values of potential , also could serve as an effective model for the nucleus where @xmath5 is the effective single particle potential . : 12.39.-x , 03.65.pm .
And you have already written the first three sentences of the full article: in 1964 gell - mann and zweig independently proposed a quark model in which all known hadrons were described as bound states of only three fundamental particles @xcite .
each of these spin-1/2 particles , which gell - mann named quarks , has their corresponding antiparticles . however , a precise mechanism of the bound states and quark confinement has still not been established .
gell - mann s model requires that the valid quark states should be colorless and so a free quark is not allowed . since a free single quark has not yet been observed , the model assumes that quarks appear as bound states ..
Please generate the next two sentences of the article | the baryons are bound states of three quarks ( or antiquarks ) and the mesons are made up of one quark and one antiquark . as a model , to describe this behavior , one can think of a hadron as a cavity in which the quark wave function is confined , and the cavity is surrounded by the qcd vacuum @xcite . therefore in a simple model quarks confined in a sphere with radius @xmath6 and the dirac equation
sould be solved within this sphere . from this point of view |
6,538 | Suppose that you have an abstract for a scientific paper: two - level system fluctuators in superconducting devices have demonstrated coherent coupling with superconducting qubits . here , we show that universal quantum logic gates can be realized in these two - level systems solely by tuning a superconducting resonator in which they are imbedded .
because of the large energy separation between the fluctuators , conventional gate schemes in the cavity qed approach that are widely used for solid - state qubits can not be directly applied to the fluctuators .
we study a scheme to perform the gate operations by exploiting the controllability of the superconducting resonator with realistic parameters .
numerical simulation that takes into account the decay of the resonator mode shows that the quantum logic gates can be realized with high fidelity at moderate resonator decay rate .
the quantum logic gates can also be realized between fluctuators inside different josephson junctions that are connected by a superconducting loop .
our scheme can be applied to explore the coupling between two - level system fluctuators and superconducting resonators as well as the coherent properties of the fluctuators . .
And you have already written the first three sentences of the full article: spurious two - level system ( tls ) fluctuators are considered a serious source of low - frequency noise in superconducting qubits @xcite , and the characterization of these fluctuators in solid - state devices has a long history @xcite .
most recently , coherent coupling between tls fluctuators and a superconducting phase qubit was observed via the novel energy splittings in spectroscopic measurements @xcite .
it was shown that the tls fluctuators have much longer decoherence times than the superconducting qubits , raising the possibility of realizing quantum manipulation on these fluctuators @xcite ..
Please generate the next two sentences of the article | the key question in manipulating the tls fluctuators is how to implement the required coherent manipulation and readout .
located sparsely inside solid - state devices , the fluctuators usually do not interact with each other , and their states are hard to control . |
6,539 | Suppose that you have an abstract for a scientific paper: we present deep , high angular resolution near infrared images of the obscured galactic giant h ii region ngc3576 .
our images reach objects to @xmath0 .
we collected high signal to noise @xmath1band spectra of eight of the brightest objects , some of which are affected by excess emission and some which follow a normal interstellar reddening law .
none of them displayed photospheric features typical of massive ob type stars .
this indicates that they are still enshrouded in their natal cocoons .
the @xmath1band brightest source ( ngc3576#48 ) shows co 2.3 @xmath2 m bandhead emission , and three others have the same co feature in absorption .
three sources display spatially unresolved @xmath3 emission , suggesting dense shocked regions close to the stars .
we conclude that the remarkable object ngc3576#48 is an early b / late o star surrounded by a thick circumstellar disk / envelope .
a number of other relatively bright cluster members also display excess emission in the @xmath1band , indicative of reprocessing disks around massive stars ( ysos ) .
such emission appears common in other galactic giant h ii regions we have surveyed .
the imf slope of the cluster , @xmath4 , is consistent with salpeter s distribution and similar to what has been observed in the magellanic cloud clusters and in the periphery of our galaxy . .
And you have already written the first three sentences of the full article: massive stars have a strong impact on the evolution of galaxies .
o type stars and their descendants , the wolf rayet stars , are the main source of uv photons , mass , energy and momentum to the interstellar medium .
they play the main role in the ionization of the interstellar medium and dust heating ..
Please generate the next two sentences of the article | the milky way is the best place to access , simultaneously , massive stellar populations and their impact on the surrounding gas and dust .
the sun s position in the galactic plane , however , produces a heavy obscuration in the optical window ( @xmath5 mag ) toward the inner galaxy , where massive star formation activity is the greatest . |
6,540 | Suppose that you have an abstract for a scientific paper: we compare the stellar populations and complex neutral gas dynamics of the m81 group dirr galaxy ddo165 using data from the _ hst _ and the _ vla_. paper i identified two kinematically distinct h i components , multiple localized high velocity gas features , and eight h i holes and shells ( the largest of which spans @[email protected] kpc ) .
using the spatial and temporal information from the stellar populations in ddo165 , we compare the patterns of star formation over the past 500 myr with the h i dynamics .
we extract localized star formation histories within 6 of the 8 h i holes identified in paper i , as well as 23 other regions that sample a range of stellar densities and neutral gas properties . from population synthesis modeling , we derive the energy outputs ( from stellar winds and supernovae ) of the stellar populations within these regions over the last 100 myr , and compare with refined estimates of the energies required to create the h i holes . in all cases , we find that `` feedback '' is energetically capable of creating the observed structures in the ism
. numerous regions with significant energy inputs from feedback lack coherent h i structures but show prominent localized high velocity gas features ; this feedback signature is a natural product of temporally and spatially distributed star formation . in ddo165 , the extended period of heightened star formation activity ( lasting more than 1 gyr ) is energetically capable of creating the observed holes and high velocity gas features in the neutral ism . .
And you have already written the first three sentences of the full article: as stars evolve , the energies from stellar winds and supernova ( sn ) explosions ( hereafter collectively referred to as `` feedback '' ) are released into the surrounding interstellar material .
the physics of this interaction is complex , with dependencies on ( at least ) the local neutral and molecular gas density and porosity , the local and total gravitational potential depth and shape , the intensity and duration of massive star formation ( sf ) , and the metal content of the parent cloud . in a simplistic scenario , a single massive star forms and evolves , unleashing a characteristic energy of @xmath010@xmath2 erg per sn event @xcite .
a fraction of this energy is converted into bulk motion of the surrounding material ..
Please generate the next two sentences of the article | this energy can be compared with the amount of energy required to move that same gas mass a certain distance within a given gravitational potential .
if the feedback energy exceeds the requisite formation energy , then stellar evolution is capable of creating structures in the interstellar medium ( ism ) . scaling this simple single - star scenario |
6,541 | Suppose that you have an abstract for a scientific paper: we show that standard solar models are in good agreement with the helioseismologically determined sound speed and density as a function of solar radius , the depth of the convective zone , and the surface helium abundance , as long as those models do not incorporate the most recent heavy element abundance determinations .
however , sophisticated new analyses of the solar atmosphere infer lower abundances of the lighter metals ( like c , n , o , ne , and ar ) than the previously widely used surface abundances .
we show that solar models that include the lower heavy element abundances disagree with the solar profiles of sound speed and density as well as the depth of the convective zone and the helium abundance . the disagreements for models with the new abundances range from factors of several to many times the quoted uncertainties in the helioseismological measurements .
the disagreements are at temperatures that are too low to affect significantly solar neutrino emission .
if errors in the calculated opal opacities are solely responsible for the disagreements , then the corrections in the opacity must extend from @xmath0k ( @xmath1 ) to @xmath2k ( @xmath3 ) , with opacity increases of order 10% . .
And you have already written the first three sentences of the full article: why are precision tests of solar models important ? the sun is a laboratory in which the predictions of stellar evolution theory can be compared with uniquely accurate and detailed measurements .
stellar evolution calculations are used throughout astronomy to classify , date , and interpret the spectra of individual stars and of galaxies .
comparisons , discussed in this paper , between helioseismological measurements and solar model calculations suggest that at least one of the ingredients of stellar evolution calculations is not known as precisely as previously believed ..
Please generate the next two sentences of the article | we shall see that there are reasons for questioning the accuracy of the most sophisticated and detailed determinations of stellar abundances , the recent measurements of the solar heavy element abundances .
alternatively , unexpectedly large changes could be required in the radiative opacity . |
6,542 | Suppose that you have an abstract for a scientific paper: the dim isolated neutron stars ( xdins ) have periods in the same range as the anomalous x - ray pulsars ( axps ) and the soft gamma - ray repeaters ( sgrs ) .
we apply the fallback disk model , which explains the period clustering and other properties of axp / sgrs , to the six xdins with measured periods and period derivatives .
present properties of xdins are obtained in evolutionary scenarios with surface dipole magnetic fields @xmath0 g. the xdins have gone through an accretion epoch with rapid spin - down earlier , and have emerged in their current state , with the x - ray luminosity provided by neutron star cooling and no longer by accretion .
our results indicate that the known xdins are not likely to be active radio pulsars , as the low @xmath1 , together with their long periods place these sources clearly below the death valley .
0minp_0 , 18sgr 0418 + 5729 42axp 0142 + 61 [ firstpage ] pulsars : individual ( axps ) stars : neutron x - rays : bursts accretion , accretion disks .
And you have already written the first three sentences of the full article: what are the physical conditions leading to formation of different populations of young , isolated ( single ) neutron stars , namely anomalous x - ray pulsars ( axps ) , soft gamma - ray repeaters ( sgrs ) , dim isolated neutron stars ( xdins ) , central compact objects ( ccos ) and rotating radio transients ( rrats ) ?
all these systems involve a single , young or middle - aged neutron star ( see mereghetti 2011a for a recent review of isolated neutron stars ) . despite striking differences , like energetic soft gamma bursts peculiar to sgrs and axps , there are also striking similarities , like the periods of axp / sgrs and xdins being clustered in the same range ( @xmath2 s ) . considering the estimated birth rates of these objects together with the galactic supernova rate ,
it is likely that there are evolutionary connections between some of these populations ( keane & kramer 2008 ) ..
Please generate the next two sentences of the article | recent efforts concentrate on the unification of the long - term x - ray luminosity and the rotational evolution of these neutron star systems in a single picture . with the assumption that these sources are evolving in vacuum with dipole torques ,
their surface dipole fields , b , inferred from the dipole torque formula range from @xmath3 g for ccos to more than @xmath4 g for axp / sgrs . in this picture , the diversity of evolutionary paths is attributed to the differences in the initial dipole and the crustal toroidal fields of the sources ( kaspi 2010 ) . |
6,543 | Suppose that you have an abstract for a scientific paper: we consider the incremental computation of minimal unsatisfiable cores ( mucs ) of qbfs . to this end , we equipped our incremental qbf solver depqbf with a novel api to allow for incremental solving based on clause groups .
a clause group is a set of clauses which is incrementally added to or removed from a previously solved qbf .
our implementation of the novel api is related to incremental sat solving based on selector variables and assumptions .
however , the api entirely hides selector variables and assumptions from the user , which facilitates the integration of depqbf in other tools .
we present implementation details and , for the first time , report on experiments related to the computation of mucs of qbfs using depqbf s novel clause group api . .
And you have already written the first three sentences of the full article: let @xmath0 be a qbf in _ prenex cnf ( pcnf ) _ where @xmath1 with @xmath2 is the prefix containing quantified propositional variables @xmath3 and @xmath4 is a quantifier - free cnf . given a pcnf @xmath0 , an _
unsatisfiable core ( uc ) _ of @xmath5 is an unsatisfiable pcnf @xmath6 such that @xmath7 and @xmath8 .
the prefix @xmath9 is obtained from @xmath10 by deleting the quantified variables which do not occur in @xmath11 ..
Please generate the next two sentences of the article | a _ _ minimal unsatisfiable core ( muc ) _ _ of @xmath5 is an unsatisfiable core @xmath12 of @xmath5 where , for every @xmath13 , the pcnf @xmath14 is satisfiable . _
incremental solving _ is crucial for the computation of mucs in the context of propositional logic ( sat ) , e.g. @xcite . |
6,544 | Suppose that you have an abstract for a scientific paper: we explain what features of string theory can be tested at the lhc .
we review the present bounds on the string mass and on extra gauge bosons as well as the prospects for the upcoming experiments . .
And you have already written the first three sentences of the full article: after the discovery of the higgs - like particle with mass around 125 gev by the atlas and cms collaborations at cern , still many convincing reasons exist to believe that the resolution of the hierarchy problem lies in new physics around the tev mass scale .
in fact , there are at least two , not necessarily mutually exclusive scenarios , offered as solutions of the hierarchy problem : low energy supersymmetry at around 1 tev . large extra dimensions and a low scale for quantum gravity at around 1 tev @xcite .
here we discuss some rather generic features about string and brane compactifications , which are relevant for the search of new physics at the lhc and which might provide concrete and fundamental realizations of the general scenarios mentioned above . in fact , the relevance of strings for the experiments at the lhc is closely linked to the question what is the typical scale of string theory , called the string mass @xmath0 ..
Please generate the next two sentences of the article | a priori , considering d - brane compactifications with open strings on branes , the string scale is a free parameter , not being determined by the standard model gauge interactions .
hence in this class of models @xmath0 can be in principle everywhere between the weak scale and the planck scale . |
6,545 | Suppose that you have an abstract for a scientific paper: electrons in a multielectron bubble in helium form a spherical , two - dimensional system coupled to the ripplons at the bubble surface . the electron - ripplon coupling ,
known to lead to polaronic effects , is shown to give rise also to cooper pairing . a bardeen - cooper - schrieffer ( bcs )
hamiltonian arises from the analysis of the electron - ripplon interaction in the bubble , and values of the coupling strength are obtained for different bubble configurations .
the bcs hamiltonian on the sphere is analysed using the richardson method .
we find that although the typical ripplon energies are smaller than the splitting between electronic levels , a redistribution of the electron density over the electronic levels is energetically favourable as pairing correlations can be enhanced .
the density of states of the system with pairing correlations is derived .
no gap is present , but the density of states reveals a strong step - like increase at the pair - breaking energy .
this feature of the density of states should enable the unambiguous detection of the proposed state with pairing correlations in the bubble , through either capacitance spectroscopy or tunneling experiments , and allow to map out the phase diagram of the electronic system in the bubble . .
And you have already written the first three sentences of the full article: spherical shells of charge carriers appear in a multitude of systems , such as multielectron bubbles in liquid helium @xcite , metal nanoshells coating a non - conducting nanograin @xcite , carbon cages and fullerenes .
although the properties of flat two - dimensional systems have been widely studied , revealing new physics , the properties of _ spherical _ two - dimensional systems are much less well - studied . in this paper
, we investigate the possibility and the properties of cooper pairing in the spherical geometry ..
Please generate the next two sentences of the article | the particular spherical two - dimensional system that we focus on is the multielectron bubble in liquid helium .
when a flat surface of helium is charged with electrons above a critical charge density , an instability occurs with the surface opening to subsume a large number of electrons forming a bubble . |
6,546 | Suppose that you have an abstract for a scientific paper: this paper analyzes libor interest rates for seven different maturities and referred to operations in british pounds , euro , swiss francs and japanese yen , during the period years 2001 to 2015 .
the analysis is performed by means of two quantifiers derived from information theory : the permutation shannon entropy and the permutation fisher information measure .
an anomalous behavior in the libor is detected in all currencies except euro during the years 20062012 .
the stochastic switch is more severe in 1 , 2 and 3 months maturities .
given the special mechanism of libor setting , we conjecture that the behavior could have been produced by the manipulation that was uncovered by financial authorities .
we argue that our methodology is pertinent as a market overseeing instrument . *
pacs : * 89.65.gh econophysics ; 74.40.de noise and chaos .
And you have already written the first three sentences of the full article: since the seminal work of bachelier @xcite , prices in a competitive market have been modeled as a memoryless stochastic process .
in fact , according to the efficient market hypothesis ( emh ) , prices fully reflect all available information @xcite .
this property was duly proved by samuelson @xcite ..
Please generate the next two sentences of the article | it is known that informational efficiency can vary over time .
this may be due to several reasons . |
6,547 | Suppose that you have an abstract for a scientific paper: in the case of two generation neutrinos , the energy - scale dependence of the lepton - flavor mixing matrix with majorana phase can be governed by only one parameter @xmath0 , which is the ratio between the diagonal elements of neutrino mass matrix . by using this parameter @xmath0
, we derive the analytic solutions to the renormalization group equations of the physical parameters , which are the mixing angle , majorana phase , and the ratio of the mass - squared difference to the mass squared of the heaviest neutrino .
the energy - scale dependence of the majorana phase is clarified by using these analytic solutions .
the instability of the majorana phase causes in the same parameter region in which the mixing angle is unstable against quantum corrections .
hep - ph/9911481 + dpnu-99 - 31 + kek - th-662 .
And you have already written the first three sentences of the full article: recent neutrino oscillation experiments suggest the strong evidences of the tiny neutrino masses and the lepton flavor mixing @xcite-@xcite .
studies of the lepton flavor mixing matrix , which we call maki - nakagawa - sakata ( mns ) matrix @xcite , will give us important cues of the physics beyond the standard model .
one of the most important studies of the lepton - flavor mixing is the analysis of quantum corrections of the mns matrix @[email protected] , the majorana phase plays the crucial role for stabilities of the mixing angle against quantum corrections @xcite . in this paper.
Please generate the next two sentences of the article | we analyze the energy - scale dependence of the mns matrix with the physical majorana phase in two generation neutrinos . according to the lsnd experiment@xcite
, the scenario of two heavy degenerate neutrinos can be realistic , where we can neglect the first generation effects in the energy - scale dependence of the mns matrix . |
6,548 | Suppose that you have an abstract for a scientific paper: diamond gave compact criteria in fuzzy numbers space endowed with @xmath0 metric and compact criteria in the space of fuzzy star - shaped numbers with respect to the origin endowed with @xmath0 metric .
however , these compact criteria are wrong . wu and zhao proposed right characterizations in these two spaces . based on this result , zhao and wu further gave compact criteria in the space of fuzzy star - shaped numbers with @xmath0 metric .
however , compare the existing compactness characterizations of fuzzy sets spaces endowed with @xmath0 metric with arzel
ascoli theorem , it finds that the latter gives the compact criteria by characterizing the totally bounded sets while the former does not seem to characterize the totally bounded sets . since , in metric spaces , totally boundedness is a key feature of compactness .
we present characterizations of totally bounded sets , relatively compact sets and compact sets in the fuzzy sets spaces @xmath1 and @xmath2 equipped with @xmath0 metric , where @xmath1 and @xmath2 are two kinds of fuzzy sets on @xmath3 which do not have any assumptions of convexity or star - shapedness .
all fuzzy sets spaces considered in this paper are subspaces of @xmath2 endowed with @xmath0 metric . based on these characterizations and the discussions on convexity and star - shapedness of fuzzy sets ,
we construct the completions of every fuzzy sets space mentioned in this paper
. then we clarify relation among all the ten fuzzy sets spaces discussed in this paper including the general fuzzy star - shaped numbers space introduced by qiu et al . at last
, it gives characterizations of totally bounded sets , relatively compact sets and compact sets in all the fuzzy sets spaces mentioned in this paper .
[ section ] [ section ] [ section ] [ section ] [ section ] [ section ] [ section ] fuzzy sets ; compact sets ; totally bounded sets ; @xmath0 metric ; star - shaped sets .
And you have already written the first three sentences of the full article: compactness is a fundamental and important property in both theory and applications @xcite .
compactness also plays an important role in the applications of fuzzy sets @xcite .
the compact criteria attracts much attention ..
Please generate the next two sentences of the article | it s well - known that arzel
ascoli theorem(s ) provide compact criteria in classic analysis and topology . |
6,549 | Suppose that you have an abstract for a scientific paper: we present radial velocity measurements for 74 globular clusters ( gcs ) in the nearby giant elliptical ngc 5128 , of which 31 are newly discovered clusters .
all the gc candidates were taken from the list of possible new clusters given in the @xcite photometric survey .
in addition to the newly confirmed clusters , we identified 24 definite foreground stars and 31 probable background galaxies . from a combined list of 299
known gcs in ngc 5128 with measured radial velocities and metallicity - sensitive @xmath0 photometric indices , we construct a new metallicity distribution function ( mdf ) for the cluster system .
the mdf shows an approximately bimodal form , with centroids at @xmath1 } = -1.46 $ ] and @xmath2 , and with nearly equal numbers of metal - poor and metal - rich clusters in the two modes .
however , there are many intermediate - color clusters in the distribution , and the fainter clusters tend to have a higher proportion of red clusters .
these features of the mdf may indicate a widespread age range within the cluster system as well as an intrinsically broad metallicity spread . .
And you have already written the first three sentences of the full article: globular clusters ( gcs ) are simple stellar populations ( single age , single metallicity ) that help to trace the formation history of their host galaxy .
gcs are also powerful tools in revealing the halo kinematics and dynamics , if large samples of globular cluster radial velocities can be obtained .
ngc 5128 , the central galaxy in the centaurus cluster 3.9 mpc away , and the nearest readily accessible giant e galaxy , provides a unique and exciting possibility to study the dynamics and formation history through its globular cluster system ( gcs ) ..
Please generate the next two sentences of the article | however , finding its clusters individually is a difficult job : at its moderately low galactic latitude of @xmath3 , field contamination by both foreground stars and background galaxies is significant , and the gcs can not be distinguished by only image morphology , object size , or color .
thus except for the very expensive and time - consuming approach of resolving the gcs into individual stars by ( say ) hst imaging , radial velocity determinations provide the only definitive method for classifying a candidate object in the ngc 5128 field as a genuine gc . |
6,550 | Suppose that you have an abstract for a scientific paper: some characteristic features in the radiation from a relativistic electron uniformly rotating along an equatorial orbit around a dielectric ball have been studied .
it was shown that at some harmonics , in case of weak absorption of radiation in the ball material , the electron may generate radiation field quanta exceeding in several dozens of times those generated by electron rotating in a continuous , infinite and transparent medium having the same real part of permittivity as the ball material .
the rise of high power radiation is due to the fact that electromagnetic oscillations of cherenkov radiation induced along the trajectory of particle are partially locked inside the ball and superimposed in nondestructive way .
pacs : 41.60.bq ; 41.60ap keywords : relativistic electron ; cherenkov radiation ; synchrotron radiation .
And you have already written the first three sentences of the full article: due to such unique properties as the high intensity , high degree of collimation , and wide spectral range ( see @xcite-@xcite and references therein ) synchrotron radiation ( sr ) serves as an extraordinary research tool for advanced studies in both the fundamental and applied sciences .
nowadays it is used worldwide by thousands of scientists in many disciplines like physics , chemistry , material science and structural biology .
these applications motivate the importance of analyzing various mechanisms for control of sr parameters . from this point of view.
Please generate the next two sentences of the article | it is of interest to study the influence of medium on spectral and angular distributions of sr .
investigations of this kind are also important for a number of astrophysical problems @xcite . |
6,551 | Suppose that you have an abstract for a scientific paper: in the framework of the schwinger - dyson equation and the bethe - salpeter equation in the improved ladder approximation , we calculate the @xmath0 mass difference on the same footing as the pion decay constant and the qcd @xmath1 parameter ( or @xmath2 ) through the difference between the vector current correlator @xmath3 and the axial - vector current correlator @xmath4 .
we find that all the results can be fit to the experimental values for rather large @xmath5 which reflects the `` scale ambiguity '' . by fitting to the calculated data using the pole saturated form of @xmath6
, we also derive masses and decay constants of @xmath7 meson and @xmath8 meson , which we found are consistent with the experiments rather insensitively to the `` scale ambiguity '' . .
And you have already written the first three sentences of the full article: the @xmath9 - @xmath10 mass difference @xmath11 is an interesting quantity to measure an explicit breaking of the chiral symmetry by the gauge coupling ( @xmath12 ) in the spontaneously broken phase of the chiral symmetry .
it in fact has been a prototype of the mass calculation of pseudo nambu - goldstone ( ng ) bosons in strong coupling gauge theories such as those in the technicolor theories @xcite and more recently in the little higgs models @xcite .
the sign as well as the absolute value of @xmath13 is an important issue ( `` vacuum alignment problem '' ) , since the negative sign would imply that the vacuum would align so as to break spontaneously the gauge symmetry ( @xmath12 in the case of pion ) which explicitly breaks the spontaneously broken symmetry ..
Please generate the next two sentences of the article | such a situation never happens in the real - life qcd but may do in other theories .
hence this type of calculation plays a central role of the model buildings . |
6,552 | Suppose that you have an abstract for a scientific paper: we consider qubit purification under simultaneous continuous measurement of the three non - commuting qubit operators @xmath0 , @xmath1 , @xmath2 .
the purification dynamics is quantified by ( i ) the average purification rate , and ( ii ) the mean time of reaching given level of purity , @xmath3 . under ideal measurements ( detector efficiency @xmath4 ) , we show in the first case an asymptotic mean purification speed - up of @xmath5 as compared to a standard ( classical ) single - detector measurement . however by the second measure
the mean time of first passage @xmath6 of the purity the corresponding speed - up is only @xmath7 .
we explain these speed - ups using the isotropy of the qubit evolution that provides an equivalence between the original measurement directions and three simultaneous measurements , one with an axis aligned along the bloch vector and the other with axes in the two complementary directions . for inefficient detectors ,
@xmath8 the mean time of first passage @xmath9 increases since qubit purification competes with an isotropic qubit dephasing . in the asymptotic high - purity limit ( @xmath10 )
we show that the increase possesses a _ scaling behavior _ : @xmath11 is a function only of the ratio @xmath12 .
the increase @xmath13 is linear for small argument but becomes exponential @xmath14 for @xmath15 large . .
And you have already written the first three sentences of the full article: pure states are an important resource in quantum computation and communication algorithms @xcite . while state purification is possible via _ cooling _ , this may be impractical for several reasons , including long relaxation times , degenerate ground states , and the presence of several dephasing mechanisms .
a different purification process is possible via _ continuous measurement _ when the ( available to the observer ) quantum state will purify continuously according to the detector measurement result . here , the speed at which one can purify the state is set by the detector measurement rate , and the final purity will depend on how close the detector is to a quantum - limited ( 100% efficient ) one . this may become an important tool since continuous measurements are also at the heart of various quantum control applications@xcite , including quantum state stabilization via quantum feedback @xcite , preparation of entangled states @xcite , and for continuous error corrections @xcite . in recent years several groups have suggested rapid purification protocols based on continuous measurement and hamiltonian feedback @xcite , which makes it possible to considerably speed - up purification . for a single qubit ,
the problem was first analyzed by jacobs @xcite , who recognized that the rate of average purification can be enhanced using unitary transformation at each measurement time step , so as to make the state always orthogonal ( in the bloch sphere sense ) to the detector s measurement basis ..
Please generate the next two sentences of the article | this feedback algorithm ( which has been rigorously shown to be optimal @xcite , and rederived in ref .
@xcite ) produces a factor of 2 speed - up in the high - purity limit , when the state approaches the bloch sphere surface . |
6,553 | Suppose that you have an abstract for a scientific paper: the phonon dynamics of the low - temperature superconductor sr@xmath0ruo@xmath1 is calculated quantitatively in linear response theory and compared with the structurally isomorphic high - temperature superconductor la@xmath0cuo@xmath1 .
our calculation corrects for a typical deficit of lda - based calculations which always predict a too large electronic @xmath2-dispersion insufficient to describe the @xmath3-axis response in the real materials . with a more realistic computation of the electronic band structure the frequency and wavevector dependent irreducible polarization part of the density response function
is determined and used for adiabatic and nonadiabatic phonon calculations .
our analysis for sr@xmath0ruo@xmath1 reveals important differences from the lattice dynamics of @xmath4- and @xmath5-doped cuprates .
consistent with experimental evidence from inelastic neutron scattering the anomalous doping related softening of the strongly coupling high - frequency oxygen bond - stretching modes ( obsm ) which is generic for the cuprate superconductors is largely suppressed or completely absent , respectively , depending on the actual value of the on - site coulomb repulsion of the ru4d orbitals .
also the presence of a characteristic @xmath6-mode with a very steep dispersion coupling strongly with the electrons is missing in sr@xmath0ruo@xmath1 .
moreover , we evaluate the possibility of a phonon - plasmon scenario for sr@xmath0ruo@xmath1 which has been shown recently to be realistic for la@xmath0cuo@xmath1 .
in contrast to la@xmath0cuo@xmath1 in sr@xmath0ruo@xmath1 the very low lying plasmons are overdamped along the @xmath3-axis . .
And you have already written the first three sentences of the full article: the discovery of superconductivity in sr@xmath0ruo@xmath1 by maeno and coworkers @xcite has attracted widespread attention partially because of the structural similarity with the cuprate - based high - temperature superconductors ( htsc s ) . while the mother compounds of the htsc s are charge transfer insulators , and they usually need to be doped to become metallic and show superconductivity , in sr@xmath0ruo@xmath1 low - temperature superconductivity at @xmath7 = 1.5 k condenses from a metallic state that is a strongly two - dimensional fermi liquid below about 20 k. the fermi surface consists of three weakly corrugated cylindrical sheets @xmath8 being hole - like and @xmath9 and @xmath10 which are electon - like @xcite .
this is in contrast to la@xmath0cuo@xmath1 where only one fermi sheet exists .
the mechanism of conduction in sr@xmath0ruo@xmath1 at higher temperatures is an interesting issue because the @xmath3-axis resistivity shows a broad maximum at around 130 k and for increasing temperatures the resistivity starts to decrease . in @xcite.
Please generate the next two sentences of the article | such a metallic to nonmetallic crossover in the @xmath3-axis resistivity of a highly anisotropic metal like sr@xmath0ruo@xmath1 with no corresponding feature in the @xmath11-plane properties has been related to the strong coupling between the electrons and a bosonic mode propagating and polarized in @xmath3-direction , like the axial oxygen breathing mode @xmath12 , at the @xmath13 point of the brillouin zone ( bz ) to be discussed in .
superconductivity in sr@xmath0ruo@xmath1 is thought to be of unconventional character and thus is intensively discussed in the literature . |
6,554 | Suppose that you have an abstract for a scientific paper: in the framework of the perturbation theory of the nonrelativistic quantum electrodynamics , a theory of spontaneous emission of a chiral molecule located near a chiral ( bi - isotropic ) spherical particle is developed . it is shown that the structure of photons in the presence of chiral spherical particles differs significantly from the structure of te or tm photons .
exact analytical expressions for the spontaneous emission radiative decay rate of a chiral molecule with arbitrary electric and magnetic dipole moments of transition located near a chiral spherical particle with arbitrary parameters are obtained and analyzed in details .
simple asymptotes for the case of a nanoparticle are obtained . substantial influence of even small chirality on a dielectric or `` left - handed '' sphere is found .
it is shown that by using chiral spherical particles it is possible to control effectively the radiation of enantiomers of optically active molecules . .
And you have already written the first three sentences of the full article: chirality is a geometric property of a three - dimensional body not to coincide with its reflection in a mirror in any shifts and turns .
such a property , for example , belongs to a human hand or a spring . the term `` chirality '' was proposed by lord kelvin in 1873 to explain some special properties of molecules @xcite .
the chirality plays an important role in biology and pharmacy , because many complex organic compounds ( amino acids , proteins , and sugars ) have chiral properties ..
Please generate the next two sentences of the article | for this reason , a body can react differently with different enantiomers of the same substance .
for example , the same drug , depending on what type of molecules it contains , may have a different taste and smell , or effect differently . in physics |
6,555 | Suppose that you have an abstract for a scientific paper: we study the dynamics of a two - level system described by a slowly varying hamiltonian and weakly coupled to the ohmic environment .
we follow the bloch
redfield perturbative approach to include the effect of the environment on qubit evolution and take into account modification of the spectrum and matrix elements of qubit transitions due to time - dependence of the hamiltonian .
we apply this formalism to two problems .
( 1 ) we consider a qubit , or a spin-1/2 , in a rotating magnetic field .
we show that once the rotation starts , the spin has a component perpendicular to the rotation plane of the field that initially wiggles and eventually settles to the value proportional to the product of angular rotation velocity of the field and the berry curvature .
( 2 ) we re - examine the landau
zener transition for a system coupled to environment at arbitrary temperature .
we show that as temperature increases , the thermal excitation and relaxation become leading processes responsible for transition between states of the system .
we also apply the lindblad master equations to these two problems and compare results with those obtained from the bloch redfield equations . .
And you have already written the first three sentences of the full article: the increasing demand for accurate control of quantum devices using high - fidelity control protocols@xcite , has stimulated interest in the study of the dynamics of quantum systems in response to slowly varying hamiltonian .
moreover , rapid progress in the field of adiabatic quantum computing has fueled further interest in and need for more careful analysis of the dynamics of quantum systems whose parameters vary slowly in time.@xcite in addition , decoherence in any real quantum system sets a rigid constraint on the time interval during which a quantum protocol must be carried out , limiting all protocols to intermediate time intervals that are shorter than the decoherence time . at these intermediate time scales , both non - adiabatic corrections and coupling to the environment
become equally important ..
Please generate the next two sentences of the article | the previous analysis@xcite of the qubit dynamics with time - dependent hamiltonians was based on the lindblad master equation@xcite that describes the interaction with environment in terms of dephasing and transition processes characterized by phenomenological decoherence rates . an alternative microscopic approach , formulated as a perturbative theory for a quantum system with a time - independent hamiltonian interacting with its environment , introduces the bloch redfield ( br ) master equation@xcite .
if the hamiltonian of the system changes in time , the br approach has to be modified to properly account for a non - adiabatic corrections . in this paper |
6,556 | Suppose that you have an abstract for a scientific paper: let @xmath0 denote a set of @xmath1 vertices . to construct a _ hypergraph process _
, create a new hyperedge at each event time of a poisson process ; the cardinality @xmath2 of this hyperedge is random , with generating function @xmath3 , where @xmath4 ; given @xmath5 , the @xmath6 vertices appearing in the new hyperedge are selected uniformly at random from @xmath0 .
assume @xmath7 .
hyperedges of cardinality @xmath8 are called _ patches _ , and serve as a way of selecting root vertices .
identifiable vertices are those which are reachable from these root vertices , in a strong sense which generalizes the notion of graph component .
hyperedges are called identifiable if all of their vertices are identifiable .
we use `` fluid limit '' scaling : hyperedges arrive at rate @xmath1 , and we study structures of size @xmath9 and @xmath10 .
after division by @xmath1 , numbers of identifiable vertices and hyperedges exhibit phase transitions , which may be continuous or discontinuous depending on the shape of the structure function @xmath11 .
both the case @xmath12 , and the case @xmath13 are considered ; for the latter , a single extraneous patch is added to mark the root vertex .
_ national security agency , university of utah , university of cambridge _ .
And you have already written the first three sentences of the full article: the _ @xmath6-core _ of a graph is the largest subgraph with minimum degree at least @xmath6 .
study the following algorithm for finding the @xmath14-core of a graph : if vertices of degree one exist , select one and remove the edge incident to it .
this may cause the degree of other vertices to drop.
Please generate the next two sentences of the article | . if there are no degree one vertices remaining , stop .
repeat . |
6,557 | Suppose that you have an abstract for a scientific paper: a detailed spectroscopic study of the iso - sws data of the red giant @xmath0 tau is presented , which enables not only the accurate determination of the stellar parameters of @xmath0 tau , but also serves as a critical review of the iso - sws calibration .
this study is situated in a broader context of an iterative process in which both accurate observations of stellar templates and cool star atmosphere models are involved to improve the iso - sws calibration process as well as the theoretical modelling of stellar atmospheres .
therefore a sample of cool stars , covering the whole a0
m8 spectral classification , has been observed in order to disentangle calibration problems and problems in generating the theoretical models and corresponding synthetic spectrum . by using stellar parameters found in the literature
large discrepancies were seen between the iso - sws data and the generated synthetic spectrum of @xmath0 tau .
a study of the influence of various stellar parameters on the theoretical models and synthetic spectra , in conjunction with the kolmogorov - smirnov test to evaluate objectively the goodness - of - fit , enables us to pin down the stellar parameters with a high accuracy : t@xmath1 @xmath2 k , @xmath3 g@xmath4 , m @xmath5 m@xmath6 , z @xmath7 dex , @xmath8 @xmath9 @xmath10 , @xmath11 @xmath12 , @xmath13(c ) @xmath14 dex , @xmath13(n ) @xmath15 dex , @xmath13(o ) @xmath16 dex and @xmath17 @xmath18 mas .
these atmospheric parameters were then compared with the results provided by other authors using other methods and/or spectra . .
And you have already written the first three sentences of the full article: the modelling and interpretation of the iso - sws ( infrared space observatory - short wavelength spectrometer ) data require an accurate calibration of the spectrometers ( schaeidt et al .
1996 ) . in the sws spectral region
( 2.38 45.2 @xmath19 m ) the primary standard calibration candles are bright , mostly cool , stars ..
Please generate the next two sentences of the article | the better the behaviour of these calibration sources in the infrared is known , the more accurate the spectrometers can be calibrated .
iso offered the first opportunity to obtain continuous mid - infrared spectra between 2.38 and 45.2 @xmath19 m at a spectral resolving power of @xmath20 , not polluted by any molecular absorptions of the earth s atmosphere . |
6,558 | Suppose that you have an abstract for a scientific paper: a growing number of observations reveal a subset of type ia supernovae undergoing circumstellar interaction ( sne ia - csm ) .
we present unpublished archival @xmath0 data on sne ia - csm 2002ic and 2005gj obtained @xmath1 and 500 days post - discovery , respectively .
both sne show evidence for late - time mid - infrared ( mid - ir ) emission from warm dust .
the dust parameters are most consistent with a pre - existing dust shell that lies beyond the forward - shock radius , most likely radiatively heated by optical and x - ray emission continuously generated by late - time csm interaction . in the case of sn 2005gj , the mid - ir luminosity more than doubles after 1 year post - discovery . while we are not aware of any late - time optical - wavelength observations at these epochs , we attribute this rebrightening to renewed shock interaction with a dense circumstellar shell . + .
And you have already written the first three sentences of the full article: the ability to standardize type ia supernova ( sn ia ) light curves yields precise cosmological distance indicators ( e.g. , * ? ? ? * ) . despite these empirical relationships ,
questions remain about the underlying physics and progenitor systems .
the sn itself is generally accepted to be the thermonuclear explosion of a c / o white dwarf ( wd ) , but the nature of the companion star remains ambiguous ..
Please generate the next two sentences of the article | evidence now exists for both single - degenerate and double - degenerate channels ( e.g. , * ? ? ?
* ; * ? ? ? |
6,559 | Suppose that you have an abstract for a scientific paper: reputation mechanisms offer an effective alternative to verification authorities for building trust in electronic markets with moral hazard .
future clients guide their business decisions by considering the feedback from past transactions ; if truthfully exposed , cheating behavior is sanctioned and thus becomes irrational .
it therefore becomes important to ensure that rational clients have the right incentives to report honestly . as an alternative to side - payment schemes that explicitly reward truthful reports ,
we show that honesty can emerge as a rational behavior when clients have a repeated presence in the market . to this end
we describe a mechanism that supports an equilibrium where truthful feedback is obtained .
then we characterize the set of pareto - optimal equilibria of the mechanism , and derive an upper bound on the percentage of false reports that can be recorded by the mechanism . an important role in the existence of this bound
is played by the fact that rational clients can establish a reputation for reporting honestly . .
And you have already written the first three sentences of the full article: the availability of ubiquitous communication through the internet is driving the migration of business transactions from direct contact between people to electronically mediated interactions .
people interact electronically either through human - computer interfaces or through programs representing humans , so - called agents . in either case ,
no physical interactions among entities occur , and the systems are much more susceptible to fraud and deception . traditional methods to avoid cheating involve cryptographic schemes and _ trusted third parties _ ( ttp s ) that overlook every transaction ..
Please generate the next two sentences of the article | such systems are very costly , introduce potential bottlenecks , and may be difficult to deploy due to the complexity and heterogeneity of the environment : e.g. , agents in different geographical locations may be subject to different legislation , or different interaction protocols .
reputation mechanisms offer a novel and effective way of ensuring the necessary level of trust which is essential to the functioning of any market . |
6,560 | Suppose that you have an abstract for a scientific paper: i generalize the theory of phonon topological band structures of isostatic lattices to frustrated antiferromagnets .
i achieve this with a discovery of a many - body supersymmetry ( susy ) in the phonon problem of balls and springs and its connection to local constraints satisfied by ground states .
the witten index of the susy model demands the maxwell - calladine index of mechanical structures .
`` spontaneous supersymmetry breaking '' is identified as the need to gap all modes in the bulk to create the topological isostatic lattice state .
since ground states of magnetic systems also satisfy local constraint conditions ( such as the vanishing of the total spin on a triangle ) i identify a similar susy structure for many common models of antiferromagnets including the square , triangluar , kagome , pyrochlore nearest neighbor antiferromagnets , and the @xmath0 square lattice antiferromagnet . remarkably , the kagome family of antiferromagnets is the analog of topological isostatic lattices among this collections of models .
thus , a solid state realization of the theory of phonon topological band structure may be found in frustrated magnetic materials .
recently , kane and lubensky@xcite ( kl ) identified topological properties of isostatic lattice phonons .
they achieved this by discovering a topological index governing mechanical structures by building on calladine s work@xcite and further utilizing a dirac - like square - root of the phonon equations of motion , a problem to which they could apply the theory of topological insulators .
remarkably , they showed the existence of lattices with gapped phonons for periodic boundary conditions that must have gapless phonons with open boundary conditions .
it is natural to wonder if this striking effect is more general and they conclude their study with `` finally , it will be interesting to explore connections with theories of frustrated magnetism@xmath1 . ''
where reference 48 is my study@xcite identifying topological gauge dynamics of....
And you have already written the first three sentences of the full article: to generalize kl theory to magnetism , we need to first identify the theoretical constructs that underpin the theory of phonons and then seek analogs of these constructs in the magnon problem . the simplest description of phonons , that of the vibrations of balls connected to springs ( in the classical limit ) , is endowed with a number of theoretical constructs that shed much light on their behavior .
to begin with , this simplicity demands a specific form of their hamiltonian .
if we define the extension of spring @xmath3 to be @xmath4 , then the most general form for an ideal balls and springs classical hamiltonian is @xmath5 here @xmath6 is the @xmath7 component of the momentum of the ball labeled by @xmath8 , @xmath9 is the matrix inverse of the `` mass tensor '' @xmath10 , @xmath11 is the spring constant matrix and repeated indices are summed over . in the simplest setting , @xmath12 and @xmath13 are proportional to identity matrices . here.
Please generate the next two sentences of the article | we leave them in the general form to aid our study of the structure of the theory and not its application .
the restriction of the hamiltonian to that of balls and springs therefore introduces two ( inverse ) metrics @xmath11 and @xmath9 in configuration space and momentum space respectively and identifies the ground state as satisfying constraints @xmath14 , @xmath15 . balls and springs are a toy - like simplification of a full phonon problem . |
6,561 | Suppose that you have an abstract for a scientific paper: over the last 15 years there has been considerable interest in the possibility of quantum - gravity - induced in - vacuo dispersion , the possibility that spacetime itself might behave essentially like a dispersive medium for particle propagation .
two very recent studies have exposed what might be in - vacuo dispersion features for grb ( gamma - ray - burst ) neutrinos of energy in the range of 100 tev and for grb photons with energy in the range of 10 gev .
we here show that these two features are roughly compatible with a description such that the same effects apply over 4 orders of magnitude in energy .
we also characterize quantitatively how rare it would be for such features to arise accidentally , as a result of ( still unknown ) aspects of the mechanisms producing photons at grbs or as a result of background neutrinos accidentally fitting the profile of a grb neutrino affected by in - vacuo dispersion . .
And you have already written the first three sentences of the full article: the possibility of quantum - gravity - induced in - vacuo dispersion , an energy dependence of the travel times of ultrarelativistic particles from a given source to a given detector , has been motivated in several studies ( see _ e.g. _ refs.@xcite and references therein ) .
part of the interest in this possibility comes from the fact that it is a rare example of candidate quantum - gravity effect that could lead to observably large manifestations , even if , as it appears to be safe to assume , its characteristic length scale is of the order of the minute planck length ( inverse of the planck energy scale @xmath0 ) or anyway not much larger than that .
the best opportunity so far studied for such experimental tests is provided by observations of grbs @xcite , which set up for us a sort of race among photons of different energies and ( probably @xcite ) neutrinos of different energies , all emitted within a relatively small time window . the fact that our understanding of the mechanisms producing grbs remains preliminary.
Please generate the next two sentences of the article | is a challenge , since any given time - of - arrival difference among two particles can in principle always be attributed to the emission mechanism , but this can be compensated by suitable techniques of statistical analysis . for more than a decade
the analyses of grb data from the in - vacuo - dispersion perspective were done considering only photons and focusing on what could be tentatively inferred from each single grb . |
6,562 | Suppose that you have an abstract for a scientific paper: the fluorescence technique has been successfully used to detect ultrahigh energy cosmic rays by indirect measurements .
the underlying idea is that the number of charged particles in the atmospheric shower , i.e , its longitudinal profile , can be extracted from the amount of emitted nitrogen fluorescence light .
however the influence of shower fluctuations and the very possible presence of different nuclear species in the primary cosmic ray spectrum make the estimate of the shower energy from the fluorescence data analysis a difficult task .
we investigate the potential of shower size at maximum depth as estimator of shower energy .
the detection of the fluorescence light is simulated in detail and the reconstruction biases are carefully analyzed .
we extend our calculations to both hires and euso experiments .
this kind of approach is of particular interest for showers that are not fully contained inside the field of view of the detector . .
And you have already written the first three sentences of the full article: the total amount of emitted fluorescence light in a shower is a very good approximation to the total number of charged particles @xmath0(@xmath1 ) , where @xmath1 is the atmospheric depth . in this sense
the number of particles at shower maximum can serve as an estimator of the shower energy .
the total energy that goes into electromagnetic charged particles is obtained by integration of the shower longitudinal profile @xmath2 where @xmath3 is the average ionization loss rate and the integral on the right - hand side represents the total track length of all charged particles in the shower projected onto the shower axis . as an alternative proposal @xcite the electromagnetic energy.
Please generate the next two sentences of the article | can also be calculated by using the fluorescence light intensity and the fluorescence efficiency , without the obligation to reconstruct the number of particles as a function of the atmospheric depth .
such approach is taken as a very precise measurement of the primary shower energy because it is supposed to be weakly dependent of the simulation models and the primary particle type . |
6,563 | Suppose that you have an abstract for a scientific paper: we construct a real - analytic cr supermanifold @xmath0 , holomorphically embedded into a superquadric @xmath1 .
a cr distribution @xmath2 on @xmath0 enables us to define a tangential cr complex @xmath3 .
we define a @xmath4-closed trace functional @xmath5 and conjecture that a chern - simons theory associated with a triple @xmath6 is equivalent to n=3 , d=4 yang - mills theory with a gauge group u@xmath7 .
we give some evidences to this conjecture .
.2 in _ dedicated to yu.i .
manin on his 70-th birthday _ .2 in .
And you have already written the first three sentences of the full article: twistor methods in gauge theory have a long history ( summarized in ref . [ p90 ] ) .
a common feature of these methods is that spacetime is replaced by a twistor ( or ambitwistor ) analytic manifold @xmath8 .
equations of motion `` emerge '' ( in terminology of penrose ) from complex geometry of @xmath8 ..
Please generate the next two sentences of the article | the twistor approach turns to be a very useful technical innovation .
for example difficult questions of classical gauge theory , e.g. the ones that appear in the theory of instantons , admit a translation into a considerably more simple questions of analytic geometry of space @xmath8 . on this way classifications theorems in the theory of instantons has been obtained ( see ref . |
6,564 | Suppose that you have an abstract for a scientific paper: in the first days of quantum mechanics dirac pointed out an analogy between the time - dependent coefficients of an expansion of the schrdinger equation and the classical position and momentum variables solving hamilton s equations .
here it is shown that the analogy can be made an equivalence in that , in principle , systems of classical oscillators can be constructed whose position and momenta variables form time - dependent amplitudes which are _ identical _ to the complex quantum amplitudes of the coupled wavefunction of an @xmath0-level quantum system with real coupling matrix elements .
hence classical motion can reproduce quantum coherence . .
And you have already written the first three sentences of the full article: in their first formulation of quantum mechanics , both schrdinger and dirac were strongly influenced by connections to the hamiltonian formulation of classical mechanics .
indeed , in one of the very first applications of schrdinger s time - dependent equation ( tdse ) , dirac @xcite indicated a close parallel between the coupled first - order set of equations arising from the tdse and the coupled first - order hamilton equations of classical mechanics .
dirac introduced the time - dependent basis set expansion , @xmath1 where the @xmath2 are complex co - efficients and @xmath3 denotes an arbitrary basis . in the tdse ( where , for the moment , we put @xmath4 ) this expansion leads to the set of first - order coupled equations , @xmath5 where @xmath6 are the matrix elements of the quantum hamiltonian ..
Please generate the next two sentences of the article | dirac then remarked that by considering the co - efficients @xmath7 and @xmath8 to be canonical variables and assuming a hamiltonian function @xmath9 the quantum equations are equivalent to the classical hamilton equations @xmath10 note , however , that this is still fully quantum mechanical since the matrix elements and the amplitudes appearing in the classical hamiltonian are all complex objects .
hence , there is no obvious classical counterpart . |
6,565 | Suppose that you have an abstract for a scientific paper: we calculated the color - octet contribution to the double spin asymmetry of @xmath0 hadroproduction with nonzero transverse momenta at fixed target energies @xmath1 gev .
it is shown that the color - octet contribution is dominant in the asymmetries .
the expected asymmetries and statistical errors in a future option of hera with longitudinally polarized protons at hera-@xmath2 should allow one to distinguish between different parametrizations for the polarized gluon distribution in the proton .
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phys .
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_ * # 1 * ( # 2 ) # 3 # 1 # 2 # 3 _ nucl .
phys .
_ * # 1 * ( # 2 ) # 3 # 1 # 2 # 3 _ phys .
lett .
_ * # 1 * ( # 2 ) # 3 # 1 # 2 # 3 _ phys .
rev .
_ * # 1 * ( # 2 ) # 3 # 1 # 2 # 3 _ phys . rep .
_ * # 1 * ( # 2 ) # 3 # 1 # 2 # 3 _ phys . rev .
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_ * # 1 * ( # 2 ) # 3 # 1 # 2 # 3 _ rev .
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phys .
_ * # 1 * ( # 2 ) # 3 # 1 # 2 # 3 _ z. phys .
_ * # 1 * ( # 2 ) # 3 jinr e2 - 96 - 431 + hep - ph/9612301 * double - spin asymmetry of @xmath0 production in polarized pp + collisions at hera-@xmath3 * + + _ bogoliubov laboratory of theoretical physics , _ + _ jinr , dubna , moscow region , 141980 , russia _ + .
And you have already written the first three sentences of the full article: the presently most accurate way to measure the polarized gluon distribution function in the nucleon is to study those processes which can be calculated in the framework of perturbative qcd ( pqcd ) , i.e. for which the involved production cross sections and subprocess asymmetries can be predicted .
one of the cleanest ways to probe qcd is to investigate heavy quarkonia production processes .
heavy quark pair production processes can be controlled perturbatively due to large mass of constituents . on the other hand ,.
Please generate the next two sentences of the article | heavy quark systems are mainly produced in gluon fusion processes and therefore , asymmetries are expected to be sensitive to the polarized gluon distribution in the nucleon .
investigation of heavy quarkonia production processes in polarized experiments would also yield additional information about the quark - antiquark pair hadronization phase . |
6,566 | Suppose that you have an abstract for a scientific paper: one - loop calculations of renormalization constants @xmath0 , @xmath1 in the model , proposed in the paper @xcite with gauge invariant ghost field lagrangian are performed .
it is shown that the model is asymptotically free and the renormalization constants satisfy the same equation as in the ordinary yang - mills theory . .
And you have already written the first three sentences of the full article: in the yang - mills theory ghost field lagrangian does nt possess gauge symmetry and together with a gauge fixing term breaks gauge invariance of the effective action .
it makes problems for regularization and renormalization of the theory .
the slavnov - taylor identities are more complicated then the ward identities in electrodynamics . recently a new formulation of the yang - mills theory.
Please generate the next two sentences of the article | was proposed @xcite in which the gauge invariance is broken only by the gauge fixing term . in the paper @xcite it was shown that in the framework of perturbation theory this model is equivalent to the usual yang - mills theory . calculating the observables in this model one can pass to the lorentz - type gauge in which the renormalizability is evident .
nevertheless a proof of renormalizability directly in the gauge proposed in the paper @xcite is absent . in the present paper we calculate at one - loop the gauge field and @xmath2-vertex renormalization constants . |
6,567 | Suppose that you have an abstract for a scientific paper: two qubit quantum computations are viewed as two player , strictly competitive games and a game - theoretic measure of optimality of these computations is developed . to this end
, the geometry of hilbert space of quantum computations is used to establish the equivalence of game - theoretic solution concepts of nash equilibrium and mini - max outcomes in games of this type , and quantum mechanisms are designed for realizing these mini - max outcomes . .
And you have already written the first three sentences of the full article: a central feature of shannon s @xcite theory of information is the notion of probability distribution , that is , a convex linear combination of outcomes of some experiment . replacing probability distributions with quantum superpositions , that is , complex projective linear combinations of outcomes of the experiment , and then following by measurement has important consequences for the treatment of information in the quantum realm .
the resultant generalization of shannon theory of information underpins many of the important applications of quantum mechanics , such as quantum computing , and the much broader theory of quantum information processing that embeds the classical treatments of probability distributions applied to observables within that of positive - definite , trace preserving maps .
much of the work on quantum games to date has focused on the issue of what quantum mechanics brings to game theory ..
Please generate the next two sentences of the article | the perspective is decidedly that quantum mechanics can offer some potential advantage , such as being able to resolve game - theoretic conundrums ( one such being that of the prisoner s dilemma ) , by the utilization of quantum resources unavailable within a classical framework of the game .
whilst this focus is interesting , it is our belief that game - theory is at its most fruitful when applied as an analysis tool for situations in which there may be an underlying competitive element . |
6,568 | Suppose that you have an abstract for a scientific paper: we review recent theoretical work on thermoelectric energy harvesting in multi - terminal quantum - dot setups .
we first discuss several examples of nanoscale heat engines based on coulomb - coupled conductors .
in particular , we focus on quantum dots in the coulomb - blockade regime , chaotic cavities and resonant tunneling through quantum dots and wells .
we then turn towards quantum - dot heat engines that are driven by bosonic degrees of freedom such as phonons , magnons and microwave photons .
these systems provide interesting connections to spin caloritronics and circuit quantum electrodynamics . .
And you have already written the first three sentences of the full article: thermoelectric effects have generated an immense interest for quite some time already because they offer the possibility to convert heat from the environment into electrical work @xcite .
this form of energy harvesting is potentially useful for electric circuits on modern computer chips that produce large amounts of heat and currently need to be cooled actively in order not to overheat .
one can also use the harvested energy to run auxiliary circuits such as autonomous sensors or recycle the lost energy to charge a battery ..
Please generate the next two sentences of the article | unfortunately , even after decades of material research current thermoelectric materials still have a very low efficiency in converting heat into electrical work and deliver only moderate powers .
for this reason , thermoelectric energy harvesting so far is restricted to certain niche applications such as in interplanetary spaceships where the fact that a thermoelectric generator does not require any moving parts and therefore no maintenance turns out to be useful . |
6,569 | Suppose that you have an abstract for a scientific paper: we report contributions to cosmic infrared background ( cib ) intensities originating from known galaxies and their faint companions at submillimeter wavelengths . using the publicly - available ultravista catalog , and maps at 250 , 350 , and 500@xmath0 m from the _ herschel _ multi - tiered extragalactic survey ( hermes )
, we perform a novel measurement that exploits the fact that uncatalogued sources may bias stacked flux densities particularly if the resolution of the image is poor and intentionally smooth the images before stacking and summing intensities . by smoothing the maps we are capturing the contribution of faint ( undetected in @xmath1 ) sources that are physically associated , or _ correlated _ , with the detected sources .
we find that the cumulative cib increases with increased smoothing , reaching @xmath2 , @xmath3 , and @xmath4 at 250 , 350 , and 500@xmath0 m at @xmath5 full width at half - maximum .
this corresponds to a fraction of the fiducial cib of @xmath6 , @xmath7 , and @xmath8 at 250 , 350 , and 500@xmath0 m , where the uncertainties are dominated by those of the absolute cib .
we then propose , with a simple model combining parametric descriptions for stacked flux densities and stellar mass functions , that emission from galaxies with log(@xmath9 can account for the most of the measured total intensities , and argue against contributions from extended , diffuse emission .
finally , we discuss prospects for future survey instruments to improve the estimates of the absolute cib levels , and observe any potentially remaining emission at @xmath10 . .
And you have already written the first three sentences of the full article: of all the light that has been emitted by stars , about half has been absorbed by interstellar dust and thermally re - radiated at far - infrared to submillimeter wavelengths , appearing as a diffuse , extragalactic , cosmic infrared background spanning 11000@xmath0 m ( cib ; * ? ? ?
* ; * ? ? ?
statistically characterizing the sources responsible for this background is necessary to gain a full understanding of galaxy formation and cosmology , and thus remains an ongoing pursuit ..
Please generate the next two sentences of the article | the cib was first detected in spectroscopy with the far infrared absolute spectrophotometer ( firas ; * ? ? ?
* ; * ? ? ? |
6,570 | Suppose that you have an abstract for a scientific paper: we present new results of the quenched simulations of the reduced d=4 supersymmetric yang - mills quantum mechanics for larger gauge groups su(n ) , @xmath0 .
the model , studied at finite temperature , reveals existence of the two distinct regions which may be precursors of a black hole and the elementary d0 branes phases of m - theory conjectured in the literature .
present results for higher groups confirm the picture found already for n=2 .
similar behaviour is observed in the preliminary simulations for the d=6 and d=10 models . .
And you have already written the first three sentences of the full article: supersymmetric yang - mills quantum mechanics ( symqm ) provides the quantitative model of m - theory @xcite . even though much simpler than the original theory the model
is not solved in spite of its long history@xcite .
we have therefore decided to set up a systematic lattice survey of symqm beginning with the simplest case of @xmath1(quenched)@xcite and gradually extending it as far as possible towards the bfss limit _.
Please generate the next two sentences of the article | i.e. _ @xmath2 and @xmath3 . in this talk
i will report on the second step along this programme : the first results for higher n will be presented . |
6,571 | Suppose that you have an abstract for a scientific paper: the katrin ( karlsruhe tritium neutrino ) experiment will be analyzing the tritium beta - spectrum to determine the mass of the neutrino with a sensitivity of @xmath0 ev ( 90% c.l . ) .
this approach to a measurement of the absolute value of the neutrino mass relies only on the principle of energy conservation and can in some sense be called model - independent as compared to cosmology and neutrino - less double beta decay . however by model
independent we only mean in case of the minimal extension of the standard model .
one should therefore also analyse the data for non - standard couplings to e.g. righthanded or sterile neutrinos . as an alternative to the frequentist minimization methods used in the analysis of the earlier experiments in mainz and troitsk we have been investigating markov chain monte carlo ( mcmc ) methods which are very well suited for probing multi - parameter spaces . we found that implementing the katrin @xmath1- function in the cosmomc package - an mcmc code using bayesian parameter inference - solved the task at hand very nicely . .
And you have already written the first three sentences of the full article: the karlsruhe tritium neutrino experiment katrin @xcite will be the first beta decay experiment attempting to measure the electron neutrino mass with sub - ev precision .
presently the experiment is commissioned to start data - taking in 2013/14 and has a projected sensitivity of 0.2 ev ( 90% c.l . ) to the neutrino mass .
katrin is the successor of the experiments in mainz @xcite and troitsk @xcite and will be using some of the same techniques as those . for the technical details of katrin.
Please generate the next two sentences of the article | see e.g. @xcite . strictly speaking when measuring the electron neutrino mass with @xmath2-decay spectra ,
what we get is the socalled kinematic neutrino mass . |
6,572 | Suppose that you have an abstract for a scientific paper: particle stabilized emulsions are ubiquitous in the food and cosmetics industry , but our understanding of the influence of microscopic fluid - particle and particle - particle interactions on the macroscopic rheology is still limited . in this paper
we present a simulation algorithm based on a multicomponent lattice boltzmann model to describe the solvents combined with a molecular dynamics solver for the description of the solved particles .
it is shown that the model allows a wide variation of fluid properties and arbitrary contact angles on the particle surfaces .
we demonstrate its applicability by studying the transition from a `` bicontinuous interfacially jammed emulsion gel '' ( bijel ) to a `` pickering emulsion '' in dependence on the contact angle , the particle concentration , and the ratio of the solvents . .
And you have already written the first three sentences of the full article: using particles in a manner similar to surfactants in order to stabilize emulsions is very attractive in particular for the food- , cosmetics- , and medical industry to stabilize , e.g. barbecue sauces and sun cremes or in order to produce sophisticated ways to deliver drugs at the right position in the human body .
the microscopic processes leading to the commercial interest can be understood by assuming an oil - water mixture . without any additives ,
phase separation would take place and the oil would float on top of the water . adding small particles , however , causes these particles to diffuse to the interface which is being stabilized due to a reduced surface energy . if for example individual droplets of one phase are covered by particles , such systems are also referred to as `` pickering emulsions '' and are known since the beginning of the last century @xcite ..
Please generate the next two sentences of the article | particularly interesting properties of such emulsions are the blocking of ostwald ripening and the rheological properties due to irreversible particle adsorption at interfaces as well as interface bridging due to particle monolayers @xcite .
recently , there has been a growing interest in particles suspended in multiphase or multicomponent flows @xcite , which led to the discovery of a new material type , the `` bicontinous interfacially jammed emulsion gel '' ( bijel ) @xcite . |
6,573 | Suppose that you have an abstract for a scientific paper: we propose a scalable implementation of grover s quantum search algorithm in a trapped - ion quantum information processor .
the system is initialized in an entangled dicke state by using simple adiabatic techniques .
the inversion - about - average and the oracle operators take the form of _ single _ off - resonant laser pulses , addressing , respectively , all and half of the ions in the trap .
this is made possible by utilizing the physical symmetries of the trapped - ion linear crystal .
the physical realization of the algorithm represents a dramatic simplification : each logical iteration ( oracle and inversion about average ) requires only _ two _ physical interaction steps , in contrast to the large number of concatenated gates required by previous approaches .
this does not only facilitate the implementation , but also increases the overall fidelity of the algorithm . .
And you have already written the first three sentences of the full article: one of the most celebrated applications of quantum information processing is grover s quantum search algorithm , which allows an initially unknown element to be determined from @xmath0 equally likely possibilities in @xmath1 queries @xcite .
this outperforms the optimum classical strategy ( a random trial and error of elements ) , which requires @xmath2 steps on average .
in addition to providing a speed - up of the unstructured search problem , grover s algorithm can also be adapted to look for solutions to a range of mathematically difficult problems that have structure , by nesting one quantum search inside another @xcite . as with other applications of quantum computing , the benefits of a quantum over a classical approach increase with the size of the database ..
Please generate the next two sentences of the article | indeed , it has been suggested that the _ primary resource _ for quantum computation is a hilbert - space dimension , which grows exponentially with the available physical resources @xcite .
another important consideration is that the physical and temporal resources required to implement the algorithm do not grow too rapidly with the register size @xmath0 . |
6,574 | Suppose that you have an abstract for a scientific paper: within a fully microscopic setting , we derive a variational principle for the non - equilibrium steady states of chemical reaction networks , valid for time - scales over which chemical potentials can be taken to be slowly varying : at stationarity the system minimizes a global function of the reaction fluxes with the form of a hopfield hamiltonian with hebbian couplings , that is explicitly seen to correspond to the rate of decay of entropy production over time . guided by this analogy ,
we show that reaction networks can be formally re - cast as systems of interacting reactions that optimize the use of the available compounds by competing for substrates , akin to agents competing for a limited resource in an optimal allocation problem . as an illustration , we analyze the scenario that emerges in two simple cases : that of toy ( random ) reaction networks and that of a metabolic network model of the human red blood cell .
= 1 .
And you have already written the first three sentences of the full article: the dynamics and thermodynamics of chemical reaction networks is a subject that goes back at least to @xcite .
recent years have seen considerable interest in the problem at different levels , from the characterization of their mass - action kinetics @xcite and of their stochastic thermodynamics based on the chemical master equation @xcite , to the analysis of their non - equilibrium steady states ( ness ) @xcite . besides their relevance for fundamental understanding
, these approaches provide an important frame for the study of real biochemical systems , like genome - scale reconstructions of cellular metabolic networks @xcite . the most basic information about these systems is usually encoded in the matrix of stoichiometric coefficients , representing in essence the ( weighted ) topology of the couplings between chemical species and reactions . with uncertainties about kinetic parameters and.
Please generate the next two sentences of the article | reaction or transport mechanisms often preventing large - scale kinetic approaches ( with exceptions like the the metabolism of human erythrocytes @xcite ) , the challenge at the simplest level is that of building stoichiometry - based predictive models of metabolic activity at genome scale .
much information on the organization of reaction fluxes in ness can indeed be obtained from constraint - based models that rely on minimal mass - balance @xcite or stability @xcite assumptions . |
6,575 | Suppose that you have an abstract for a scientific paper: we consider the correlated multiarmed bandit ( mab ) problem in which the rewards associated with each arm are modeled by a multivariate gaussian random variable , and we investigate the influence of the assumptions in the bayesian prior on the performance of the upper credible limit ( ucl ) algorithm and a new correlated ucl algorithm .
we rigorously characterize the influence of accuracy , confidence , and correlation scale in the prior on the decision - making performance of the algorithms .
our results show how priors and correlation structure can be leveraged to improve performance . multiarmed bandit problem , bayesian algorithms , decision - making , spatial search , upper credible limit algorithm , influence of priors .
And you have already written the first three sentences of the full article: mab problems @xcite are a class of resource allocation problems in which a decision - maker allocates a single resource by sequentially choosing one among a set of competing alternative options called arms . in the so - called stationary mab problem , a decision - maker at each discrete time instant chooses an arm and
collects a reward drawn from an unknown stationary probability distribution associated with the selected arm .
the objective of the decision - maker is to maximize the total expected reward aggregated over the sequential allocation process ..
Please generate the next two sentences of the article | these problems capture the fundamental trade - off between exploration ( collecting more information to reduce uncertainty ) and exploitation ( using the current information to maximize the immediate reward ) , and they model a variety of robotic missions including search and surveillance .
recently , there has been significant interest in bayesian algorithms for the mab problem @xcite . |
6,576 | Suppose that you have an abstract for a scientific paper: in a number of recent experiments it has been demonstrated that in ultra - narrow superconducting channels quantum fluctuations of the order parameter , alternatively called quantum phase slips , are responsible for the finite resistance well below the critical temperature .
the acceptable agreement between those experiments and the models describing quantum fluctuations in quasi - one - dimensional superconductors has been established .
however the very concept of the phase slip is justified when these fluctuations are the relatively rare events , meaning that the effective resistance of the system should be much smaller than the normal state equivalent . in this paper
we study the limit of the strong quantum fluctuations where the existing models are not applicable .
in particular case of ultra - thin titanium nanowires it is demonstrated that below the expected critical temperature the resistance does not demonstrate any trend towards the conventional for a superconductor zero - resistivity state even at negligibly small measuring currents .
application of a small magnetic field leads to an unusual negative magnetoresistance , which becomes more pronounced at lower temperatures .
the origin of the negative magnetoresistance effect is not clear . .
And you have already written the first three sentences of the full article: since the early years of superconductivity studies it has been noticed that any superconducting transition @xmath0 always has a finite width .
very often sample inhomogeneity is the dominating factor .
however with refinement of fabrication methodology it became clear that even in the most homogeneous samples the @xmath0 transition is not infinitely narrow ..
Please generate the next two sentences of the article | the broadening of the @xmath0 dependence is most pronounced in systems with reduced dimensions where the thermodynamic fluctuations have a larger effect . in particular case of quasi - one - dimensional ( 1d ) channels fluctuation - driven phase slips ,
the concept first introduced by w. little in 1967 @xcite , are responsible for the finite resistivity in a narrow region below the critical temperature @xcite @xmath1 , where @xmath2 is the condensation energy of the smallest statistically independent volume of the wire . soon after formulation of the model @xcite experiments |
6,577 | Suppose that you have an abstract for a scientific paper: a variety of detectors has been proposed for dark matter direct detection , but most of them by the fact are still at r&d stage . in many cases , it is claimed that the lack of an adequate detectors radio - purity might be compensated through heavy uses of montecarlo simulations , subtractions and handlings of the measured counting rates , in order to claim higher sensitivity ( just for a particular scenario ) .
the relevance of a correct evaluation of systematic effects in the use of montecarlo simulations at very low energy ( which has always been safely discouraged in the field so far ) and of multiple subtractions and handling procedures applied to the measured counting rate is shortly addressed here at some extent .
many other aspects would also deserve suitably deep investigations . in this paper
some arguments presented at the taup09 conference will be shortly summarized .
more details , tables and figures can be found in the slides at the conference site@xcite .
let us firstly comment the possibility of reliable evaluations of the background contributions at the kev energy region in the field of dark matter searches . as well known , it has been generally discouraged this procedure in the field of dark matter over more than twenty years .
in fact , the estimation by a montecarlo simulation of the background component in the counting rate from the residual radioactivity requires a detailed knowledge of : i ) the exact set - up geometry ( detector or detectors matrix , all materials , details of the assembling , of the shield layers , of the site , etc . ) ; ii ) the detector response function ( e.g. energy resolution , @xmath0 ratio , channeling , etc . ) ; iii ) the nature , the position and the concentration of all the existing radioactive contaminants ; iv ) etc .. unfortunately , apart from the geometrical layout of the set - up that are generally well known by people inside the experimental group , all the other quantities necessary in the montecarlo simulation require....
And you have already written the first three sentences of the full article: 99 f. nozzoli , presentation given at this conference ( taup 2009 ) http://taup2009.lngs.infn.it/slides/jul3/nozzoli.pdf or http://people.roma2.infn.it/ dama / pdf / nozzoli_taup09.pdf .
r. bernabei et al .
instr . & meth . a 592 ( 2008 ) 297 ..
Please generate the next two sentences of the article | r. bernabei et al .
, isbn 978 - 88 - 95688 - 12 - 1 , pages 1 - 53 ( 2009 ) exorma ed . |
6,578 | Suppose that you have an abstract for a scientific paper: the recent discovery of the @xmath0-ray emission from the lobes of the closest radio galaxy centaurus a by _ fermi _ implies the presence of high - energy electrons at least up to @xmath1 - 10@xmath2 .
these high - energy electrons are required to interpret the observed @xmath0-ray radiation in terms of inverse compton emission off the cosmic microwave background ( ic / cmb ) ; the widely accepted scenario to describe the x - ray emission of radio galaxy lobes . in this letter , we consider the giant radio lobes of fr ii radio galaxies showing that it is possible to maintain electrons at energies @xmath0 @xmath3 10@xmath4 - 10@xmath2 , assuming an acceleration scenario ( driven by turbulent magnetic fields ) that compensates the radiative losses .
in addition , we consider the contribution to the diffuse extragalactic @xmath0-ray background due to the ic / cmb emission of friis lobes showing its relevance in the kev to mev energy range . .
And you have already written the first three sentences of the full article: radio galaxies exhibit several extended components on the kpc scale , namely : jets , hotspots and lobes .
the lobes are double structures extended over large scales , roughly symmetrical and ellipsoidal lying on both sides of the active nuclei of radio galaxies .
it was first noticed by fanaroff & riley ( 1974 ) that the relative positions of regions of high and low surface brightness in the extended components of extragalactic radio sources are correlated with their radio luminosity ..
Please generate the next two sentences of the article | it was found that nearly all sources with luminosity @xmath5 @xmath6 2 @xmath7 10@xmath8 @xmath9 w hz@xmath10 str@xmath10 were of class i ( i.e. , fri ) while the brighter sources were nearly all of class ii ( i.e. , frii ) .
fris have a surface brightness which is larger toward their cores while friis have it larger toward their edges . |
6,579 | Suppose that you have an abstract for a scientific paper: non - empirical effective contact pairing forces to be used in self - consistent mean - field calculations are presented .
these pairing forces , constructed so as to reproduce exactly any given microscopic pairing gaps in infinite homogeneous nuclear matter for any isospin asymmetry , are given in analytical form .
as a by - product , this work provides an analytical solution of the bcs gap equations which could be applied to describe various many - body systems . .
And you have already written the first three sentences of the full article: self - consistent mean - field calculations using effective interactions have been very successful in describing the properties and the dynamics of a wide range of nuclei @xcite .
one of the most popular effective interactions are zero - range interactions of the skyrme type because of the fast numerical computations which can thus be performed @xcite .
even though negele and vautherin @xcite showed a long time ago how to obtain effective interactions using nuclear many - body methods , a more empirical approach has been usually followed ..
Please generate the next two sentences of the article | a specific parametric form of the effective interaction is postulated and the unknown parameters are determined _ a posteriori _ so as to reproduce a set of nuclear data selected according to a specific purpose .
the non - uniqueness of the fitting procedure has thus lead to a large number of different parametrizations . |
6,580 | Suppose that you have an abstract for a scientific paper: we study two experimental ways to measure the heavy - quark content of the proton : using the callan - gross ratio @xmath0 and/or azimuthal @xmath1 asymmetry in deep inelastic lepton - nucleon scattering .
our approach is based on the perturbative stability of the qcd predictions for these two quantities .
we resume the mass logarithms of the type @xmath2 and conclude that heavy - quark densities in the nucleon can , in principle , be determined from data on the callan gross ratio and/or azimuthal asymmetry . in particular ,
the charm content of the proton can be measured in future studies at the proposed large hadron electron ( lhec ) and electron ion ( eic ) colliders . .
And you have already written the first three sentences of the full article: the notion of the intrinsic charm ( ic ) content of the proton has been introduced about 30 years ago in works @xcite .
it was shown that , in the light - cone fock space picture , it is natural to expect a five - quark state contribution of the type @xmath3 to the proton wave function @xcite .
this component can be generated by @xmath4 fluctuations inside the proton where the gluons are coupled to different valence quarks ..
Please generate the next two sentences of the article | the original concept of the charm density in the proton @xcite has nonperturbative nature because the five - quark contribution @xmath3 scales as @xmath5 where @xmath6 is the @xmath7-quark mass @xcite . in the middle of nineties , another point of view on the charm content of the proton
has been proposed in the framework of the variable - flavor - number scheme ( vfns ) of quantum chromodynamics ( qcd ) @xcite . |
6,581 | Suppose that you have an abstract for a scientific paper: we discuss the effect of the spin - orbit interaction on the band structure , wave functions and low temperature conductance of long quasi - one - dimensional electron systems patterned in two - dimensional electron gases ( 2deg ) .
our model for these systems consists of a linear ( rashba ) potential confinement in the direction perpendicular to the 2deg and a parabolic confinement transverse to the 2deg .
we find that these two terms can significantly affect the band structure introducing a wave vector dependence to subband energies , producing additional subband minima and inducing anticrossings between subbands .
we discuss the origin of these effects in the symmetries of the subband wave functions . 2 .
And you have already written the first three sentences of the full article: in 1986 , the first experimental realisation of a quasi - one - dimensional electron system ( q1des ) in a dynamically confined two - dimensional electron gas ( 2deg ) was achieved @xcite . since
then there has been an extensive theoretical and experimental effort into understanding their basic properties ( see , e.g. , review @xcite and book @xcite and references therein ) .
the interest in these systems stems from two facts ..
Please generate the next two sentences of the article | first , the effective transverse size of a q1des can be easily controlled and made remarkably small , down to the de broglie wavelength of an electron .
this makes it possible to realise experimental systems which have an arbitrary number of occupied transverse modes . |
6,582 | Suppose that you have an abstract for a scientific paper: the impacts of both exchange interaction and electron correlation , as well as their combined impact , on electron elastic scattering off a semifilled shell mn( ... @xmath0@xmath1 , @xmath2 ) atom are theoretically studied in the electron energy range of @xmath3 ev . corresponding elastic scattering phase shifts @xmath4 as well as
partial @xmath5 and total @xmath6 cross sections are found to be subject to a strong correlation impact .
the latter is shown to be drastically different for oppositely spin - polarized scattered electrons , in some cases , thereby bringing significant differences in corresponding @xmath4s , @xmath5s , and @xmath6s between said electrons .
this is proven to be an inherent features of electron scattering off a semifilled shell atom in general .
electron correlation is accounted for in the framework of the self - energy part @xmath7 of the green function of a scattered electron concept .
the latter is calculated both in the second - order perturbation theory in the coulomb interelectron interaction as well as beyond it by solving the dyson equation for @xmath7 .
the significance of the `` dyson '' correlation corrections in e@xmath8mn scattering is unraveled .
they are shown to aggravate noticeably the inherent differences between elastic scattering phase shifts and cross sections of spin - up ( @xmath9 ) and spin - down ( @xmath10 ) polarized electrons scattered off a spin - polarized mn atom , in some cases .
in particular , the existence of a narrow resonant maximum in @xmath11 near @xmath12 ev but the absence of such in @xmath13 in e@xmath8mn scattering is predicted . .
And you have already written the first three sentences of the full article: the @xmath0 semifilled shell mn( ... @xmath0@xmath1 ,
@xmath2 ) atom has long served as the bridge to , and touchstone for , a better understanding of the interaction of transition metal atoms with x - ray and vacuum - ultraviolet radiations from early days ( see , e.g. , works by connerade et.al .
@xcite , davis and feldkamp @xcite , amusia et.al ..
Please generate the next two sentences of the article | @xcite ) to now ( see review papers by sonntag and zimmermann @xcite , martins et.al .
@xcite , as well as some of the most recent papers by frolov et.al . |
6,583 | Suppose that you have an abstract for a scientific paper: big bang nucleosynthesis ( bbn ) is affected by the energy density of a primordial magnetic field ( pmf ) . for an easy derivation of constraints on models for pmf generations
, we assume a pmf with a power law ( pl ) distribution in wave number defined with a field strength , a pl index , and maximum and minimum scales at a generation epoch .
we then show a relation between pl - pmf parameters and the scale invariant ( si ) strength of pmf for the first time .
we perform a bbn calculation including pmf effects , and show abundances as a function of baryon to photon ratio @xmath0 .
the si strength of the pmf is constrained from observational constraints on abundances of @xmath1he and d. the minimum abundance of @xmath2li / h as a function of @xmath0 slightly moves to a higher @xmath2li / h value at a larger @xmath0 value when a pmf exists during bbn .
we then discuss degeneracies between the pl - pmf parameters in the pmf effect .
in addition , we assume a general case in which both the existence and the dissipation of pmf are possible . it is then found that an upper limit on the si strength of the pmf can be derived from a constraint on @xmath1he abundance , and that a lower limit on the allowed @xmath2li abundance is significantly higher than those observed in metal - poor stars . .
And you have already written the first three sentences of the full article: element abundances in the early universe are important observables to determine the features of the physical processes at the epoch of big bang nucleosynthesis ( bbn ) . from a discovery of expansion of universe @xcite and the development of the cosmological theory @xcite ,
it was suggested that the early universes was enough hot and dense enough to allow nuclear fusion to be operative , which is the original idea of bbn @xcite .
it was assumed that radiative neutron capture reaction generates primordial elements in hot and dense conditions ..
Please generate the next two sentences of the article | however , neutrons and protons can be converted to each other via weak interactions .
hayashi studied this effect and proposed that bbn started from not a pure neutron gas , but a hybrid gas composed of neutrons and protons as well as radiation @xcite . |
6,584 | Suppose that you have an abstract for a scientific paper: in the analysis a status and parameters of the scalar , vector , and tensor mesonic resonances are obtained and compared with other results . possible classification of the resonance states in terms of the su(3 ) multiplets is discussed .
* outline : * * motivation * method of analysis * analysis of the isoscalar - scalar sector * analysis of the isovector @xmath0-wave of @xmath1 scattering * analysis of the isoscalar - tensor sector * spectroscopic implications from the analysis .
And you have already written the first three sentences of the full article: the spectroscopy of light mesons plays an important role in understanding the strong interactions at low energies . among possibilities to study the spectrum of light mesons , analysis of the @xmath1 interaction
is particularly useful and , therefore , it has always been an object of continuous theoretical and experimental investigation @xcite . here , we present results of the coupled - channel analysis of data on processes @xmath2 in the channels with @xmath3 and @xmath4 and on the @xmath1 scattering in the channel with @xmath5 .
the scalar sector is problematic up to now especially as to an assignment of the discovered mesonic states to quark - model configurations in spite of a big amount of work devoted to these problems ( see , _ e.g. _ , ref ..
Please generate the next two sentences of the article | @xcite and references therein ) .
an exceptional interest to this sector is supported by the fact that there , possibly indeed , we deal with a glueball @xmath6 ( see , _ |
6,585 | Suppose that you have an abstract for a scientific paper: integral expressions for positive - part moments @xmath0 ( @xmath1 ) of random variables @xmath2 are presented , in terms of the fourier - laplace or fourier transforms of the distribution of @xmath2 . a necessary and sufficient condition for the validity of such an expression
is given .
this study was motivated by extremal problems in probability and statistics , where one needs to evaluate such positive - part moments .
address : department of mathematical sciences + michigan technological university + houghton , michigan 49931 , usa + e - mail : ` [email protected] ` + telephone : 906 - 487 - 2108 running head : positive - part moments via the fourier - laplace transform .
And you have already written the first three sentences of the full article: in a number of extremal problems in probability and statistics ( see e.g. @xcite ) one needs to evaluate the positive - part moments @xmath0 of random variables ( r.v.s ) @xmath2 , where @xmath3 , the positive part of @xmath4 , and @xmath5 , for any @xmath6 and @xmath1 .
in particular , an effective procedure was needed in @xcite to compute @xmath0 for @xmath7 and r.v.s of the form @xmath8 , where @xmath9 are positive real numbers , @xmath10 , @xmath11 and @xmath12 are independent r.v.s , @xmath11 has the normal distribution with parameters @xmath13 and @xmath14 , and @xmath12 has the poisson distribution with parameter @xmath15 . for purely normal r.v.s @xmath2 ( without the poisson component ) such
a computation is easy ..
Please generate the next two sentences of the article | however , the naive approach , by the formula @xmath16 did not work well , especially when @xmath17 is small . on the other hand , the series of the form @xmath18 ( which is the laplace - fourier transform of the poisson distribution ) is easily computable .
therefore , a natural idea was to perform a harmonic analysis of the function @xmath19 . |
6,586 | Suppose that you have an abstract for a scientific paper: the combination of mid - infrared and recent submm / mm measurements allows us to set up the first comprehensive spectral energy distribution ( sed ) of the circumstellar material around a young brown dwarf .
simple arguments suggest that the dust is distributed in the form of a disk .
we compare basic models to explore the disk parameters .
the modeling shows that a flat disk geometry fits well the observations .
a flared disk explains the sed _ only _ if it has a puffed - up inner rim and an inner gap much larger than the dust sublimation radius .
similarities and differences with disks around t tauri stars are discussed . .
And you have already written the first three sentences of the full article: hundreds of brown dwarfs ( bds ) have been discovered in the last few years , both within star - forming regions @xcite and among field stars @xcite . still
very little is known about their formation processes .
first indications that bds may form as ordinary stars , i.e. via accretion from a circumstellar disk , come from observations of h@xmath0 @xcite and near - infrared excess emission @xcite ..
Please generate the next two sentences of the article | however , in the case of bds only excess emission at longer wavelengths provides the indisputable evidence for the presence of circumstellar material @xcite . thermal emission of warm dust around bds has been observed by a number of groups @xcite .
very recently , our search for submm / mm emission from young bds provided the first detection of cold dust around two of them @xcite . |
6,587 | Suppose that you have an abstract for a scientific paper: recent results from searches for new physics at hera are reviewed . exploiting the uniqueness of lepton - hadron collisions at high energy ,
searches are performed for electron - quark resonant states ( leptoquarks or squarks in @xmath0-parity - violating supersymmetry ) or excited states of fermions .
new phenomena at a very high energy scale , manifested at present energies as effective four - fermion contact interaction , are also investigated , including cases with lepton - flavor violation .
finally , the status of events with a high - energy lepton and missing transverse momentum is presented , resulting in the most stringent constraint on the flavor - changing neutral current @xmath1-@xmath2-@xmath3 coupling which could yield single - top production .
= 14.5pt .
And you have already written the first three sentences of the full article: hera collides an electron or positron beam of 27.5 gev and a proton beam of 920 gev ( 820 gev until 1997 ) , yielding 318 gev ( 300 gev ) center - of - mass energy ( @xmath4 ) .
the square of the momentum transfer ( @xmath5 ) in deep inelastic scattering ( dis ) can reach several times @xmath6 , which means that the structure of the proton is probed with a wavelength as small as one thousandth ( @xmath7 cm ) of its radius . during the years 1994 - 2000 , each of the two collider experiments , h1 and
zeus , has collected approximately 110 @xmath8 of @xmath9 and 15 @xmath8 of @xmath10 data . with these data ,.
Please generate the next two sentences of the article | the experiments are sensitive to rare processes with a cross section of a fraction of a picobarn , and searches for exotic signals of physics beyond the standard model ( sm ) are extensively performed .
possible signals of new physics include : * resonant states formed by electron - quark fusion . examples of such states are leptoquarks or squarks ( superpartners of quarks ) in supersymmetry ( susy ) with @xmath0-parity violation . |
6,588 | Suppose that you have an abstract for a scientific paper: bose - einstein condensation ( bec ) of an ideal gas is investigated , beyond the thermodynamic limit , for a finite number @xmath0 of particles trapped in a generic three - dimensional power - law potential .
we derive an analytical expression for the condensation temperature @xmath1 in terms of a power series in @xmath2 , where @xmath3 denotes the zero - point energy of the trapping potential .
this expression , which applies in cartesian , cylindrical and spherical power - law traps , is given analytically at infinite order .
it is also given numerically for specific potential shapes as an expansion in powers of @xmath4 up to the second order .
we show that , for a harmonic trap , the well known first order shift of the critical temperature @xmath5 is inaccurate when @xmath6 , the next order ( proportional to @xmath7 ) being significant . we also show that finite size effects on the condensation temperature cancel out in a cubic trapping potential , _
e.g. _ @xmath8 .
finally , we show that in a generic power - law potential of higher order , _
e.g. _ @xmath9 with @xmath10 , the shift of the critical temperature becomes positive .
this effect provides a large increase of @xmath1 for relatively small atom numbers .
for instance , an increase of about + 40% is expected with @xmath11 atoms in a @xmath12 trapping potential . .
And you have already written the first three sentences of the full article: bose - einstein condensation , first predicted in the years 1924 - 25 @xcite , was observed in 1995 on rubidium and sodium vapors @xcite .
these remarkable experiments have generated since then a clear interest in the critical properties of this dilute macroscopic quantum state of matter .
in particular , the transition temperature @xmath1 is a crucial parameter whose exact determination has been a matter of discussion for decades @xcite ..
Please generate the next two sentences of the article | it is indeed rather difficult to estimate the influence of atomic interactions on the condensation temperature for a _ uniform _ dilute weakly interacting bose gas .
this comes from the fact that this is a many - body problem affected by long - range critical fluctuations which have to be described non - perturbatively @xcite . as a consequence , |
6,589 | Suppose that you have an abstract for a scientific paper: the existence , uniqueness , and asymptotic behavior of steady transonic flows past a curved wedge , involving transonic shocks , governed by the two - dimensional full euler equations are established .
the stability of both weak and strong transonic shocks under the perturbation of both the upstream supersonic flow and the wedge boundary is proved .
the problem is formulated as a one - phase free boundary problem , in which the transonic shock is treated as a free boundary .
the full euler equations are decomposed into two algebraic equations and a first - order elliptic system of two equations in lagrangian coordinates . with careful elliptic estimates by using appropriate weighted hlder norms , the iteration map is defined and analyzed , and the existence of its fixed point is established by performing the schauder fixed point argument .
the careful analysis of the asymptotic behavior of the solutions reveals particular characters of the full euler equations . .
And you have already written the first three sentences of the full article: we are concerned with the existence , uniqueness , and asymptotic behavior of steady transonic flows past a curved wedge , involving transonic shocks , governed by the two - dimensional full euler equations .
when a supersonic flow past a straight - sided wedge whose half - angle is less than the detachment angle , a shock is expected to form , which is attached to the wedge vertex . if the upstream steady flow is a uniform supersonic state , we can find the corresponding constant flow downstream along the straight - sided wedge boundary , together with a straight shock separating the two states ( see fig .
[ fig - perturbedshock ] ) , by using the shock polar determined by the rankine - hugoniot jump conditions and the entropy condition ( _ cf ..
Please generate the next two sentences of the article | [ fig - shockpolaruv ] ) .
however , the downstream state is not uniquely solvable . in general , there are two solutions |
6,590 | Suppose that you have an abstract for a scientific paper: in the present work , we study morphologies arising due to competing substrate interaction , electric field and confinement effects on a symmetric diblock copolymer . we employ a coarse grained non - local cahn - hilliard phenomenological model taking into account the appropriate contributions of substrate interaction and electrostatic field . the proposed model couples the ohta - kawasaki functional with maxwell equation of electrostatics , thus alleviating the need for any approximate solution used in previous studies .
we calculate the phase diagram in electric field - substrate strength space for different film thicknesses .
in addition to identifying the presence of parallel , perpendicular and mixed lamellae phases similar to analytical calculations , we also find a region in the phase diagram where hybrid morphologies ( combination of two phases ) coexist .
these hybrid morphologies arise either solely due to substrate affinity and confinement or are induced due to the applied electric field .
the dependence of the critical fields for transition between the various phases on substrate strength , film thickness and dielectric contrast is discussed .
some preliminary 3d results are also presented to corroborate the presence of hybrid morphologies . .
And you have already written the first three sentences of the full article: self - assembly of block copolymers has been an actively pursued field of study because of its wide technological implications @xcite .
depending upon the volume fraction of the components and segregation regime , block copolymers exhibit a range of periodic morphologies such as lamellae , gyroids , cylinders , spheres etc.@xcite as we intend to study symmetric diblock copolymers which order into lamellar structure , the rest of the paper will focus only on this particular morphology . in the absence of any external field , a symmetric diblock copolymer forms domains of lamellar morphology with various degrees of alignment .
practical applications , however , require complete alignment of the microphase separated domains . in general this can be achieved by application of external fields , primary among them being substrate field @xcite , shear field @xcite and electric field @xcite . since the microphase separation generally takes place on a substrate , it is impractical to assume that the experiments are devoid of surface effects . typically , interfacial energy difference between the two blocks in contact with a substrate ( i.e @xmath0 , where @xmath1 and @xmath2 are the interfacial energies between a monomer a or b and substrate s ) can cause surface induced ordering resulting in parallel arrangement of the domains with respect to the surface @xcite ..
Please generate the next two sentences of the article | if the copolymer system is confined between two rigid substrate walls , two different interaction cases may be considered , ( a ) the walls are symmetric i.e. both walls attract the same monomer and ( b ) antisymmetric walls i.e. both walls attract different monomers @xcite . as shown in fig .
[ fig1 ] ( a ) and ( b ) , the system either forms integral @xmath3 or half - integral @xmath4 number of lamellae , where @xmath5 is the equilibrium lamellar spacing , depending on whether the wall is symmetric or antisymmetric respectively @xcite . if the film thickness is incommensurate with the lamellar spacing , the copolymers are said to be in a frustrated state @xcite . |
6,591 | Suppose that you have an abstract for a scientific paper: in this work , we show that the quantum compass model on an square lattice can be mapped to a fermionic model with local density interaction . we introduce a mean - field approximation where the most important fluctuations , those perpendicular to the ordering direction , are taken into account exactly .
it is found that the quantum phase transition point at @xmath0 marks a first order phase transition .
we also show that the mean field result is robust against the remaining fluctuation corrections up to the second order . .
And you have already written the first three sentences of the full article: quantum compass model @xcite has recently attracted great interests @xcite .
it was originally proposed as a simplified model to describe some mott insulators with orbit degeneracy described by a pseudospin . in particular
, compass model describes a system where the anisotropy of the spin coupling is related to the orientation of bonds ..
Please generate the next two sentences of the article | more recently , it was also proposed as a realistic model to generate protected qubits @xcite .
it has been argued that the eigenstates of the quantum compass model are two and only two fold degenerate @xcite . |
6,592 | Suppose that you have an abstract for a scientific paper: we construct the gravitational solution of the witten - sakai - sugimoto model by introducing a magnetic field on the flavor brane . with taking into account their backreaction ,
we re - solve the type iia supergravity in the presence of the magnetic field .
our calculation shows the gravitational solutions are magnetic - dependent and analytic both in the confined and deconfined case .
we study the dual field theory at the leading order in the ratio of the number of flavors and colors , also in the veneziano limit . some physical properties related to the hadronic physics in an external magnetic field
are discussed by using our confined backreaction solution holographically .
we also study the thermodynamics and holographic renormalization of this model in both phases by our magnetic - dependent solution .
since the backreaction of the magnetic field is considered in our gravitational solution , it allows us to study the hawking - page transition with flavors and colors of this model in the presence of the magnetic field .
finally we therefore obtain the holographic phase diagram with the contributions from the flavors and the magnetic field .
our holographic phase diagram is in agreement with lattice qcd result qualitatively , which thus can be interpreted as the inhibition of confinement or chirally broken symmetry by the magnetic field .
si - wen li and tuo jia _ department of modern physics , _ + _ university of science and technology of china , _ + _ hefei 230026 , anhui , china _ .
And you have already written the first three sentences of the full article: recent years , in some results from lattice qcd @xcite , it seems the qcd phase could be changed by a strong magnetic field . by the analysis of some thermodynamic observables ,
it has been found the critical temperature of the crossover region should fall when the magnetic field increases @xcite .
it implies the confinement / deconfinement phase transition or the chiral phase transition @xcite would tend to be induced by a strong magnetic field . with the mit bag model , this result could be reproduced qualitatively @xcite , reflecting the great significance of quark confinement ..
Please generate the next two sentences of the article | furthermore , the approach of large-@xmath0 qcd has already been considered in @xcite . from the analysis of the flavor correction @xmath1 to the pressure , this effect has also been obtained due to the quark degrees of freedom .
on the other hand , gauge / gravity duality or ads / cft has become a framework to understand non - perturbative aspects of strong - coupled quantum field theory @xcite . |
6,593 | Suppose that you have an abstract for a scientific paper: @xmath0 summary : we study conformations assumed by single diblock star copolymers in a poor solvent by means of the gaussian variational theory and monte carlo simulation in continuous space .
cases of stars with internal and external hydrophobic blocks are analysed .
while in the former case the collapsed state has an obvious micellar shape , the latter case exhibits two nontrivial conformational structures .
apart from the equilibrium state of a globular hydrophobic core with hydrophilic daisy loops , one also finds here a metastable state of outstretched hydrophilic blocks with hydrophobic subglobules at their ends .
such a state appears to be rather long lived during the kinetics of collapse of a swollen star .
the plots of monomer densities and other observables computed by both techniques are found to be in good agreement with each other . .
And you have already written the first three sentences of the full article: presently there is a great deal of interest in properties of amphiphilic copolymers because of the variety and extent of conformational transitions they show under a temperature or ph variation @xcite .
for instance , as such copolymers contain both hydrophobic and hydrophilic ( polar ) monomers they can form monomolecular micelles with a hydrophobic core in water , as well as inverted micelles in apolar solvents . furthermore , these systems have an interesting analogy to globular proteins in the folded state @xcite . for a discussion of similarities between `` coarse grained '' features of proteins and those of amphiphilic polymers we refer to ref .
@xcite ..
Please generate the next two sentences of the article | linear copolymers , in particular linear diblock copolymers , would aggregate under certain conditions , giving rise to a fascinating range of self assembled supramolecular ordering in the absence of solvent @xcite , and therefore the main issues of study traditionally have been the critical micelle concentration and the solid state morphology . on the other hand ,
the possibility of forming monomolecular micelles is greatly increased by using more complicated topologies , for instance star or comb polymers @xcite . |
6,594 | Suppose that you have an abstract for a scientific paper: we examine the potential of the compass experiment at cern to study color transparency via exclusive vector meson production in hard muon - nucleus scattering . it is demonstrated that compass has high sensitivity to test this important prediction of perturbative qcd .
2(c)^2 ps .
|_| 2r^2 2@xmath0 2c2gev@xmath1/@xmath2 2 ^ 2 # 1#2#3#4#1 * # 2 * , # 3 ( # 4 ) 2 2pigamma taup-2671 - 2001 + 12 june 2001 + feasibility study + @xmath3 sotan institute for nuclear studies , ul . hoa 69 , pl 00 - 681 warsaw , poland , @xmath4 school of physics and astronomy , r. and b. sackler faculty of exact sciences , + tel aviv university , 69978 ramat aviv , israel _ e - mails : [email protected] , [email protected] , [email protected] , [email protected]_ .
And you have already written the first three sentences of the full article: ( ct ) is a phenomenon of perturbative qcd ( pqcd ) , whose characteristic feature is that small color - singlet objects interact with hadrons with small cross sections @xcite .
cross section for the interaction of such small object , or small size configuration ( ssc ) , with a hadron target has been calculated in qcd using the factorization theorem @xcite .
these qcd calculations confirmed the hypothesis of f. low @xcite on smallness of the cross section for the interaction of ssc with a hadron , if the gluon density in the hadron is not very high ( moderately small @xmath5 ) ..
Please generate the next two sentences of the article | they also predict a related phenomenon of _ color opacity _ when the gluon density becomes very large ( at small @xmath5 ) and ssc interacts with the hadron with large cross section @xcite .
the prerequisite for observing ct is to select a sample containing ssc s via a hard process ( i.e. with large @xmath6 , high @xmath7 , or large produced mass ) . to suppress non - perturbative ( not ssc ) background different additional restrictions |
6,595 | Suppose that you have an abstract for a scientific paper: we study the renormalization group flow of @xmath0-invariant supersymmetric and non - supersymmetric scalar models in the local potential approximation using functional renormalization group methods .
we focus our attention on the fixed points of the renormalization group flow of these models , which emerge as scaling solutions . in two dimensions
these solutions are interpreted as the minimal ( supersymmetric ) models of conformal field theory , while in three dimensions they are manifestations of the wilson - fisher universality class and its supersymmetric counterpart .
we also study the analytically continued flow in fractal dimensions between @xmath1 and @xmath2 and determine the critical dimensions for which irrelevant operators become relevant and change the universality class of the scaling solution .
we include novel analytic and numerical investigations of the properties that determine the occurrence of the scaling solutions within the method .
for each solution we offer new techniques to compute the spectrum of the deformations and obtain the corresponding critical exponents . .
And you have already written the first three sentences of the full article: the birth of functional renormalization group methods is tightly connected to the investigation of scaling properties of the effective potential in statistical field theories with @xmath0 or @xmath3 symmetries @xcite , and it represents its first non - trivial application @xcite . over the years
the interest in properties that can be extracted from the renormalization group flow of the potential in a local approximation has been revitalized at various stages @xcite .
the effective potential of a @xmath0-symmetric scalar field theory has been studied with various techniques to unveil the underlying universality classes , which include the ising model ..
Please generate the next two sentences of the article | the critical exponents have been determined to high accuracy within polynomial expansions @xcite and non - polynomial solutions have been studied numerically by applying scaling solutions methods @xcite . recently
, even global solutions have been constructed with very high numerical precision @xcite . in the past few years |
6,596 | Suppose that you have an abstract for a scientific paper: the crossing of the galactic disk by a globular cluster could produce star formation due to gravitational focussing or compression of disk material .
we report on simulations of the effect on disk material which reveal that the crossing can sometimes cause local gravitational focussing of disk material .
we also present the salient points of a little - known paper by levy ( 2000 ) , that shows that strong compression can result from the shock wave generated by gc disk crossing .
the main thrust of our paper is a search for remnants of disk crossings by globular clusters . using
the gravitational potential of the galaxy to locate the position of the most recent crossings of a subset of fifty - four globular clusters reveals that systematic errors and uncertainties in initial conditions limit the scope for unequivocal identification . from the subset of fifty - four ,
six possible search sites with the best constraints are retained for further scrutiny .
three of the six potentially promising search areas in the disk are from globular clusters ngc 3201 , 6397 and ngc 6838 , for which we can not rule out some observed star associations observed nearby as being remnants .
the three other of the six areas are too large to provide meaningful identification of remnants .
also , a possible remnant ( open cluster ngc6231 ) is shown not to be due to globular cluster impact , contrary to a previous report . in a more wide - ranging screening of one hundred and fifty - five globular clusters we identify which globular clusters are compatible with being responsible for the formation of any of the galaxy s five most prominent star super clusters . [ firstpage ]
galaxy : disk globular clusters : general . .
And you have already written the first three sentences of the full article: one of the less - studied interactions within our galaxy concerns the effect of the passage of a globular cluster ( gc ) through the disk , on the disk itself . on average
, one globular cluster will cross the galactic disk about every million years . while the globular cluster is in the vicinity of the disk , its gravitational field will attract stars and gas in the disk . the result could be a density increase sufficient to cause star formation . whereas the impacts of high velocity clouds with the disk have been examined in some detail ( comern and torra , 1994 ) ,
as they cause gas compression and star formation ( and are perhaps the origin of the gould belt ) , the effect of gc impacts on the disk has received almost no attention ..
Please generate the next two sentences of the article | the earliest mention of the effect of disk crossing by a globular cluster on the disk , is from brosche et al .
( 1991 ) who calculated the orbits of globular clusters ngc362 and ngc6218 , and suggested observers examine their latest crossing points , to see whether any remnants may be present . |
6,597 | Suppose that you have an abstract for a scientific paper: we point out an apparently overlooked consequence of the boundary conditions obeyed by the electric displacement vector at air - metal interfaces : the continuity of the normal component combined with the quantum mechanical penetration of the electron gas in the air implies the existence of a surface on which the dielectric function vanishes .
this , in turn , leads to an enhancement of the normal component of the total electric field .
we study this effect for a planar metal surface , with the inhomogenous electron density accounted for by a jellium model .
we also illustrate the effect for equilateral triangular nanoislands via numerical solutions of the appropriate maxwell equations , and show that the field enhancement is several orders of magnitude larger than what the conventional theory predicts . .
And you have already written the first three sentences of the full article: electromagnetic field enhancement in nanoplasmonic structures plays an important role in a number of applications such as nano antennas @xcite , single - photon emitters @xcite , and surface - enhanced spectroscopy techniques in general @xcite , including surface - enhanced raman spectroscopy ( sers ) @xcite .
field localization is the key to understanding and further enhancing the resolution of sers , and the use of highly engineered surface plasmonic structures has been envisioned @xcite .
strong field enhancement has so far been inherently connected to singularities @xcite ..
Please generate the next two sentences of the article | it is commonplace to study the plasmonic response using maxwell s equations with the bulk dielectric function of the metal , with an abrupt change at the air - metal interface @xcite .
though clearly neglecting surface and confinement effects for the electrons in the metal , this is a celebrated approximation which predicts the existence of surface plasmons forming the heart of nanoplasmonics . |
6,598 | Suppose that you have an abstract for a scientific paper: the correlated motion of electrons in the presence of strong orbital fluctuations and correlations is investigated with respect to magnetic couplings and excitations in an orbitally degenerate ferromagnet within the framework of a non - perturbative goldstone - mode - preserving approach based on a systematic inverse - degeneracy expansion scheme .
introduction of the orbital degree of freedom results in a class of diagrams representing spin - orbital coupling which become particularly important near the orbital ordering instability .
low - energy staggered orbital fluctuation modes , particularly with momentum near @xmath0 ( corresponding to period @xmath1 orbital correlations as in ce phase of manganites involving staggered arrangement of nominally @xmath2 ions , and staggered ordering of occupied @xmath3 orbitals on alternating @xmath4 sites ) , are shown to generically yield strong intrinsically non - heisenberg @xmath5 magnon self energy correction , resulting in no spin stiffness reduction , but strongly suppressed zone - boundary magnon energies in the @xmath6-x direction .
the zone - boundary magnon softening is found to be strongly enhanced with increasing hole doping and for narrow - band materials , which provides insight into the origin of zone - boundary anomalies observed in ferromagnetic manganites . .
And you have already written the first three sentences of the full article: the orbital degree of freedom of the electron has attracted considerable attention in recent years due to the rich variety of electronic , magnetic , and transport properties exhibited by orbitally degenerate systems such as the ferromagnetic manganites , which have highlighted the interplay between spin and orbital degrees of freedom in these correlated electron systems.@xcite orbital fluctuations , correlations , and orderings have been observed in raman spectroscopic studies@xcite of orbiton modes in @xmath7 , polarization - contrast - microscopy studies@xcite of @xmath8 , magnetic susceptibility and inelastic neutron scattering studies@xcite of @xmath9 , and resonant inelastic soft x - ray scattering studies@xcite of @xmath10 and @xmath11 . a new detection method for orbital structures and ordering based on spectroscopic imaging scanning tunneling microscopy is of strong current interest@xcite in orbitally active metallic systems such as strontium ruthenates and iron pnictide superconductors .
the role of orbital fluctuations on magnetic couplings and excitations is of strong current interest in view of the several zone - boundary anomalies observed in spin - wave excitation measurements in the metallic ferromagnetic phase of colossal magnetoresistive ( cmr ) manganites.@xcite the presence of short - range dynamical orbital fluctuations has been suggested in neutron scattering studies of ferromagnetic metallic manganite @xmath12.@xcite these observations are of the crucial importance for a quantitative understanding of the carrier - induced spin - spin interactions , magnon excitations , and magnon damping , and have highlighted possible limitations of existing theoretical approaches .
for example , the observed magnon dispersion in the @xmath6-x direction shows significant softening near the zone boundary , indicating non - heisenberg behaviour usually modeled by including a fourth neighbour interaction term @xmath13 , and highlighting the limitation of the double - exchange model ..
Please generate the next two sentences of the article | similarly , the prediction of magnon - phonon coupling as the origin of magnon damping@xcite and of disorder as the origin of zone - boundary anomalous softening@xcite have been questioned in recent experiments.@xcite furthermore , the dramatic difference in the sensitivity of long - wavelength and zone - boundary magnon modes on the density of mobile charge carriers has emerged as one of the most puzzling feature . observed for a finite range of carrier concentrations , while the spin stiffness remains almost constant , the anomalous softening and broadening of the zone - boundary modes show substantial enhancement with increasing hole concentration.@xcite theoretically , the role of orbital - lattice fluctuations and correlations on magnetic couplings and excitations has been investigated within an orbitally degenerate double exchange model with an inter - orbital interaction @xmath14 and the jahn - teller coupling.@xcite based on a strong coupling expansion , this approach is restricted to the strong coupling limit @xmath15 .
the final calculations for the magnon self energy , carried out in terms of a phenomenological parameter , show significant zone - boundary magnon softening only for ferromagnetic orbital correlations , and extremely close to the orbital ordering instability . |
6,599 | Suppose that you have an abstract for a scientific paper: we present multicolor optical observations of the nearby ( @xmath0 ) grb030329 obtained with the same instrumentation over a time period of 6 hours for a total of an unprecedented 475 quasi - simultaneous @xmath1 observations .
the achromatic steepening in the optical , which occurs at @xmath2days , provides evidence for a dynamic transition of the source , and can be most readily explained by models in which the grb ejecta are collimated into a jet . since the current state - of - the - art modeling of grb jets is still flawed with uncertainties , we use these data to critically assess some classes of models that have been proposed in the literature
. the data , especially the smooth decline rate seen in the optical afterglow , are consistent with a model in which grb030329 was a homogeneous , sharp - edged jet , viewed near its edge interacting with a uniform external medium , or viewed near its symmetry axis with a stratified wind - like external environment .
the lack of short timescale fluctuations in the optical afterglow flux down to the 0.5 per cent level puts stringent constraints on possible small scale angular inhomogeneities within the jet or fluctuations in the external density . .
And you have already written the first three sentences of the full article: a watershed event occurred on 29 march 2003 when _ hete - ii _ localized rapidly a long grb @xcite .
the prompt discovery of the fading optical counterpart @xcite combined with its exceptional brightness allowed densely sampled observations of this afterglow ( lipkin et al .
2004 and references therein ) . at @xmath0 @xcite ,.
Please generate the next two sentences of the article | grb030329 is the third closest grb to date for which an optical afterglow ( oa ) has been discovered .
it is by detailed study of such nearby events that we have learned the most about the range of physical processes relevant to grbs . |
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