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5,900 | Suppose that you have an abstract for a scientific paper: we compute the magnetic profile of spin peierls solitons in a simple heisenberg model with magneto elastic couplings , using independently the dmrg method of white and the hartree fock approximation .
the results obtained in such a static model are incompatible with existing nmr data on cugeo , but the distribution of averaged spins agrees qualitatively with the data .
we conclude that the dynamics in the spin plus lattice system must be included in a more detailed theory of the spin peierls transition in cugeo .
pacs numbers : 75.10.jm , 75.50.ee , 76.60.-k .
And you have already written the first three sentences of the full article: spin peierls compounds such as cugeo have solitons in their incommensurate phase @xcite the magnetic profile of which can be measured by nmr techniques @xcite and which must be accounted for by any theoretical model . recently a systematic study of solitons in the heisenberg spin peierls model was done by quantum monte carlo methods@xcite , with results that differ essentially from those obtained in the xy model@xcite . however
, these authors did not determine the distribution of spins and the corresponding nmr signal in the incommensurate phase , which are the subject of the present paper .
here we calculate the magnetic structure of solitons in the heisenberg spin peierls model via the dmrg method of white @xcite and also within the hartree fock approximation @xcite ..
Please generate the next two sentences of the article | our ( essentially exact ) dmrg results in the dimerised phase agree with those of ref@xcite and they are also surprisingly close to the results of a hartree fock calculation . the magnetic profiles in the incommensurate phase that we compute by hartree fock disagree with those reconstructed from nmr data @xcite .
however , if we eliminate the oscillations in these profiles by averaging over even and odd sites , we find spin distributions that agree qualitatively with those obtained by nmr in ref[@xcite ] . the spin gap peierls in cugeo and similar materials @xcite may be due to ( i ) magnetoelastic couplings @xcite and/or ( ii ) interactions among the chains @xcite . |
5,901 | Suppose that you have an abstract for a scientific paper: we study the quantum phase transition between the superfluid and the mott insulator in the one - dimensional ( 1d ) bose - hubbard model . using the time - evolving block decimation method
, we numerically calculate the tunneling splitting of two macroscopically distinct states with different winding numbers . from the scaling of the tunneling splitting with respect to the system size
, we determine the critical point of the superfluid to mott insulator transition for arbitrary integer filling factors .
we find that the critical values versus the filling factor in 1d , 2d , and 3d are well approximated by a simple analytical function .
we also discuss the condition for determining the transition point from a perspective of the instanton method . .
And you have already written the first three sentences of the full article: systems of cold atoms in optical lattices have provided a highly controllable testing ground for quantum many - body physics @xcite .
particularly , a transition from superfluid ( sf ) to mott - insulator ( mi ) has attracted much attention . the sf to mi transition
can be induced by increasing the depth of the optical lattice potential , and has been experimentally realized in 1d @xcite , 2d @xcite , and 3d @xcite ..
Please generate the next two sentences of the article | it has been established that a system of cold bosonic atoms in an optical lattice can be quantitatively described by the bose - hubbard ( bh ) model @xcite , @xmath0 when the lattice is sufficiently deep , i.e. in the tight binding regime . here
@xmath1 annihilates a boson at the lowest level localized on the @xmath2th site and @xmath3 is the number operator . |
5,902 | Suppose that you have an abstract for a scientific paper: the upper limit of the total cross section for the @xmath0 reaction has been determined near the kinematical threshold in the excess energy range from 0 to 24 mev .
the measurement was performed using the cosy-11 detector setup , a deuteron cluster target , and the proton beam of cosy with a momentum of 3.35 gev / c .
the energy dependence of the upper limit of the cross section was extracted exploiting the fermi momenta of nucleons inside the deuteron .
comparison of the determined upper limit of the ratio @xmath1 with the corresponding ratio for @xmath2-meson production does not favor the dominance of the @xmath3 resonance in the production process of the @xmath4 meson and suggests nonidentical production mechanisms for @xmath2 and @xmath4 mesons . .
And you have already written the first three sentences of the full article: studies of @xmath2 and @xmath4 mesons and their interactions with nucleons provide an interesting window on axial u(1 ) dynamics .
the flavor - singlet @xmath5 channel is characterized by a large okubo - zweig - iizuka ( ozi ) violation : the masses of the @xmath2 and @xmath6 mesons are 300400 mev larger than the values they would have if these mesons were pure would - be goldstone bosons associated with spontaneously broken chiral symmetry @xcite .
one needs extra mass in the singlet channel associated with nonperturbative topological gluon configurations and the qcd axial anomaly @xcite ..
Please generate the next two sentences of the article | the strange quark mass induces considerable @xmath2-@xmath6 mixing . for the physical @xmath2-@xmath6 mixing angle @xmath7 degrees
, the singlet component in the @xmath2 has the potential to induce a factor of 2 increase in the @xmath2-nucleon scattering length @xmath8 relative to the value one would expect if the @xmath2 were a pure octet state @xcite . |
5,903 | Suppose that you have an abstract for a scientific paper: using a coarse - grained bead - spring model for semi - flexible macromolecules forming a polymer brush , structure and dynamics of the polymers is investigated , varying chain stiffness and grafting density . the anchoring condition for the grafted chains
is chosen such that their first bonds are oriented along the normal to the substrate plane .
compression of such a semi - flexible brush by a planar piston is observed to be a two - stage process : for small compressions the chains contract by `` buckling '' deformation whereas for larger compression the chains exhibit a collective ( almost uniform ) bending deformation .
thus , the stiff polymer brush undergoes a @xmath0-nd order phase transition of collective bond reorientation .
the pressure , required to keep the stiff brush at a given degree of compression , is thereby significantly _ smaller _ than for an otherwise identical brush made of entirely flexible polymer chains ! while both the brush height and the chain linear dimension in the @xmath1-direction perpendicular to the substrate increase monotonically with increasing chain stiffness , lateral @xmath2 chain linear dimensions exhibit a maximum at intermediate chain stiffness .
increasing the grafting density leads to a strong decrease of these lateral dimensions , compatible with an exponential decay .
also the recovery kinetics after removal of the compressing piston is studied , and found to follow a power - law / exponential decay with time . a simple mean - field theoretical consideration , accounting for the buckling / bending behavior of semi - flexible polymer brushes under compression , is suggested . .
And you have already written the first three sentences of the full article: since several decades polymer brushes find abiding interest for various applications , and have been studied very intensively by experiment , analytical theory , and computer simulations @xcite .
the structure of these soft polymeric layers and their response to various external perturbations depends in a delicate way on various control parameters such as molecular weight , grafting density , quality of the solvent , and character of the interactions between monomeric units and the substrate to which the macromolecules are grafted .
however , inspired by the early works @xcite , mostly brushes formed from completely flexible chains were considered , where the elastic response is entirely entropic , due to the configurational degrees of freedom of the tethered chain molecules . in such brushes.
Please generate the next two sentences of the article | , chains may be nevertheless strongly stretched in the direction perpendicular to the substrate , to avoid unfavorable monomer - monomer overlap in the case of sufficiently dense grafting .
effects of intrinsic chain stiffness , as are expected for semi - flexible polymers @xcite , did find rather little attention @xcite , apart from the case where one considers grafted semi - flexible chains in nematic solvents @xcite and their liquid crystalline order @xcite . |
5,904 | Suppose that you have an abstract for a scientific paper: granular flows due to simultaneous vertical and horizontal excitations of a flat - bottomed cylindrical pan are investigated using event - driven molecular dynamics simulations . in agreement with recent experimental results ,
we observe a transition from a solid - like state , to a fluidized state in which circulatory flow occurs simultaneously in the radial and tangential directions . by going beyond the range of conditions explored experimentally , we find that each of these circulations reverse their direction as a function of the control parameters of the motion .
we numerically evaluate the dynamical phase diagram for this system and show , using a simple model , that the solid - fluid transition can be understood in terms of a critical value of the radial acceleration of the pan bottom ; and that the circulation reversals are controlled by the phase shift relating the horizontal and vertical components of the vibrations .
we also discuss the crucial role played by the geometry of the boundary conditions , and point out a relationship of the circulation observed here and the flows generated in vibratory conveyors . .
And you have already written the first three sentences of the full article: in a recent experimental work , sistla , et al .
@xcite observed a novel granular circulation occurring in a flat - bottomed cylindrical container ( or `` pan '' ) subjected to coupled horizontal and vertical vibrations .
the apparatus studied was a commonly available industrial device used mainly for sieving and polishing of granular particles ..
Please generate the next two sentences of the article | of particular interest was the appearance of a `` toroidal '' circulation , in which granular flow occurred simultaneously in the tangential direction ( i.e. a circulation in the horizontal plane about the vertical axis ) , as well as radially ( i.e. particles flowed outward along the bottom surface and then back to the center of the pan along the top surface of the granular bed ) . in this mode ,
the trajectory of a single particle would therefore approximate a helix on the surface of a torus . among several other phenomena |
5,905 | Suppose that you have an abstract for a scientific paper: the previously introduced quantum arnold transformation , a unitary operator mapping the solutions of the schrdinger equation for time dependent quadratic hamiltonians into the solutions for the free particle , is revised and some interesting extensions are introduced , providing in particular a generalization of the ermakov - pinney equation . .
And you have already written the first three sentences of the full article: in @xcite , v.i . arnold introduced a theorem stating that the family of graphs of solutions of any linear second - order differential equation ( lsode ) , with arbitrary time dependent coefficients , is locally diffeomorphic to the family of graphs of solutions of the simplest one - dimensional equation of motion , i.e. , the equation of motion of a free particle .
this important result allows to establish a direct relationship between the symmetries of an arbitrary classical linear system , whose equation of motion is a lsode , with that of the free particle , which is known to have the largest possible symmetry group , @xmath0 ) .
the diffeomorphism was explicitly given in @xcite , namely the classical arnold transformation ( cat ) , and can be seen as a particular class of more general lie transformations relating systems defined by second order differential equations with the free particle @xcite ..
Please generate the next two sentences of the article | in @xcite , the authors , in collaboration with v. aldaya and f. cosso , introduced the quantum version of the cat , the quantum arnold transformation ( henceforth qat ) , as a unitary map that relates the hilbert space of solutions of the time - dependent schrdinger equation for a generalized caldirola - kanai oscillator ( the quantum version of a classical system whose equation of motion is a lsode ) into the corresponding one for the free particle . in the present paper
we revise the qat and extend it in two respects . |
5,906 | Suppose that you have an abstract for a scientific paper: here we present the first results from alma observations of 1 mm polarized dust emission towards the w43-mm1 high mass star forming clump .
we have detected a highly fragmented filament with source masses ranging from 14 to 312 , where the largest fragment , source a , is believed to be one of the most massive in our galaxy .
we found a smooth , ordered , and detailed polarization pattern throughout the filament which we used to derived magnetic field morphologies and strengths for 12 out of the 15 fragments detected ranging from 0.2 to 9 mg .
the dynamical equilibrium of each fragment was evaluated finding that all the fragments are in a super - critical state which is consistent with previously detected infalling motions towards w43-mm1
. moreover , there are indications suggesting that the field is being dragged by gravity as the whole filament is collapsing . .
And you have already written the first three sentences of the full article: w43-mm1 is a large and young high mass star forming clump located within the w43 region and at 5.5 kpc from the sun @xcite .
the clump is near @xmath0 and at an interface with an extended region powered by a cluster of o type and wolf - rayet stars . @xcite .
w43-mm1 has been well studied in continuum from 1.3 mm to 70 @xmath1 m @xcite ..
Please generate the next two sentences of the article | these studies identified a large sample of clumps in w43 , from which w43-mm1 is the most massive with an estimated mass of 2128 and a deconvolved size of 0.09 pc @xcite .
infalling motions have been detected towards w43-mm1 @xcite suggesting that the clump is undergoing gravitational collapse . |
5,907 | Suppose that you have an abstract for a scientific paper: understanding the motion of a tracer particle in a rarefied gas is of fundamental and practical importance .
we report the experimental investigation of individual cs atoms impinging on a dilute cloud of ultracold rb atoms with variable density .
we study the nonequilibrium relaxation of the initial nonthermal state and detect the effect of single collisions which has eluded observation so far .
we show that after few collisions , the measured spatial distribution of the light tracer atoms is correctly described by a generalized langevin equation with a velocity - dependent friction coefficient , over a large range of knudsen numbers .
diffusion is an essential and omnipresent transport phenomenon in nature .
the motion of a tagged particle in a fluid is determined by its mass @xmath0 and by the density of the fluid via the knudsen number @xmath1 @xcite . in the regime of large densities
@xmath2 , the interparticle collision frequency is high and the fluid may be treated as a continuum medium . on the other hand , for low densities @xmath3 , individual collisions matter and
the discrete nature of the fluid is apparent .
the only closed equation applicable to all values of @xmath1 is the boltzmann equation for the phase - space distribution of the particles @xcite
. solutions of this nonlinear kinetic equation have been obtained in the extreme situations of vanishing and infinite knudsen numbers , and in the brownian limit of a heavy tracer particle , @xmath4 , where @xmath5 is the mass of the fluid particles @xcite . however , despite its central importance for the foundations of statistical physics and the study of e.g. fluid flows in the upper atmosphere and aerosols dynamics @xcite , much less is known , both theoretically and experimentally , about the long - standing problem of light tagged particles diffusing in a dilute gas at intermediate @xmath1 @xcite .
an alternative and highly successful description of a tagged particle is offered by the langevin equation @xcite . in....
And you have already written the first three sentences of the full article: the knudsen number is defined as @xmath69 , where @xmath70 is the density - dependent mean - free path within the gas and @xmath71 is the typical length scale associated with the diffusing particle @xcite . for the cs atoms ,
the mean free path is given by @xmath72 , where @xmath73 is the interspecies scattering cross - section and @xmath74 @xcite the @xmath75-wave scattering length between two rb atoms ( @xmath76 is the bohr radius ) . on the other hand , in the absence of the rb cloud ,
the dynamics is dominated by collisions with the trapping potential in the radial directions @xmath77 ..
Please generate the next two sentences of the article | we thus identify @xmath78 , the radial @xmath33 width of the thermal rb cloud with @xmath79 the radial angular trap frequency . despite using ultracold temperatures in the micro kelvin range ,
the dynamics of the atoms in our experiments can be described classically . |
5,908 | Suppose that you have an abstract for a scientific paper: a release of multicolor broad band ( @xmath0 ) photometry for a subsample of 44 isolated spirals drawn from the _ catalogue of isolated galaxies _ ( cig ) is presented .
total magnitudes and colors at various circular apertures , as well as some global structural / morphological parameters are estimated .
morphology is reevaluated through optical and sharp / filtered @xmath1 band images , ( @xmath2 ) color index maps , and archive near ir @xmath3 images from the two micron survey .
the @xmath4 structural parameters ( concentration , asymmetry , and clumpiness ) were calculated from the images in each one of the bands .
the fraction of galaxies with well identified optical / near ir bars ( sb ) is 63% , while a 17% more shows evidence of weak or suspected bars ( sab ) .
the sample average value of the maximum bar ellipticity is @xmath5 .
half of the galaxies in the sample shows rings .
we identify two candidates for isolated galaxies with disturbed morphology .
the structural @xmath4 parameters change with the observed band , and the tendencies they follow with the morphological type and global color are more evident in the redder bands . in any band , the major difference between our isolated spirals and a sample of interacting spirals is revealed in the @xmath6 plane .
a deep and uniformly observed sample of isolated galaxies is intended for various purposes including ( i ) comparative studies of environmental effects , ( ii ) confronting model predictions of galaxy evolution and ( iii ) evaluating the change of galaxy properties with redshift . .
And you have already written the first three sentences of the full article: the concept of a `` field '' population of galaxies as distinct from the group / cluster populations has existed since the earliest days of extragalactic astronomy ( hubble 1936 ) and it is used recurrently in studies aimed to explore the effects of large scale environment on galaxy properties . however , the definition of `` field '' is fuzzy .
the distribution of galaxies in space is actually strongly clustered and a large fraction of them is prone to form gravitationally - bound multiple systems , from very populated clusters to loose groups , the majority being in normal groups ( tully 1987 ) . _
isolation _ is an important requirement beyond the concept of `` field '' galaxies ..
Please generate the next two sentences of the article | a galaxy is isolated if it has not suffered any interaction with another normal galaxy or with a group environment over a hubble time or at least since approximately one half of its mass was assembled .
this makes the observational finding and study of isolated galaxies important because , among other reasons , ( i ) they can be used as comparison objects in studies of the environmental effects on galaxies belonging to groups and clusters , and ( ii ) they are ideal for confronting with theoretical and model predictions of galaxy evolution . |
5,909 | Suppose that you have an abstract for a scientific paper: we calculate the photoproduction of heavy quarks in proton - proton collisions at rhic , tevatron and lhc energies , where the photon reaches energies larger than those ones accessible at desy - hera . the integrated cross section and the rapidity distributions for open charm and bottom production
are computed employing sound high energy qcd formalisms . for the linear pqcd
approaches we consider both the usual collinear factorization and the @xmath0-factorization formalisms , whereas for the nonlinear qcd ( saturation ) calculations one considers the golec - biernat - wsthoff and the iancu - itakura - munier parameterizations for the dipole cross section within the color dipole picture . .
And you have already written the first three sentences of the full article: heavy quark production in hard collisions of hadrons , leptons , and photons has been considered as a clean test of perturbative qcd ( for a recent review see , e.g. , ref @xcite ) .
this process provides not only many tests of perturbative qcd , but also some of the most important backgrounds to new physics processes , which have motivated an extense phenomenology at desy - hera , tevatron and lhc .
these studies are mainly motivated by the strong dependence of the cross section on the behavior of the gluon distribution , which determines the qcd dynamics at high energies ..
Please generate the next two sentences of the article | in particular , the heavy quark photoproduction on nucleon and nuclei targets has been studied in detail in refs .
@xcite , considering the several available scenarios for the qcd dynamics at high energies . |
5,910 | Suppose that you have an abstract for a scientific paper: a list of radial velocities , hi line widths and peculiar velocities of 1327 galaxies from the rfgc catalogue has been compiled using actual observations and literature data .
the list can be used for studying bulk motions of galaxies , construction of the field of peculiar velocities and other tasks .
september 27 , 2000 .
And you have already written the first three sentences of the full article: the study of non - hubble motions and of the peculiar velocity field of galaxies on different scales forms an observational foundation for many tasks of present - day cosmology ( see the survey of strauss and willick , 1995 ) . for detailed analysis of peculiar velocities ample samples of galaxies with measured radial velocities @xmath0 and independent distance estimates @xmath1 are required .
the first homogeneous catalogue of this kind , markiii , was compiled as a result of integration and unification of data of observations of radial velocities and rotational velocities ( in the radio or optical ranges ) of galaxies from different samples , which were made by different groups of authors in 19821996 ( willick et al . , 1995 , 1997b ) .
it was based on mutual coordination of the tf relations ( tully fisher , 1977 ) , which were represented in the form `` luminosity line width '' for the samples of spiral galaxies of clusters and of the field ..
Please generate the next two sentences of the article | the sample of spirals ( han and mould , 1992 ) was adopted as the reference one . the @xmath2 samples were later also included in markiii , and relative zero points for the arrays of e and s galaxies ( dekel et al . , 1999 ) were determined . without going into details of constructing markiii , which were described comprehensively by the authors ,
let us note that standardization of the selection criterion was an important part of the work since the initial observational samples incorporated galaxies from different optical catalogues with different limits in apparent magnitude or angular diameter and having different angles of inclination to the line of sight . |
5,911 | Suppose that you have an abstract for a scientific paper: the low temperature phase of single crystals of nd@xmath0ca@xmath0mno@xmath1 and gd@xmath0ca@xmath0mno@xmath1 manganites is investigated by squid magnetometry .
nd@xmath0ca@xmath0mno@xmath1 undergoes a charge - ordering transition at @xmath2=245k , and a long range ce - type antiferromagnetic state is established at @xmath3=145k .
the dc - magnetization shows a cooling rate dependence below @xmath3 , associated with a weak spontaneous moment .
the associated excess magnetization is related to uncompensated spins in the ce - type antiferromagnetic structure , and to the presence in this state of fully orbital ordered regions separated by orbital domain walls .
the observed cooling rate dependence is interpreted to be a consequence of the rearrangement of the orbital domain state induced by the large structural changes occurring upon cooling . .
And you have already written the first three sentences of the full article: hole - doped manganites r@xmath4a@xmath5mno@xmath1 ( r = la , nd , pr , ... and a = sr , ca , ... ) , exhibit colossal magnetoresistive@xcite ( cmr ) properties , associated with the mixed manganese valence mn@xmath6 ( @xmath7)/mn@xmath8(@xmath9 ) resulting from the substitution of trivalent r ions by @xmath10 divalent a ions .
the @xmath10 @xmath11 0.5 doping is particularly interesting , since the magnetic interaction is affected by i ) the ordering of the mn@xmath6 and mn@xmath8 charges@xcite , commonly referred as charge - ordering ( co ) , ii ) the ordering of the @xmath12 electron orbitals on the mn@xmath6 sites and iii ) the coupling between orbital degree of freedom and the lattice .
for example , nd@xmath0ca@xmath0mno@xmath1 ( ncmo ) undergoes a co transition@xcite at @xmath2=245k with partial orbital ordering ( oo ) and magnetic correlations of short range . at lower temperatures , the oo increases and a long range ce - type@xcite antiferromagnetic ( afm ) state.
Please generate the next two sentences of the article | is established at @xmath3=145k .
an insulator - to - metal transition occurs around this temperature in intermediate ( @xmath115 t or higher ) magnetic fields@xcite . |
5,912 | Suppose that you have an abstract for a scientific paper: nighttime sky transparency statistics on mauna kea are reported based on data from the canada - france - hawaii telescope skyprobe monitor .
we focus on the period beginning with the start of megacam wide - field optical imager operations in 2003 , and continuing for almost three years .
skies were clear enough to observe on 76% of those nights ; attenuations were less than 0.2 magnitudes up to 60% of the time .
an empirical model of cloud attenuation and duration is presented allowing us to further characterize the photometric conditions .
this is a good fit to the skyprobe data , and indicates that mauna kea skies are truly photometric ( without cloud ) an average of 56% of the time , with moderate seasonal variation .
continuous monitoring of transparency during the night is necessary to overcome fluctuations in attenuation due to thin cloud . .
And you have already written the first three sentences of the full article: sky transparency is a fundamental parameter governing the operation of any optical observatory .
best telescope performance comes when skies are photometric - cloud - free - and in general , efficiency at a given site depends directly on the fraction of time that skies are clear enough to observe . as more telescopes employ adaptive optics ( ao ) facilities employing lasers , even thin
cloud can have a significant impact on telescope operations ..
Please generate the next two sentences of the article | attenuation of the beam from cirrus will not only reduce laser return power and affect ao wavefront - sensor performance , but reflected rayleigh - backscatter light may be of concern to other nearby optical observatories .
several sources of sky clarity measurements are available for mauna kea . |
5,913 | Suppose that you have an abstract for a scientific paper: the standard model has been effective way beyond expectations in foreseeing the result of almost all the experimental tests done up so far . in it
, neutrinos are massless .
nonetheless , in recent years we have collected solid proofs indicating little but non zero masses for the neutrinos ( when contrasted with those of the charged leptons ) .
these masses permit neutrinos to change their flavor and oscillate , indeed a unique treat . in these lectures ,
i discuss the properties and the amazing potential of neutrinos in and beyond the standard model . .
And you have already written the first three sentences of the full article: last decade witnessed a brutal transformation in neutrino physics .
it has been experimentally observed that neutrinos have nonzero masses , implying that leptons blend .
this fact was demonstrated by the experimental evidence that neutrinos can change from one state , or `` flavour '' , to another ..
Please generate the next two sentences of the article | all the information we have accumulated about neutrinos , is quite recent .
less that twenty years old . |
5,914 | Suppose that you have an abstract for a scientific paper: gaining control of the building blocks of magnetic materials and thereby achieving particular characteristics will make possible the design and growth of bespoke magnetic devices .
while progress in the synthesis of molecular materials , and especially coordination polymers , represents a significant step towards this goal , the ability to tune the magnetic interactions within a particular framework remains in its infancy .
here we demonstrate a chemical method which achieves dimensionality selection via preferential inhibition of the magnetic exchange in an @xmath0 antiferromagnet along one crystal direction , switching the system from being quasi - two- to quasi - one - dimensional while effectively maintaining the nearest - neighbour coupling strength .
coordination polymers are self - organising materials consisting of arrays of metal ions linked via molecular ligands , with non - coordinated counterions supplying charge neutrality .
the choice of initial components permits a high level of control over the final product , enabling many different polymeric architectures to be obtained @xcite .
these materials provide a route to successful crystal engineering , and a number of functionalities are being actively studied , including gas storage @xcite , optoelectronic @xcite , ferroelectric @xcite and magnetic properties @xcite .
although it is now possible to generate an assortment of disparate magnetic lattices using this method @xcite , true control of magnetic exchange interactions implies an ability to adjust selected parameters while keeping others constant . to this end ,
a series of coordination polymers based on cu(ii ) ions bridged by pyrazine ( c@xmath1h@xmath1n@xmath2 ) molecules have proven to be highly versatile . in these systems
it has been shown that it is possible to alter significantly the primary exchange energies via adjustment of the ligands @xcite and the counterions @xcite , or fine - tune the exchange by a few percent via isotopic substitution @xcite ,....
And you have already written the first three sentences of the full article: * synthesis of planar [ cu(pyz)@xmath12(pyo)@xmath12](pf@xmath14)@xmath12*. in the minimum amount of water , cucl@xmath582h@xmath2o ( 0.502 g , 2.95 mmol ) and agpf@xmath4 ( 1.489 g , 5.89 mmol ) were mixed together to yield a white precipitate of agcl and a pale blue solution containing the `` cu(pf@xmath4)@xmath2 '' product . to recover the blue solution , the agcl solid
was removed by careful vacuum filtration . in a separate solution , pyrazine and pyridine-@xmath5-oxide in a 3:1 ratio
were dissolved in a 1:1 mixture of h@xmath2o and ethanol to give a colourless solution . to this latter solution.
Please generate the next two sentences of the article | was added the `` cu(pf@xmath4)@xmath2 '' solution . upon slow mixing of the chemical reagents , a small amount of pale blue powder formed , but was removed by vacuum filtration to afford a blue solution .
slow evaporation of this solution yielded a large mass of deep green square plates . |
5,915 | Suppose that you have an abstract for a scientific paper: we undertake a quantitative investigation , using monte carlo simulations , of the amount by which quasars are expected to exceed radio galaxies in optical luminosity in the context of the ` receding torus ' model .
we compare these simulations with the known behaviour of the @xmath05007 and @xmath03727 emission lines and conclude that is the better indicator of the strength of the underlying non - stellar continuum .
# 1to 0pt#1 galaxies : active galaxies : nuclei quasars : emission lines radio continuum : galaxies .
And you have already written the first three sentences of the full article: it is widely believed that radio - loud quasars and radio galaxies differ from each other only in terms of the angle between their radio axes and the line of sight ( scheuer 1987 ; barthel 1989 ) .
quasars are observed fairly close to the line of sight ( @xmath1 ) and therefore frequently exhibit the effects of beaming , such as superluminal motion and luminous flat - spectrum radio cores , whereas radio galaxies are observed with their axes close to the plane of the sky , and do not show these effects .
however , quasars also possess a luminous non - stellar optical continuum and broad emission lines , which are absent in radio galaxies ..
Please generate the next two sentences of the article | it has therefore been proposed that there is material around the nucleus which lies preferentially in the plane perpendicular to the radio axis and obscures the central regions from view in radio galaxies .
because of the geometry of this material , it is often referred to as the `` torus '' , but other geometries ( e.g. a warped disk ) are possible . although the broad lines are hidden from direct view by this material , the narrow line region ( nlr ) is much larger in size and should be less strongly affected . |
5,916 | Suppose that you have an abstract for a scientific paper: the infrared dynamics in the ( @xmath0)dimensional supersymmetric and non supersymmetric nambu jona lasinio model in a constant magnetic field is studied . while at strong coupling the dynamics in these two models is essentially different , it is shown that the models become equivalent at weak coupling . in particular , at weak coupling , as the strength of the magnetic field goes to infinity , both the supersymmetric and non supersymmetric nambu
jona
lasinio models are reduced to a continuum set of independent ( 1 + 1)dimensional gross neveu models , labeled by the coordinates in the plane perpendicular to the magnetic field .
the relevance of these results for cosmological models based on supersymmetric dynamics is pointed out . .
And you have already written the first three sentences of the full article: it has been recently shown @xcite that a constant magnetic field in @xmath1 and @xmath0 dimensions is a strong catalyst of dynamical chiral symmetry breaking , leading to the generation of a fermion dynamical mass even at the weakest attractive interaction between fermions .
the essence of the effect is the dimensional reduction @xmath2 ( i.e. @xmath3 and @xmath4 ) in the infrared dynamics of the fermion pairing in a magnetic field .
the physical reason of this reduction is the fact that the motion of charged particles is restricted in those directions that are perpendicular to the magnetic field ..
Please generate the next two sentences of the article | this is in turn connected with the point that , at weak coupling between fermions , the fermion pairing , leading to the chiral condensate , is mostly provided by fermions from the lowest landau level ( lll ) whose dynamics are ( @xmath5)dimensional . in this paper , we shall further clarify the effect of the dynamical reduction , studying in detail the infrared dynamics in the ( @xmath0)dimensional nambu
jona lasinio ( njl ) model in a magnetic field . |
5,917 | Suppose that you have an abstract for a scientific paper: we introduce the ` illustris zoom simulation project ' , which allows the study of selected galaxies forming in the @xmath0cdm cosmology with a 40 times better mass resolution than in the parent large - scale hydrodynamical illustris simulation .
we here focus on the starburst properties of the gas in four cosmological simulations of major mergers .
the galaxies in our high - resolution zoom runs exhibit a bursty mode of star formation with gas consumption timescales 10 times shorter than for the normal star formation mode .
the strong bursts are only present in the simulations with the highest resolution , hinting that a too low resolution is the reason why the original illustris simulation showed a dearth of starburst galaxies .
very pronounced bursts of star formation occur in two out of four major mergers we study .
the high star formation rates , the short gas consumption timescales and the morphology of these systems strongly resemble observed nuclear starbursts .
this is the first time that a sample of major mergers is studied through self - consistent cosmological hydrodynamical simulations instead of using isolated galaxy models setup on a collision course .
we also study the orbits of the colliding galaxies and find that the starbursting gas preferentially appears in head - on mergers with very high collision velocities . encounters with large impact parameters do typically not lead to the formation of starbursting gas .
[ firstpage ] cosmology : theory methods : numerical galaxies : evolution galaxies : formation galaxies : star formation galaxies : starburst . .
And you have already written the first three sentences of the full article: galaxies appear to form stars in at least two modes ; a quiescent and a starburst mode .
an observational relation revealing these modes is the kennicutt
schmidt relation between the gas surface density ( @xmath1 ) and the star formation rate per surface area ( @xmath2 ) within a galaxy @xcite ..
Please generate the next two sentences of the article | quiescently star - forming disc galaxies typically follow a power law relation , @xmath3 @xcite , whereas starburst galaxies follow a relation with a similar power index , but a @xmath4 times higher normalisation , implying that gas is converted much faster into stars in these galaxies .
a key element for characterizing these modes is hence the timescale with which star formation consumes the gas within a galaxy . |
5,918 | Suppose that you have an abstract for a scientific paper: exact - diagonalization calculations for @xmath0 electrons in anisotropic quantum dots , covering a broad range of confinement anisotropies and strength of inter - electron repulsion , are presented for zero and low magnetic fields .
the excitation spectra are analyzed as a function of the strength of the magnetic field and for increasing quantum - dot anisotropy .
analysis of the intrinsic structure of the many - body wave functions through spin - resolved two - point correlations reveals that the electrons tend to localize forming wigner molecules . for certain ranges of dot parameters ( mainly at strong anisotropy ) , the wigner molecules acquire a linear geometry , and the associated wave functions with a spin projection @xmath1 are similar to the representative class of strongly entangled states referred to as @xmath2-states . for other ranges of parameters ( mainly at intermediate anisotropy ) ,
the wigner molecules exhibit a more complex structure consisting of two mirror isosceles triangles .
this latter structure can be viewed as an embryonic unit of a zig - zag wigner crystal in quantum wires .
the degree of entanglement in three - electron quantum dots can be quantified through the use of the von neumann entropy . .
And you have already written the first three sentences of the full article: three - electron quantum dots are expected to attract a lot of attention in the near future due to several developments , both experimental and theoretical .
first , it was recently demonstrated@xcite that detailed excitation spectra of two - electron quantum dots ( in addition to earlier ground - state measurements@xcite ) can be measured , and theoretically understood , as a function of the externally applied magnetic field .
thus , exploration of the excitation spectra of three - electron quantum dots appears to be a next step to be taken ..
Please generate the next two sentences of the article | second , three - qubit electron spin devices are expected to exhibit enhanced efficiency@xcite for quantum - computing and quantum - information purposes compared to single - qubit and two - qubit ones . in this paper
, we carry out exact diagonalization ( exd ) studies for a three - electron single quantum dot under low and moderate magnetic fields . unlike previous exd studies@xcite that focused mainly on the ground states ( gss ) of circular quantum dots,@xcite we investigate , in addition , the excitation spectra for three electrons in quantum dots with a wide range of anisotropies . |
5,919 | Suppose that you have an abstract for a scientific paper: in order to describe the recently observed effect of current induced magnetization reversal in magnetic nanostructures , the thermokinetic theory is applied to a metallic ferromagnet in contact with a reservoir of spin polarized conduction electrons .
the spin flip relaxation of the conduction electrons is described thermodynamically as a chemical reaction .
the diffusion equation of the chemical potential ( or the giant magnetoresistance ) and the usual landau - lifshitz - gilbert ( llg ) equation are derived from the entropy variation .
the expression of the conservation laws of the magnetic moments , including spin dependent scattering processes , leads then to the generalized llg equation with spin polarized current .
the equation is applied to the measurements obtained on single magnetic ni nanowires .
an unexpected and spectacular effect due to spin polarization of conduction electrons in metallic ferromagnets , the giant magnetoresistance ( gmr ) , appeared with the first transport studies on magnetic nanostructures @xcite .
the spin diffusion length of conduction electrons being of some few tens of nm , the relaxation of the conduction electron spins becomes observable when the magnetization can be controlled over this typical length .
some predictions about the inverse effect , namely the influence of spin polarized current on the dynamics of the magnetization , were also proposed .
berger predicted the existence of some surprising phenomena due to the action of spin polarized conduction electrons on domain walls @xcite or spin waves @xcite in magnetic thin films .
slonczewski predicted the rotation of the magnetization due to polarized current in multilayered systems @xcite , and bazaliy et al .
derived from microscopic considerations a generalized landau - lifshitz - gilbert equation @xcite . all the above mentioned approaches
are microscopic and based on the ballistic approximation . from an experimental point of view ,
freitas and berger , hung and berger @xcite ,....
And you have already written the first three sentences of the full article: spin - dependent transport processes in layered structures are described on the basis of the following simple picture . after entering in the k - th layer @xmath0 , the incident current ( which was spin polarized along the axis described by the unite vector @xmath1 in the layer @xmath2 )
first aligns @xcite along the axis @xmath3 . inside the ferromagnetic layer ,
the population of spin up ( @xmath4 ) and spin down ( @xmath5 ) is then not conserved due to spin - flip scattering , and some of the down spins relax to the up direction . in this picture.
Please generate the next two sentences of the article | , the states of the sub - system @xmath0 are described by the variables @xmath6 where @xmath7 is the entropy , @xmath8 is the magnetization of the layer k without current , @xmath9 is the number of conduction electrons with spin parallel to the unit vector @xmath3 and @xmath10 is the time derivative of the magnetization in the layer k without current .
if @xmath11 and @xmath9 are independent variables , the conservation of the magnetic momentum reads @xmath12 where @xmath13 is the bohr magneton and @xmath14 is the land factor . in order to write the conservation laws , |
5,920 | Suppose that you have an abstract for a scientific paper: we illustrate how a completely new world of gauge force emerges from a conventional condensed matter system in a rigorous way .
a characteristic energy scale ( mott gap ) separates such an exotic universe from the ordinary one that we condensed matter physicists are more familiar with at higher energies .
the governing physical law is no longer about individual electrons but concerns fractionalized particles , i.e. , partons , as the new collective modes resulted from strong correlation among the electrons .
novel phenomena in this low - energy universe are clearly distinguished from landau s fermi liquid described by the perturbative quantum many - body theory . .
And you have already written the first three sentences of the full article: in 1974 , c. n. yang@xcite pointed out that a fundamental gauge force is completely and intrinsically characterized by a non - integrable phase factor that an elementary particle of charge @xmath0 picks up when it moves from a to b points : @xmath1 here @xmath2 is the gauge potential and @xmath3 stands for path ordering . today
it has been fully established that the fundamental forces of weak , electromagnetic , and strong interactions between the elementary particles are all dictated by ( [ nonit ] ) as gauge forces , which is a great triumph of physics in the twentieth century .
the world of condensed matter physics is within the realm of a particular fundamental force , namely , the electromagnetic force . in the presence of millions of other electrons and ionic atoms ,.
Please generate the next two sentences of the article | an electron moving in a solid is no longer a free ` bare ' electron in the vacuum .
nevertheless , the electron still remains ` free ' as a bloch electron in a periodic array of the ionic atoms as if the latter is ` transparent ' , only with its energy spectrum being altered into the so - called energy bands . |
5,921 | Suppose that you have an abstract for a scientific paper: a quantum game - theoretic setting enables the analysis of strategic interaction among agents with access to quantum resources .
one of the original motivations for re - expressing quantum algorithms , and quantum communication protocols , in terms of competing quantum agents was to provide new insights into their workings .
looking closely , one finds that quantum strategic interactions utilize quantum probabilities and such probabilities are realizable in quantum mechanical experiments that allow implementation of unitary transformations , quantum measurements etc .
this paper presents a perspective on a quantum game - theoretic framework involving quantum probabilities , which are not subject to the strong factorizability constraints that classical probabilities are found to possess .
we suggest that a quantum version of a classical game can be obtained more directly if we replace the factorizability relations for probabilities in a classical game with two weaker constraints that are also obeyed by the quantum probabilities .
the solutions of symmetric bimatrix games with such ` non - factorizable ' probabilities are then analyzed and compared to the solutions that appear in the standard version of a quantum game . .
And you have already written the first three sentences of the full article: presently , it is well known that information has become the most important resource leading to many major paradigm shifts . the realization has now emerged that the processing of information can not be separated from the underlying fundamental physics and that the physical aspects of information processing must be taken into consideration .
this has led to a new understanding of the information processing , cryptography , and the methods and techniques used for communication @xcite that is based on the rules of quantum theory @xcite .
a venue where information plays a central role is in the playing of games for which the established branch of mathematics called game theory binmore , rasmusen , osborne provides the necessary analytic tools , methods , and solution concepts ..
Please generate the next two sentences of the article | any analysis of games is based on some fundamental assumptions relating to what information is available to each participating player at a particular stage of the game .
the finding that physical aspects can have crucial role in the information processing has natural implications for playing of games and considerations of the underlying fundamental physics become important also for game theory . |
5,922 | Suppose that you have an abstract for a scientific paper: i review the status of large - scale structure studies based on redshift surveys of galaxies and clusters of galaxies .
in particular , i compare recent results on the power spectrum and two - point correlation correlation function from the 2df and reflex surveys , highlighting the advantage of x - ray clusters in the comparison to cosmological models , given their easy - to - understand mass selection function . unlike for galaxies , this allows the overall normalization of the power spectrum to be measured directly from the data , providing an extra constraint on the models . in the context of cdm models , both the shape and amplitude of the reflex p(k )
require , consistently , a low value for the mean matter density @xmath0 .
this shape is virtually indistinguishable from that of the galaxy power spectrum measured by the 2df survey , simply multiplied by a constant cluster - galaxy bias factor .
this consistency is remarkable for data sets which use different tracers and are very different in terms of selection function and observational biases .
similarly , the knowledge of the power spectrum normalization yields naturally a value @xmath1 for the bias parameter of @xmath2-selected ( as in 2df ) galaxies , also in agreement with independent estimates using higher - order clustering and cmb data . in the final part
, i briefly describe the measurements of the matter density parameter from redshift space distortions in galaxy surveys , and show evidence for similar streaming motions of clusters in the reflex redshift - space correlation function @xmath3 . with no exception ,
this wealth of independent clustering measurements point in a remarkably consistent way towards a low - density cdm universe with @xmath4 . .
And you have already written the first three sentences of the full article: the last couple of years have witnessed an impressive series of achievements in the field of large - scale structure , thanks to new large surveys of galaxies and clusters of galaxies .
the enthusiasm for new results on the clustering of galaxies and clusters has been strenghtened by the unprecedented possibility to couple these to the anisotropies in the cosmic microwave background over an overlapping range of scales ( see contributions by melchiorri and cooray , this volume ) . in this brief review
i have tried and provide a general guide for the non - specialist through some of the large - scale structure results ..
Please generate the next two sentences of the article | clearly , such a review is far from being complete , although the references indicated should allow the reader to find further links to the available literature on the subject ( before february 2002 ) .
i therefore apologize to those colleagues whose work has not been adequately covered . |
5,923 | Suppose that you have an abstract for a scientific paper: we introduce a formalism for the geometry of eukaryotic cells and organisms .
cells are taken to be star - convex with good biological reason .
this allows for a convenient description of their extent in space as well as all manner of cell surface gradients .
we assume that a spectrum of such cell surface markers determines an epigenetic code for organism shape .
the union of cells in space at a moment in time is by definition the organism taken as a metric subspace of euclidean space , which can be further equipped with an arbitrary measure .
each cell determines a point in space thus assigning a finite configuration of distinct points in space to an organism , and a bundle over this configuration space is introduced with fiber a hilbert space recording specific epigenetic data . on this bundle , a lagrangian formulation of morphogenetic dynamics is proposed based on gromov - hausdorff distance which at once describes both embryo development and regenerative growth . .
And you have already written the first three sentences of the full article: we seek to posit a geochemical model for morphogenesis of eukaryotic organisms that includes cellular details .
our aim is to describe the main laws underlying the morphogenetic processes during normal development as well as during possible perturbations resulting in creating structure de novo as in the course of regeneration @xcite . in this inherently multi - scale context
, we must describe the nano - biology of the cell in its environment without unnecessary detail in a manner compatible with macro - biological aspects of the geometrical shape of an organ or entire organism . indeed.
Please generate the next two sentences of the article | , we shall proceed with a series of anstze , one after another , the first group of which are effectively axiomatic mathematical statements about the structure of cells and the organisms which they comprise .
some aspects of this are inspired by biology as we shall discuss in detail , and others are nothing more than rather obvious but new mathematical formalizations of elementary biological structure . |
5,924 | Suppose that you have an abstract for a scientific paper: in order to understand the r - process nucleosynthesis , we suggest precision required for mass and @xmath0-decay half - life measurements planned at future ri - beam facilities . to satisfy a simple requirement that we put on nuclear model predictions ,
it is concluded that the detectors for the mass measurements must have a precision of 1@xmath1 250 kev , and that the detectors for the half - life measurements demand a precision of 1@xmath1 0.15 ms .
both the above precisions are required at the neutron richness of @xmath2 = 3.0 at the @xmath3=82 shell closure and @xmath2 = 2.9 at the @xmath3=50 shell closure . for the doubly magic nuclide @xmath4ni ,
a precision of 1@xmath1 300 kev and 1@xmath1 5 ms are required , respectively , for mass and half - life measurements .
this analysis aims to provide a first rough guide for ongoing detector developments . .
And you have already written the first three sentences of the full article: the r - process nucleosynthesis is called for to explain the origin of about half the elements heavier than iron observed in nature .
its astrophysical origin remains a mystery .
the r - process is one of the most complex nucleosynthesis process to explore because of the numerous difficulties still affecting the description of both the explosive astrophysical conditions believed to host the process and the nuclear properties of the exotic neutron - rich nuclei involved . from the nuclear physics point of view.
Please generate the next two sentences of the article | , the major difficulty lies in the determination of nuclear data for the thousands of nuclei far from the @xmath0-stability , for which essentially no experimental data exist nowadays .
these concern mainly nuclear structure properties , @xmath0-decays , neutron captures , photodisintegrations as well as fission processes . |
5,925 | Suppose that you have an abstract for a scientific paper: we critically examine the basic paradigm for the origin of the 2 - 3 hr period gap in cataclysmic variables ( cvs ) , i.e. , binary systems in which a white dwarf accretes from a relatively unevolved , low - mass donor star . the observed orbital period distribution for @xmath0
cvs shows that these systems typically have orbital periods , @xmath1 , in the range of @xmath2 min to @xmath3 hr , but a distinct dearth of systems with 2 @xmath4(hr ) @xmath5 .
this latter feature of the period distribution is often referred to as the period gap " .
the conventional explanation for the period gap involves a thermal bloating of the donor star for @xmath6 hr due to mass transfer rates which are enhanced over those which could be driven by gravitational radiation ( gr ) losses alone ( e.g. , magnetic braking ) .
if for some reason the supplemental angular momentum losses become substantially reduced when @xmath1 decreases below @xmath7 hr , the donor star will relax thermally and shrink inside of its roche lobe .
this leads to a cessation of mass transfer until gr losses can bring the system into roche - lobe contact again at @xmath8 hr .
we carry out an extensive population synthesis study of cvs starting from @xmath9 primordial binaries , and evolving some @xmath10 surviving systems through their cv phase .
in particular we study current - epoch distributions of cvs in the @xmath11 , @xmath12 , @xmath13 , @xmath14 , @xmath15 , and @xmath16 planes , where @xmath17 is the mass transfer rate , @xmath18 is the mass ratio @xmath19/@xmath20 , and @xmath19 , @xmath21 , @xmath22 , and @xmath23 are the donor star mass , radius , effective temperature , and luminosity , respectively .
this work presents a new perspective on theoretical studies of the long - term evolution of cvs .
in particular , we show that if the current paradigm is correct , the secondary masses in cvs just above the period gap should be as much as @xmath24 lower than would be inferred if one assumes a main - sequence radius - mass....
And you have already written the first three sentences of the full article: cataclysmic variables ( cv ) are short period binary systems consisting of a white dwarf that accretes matter via roche - lobe overflow from a low - mass companion star . these objects exhibit a wide range of phenomenology including optical flickering in nova - like systems , dwarf nova eruptions which are thought to be caused by thermal instabilities in the accretion disks , and classical nova explosions which are thermonuclear runaways of the accreted matter on the white dwarf ( see , e.g. , warner 1995 ) .
the range of observed phenomena depends on the mass transfer rate , the mass ratio of the stellar components , and the magnetic field strength of the accreting white dwarf .
the orbital periods of the majority of cvs range from 8 hours down to about 78 minutes , but both longer and shorter period systems are known . in the former case ,.
Please generate the next two sentences of the article | the donor stars are typically somewhat evolved , while in the latter case , the donor stars are hydrogen exhausted . in this paper
we focus on the gap that exists in the orbital period distribution of cvs in the range of @xmath27 hr ( see , e.g. , warner 1976 ; rappaport , verbunt , & joss 1983 , hereafter rvj ; spruit & ritter 1983 ; hameury , et al . 1988a ; warner 1995 ) . |
5,926 | Suppose that you have an abstract for a scientific paper: by simulating a nonequilibrium coupled map lattice that undergoes an ising - like phase transition , we show that the lyapunov spectrum and related dynamical quantities such as the dimension correlation length @xmath0 are insensitive to the onset of long - range ferromagnetic order . as a function of lattice coupling constant @xmath1 and for certain lattice maps , the lyapunov dimension density and other dynamical order parameters go through a minimum .
the occurrence of this minimum as a function of @xmath1 depends on the number of nearest neighbors of a lattice point but not on the lattice symmetry , on the lattice dimensionality or on the position of the ising - like transition . in one - space dimension , the spatial correlation length associated with magnitude fluctuations and the length @xmath0 are approximately equal , with both varying linearly with the radius of the lattice coupling . .
And you have already written the first three sentences of the full article: laboratory experiments @xcite and numerical simulations @xcite can now systematically explore sustained homogeneous nonequilibrium systems of quite large aspect ratios ( @xmath2 ) which possibly approximate a thermodynamic limit of infinite system size .
these advances raise the theoretical question of identifying order parameters for analyzing and classifying spatiotemporal chaotic states so that a quantitative comparison can be made between theory and experiment @xcite .
the most appropriate order parameter for a given nonequilibrium system is presently not well understood although numerous possibilities have been studied ..
Please generate the next two sentences of the article | some order parameters , such as spatial correlation lengths obtained from exponentially decaying correlation functions , emphasize the average spatial disorder and have been widely used in condensed matter physics @xcite .
others such as the metric entropy and the lyapunov fractal dimension @xcite are familiar from nonlinear dynamics and emphasize the average temporal disorder or dynamical complexity arising from the geometric structure of an attractor in phase space . |
5,927 | Suppose that you have an abstract for a scientific paper: braiding of majorana fermions gives accurate topological quantum operations that are intrinsically robust to noise and imperfection , providing a natural method to realize fault - tolerant quantum information processing .
unfortunately , it is known that braiding of majorana fermions is not sufficient for implementation of universal quantum computation . here
we show that topological manipulation of majorana fermions provides the full set of operations required to generate random numbers by way of quantum mechanics and to certify its genuine randomness through violation of a multipartite bell inequality .
the result opens a new perspective to apply majorana fermions for robust generation of certified random numbers , which has important applications in cryptography and other related areas .
the complex - valued solutions to the dirac equation predict that every elementary particle should have a complex conjugate counterpart , namely an antiparticle .
for example , an electron has a positron as its antiparticle .
however , in @xmath0 ettore majorana @xcite showed that the complex dirac equation can be modified to permit real wave - functions , leading to the possible existence of the so called _ majorana fermions _ which are their own antiparticles @xcite . in condensed matter physics
, majorana fermions may appear as elementary qusi - particle excitations . to search for majorana fermions ,
several proposals have been made in recent years , including @xmath1 fractional quantum hall system @xcite , topological insulator ( ti)superconductor ( sc ) interface @xcite , interacting quantum spins @xcite , chiral p - wave superconductors @xcite , spin - orbit coupled semiconductor thin film @xcite or quantum nanowire @xcite in the proximity of an external s - wave superconductor .
based on these proposals , experimentalists have made great progress recently .
for instance , ref .
@xcite reported an experimental observation of coexistence of the superconducting gap and the....
And you have already written the first three sentences of the full article: this supplementary information gives more details about realization of fault - tolerant quantum random number generator through topological manipulation of majorana fermions . in sec .
i , we give the detailed proof on how to certify genuine randomness through observation of violation of the mabk inequality . in sec .
ii , we summarize the topological properties of majorana fermions and show the implementation of the necessary topological quantum gates on the logic qubits encoded with these majorana fermions . [ [ randomness - certified - by - observation - of - violation - of - the - mabk - inequality ] ] randomness certified by observation of violation of the mabk inequality ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ in this section , we establish a link between randomness of the measurement outputs of a quantum system and violation of the mabk inequality . a link between randomness and violation of the bell - chsh inequality has been established in ref ..
Please generate the next two sentences of the article | @xcite . here
, we generalize the result from the two - qubit chsh inequality to the three - qubit mabkinequality . |
5,928 | Suppose that you have an abstract for a scientific paper: we have carried out k - band speckle observations of a sample of 114 x - ray selected weak - line ttauri stars in the nearby scorpius - centaurus ob association .
we find that for binary ttauri stars closely associated to the early type stars in upper scorpius , the youngest subgroup of the ob association , the peak in the distribution of binary separations is at 90 a.u . for binary ttauri stars located in the direction of an older subgroup , but
not closely associated to early type stars , the peak in the distribution is at 215 a.u .
a kolmogorov - smirnov test indicates that the two binary populations do not result from the same distribution at a significance level of 98% .
apparently , the same physical conditions which facilitate the formation of massive stars also facilitate the formation of closer binaries among low - mass stars , whereas physical conditions unfavorable for the formation of massive stars lead to the formation of wider binaries among low - mass stars .
the outcome of the binary formation process might be related to the internal turbulence and the angular momentum of molecular cloud cores , magnetic field , the initial temperature within a cloud , or - most likely - a combination of all of these .
we conclude that the distribution of binary separations is not a universal quantity , and that the broad distribution of binary separations observed among main - sequence stars can be explained by a superposition of more peaked binary distributions resulting from various star forming environments .
the overall binary frequency among pre - main - sequence stars in individual star forming regions is not necessarily higher than among main - sequence stars . .
And you have already written the first three sentences of the full article: taurus - auriga is the star forming region which has been most thoroughly surveyed for pre - main - sequence binary and multiple systems ( see mathieu 1994 for a review ) . for separations from 15 a.u . to 2000 a.u .
, the binary frequency among ttauri stars in taurus is 1.9 times as high as among nearby main - sequence stars ( khler & leinert 1998 ) . extrapolating over the whole range of separations yields a binary frequency of 100% ,
i.e. , each ttauri star in taurus should be member of a binary or multiple systems ..
Please generate the next two sentences of the article | this apparent overabundance of binaries among pre - main - sequence stars is puzzling .
one possible explanation is a decrease in the binary frequency as a function of the age of a stellar population ( patience et al . |
5,929 | Suppose that you have an abstract for a scientific paper: we introduce a technique that is capable to filter out information from complex systems , by mapping them to networks , and extracting a subgraph with the strongest links .
this idea is based on the minimum spanning tree , and it can be applied to sets of graphs that have as links different sets of interactions among the system s elements , which are described as network nodes . it can also be applied to correlation - based graphs , where the links are weighted and represent the correlation strength between all pairs of nodes . we applied this method to the european scientific collaboration network , which is composed of all the projects supported by the european framework program fp6 , and also to the correlation - based network of the 100 highest capitalized stocks traded in the nyse . for both cases we identified meaningful structures , such as a strongly interconnected community of countries that play important role in the collaboration network , and clusters of stocks belonging to different sectors of economic activity , which gives significant information about the investigated systems . .
And you have already written the first three sentences of the full article: the study of complex systems , a name that is frequently used for systems having a large number of elements that interact in ( usually ) non trivial ways , has been greatly advanced in recent years by the use of graph theory @xcite .
one can map a complex system to a complex network by representing the interacting elements of the system with nodes and their interactions with links between the nodes .
examples of complex systems that have been recently investigated in this perspective include the internet @xcite , the world wide web @xcite , communication networks @xcite , food webs @xcite , sexual contacts among individuals @xcite , economic networks @xcite , the network of collaborations in eu funded projects @xcite , etc ..
Please generate the next two sentences of the article | complex systems are not always static , meaning that they may evolve dynamically over time .
this evolution can provide a wealth of information about the processes driving the system . |
5,930 | Suppose that you have an abstract for a scientific paper: we examine the out - of - equilibrium dynamical evolution of density profiles of ultrasoft particles under time - varying external confining potentials in three spatial dimensions .
the theoretical formalism employed is the dynamical density functional theory ( ddft ) of marini bettolo marconi and tarazona [ j. chem .
phys . * 110 * , 8032 ( 1999 ) ] , supplied by an equilibrium excess free energy functional that is essentially exact .
we complement our theoretical analysis by carrying out extensive brownian dynamics simulations .
we find excellent agreement between theory and simulations for the whole time evolution of density profiles , demonstrating thereby the validity of the ddft when an accurate equilibrium free energy functional is employed .
density functional theory ( dft ) is a very powerful tool for the quantitative description of the equilibrium states of many - body systems under arbitrary external fields .
it rests on the exact statement that the helmholtz free energy of the system , @xmath0 $ ] , is a unique functional of the inhomogeneous one - particle density @xmath1 .
moreover , the equilibrium profile @xmath2 minimises @xmath0 $ ] under the constraint of fixed particle number @xmath3 @xcite .
the task is then to approximate the unknown functional @xmath0 $ ] from which all equilibrium properties of the system follow .
much more challenging is the problem of studying _ out - of equilibrium dynamics _ of many - body systems , for which analogous uniqueness and minimisation principles are lacking . in this paper , we present results based on a recently - proposed dynamical density functional theory ( ddft ) formalism and we demonstrate that the latter is capable of describing out - of - equilibrium diffusive processes in colloidal systems at the brownian time scale .
we are concerned with the dynamics of typical soft - matter systems , such as suspensions of mesoscopic spheres and polymer chains in a microscopic solvent @xcite .
the enormous difference in the....
And you have already written the first three sentences of the full article: .
Please generate the next two sentences of the article | |
5,931 | Suppose that you have an abstract for a scientific paper: within the 5d standing wave braneworld model numerical solutions of the equations for matter fields with various spins are found .
it is shown that corresponding action integrals are factorizable and convergent over the extra coordinate , i.e. 4d fields are localized on the brane .
we find that only left massless fermions are localized on the brane , while the right fermions are localized in the bulk .
we demonstrate also quantization of kaluza - klein excited modes in our model . 0.3 cm pacs numbers : 04.50.-h , 11.25.-w , 11.27.+d keywords : brane ; standing waves ; zero modes .
And you have already written the first three sentences of the full article: braneworld models with large extra dimensions @xcite have attracted wide attention owing to their success in solving some open questions in modern physics @xcite . to realize the braneworld idea one should find a mechanism of localization , however , there are some difficulties in this matter within standard brane approaches @xcite .
it is especially economical to consider models with a pure gravitational localization mechanism , since gravity has universal couplings with all matter fields . in this paper
we consider one such scenario within the standing waves braneworld @xcite and explicitly show existence of the universal gravitational trapping of all kinds of matter fields on the brane ..
Please generate the next two sentences of the article | main differences of the model with the most brane scenarios are that our metric _ ansatz _ is time - dependent and contains increasing warp factor
. the standing waves braneworld is formed by the background solution @xcite : @xmath0 of the coupled einstein and massless ghost scalar field equations . in ( [ metric ] ) @xmath1 denotes the extra space - like coordinate , @xmath2 is a curvature scalar ( we choice increasing warp factor ) , the determinant , @xmath3 is @xmath4-independent and the oscillatory function @xmath5 has the form : @xmath6 here @xmath7 denotes the oscillation frequency , @xmath8 is an integration constant and @xmath9 is the second - order bessel function of the second kind . |
5,932 | Suppose that you have an abstract for a scientific paper: we show that qed radiative corrections change the propagator of a charged dirac particle so that it acquires a fractional anomalous exponent connected with the fine structure constant .
the result is a nonlocal object which represents a particle with a roughened trajectory whose fractal dimension can be calculated .
this represents a significant shift from the traditional wigner notions of asymptotic states with sharp well - defined masses .
non - abelian long - range fields are more difficult to handle , but we are able to calculate the effects due to newtonian gravitational corrections .
we suggest a new approach to confinement in qcd based on a particle trajectory acquiring a fractal dimension which goes to zero in the infrared as a consequence of self - interaction , representing a particle which , in the infrared limit , can not propagate .
pacs numbers : 12.20.-m,03.70.+k , 12.38.aw , 12.38.lg,05.45.df keyword : qed , theory of quantized fields , qcd , confinement , nonperturbative methods , fractals .
And you have already written the first three sentences of the full article: in @xcite , a gauge - invariant calculation was presented showing that the propagator for a charged particle acquires an interesting fractal structure from its self - interaction in quantum electrodynamics . in simple terms , the usual dirac propagator @xmath0 is replaced by the nonlocal expression @xmath1^{\big(1+(\alpha /\pi ) \big)}}\right\ } , \label{gai27}\end{aligned}\ ] ] where @xmath2 , @xmath3 is a short distance length scale , the fractional exponent @xmath4 is a function of the coupling strength @xmath5 which we find to be @xmath6 and the usual gamma function is @xmath7 this represents a rather radical departure from the usual textbook discussions of particle propagators ( with the notable exception of @xcite ) and from the usual wigner classification of elementary particles in terms of a sharp mass and spin ( see , for example , @xcite ) .
this is despite the fact that it is well - known that particles coupled to long - range massless fields can not have sharp masses@xcite
. a good review of the basic issues can be found in @xcite . aside from having been neglected in textbooks , the actual exponent in the above expression has been the subject of some controversy.
Please generate the next two sentences of the article | . there are calculations in the literature based on either infinite sums of logarithmic feynman diagrams@xcite or non - perturbative schwinger@xcite computations which argue that such an electron propagator should be of the _ form _ we obtained : @xmath8^{(1+\gamma ) } } \right\ } , \label{appelquist}\ ] ] . in the literature
there has not been full agreement about what constitutes the correct function @xmath9 , nor has there been a consensus as to whether or not it can be set to zero by a suitable choice of gauge . |
5,933 | Suppose that you have an abstract for a scientific paper: a geyser can be reproduced by a toy experiment composed of a water pool located above a water reservoir , the two being connected by a long and narrow tube . when the bottom reservoir is heated , the system experiences periodic eruptions of hot water and steam at the top similarly to the geyser effect occurring in nature .
the eruption frequency of a toy geyser is inspected experimentally as a function of the heating power and the height of the set - up .
we propose a thermodynamic model of this system which predicts the time between eruptions .
besides , the geometric and thermodynamic conditions required to observe a geyser effect are discussed . the study of the toy geyser
is then extended to the case of two reservoirs connected to the same tube .
in such a configuration , an eruption in a reservoir may entrain the eruption of the other .
such a coupled system adopts a complex time - evolution which reflects the dynamics of natural geysers .
we analyze the behavior of a toy geyser with two reservoirs by the way of statistical tools and develop a theoretical model in order to rationalize our observations . .
And you have already written the first three sentences of the full article: a geyser can be defined as a periodically eruptive spring resulting from earth s thermal activity .
one of the most famous geyser is the old faithful [ fig .
[ fig : geyser](a ) ] in the yellowstone national park in the united states ..
Please generate the next two sentences of the article | it erupts about every 90 minutes and projects hot water up to 56 m high@xcite .
probably the first scientist to describe the principle of a geyser was robert bunsen in 1845 after the danish government sponsored him to study the eruption of mount hekla in iceland @xcite . |
5,934 | Suppose that you have an abstract for a scientific paper: we present our spectroscopic measurements of the radial velocity , effective temperature , and projected rotational velocity of several of the known members of the tw hya association , as well as measurements for candidate members selected on the basis of their x - ray or kinematic properties .
a number of our targets turn out to be binaries , but most are non - members . the radial velocities for some of the other candidates support the conclusion that they are kinematically associated with the group , although further observations are required to show that they are indeed pre - main sequence objects .
# 1_#1 _ # 1_#1 _ = # 1 1.25 in .125 in .25 in .
And you have already written the first three sentences of the full article: the tw hya association , a loose grouping of very young stars that does not appear to be related to any nearby molecular cloud material , has been the subject of considerable attention in recent years .
the prototype of the association , tw hya itself , was the first recognized example of an isolated t tauri star .
the first few members of the association were discovered more or less by accident , and were only later recognized to be related . aside from these , the systematic search for additional stars belonging to the group has relied on their x - ray properties ( such as their detection as a rosat source ) , or their similar kinematics ( proper motions ) ..
Please generate the next two sentences of the article | follow - up studies have been made in many cases to establish the youth of the candidate members , for example by the presence of strong lithium @xmath06708 absorption , h@xmath1 emission , infrared excess , etc . to date
there are 19 objects recognized as true members in the published literature ( see , e.g. , kastner et al . |
5,935 | Suppose that you have an abstract for a scientific paper: we investigate the approximate quantum state sharing protocol based on random unitary channels , which is secure against any exterior or interior attackers in principle . although the protocol leaks small information for a security parameter @xmath0 , the scheme still preserves its information - theoretic secrecy , and reduces some pre - shared classical secret keys for a private quantum channel between a sender and two receivers . the approximate private quantum channels constructed via random unitary channels play a crucial role in the proposed quantum state sharing protocol .
And you have already written the first three sentences of the full article: quantum physics allows us a perfect randomness , so most of all quantum information - theoretic primitives try to offer an unconditional security under the randomness . for examples , quantum key distribution protocols such as bb84 @xcite and b92
@xcite highly depend on a random measurements for given classified non - orthogonal quantum states . instead of the random measurement on non - orthogonal states
, we can consider a direct randomization of quantum states through a quantum channel ..
Please generate the next two sentences of the article | this randomizing procedures are efficiently accomplished via the private quantum channels ( pqc ) _ or _ quantum one - time pads @xcite . in the paper we are interest to some schemes for _ approximate _ encryptions ( no perfect ) and we make an attempt to reducing some classical communication resources .
we would like to call the randomizing procedures or maps as random unitary channels ( ruc ) in terms of quantum channels . |
5,936 | Suppose that you have an abstract for a scientific paper: equal - mass two - component fermi gases under spherically symmetric external harmonic confinement with large @xmath0-wave scattering length are considered . using the stochastic variational approach , we determine the lowest 286 and 164 relative eigenenergies of the @xmath1 and @xmath2 systems at unitarity as a function of the range @xmath3 of the underlying two - body potential and extrapolate to the @xmath4 limit .
our calculations include all states with vanishing and finite angular momentum @xmath5 ( and natural and unnatural parity @xmath6 ) with relative energy up to @xmath7 , where @xmath8 denotes the angular trapping frequency of the external confinement .
our extrapolated zero - range energies are estimated to have uncertainties of 0.1% or smaller .
the @xmath1 and @xmath2 energies are used to determine the fourth - order virial coefficient of the trapped unitary two - component fermi gas in the low - temperature regime .
our results are compared with recent predictions for the fourth - order virial coefficient of the homogeneous system .
we also calculate small portions of the energy spectra of the @xmath9 and @xmath10 systems at unitarity . .
And you have already written the first three sentences of the full article: small trapped fermi gases with contact or short - range interactions have attracted a great deal of attention recently @xcite . using lithium or potassium , for example
, equal - mass two - component systems can be realized experimentally by occupying two different hyperfine states . for typical experimental conditions , @xmath11-wave or higher partial wave interactions between two like atoms ( say , two spin - up atoms ) and between two unlike atoms ( a spin - up and a spin - down atom )
are negligibly small ..
Please generate the next two sentences of the article | furthermore , by tuning an external magnetic field in the vicinity of a fano - feshbach resonance , the @xmath0-wave scattering length @xmath12 can be adjusted to essentially any value @xcite . in this paper
, we consider the regime where the @xmath0-wave scattering length is much larger than the range @xmath3 of the underlying two - body model potential . in the limit that @xmath3 goes to zero and |
5,937 | Suppose that you have an abstract for a scientific paper: we report the discovery of the closest collisional ring galaxy to the milky way .
such rare systems occur due to `` bulls - eye '' encounters between two reasonably matched galaxies . the recessional velocity of about 840kms@xmath0 is low enough that it was detected in the aao / ukst survey for galactic h@xmath1 emission .
the distance is only 10.0mpc and the main galaxy shows a full ring of star forming knots , 6.1kpc in diameter surrounding a quiescent disk .
the smaller assumed bullet " galaxy also shows vigorous star formation .
the spectacular nature of the object had been overlooked because of its location in the galactic plane and proximity to a bright star and even though it is the 60@xmath2 brightest galaxy in the hi parkes all sky survey ( hipass ) hi survey .
the overall system has a physical size of @xmath315kpc , a total mass of @xmath4m@xmath5 ( stars + hi ) , a metallicity of [ o / h]@xmath6 , and a star formation rate of 0.2 - 0.5m@xmath5yr@xmath0 , making it a magellanic - type system .
collisional ring galaxies therefore extend to much lower galaxy masses than commonly assumed .
we derive a space density for such systems of @xmath7 , an order of magnitude higher than previously estimated .
this suggests kathryn s wheel is the nearest such system .
we present discovery images , ctio 4-m telescope narrow - band follow - up images and spectroscopy for selected emission components . given its proximity and modest extinction along the line of sight , this spectacular system provides an ideal target for future high spatial resolution studies of such systems and for direct detection of its stellar populations .
galaxies : groups : general galaxies : interactions galaxies : kinematics and dynamics galaxies : star formation galaxies : individual ( eso179 - 13 ) .
And you have already written the first three sentences of the full article: among the structures shown by interacting galaxies ( barnes & hernquist 1992 ) , the so - called collisional ring galaxies ( theys & spiegel 1976 , 1977 ) are a rare and most distinctive sub - class ( appelton & struck - marcell 1996 ) .
collisional ring galaxies occur from an almost head - on collision between a smaller galaxy travelling along the minor axis of a larger galaxy passing through , or close to , its centre ( appleton & struck - marcell 1996 ) .
the shock wave sweeps up and expels gas from the system , usually leaving a gas - poor galaxy behind ( freeman & de vaucoleurs 1974 ) ..
Please generate the next two sentences of the article | the pre - eminent example is the cartwheel galaxy ( eso350 - 40 ; am0035 - 335 ) at a distance of 124mpc . the cartwheel was discovered by zwicky ( 1941 ) , and studied in - depth by fosbury & hawarden ( 1977 ) and amram et al .
the cartwheel shows a spectacular ring of star formation , with interior spokes surrounding the host galaxy . |
5,938 | Suppose that you have an abstract for a scientific paper: we calculate the conductance of a superconductor / ferromagnet ( s / f ) mesoscopic structure in the dirty limit .
first we assume that the ferromagnet exhibits a homogeneous magnetization and consider the case that the penetration of the condensate into the f wire is negligible and the case in which the proximity effect is taken into account .
it is shown that if the exchange field is large enough , the conductance below the critical temperature @xmath0 , is always smaller than the conductance in the normal state .
at last , we calculate the conductance for a f / s structure with a local inhomogeneity of the magnetization in the ferromagnet .
we demonstrate that a triplet component of the condensate is induced in the f wire.this leads to a increase of the conductance below @xmath0
. 0.5 cm 15.5 cm 0.5 cm 0.5 cm .
And you have already written the first three sentences of the full article: in the last decade transport properties of mesoscopic superconductor / normal metal ( s / n ) structures were intensively studied ( see for example the review articles @xcite and references therein ) . it was established that in these nano - structures , i.e. in structures whose dimensions are less than the phase coherence length @xmath1 and the inelastic scattering length @xmath2 , the conductance changes when decreasing the temperature below the critical temperature @xmath3 of the superconducting transition and this variation may be both positive ( @xmath4 ) and negative ( @xmath5 ) @xcite . the increase or decrease of the conductance
@xmath6 depends , in particular , on the interface resistances and is determined by a competition between two contributions caused by the proximity effect .
one of them is due to the suppression of the density - of - state ( dos ) and leads to a decrease of the conductance ..
Please generate the next two sentences of the article | the second one results in increasing @xmath6 and is similar to the maki - thompson term @xcite .
these studies apparently were stimulated by the theoretical work @xcite in which a weak - localization correction to the conductance of a s / n / s mesoscopic structure was calculated and an oscillatory dependence of this correction on the phase difference @xmath7 between the superconductors s was predicted . |
5,939 | Suppose that you have an abstract for a scientific paper: methods for revealing the distribution of gluon fields within the three - quark static - baryon potential are presented . in particular , we outline methods for studying the sensitivity of the source on the emerging vacuum response for the three - quark system . at the same time , we explore the possibility of revealing gluon - field distributions in three - quark systems in qcd without the use of gauge - dependent smoothing techniques .
renderings of flux tubes from a preliminary high - statistics study on a @xmath0 lattice are presented . .
And you have already written the first three sentences of the full article: recently there has been renewed interest in studying the distribution of quark and gluon fields in the three - quark static - baryon potential .
while early studies were inconclusive @xcite , improved computing resources and analysis techniques now make it possible to study this system in a quantitative manner @xcite . in particular , it is possible to directly compute the gluon flux distribution @xcite using lattice qcd techniques similar to those pioneered in mesonic static - quark systems @xcite . like okiharu and woloshyn @xcite
our first interest is to test the static - quark source - shape dependence of the observed flux distribution , as represented by correlations between the quark positions and the action or topological charge density of the gauge fields . to this end , we choose three different ways of connecting the gauge link paths required to create gauge - invariant wilson loops . in the first case , quarks are connected along a t - shape path , while in the second case an l - shape is considered ..
Please generate the next two sentences of the article | finally symmetric link paths approximating a y - shape such that the quarks approximate an equilateral triangle are considered .
the latter is particularly interesting as the probability of observing @xmath1-shape flux - tubes are maximized in this equidistant case . because the signal decreases in an exponential fashion with the size of the loop , it is essential to use a method to enhance the signal . |
5,940 | Suppose that you have an abstract for a scientific paper: we consider the solution of complex symmetric shifted linear systems .
such systems arise in large - scale electronic structure simulations and there is a strong need for the fast solution of the systems . with the aim of solving the systems efficiently , we consider a special case of the qmr method for non - hermitian shifted linear systems and propose its weighted quasi - minimal residual approach . a numerical algorithm , referred to as shifted qmr_sym(@xmath0 ) ,
is given by the choice of a particularly cost - effective weight .
numerical examples are presented to show the performance of the shifted qmr_sym(@xmath0 ) method . .
And you have already written the first three sentences of the full article: in this paper we consider the solution of complex symmetric shifted linear systems of the form @xmath1 where @xmath2 are nonsingular @xmath3-by-@xmath3 complex symmetric sparse matrices , i.e. , @xmath4 , with scalar shifts @xmath5 , @xmath6 is the @xmath3-by-@xmath3 identity matrix , and @xmath7 are complex vectors of length @xmath3 . the above systems
arise in large - scale electronic structure simulations @xcite , and there is a strong need for the fast solution of the systems . since the given shifted linear systems ( [ cs_sls ] ) are a set of sparse linear systems
, it is natural to use krylov subspace methods , and moreover since the coefficient matrices are complex symmetric , one of the simplest ways to solve the shifted linear systems is applying ( preconditioned ) krylov subspace methods for solving complex symmetric linear systems such as the cocg method @xcite , the cocr method @xcite , and the qmr_sym method @xcite to all of the shifted linear systems ( [ cs_sls ] ) . on the other hand , denoting the @xmath8-dimensional krylov subspace with respect to @xmath9 and @xmath10 as @xmath11 , we observe that @xmath12 this implies that once basis vectors are generated for one of the krylov subspaces @xmath13 , these basis vectors can be used to solve all the shifted linear systems ..
Please generate the next two sentences of the article | in other words , there is no need to generate all krylov subspaces @xmath14 , and thus computational costs involving the basis generation , e.g. , matrix - vector multiplications , are saved . here
we give a concrete example : if we apply the conjugate orthogonal conjugate gradient ( cocg ) method to all the linear systems ( [ cs_sls ] ) , then bases for @xmath14 are generated for @xmath15 . |
5,941 | Suppose that you have an abstract for a scientific paper: we present a study of the host - galaxy morphologies of narrow- and broad - line seyfert 1 galaxies ( nls1s and bls1s ) based on broad - band optical images from the _ hubble space telescope _ archives .
we find that large - scale stellar bars , starting at @xmath01 kpc from the nucleus , are much more common in nls1s than bls1s .
furthermore , the fraction of nls1 spirals that have bars increases with decreasing full - width at half - maximum ( fwhm ) of the broad component of h@xmath1 .
these results suggest a link between the large - scale bars , which can support high fueling rates to the inner kpc , and the high mass - accretion rates associated with the supermassive black holes in nls1s . .
And you have already written the first three sentences of the full article: seyfert galaxies are relatively nearby ( @xmath2 0.1 ) , moderate - luminosity ( @xmath3 @xmath4 10@xmath5 10@xmath6 erg s@xmath7 ) active galaxies . the large - scale morphologies of these galaxies typically resemble those of normal ( i.e. , inactive ) spiral galaxies , although there are some examples of peculiar or interacting systems ( de robertis , hayhoe , & yee 1998 ) .
optical and uv spectra of their nuclei are characterized by strong atomic emission lines .
based on the widths of these lines , seyfert galaxies are generally divided into two types ( khachikian & weedman 1974 ) : type 1s possess broad permitted lines with full - width at half - maximum ( fwhm ) typically @xmath8 1000 km s@xmath7 and narrow forbidden lines with fwhm @xmath9 500 km s@xmath7 , while the spectra of type 2s show narrow permitted and forbidden lines . those seyferts that show both broad and narrow components in their permitted lines are classified as intermediate types , ranging from 1.2 to 1.9 ( osterbrock , 1977 ; 1981 ) ..
Please generate the next two sentences of the article | osterbrock & pogge ( 1985 ) discovered a class of active galactic nuclei ( agn ) with relatively narrow ( fwhm @xmath10 2000 km s@xmath7 ) permitted lines , like seyfert 2 galaxies , but with emission - ratios that indicate the presence of a high - density region , like the broad - line region ( blr ) in seyfert 1 galaxies .
they dubbed these objects `` narrow - line seyfert 1s '' ( nls1s ) . |
5,942 | Suppose that you have an abstract for a scientific paper: we studied screening masses in the equilibrium thermodynamics of @xmath0 and @xmath1 pure gauge theories on the lattice . at a temperature of @xmath2 we found strong evidence for dimensional reduction in the non - perturbative spectrum of screening masses .
mass ratios in the high temperature @xmath1 theory are consistent with those in the pure gauge theory in three dimensions . at the first order @xmath1 phase transition
we report the first measurement of the true scalar screening mass .
@=11 addtoresetequationsection
@=12
# 1to # 1 * dimensional reduction and screening masses + in pure gauge theories at finite temperature * saumen datta and sourendu gupta + department of theoretical physics , + tata institute of fundamental research , + homi bhabha road , mumbai 400005 , india . .
And you have already written the first three sentences of the full article: the equilibrium thermodynamics of a gauge theory is studied in the non - perturbative domain by lattice simulations of the partition function .
much is now known about the phase transitions in @xmath0 and @xmath1 pure gauge theory and in qcd , including the order , the transition temperature , @xmath3 , entropy density , pressure , specific and latent heats and other such quantities @xcite . also of interest
are the screening masses at finite temperatures ..
Please generate the next two sentences of the article | these are defined in general by the exponential spatial falloff of the correlation of two static sources .
a classification of all masses is provided by the transformation properties of the sources . for glueball - like screening masses , |
5,943 | Suppose that you have an abstract for a scientific paper: we compare the velocity dispersion of the intracluster medium ( icm ) of the perseus cluster of galaxies as observed by the hitomi x - ray telescope to our three - dimensional hydrodynamical simulations of jet - inflated bubbles in cluster cooling flows , and conclude that the observations support the mixing - heating mechanism of the icm . in the mixing - heating mechanism
the icm is heated by mixing of hot bubble gas with the icm .
this mixing is caused by vortices that are formed during the inflation process of the bubble .
sound waves and turbulence are also excited by the vortices , but they contribute less than 20 per cents to the heating of the icm .
shocks that are excited by the jets contribute even less .
_ key words : _ galaxies : clusters : intracluster medium galaxies : clusters : individual : perseus galaxies : jets [ firstpage ] .
And you have already written the first three sentences of the full article: in its very short life time the hitomi x - ray observatory has revealed extremely valuable information on the nature of the intracluster medium ( icm ) of the perseus cluster of galaxies @xcite .
the analysis of hitomi x - ray observations by @xcite show a relatively quiescent icm .
the hot gas has a line - of - sight velocity dispersion of @xmath0 in the region @xmath1 to @xmath2 from the central nucleus ..
Please generate the next two sentences of the article | this implies that the heating of the icm by dissipation of turbulence energy can not offset radiative cooling .
another heating mechanism is at work in the perseus cluster . |
5,944 | Suppose that you have an abstract for a scientific paper: as solute molecules permeate into a vesicle due to a concentration difference across its membrane , the vesicle swells through osmosis . the swelling can be divided into two stages : ( a ) an `` ironing '' stage , where the volume - to - area ratio of the vesicle increases without a significant change in its area ; ( b ) a stretching stage , where the vesicle grows while remaining essentially spherical , until it ruptures .
we show that the crossover between these two stages can be represented as a broadened continuous phase transition .
consequently , the swelling curves for different vesicles and different permeating solutes can be rescaled into a single , theoretically predicted , universal curve .
such a data collapse is demonstrated for giant unilamellar popc vesicles , osmotically swollen due to the permeation of urea , glycerol , or ethylene glycol .
we thereby gain a sensitive measurement of the solutes membrane permeability coefficients , finding a concentration - independent coefficient for urea , while those of glycerol and ethylene glycol are found to increase with solute concentration .
in addition , we use the width of the transition , as extracted from the data collapse , to infer the number of independent bending modes that affect the thermodynamics of the vesicle in the transition region . .
And you have already written the first three sentences of the full article: membrane vesicles are made of a closed bilayer of amphiphilic molecules in aqueous solution , having length scales of @xmath0@xmath1 @xmath2 m .
used as simplified models of biological membranes , they have been one of the most extensively studied systems in soft - matter physics @xcite .
vesicles usually enclose both solvent ( water ) and solute molecules ..
Please generate the next two sentences of the article | such vesicular capsules are ubiquitous in cell functions @xcite and used as microreactors and delivery vehicles in various biomedical and cosmetic applications @xcite .
the hydrophobic core of the bilayer membrane poses a kinetic barrier to the permeation of water and water - soluble molecules into and out of the vesicle . |
5,945 | Suppose that you have an abstract for a scientific paper: we present the first results from an on - going survey to characterize the circumgalactic medium ( cgm ) of the massive high - redshift galaxies detected as submillimeter galaxies ( smgs ) .
we constructed a parent sample of 163 smg - qso pairs with separations less than @xmath036 by cross - matching far - infrared - selected galaxies from _ herschel _ with spectroscopically confirmed qsos .
the _
herschel _ sources were selected to match the properties of smgs .
we determined the sub - arcsecond positions of six _ herschel _ sources with the very large array and obtained secure redshift identification for three of those with near - infrared spectroscopy . the qso sightlines probe transverse proper distances of 112 , 157 , and 198 kpc at foreground redshifts of 2.043 , 2.515 , and 2.184 , respectively , which are comparable to the virial radius of the @xmath1 @xmath2 halos expected to host smgs .
high - quality absorption - line spectroscopy of the qsos reveals systematically strong hi ly@xmath3 absorption around all three smgs , with rest - frame equivalent widths of @xmath4 .
however , none of the three absorbers exhibits compelling evidence for optically thick hi gas or metal absorption , in contrast to the dominance of strong neutral absorbers in the cgm of luminous @xmath5 qsos .
the low covering factor of optically thick hi gas around smgs tentatively indicates that smgs may not have as prominent cool gas reservoirs in their halos as the co - eval qsos and that they may inhabit less massive halos than previously thought . .
And you have already written the first three sentences of the full article: rrrccc crrcc helms 0015@xmath60404 & 3.9286&@xmath64.0715 & [email protected] & [email protected] & [email protected]&26.5 & 3.93038&@xmath64.07262 & [email protected] & [email protected] + helms 0041@xmath80410 & 10.3541&@xmath84.1679 & [email protected] & [email protected] & [email protected]&15.8 & & & @xmath935.1 & + l6-xmm 0223@xmath80605 & 35.8056&@xmath86.0860 & [email protected] & [email protected] & [email protected]&69.7 & & & @xmath914.4 & + g09 0918@xmath80039 & 139.6159&@xmath80.6644 & [email protected] & [email protected] & [email protected]&18.9 & & & @xmath917.7 & + g09 0920@xmath60024 & 140.2475&@xmath60.4049 & [email protected] & [email protected] & [email protected]&22.9 & & & @xmath918.6 & + ngp 1313@xmath62924 & 198.4530&@xmath629.4126 & [email protected] & [email protected] & [email protected]&17.2 & & & @xmath942.3 & + ngp 1330@xmath62540 & 202.5866&@xmath625.6749 & [email protected] & [email protected] & [email protected]&18.0 & & & @xmath915.3 & + ngp 1333@xmath62357 & 203.3743&@xmath623.9592 & [email protected] & [email protected] & [email protected]&55.2&203.37514&@xmath623.95909 & [email protected] & [email protected] + ngp 1335@xmath62805 & 203.9409&@xmath628.0986 & [email protected] & [email protected] & [email protected]&27.6&203.94249&@xmath628.09750 & [email protected] & [email protected] + g15 1413@xmath60058 & 213.4580&@xmath60.9725 & [email protected] & [email protected] & [email protected]&16.2&213.45743&@xmath60.97321 & [email protected] & [email protected] + g15 1435@xmath60110 & 218.9043&@xmath61.1682 & [email protected] & [email protected] & [email protected] & 9.2&218.90494&@xmath61.16958 & [email protected] & [email protected] + g15 1450@xmath60026 & 222.6773&@xmath60.4351 & [email protected] & [email protected] & [email protected]&16.3 & & & @xmath918.0 & + l6-fls 1712@xmath66001 & 258.0352&@xmath660.0281 & [email protected] & [email protected] & [email protected]&30.1&258.03111&@xmath660.02722 & [email protected] & [email protected] + & & & & & & & 258.04010 & @xmath660.02625 & [email protected] & [email protected] the first milli - jansky - level submillimeter surveys discovered a population of distant....
Please generate the next two sentences of the article | the observed molecular and stellar emission indicates that they are massive gas - rich galaxies ( @xmath15@xmath2 ; e.g. , * ? ? ?
* ; * ? ? ? |
5,946 | Suppose that you have an abstract for a scientific paper: results from the first two years of data from the taiwanese - american occultation survey ( taos ) are presented .
stars have been monitored photometrically at 4 hz or 5 hz to search for occultations by small ( @xmath03 km ) kuiper belt objects ( kbos ) .
no statistically significant events were found , allowing us to present an upper bound to the size distribution of kbos with diameters 0.5 km @xmath1 28 km . .
And you have already written the first three sentences of the full article: the study of the kuiper belt has exploded since the discovery of 1992 qb1 by @xcite .
the brightness distribution of objects with @xmath2 magnitude brighter than @xmath026 is relatively well - established by many surveys , most recently by ( * ? ? ?
* and references therein ) ..
Please generate the next two sentences of the article | the brightness distribution is adequately described by a simple cumulative luminosity function , where @xmath3 and @xmath4 , for objects with magnitude @xmath5 .
there is clear evidence for a break to a shallower slope for fainter objects : the deepest survey , conducted using the advanced camera for surveys on the _ hubble space telescope _ |
5,947 | Suppose that you have an abstract for a scientific paper: despite improved control measures , ebola remains a serious public health risk in african regions where recurrent outbreaks have been observed since the initial epidemic in @xmath0 . using epidemic modeling and data from two well - documented ebola outbreaks ( congo @xmath1 and uganda @xmath2 ) , we estimate the number of secondary cases generated by an index case in the absence of control interventions ( @xmath3 ) .
our estimate of @xmath3 is @xmath4 ( sd @xmath5 ) for congo ( 1995 ) and @xmath6 ( sd @xmath7 ) for uganda ( 2000 ) .
we model the course of the outbreaks via an seir ( susceptible - exposed - infectious - removed ) epidemic model that includes a smooth transition in the transmission rate after control interventions are put in place .
we perform an uncertainty analysis of the basic reproductive number @xmath3 to quantify its sensitivity to other disease - related parameters .
we also analyze the sensitivity of the final epidemic size to the time interventions begin and provide a distribution for the final epidemic size .
the control measures implemented during these two outbreaks ( including education and contact tracing followed by quarantine ) reduce the final epidemic size by a factor of @xmath8 relative the final size with a two - week delay in their implementation . .
And you have already written the first three sentences of the full article: ebola hemorrhagic fever is a highly infectious and lethal disease named after a river in the democratic republic of the congo ( formerly zaire ) where it was first identified in 1976 @xcite .
twelve outbreaks of ebola have been reported in congo , sudan , gabon , and uganda as of september 14 , 2003 @xcite .
two different strains of the ebola virus ( ebola - zaire and the ebola - sudan ) have been reported in those regions . despite extensive search ,.
Please generate the next two sentences of the article | the reservoir of the ebola virus has not yet been identified @xcite .
ebola is transmitted by physical contact with body fluids , secretions , tissues or semen from infected persons @xcite . |
5,948 | Suppose that you have an abstract for a scientific paper: the value of the quarkonium wave function at the origin is an important quantity for studying many physical problems concerning a heavy quarkonium .
this is because it is widely used to evaluate the production and decay amplitudes of the heavy quarkonium within the effective field theory framework , e.g. , the nonrelativistic qcd ( nrqcd ) . in this paper , the values of the schr@xmath0dinger radial wave function or its first nonvanishing derivative at zero quark - antiquark separation , i.e. , @xmath1\rangle$ ] , @xmath2\rangle$ ] , and @xmath3\rangle$ ] quarkonium ,
have been tabulated under five potential models with new parameters for the heavy quarkonium .
moreover , the production of the lower - level fock states @xmath4\rangle$ ] and @xmath5\rangle$ ] , together with the higher excited fock states @xmath6\rangle$ ] and @xmath7\rangle$ ] ( @xmath8 stands for the @xmath9 or @xmath10 quark ; @xmath11 ) through top quark decays has been studied with the new values of heavy quarkonium wave functions at the origin under the framework of nrqcd . at the lhc with the luminosity @xmath12 and the center - of - mass energy @xmath13 tev
, sizable heavy quarkonium events can be produced through top quark decays , i.e. , @xmath14 @xmath15 and @xmath16 , and @xmath17 @xmath18 and @xmath19 events per year can be obtained according to our calculation . + * pacs numbers : * 12.38.bx , 14.65.ha , 14.40.nd , 14.40.pq .
And you have already written the first three sentences of the full article: among the heavy quarkona , the @xmath15 meson being the unique meson with two different heavy quarks in the standard model has aroused great interest since its discovery by the cdf collaboration @xcite . although the direct " hadronic production of the @xmath15 meson has been systematically studied in refs .
@xcite , as a compensation to understand the production mechanism and the @xmath15 meson properties , it would be helpful to study its production indirectly " through @xmath20(@xmath21)-quark , @xmath22-boson , and @xmath23-boson decays , as too many directly produced @xmath15 events shall be cut off by the trigging condition @xcite .
a systematical study on the indirect production of @xmath15 mesons through @xmath20(@xmath21)-quark , @xmath22-boson , and @xmath23-boson decay can be found in refs ..
Please generate the next two sentences of the article | @xcite , refs .
@xcite , and refs . |
5,949 | Suppose that you have an abstract for a scientific paper: within the light - front framework , form factors for @xmath0 and @xmath1 transitions ( @xmath2 : pseudoscalar meson , @xmath3 : vector meson ) due to the valence - quark configuration are calculated directly in the entire physical range of momentum transfer .
the behavior of the form factors in the infinite quark mass limit are examined to see if the requirements of heavy - quark symmetry are fulfilled .
we find that the bauer - stech - wirbel type of light - front wave function fails to give a correct normalization for the isgur - wise function at zero recoil in @xmath1 transition .
some of the @xmath1 form factors are found to depend on the recoiling direction of the daughter mesons relative to their parents .
thus , the inclusion of the non - valence contribution arising from quark - pair creation is mandatory in order to ensure that the physical form factors are independent of the recoiling direction .
the main feature of the non - valence contribution is discussed .
0.25 true cm pacs numbers : 13.20 , 14.40.j 6.5 in 1.0 cm .29 in .
And you have already written the first three sentences of the full article: the hadronic matrix element of weak @xmath0 transition ( @xmath2 : pseudoscalar meson ) is described by two form factors , whereas in general it requires four form factors to parametrize the weak matrix element for @xmath1 transition ( @xmath3 : vector meson ) .
heavy quark symmetry predicts that , all the mesonic form factors in the infinite quark mass limit @xmath4 are related to a single universal isgur - wise function @xcite .
the symmerty breaking @xmath5 corrections can be studied in a systematic framework , namely the heavy quark effective theory ( for a review , see @xcite ) ..
Please generate the next two sentences of the article | the isgur - wise function is normalized to unity at zero recoil , but otherwise remains unknown .
phenomenologically , the hadronic form factors can be evaluated in various models among which the quark model is a popular one . however , since usual quark - model wave functions best resemble meson states in the rest frame or where the meson velocities are small , hence the form factors calculated in non - relativistic quark model or the mit bag model are trustworthy only when the recoil momentum of the daughter meson relative to the parent meson is small . as the recoil momentum increases ( corresponding to a decreasing @xmath6 ) |
5,950 | Suppose that you have an abstract for a scientific paper: the d / h ratio in interstellar gas varies on scales of a few hundred pc in the local milky way , with d / h values ranging from @xmath07@xmath1ppm to @xmath022@xmath1ppm .
the reduction in d / h relative to the primordial value of d / h@xmath2ppm is usually attributed to `` astration '' conversion of d into other elements by nuclear fusion in stars .
however , it is shown here that astration has difficulty accounting for the observations because the expected associated variations in o / h are not seen . the lower d / h values are instead likely due to `` depletion '' of the d onto dust grains .
polycyclic aromatic hydrocarbons ( pahs ) are a possible repository for the missing d , and it appears possible for gas - grain reactions to achieve extreme deuteration of carbonaceous grain material .
grain destruction will release d from the grains ; the gas phase abundance of d should therefore be positively correlated with the gas phase abundances of other elements that exhibit strong depletions , such as mg , si , ti , and fe , which also will be returned to the gas by grain destruction . .
And you have already written the first three sentences of the full article: in recent years it has become clear that the gas - phase d / h ratio varies significantly from one sightline to another within a few hundred pc of the sun ( see , e.g. , moos et al .
2002 ; steigman 2003 ; wood et al . 2004 ; hbrard 2005 ) .
this has often been taken to result from regional variations in the extent to which nucleosynthesis in stars , followed by return of matter to the interstellar medium via stellar winds and ejecta , has lowered the interstellar d / h ratio from the primordial value established by nucleosynthesis in the big bang ..
Please generate the next two sentences of the article | i argue here that the observed local variations in the gas - phase d / h ratio are not due to variable astration .
the low values of ( d / h)@xmath3 seen on some sightlines are instead attributed to incorporation of d into dust grains . |
5,951 | Suppose that you have an abstract for a scientific paper: recently , syljusen and sandvik proposed a new framework for constructing algorithms of quantum monte carlo simulation .
while it includes new classes of powerful algorithms , it is not straightforward to find an efficient algorithm for a given model . based on their framework , we propose an algorithm that is a natural extension of the conventional loop algorithm with the split - spin representation .
a complete table of the vertex density and the worm - scattering probability is presented for the general @xmath0 model of an arbitrary @xmath1 with a uniform magnetic field . .
And you have already written the first three sentences of the full article: among many numerical techniques for condensed matter physics , the monte carlo method is a popular choice when a long correlation length or a small excitation gap is anticipated .
apart from the negative sign difficulty , most of the shortcomings of the quantum monte carlo ( qmc ) method for spin systems have been removed or reduced . in particular , the qmc for finite temperature based on the path - integral representation has been improved considerably during the past decade .
the improvement was achieved mainly by the development of the loop - cluster algorithms@xcite and related methods ..
Please generate the next two sentences of the article | for instance , the critical slowing down was tamed by the loop - cluster algorithms for a broad class of quantum spin systems@xcite .
it was shown@xcite that the typical size of the clusters coincides with the correlation length . |
5,952 | Suppose that you have an abstract for a scientific paper: we investigate the problem of quantum searching on a noisy quantum computer . taking a _ fault - ignorant _ approach ,
we analyze quantum algorithms that solve the task for various different noise strengths , which are possibly unknown beforehand .
we prove lower bounds on the runtime of such algorithms and thereby find that the quadratic speedup is necessarily lost ( in our noise models ) .
however , for low but constant noise levels the algorithms we provide ( based on grover s algorithm ) still outperform the best noiseless classical search algorithm . .
And you have already written the first three sentences of the full article: since the inception of quantum computing @xcite , a large effort has been devoted to making quantum computers function in a noisy environment and securing them against imperfections in the physical setup itself .
the theoretical literature offers several ways to cope with such errors .
the leading idea is to encode quantum states into a larger system @xcite such that noise hits can be recognized and subsequently corrected . a quantum computation.
Please generate the next two sentences of the article | can then be performed in a fault - tolerant way directly on these encoding systems @xcite , and nested levels of error - correction can make the computation error - free .
the last statement assumes that the initial error rate is not too high and that the error hits are not too correlated , e.g. occur locally . beyond these assumptions , |
5,953 | Suppose that you have an abstract for a scientific paper: the bilateral filter is a versatile non - linear filter that has found diverse applications in image processing , computer vision , computer graphics , and computational photography .
a common form of the filter is the gaussian bilateral filter in which both the spatial and range kernels are gaussian .
a direct implementation of this filter requires @xmath0 operations per pixel , where @xmath1 is the standard deviation of the spatial gaussian . in this paper
, we propose an accurate approximation algorithm that can cut down the computational complexity to @xmath2 per pixel for any arbitrary @xmath1 ( constant - time implementation ) .
this is based on the observation that the range kernel operates via the translations of a fixed gaussian over the range space , and that these translated gaussians can be accurately approximated using the so - called gauss - polynomials .
the overall algorithm emerging from this approximation involves a series of spatial gaussian filtering , which can be efficiently implemented ( in parallel ) using separability and recursion .
we present some preliminary results to demonstrate that the proposed algorithm compares favorably with some of the existing fast algorithms in terms of speed and accuracy . bilateral filter , approximation , gauss - polynomial , convolution , fast algorithm . .
And you have already written the first three sentences of the full article: the bilateral filter of tomasi and maduchi @xcite is a particular instance of an edge - preserving smoothing filter .
the origins of the filter can be traced back to the work of lee @xcite and yaroslavsky @xcite .
the susan framework of smith and brady @xcite is also based on a similar idea ..
Please generate the next two sentences of the article | the relation between the bilateral and other closely related filters is surveyed in @xcite .
the bilateral filter has turned out to be a versatile tool that has found widespread applications in image processing , computer graphics , computer vision , and computational photography . |
5,954 | Suppose that you have an abstract for a scientific paper: we give a direct calculation of the curvature of the hitchin connection , in geometric quantization on a symplectic manifold , using only differential geometric techniques .
in particular , we establish that the curvature acts as a first - order operator on the quantum spaces .
projective flatness follows if the khler structures do not admit holomorphic vector fields .
following witten , we define a complex variant of the hitchin connection on the bundle of prequantum spaces .
the curvature is essentially unchanged , so projective flatness holds in the same cases .
finally , the results are applied to quantum chern - simons theory , both for compact and complex gauge groups . .
And you have already written the first three sentences of the full article: since their introduction by atiyah @xcite , segal @xcite and witten @xcite , topological quantum field theories ( tqfts ) have been studied intensely using a wide range of techniques . the first construction in 2 + 1 dimensions was given by reshetikhin and turaev @xcite using representation theory of quantum groups at roots of unity to construct link invariants and in turn derive invariants of 3-manifolds through surgery and kirby calculus .
shortly thereafter , a combinatorial construction was given by blanchet , habegger , masbaum and vogel @xcite in the language of skein theory .
a geometric realization was proposed by witten @xcite , suggesting the use of quantum chern - simons theory or conformal field theory to construct the 2-dimensional part ..
Please generate the next two sentences of the article | the gauge theoretic approach was studied independently by axelrod , della pietra and witten @xcite and hitchin @xcite , proving that the quantum spaces arising from geometric quantization of chern - simons theory for compact gauge group are indeed independent of the conformal structure on the surface , in the sense that they are identified by parallel transport of a projectively flat connection over the teichmller space of the surface .
these constructions have been expressed and generalized in purely differential geometric terms in @xcite and @xcite , and we shall be mainly concerned with this description in the present paper . the other construction proposed by witten , through conformal field theory , was provided by tsuchiya , ueno and yamada @xcite , and the link to the gauge theoretic construction was established by laszlo @xcite . |
5,955 | Suppose that you have an abstract for a scientific paper: we study unitary random matrix ensembles in the critical case where the limiting mean eigenvalue density vanishes quadratically at an interior point of the support .
we establish universality of the limits of the eigenvalue correlation kernel at such a critical point in a double scaling limit .
the limiting kernels are constructed out of functions associated with the second painlev equation .
this extends a result of bleher and its for the special case of a critical quartic potential .
the two main tools we use are equilibrium measures and riemann - hilbert problems . in our treatment of equilibrium measures
we allow a negative density near the critical point , which enables us to treat all cases simultaneously .
the asymptotic analysis of the riemann - hilbert problem is done with the deift / zhou steepest descent analysis . for the construction of a local parametrix at the critical point
we introduce a modification of the approach of baik , deift , and johansson so that we are able to satisfy the required jump properties exactly . .
And you have already written the first three sentences of the full article: we consider the unitary random matrix model @xmath0 defined on hermitian @xmath1 matrices @xmath2 in a critical regime where the limiting mean density of eigenvalues vanishes at an interior point .
it is a basic fact of random matrix theory @xcite that the eigenvalues of the random matrix ensemble ( [ 1-randommatrixmodel ] ) follow a determinantal point process with correlation kernel @xmath3 where @xmath4 denotes the @xmath5th degree orthonormal polynomial with respect to the weight @xmath6 on @xmath7 .
we assume in this paper that the confining potential @xmath8 in ( [ 1-randommatrixmodel ] ) is real analytic and that it satisfies the growth condition @xmath9 these assumptions ensure that the mean eigenvalue density @xmath10 has a limit as @xmath11 , @xmath12 , see e.g. @xcite , which we denote by @xmath13 ..
Please generate the next two sentences of the article | it is known that @xmath14 is the density of the measure @xmath15 which minimizes the weighted energy @xmath16 among all probability measure on @xmath7 .
the measure @xmath15 is called the equilibrium measure in the external field @xmath17 . |
5,956 | Suppose that you have an abstract for a scientific paper: we study the 6-vertex model with fixed boundary conditions . in the thermodynamical limit
there is a formation of the limit shape .
we collect most of the known results about the analytical properties of the free energy of the model as the function of electric fields and study the asymptotical behavior near singularities .
we also study the asymptotic of limit shapes and the structure of correlation functions in the bulk . .
And you have already written the first three sentences of the full article: ising and dimer models were among the first models in two - dimensional statistical mechanics for where the partition function and for some of the correlation functions were computed explicitly in terms of pfaffians of certain matrices .
for this reason both of these models can be regarded as theories of gaussian discrete two dimensional fermi field .
the ising model was solved by onsager and for dimer models the pfaffian solution was found by kasteleyn . the @xmath0-vertex model , a particular case of which is the ice model is interesting for a number of reasons . physically , it is a model of ferro- and antiferro- electricity ..
Please generate the next two sentences of the article | it has many equivalent reformulations , one of them ( which we will use ) describe the 6-vertex configurations on a planar connected simply connected region in terms of stepped surfaces .
one of the combinatorial reformulations of the 6-vertex model for specific value of parameters @xcite is related to alternating sign matrices @xcite . |
5,957 | Suppose that you have an abstract for a scientific paper: the macho project collected photometry of many rr lyrae stars from its observations of the milky way s bulge .
we examined the lightcurves of 3256 stars identified as rrab lyr variables by @xcite , subtracting an empirical model of the pulsation lightcurve and searching for periodic variation in the residuals .
there are no systems which show the brief dips in light characteristic of detached eclipsing binary systems .
we discuss the results for objects which show the largest residual periodic modulation , most of which are probably due to aliases of the fundamental period . .
And you have already written the first three sentences of the full article: measuring the distances to objects is one of the most fundamental tasks in astronomy , yet it is also one of the most difficult . among the many indirect methods astronomers have devised for dealing with this problem is the technique of `` standard candles : '' identifying a class of sources which have the same luminosity and are easy to recognize .
rr lyrae stars fit into this category : they vary in brightness by a considerable amount ( amplitudes of order half a magnitude ) in a short time ( periods of order half a day ) .
moreover , their light curves exhibit a characteristic shape : a rapid rise in brightness followed by a leisurely fall @xcite ..
Please generate the next two sentences of the article | although rr lyr stars have become important tools for the investigation of galactic structure , they are not as well understood as one would wish for such fundamental calibrators . for example , we can not compare rigorously our models of stellar structure and their predictions for pulsation to observations , because we do not know precisely the mass of any rr lyr star .
the reason is simple : despite a few false alarms @xcite , and one case |
5,958 | Suppose that you have an abstract for a scientific paper: we propose a method of analysis of dynamical networks based on a recent measure of granger causality between time series , based on kernel methods .
the generalization of kernel granger causality to the multivariate case , here presented , shares the following features with the bivariate measures : ( i ) the nonlinearity of the regression model can be controlled by choosing the kernel function and ( ii ) the problem of false - causalities , arising as the complexity of the model increases , is addressed by a selection strategy of the eigenvectors of a reduced gram matrix whose range represents the additional features due to the second time series .
moreover , there is no _ a priori _ assumption that the network must be a directed acyclic graph .
we apply the proposed approach to a network of chaotic maps and to a simulated genetic regulatory network : it is shown that the underlying topology of the network can be reconstructed from time series of node s dynamics , provided that a sufficient number of samples is available . considering a linear dynamical network , built by preferential attachment scheme
, we show that for limited data use of bivariate granger causality is a better choice w.r.t methods using @xmath0 minimization .
finally we consider real expression data from hela cells , 94 genes and 48 time points .
the analysis of static correlations between genes reveals two modules corresponding to well known transcription factors ; granger analysis puts in evidence nineteen causal relationships , all involving genes related to tumor development . .
And you have already written the first three sentences of the full article: dynamical networks @xcite model physical and biological behavior in many applications ; examples range from networks of neurons @xcite , josephson junctions arrays @xcite to genetic networks @xcite , protein interaction nets @xcite and metabolic networks @xcite . synchronization in dynamical networks
is influenced by the topology of the network @xcite . a great need exists for the development of effective methods of inferring network structure from time series data ;
a method for detecting the topology of dynamical networks , based on chaotic synchronization , has been proposed in @xcite ; a recent approach deals with the case of low number of samples and proposed methods rooted on l1 minimization @xcite ..
Please generate the next two sentences of the article | granger causality has become the method of choice to determine whether and how two time series exert causal influences on each other @xcite .
this approach is based on prediction : if the prediction error of the first time series is reduced by including measurements from the second one in the linear regression model , then the second time series is said to have a causal influence on the first one . |
5,959 | Suppose that you have an abstract for a scientific paper: we present a detailed imaging and spectral analysis of the merging environment of the bimodal cluster a3395 using x - ray and radio observations .
x - ray images of the cluster show five main constituents of diffuse emission : a3395 ne , a3395 sw , a3395 nw , a3395 w , and a filament connecting ne to w. x - ray surface - brightness profiles of the cluster did not show any shock fronts in the cluster .
temperature and entropy maps show high temperature and high entropy regions in the w , the nw , the filament and between the ne and sw subclusters .
the ne , sw and w components have x - ray bolometric luminosities similar to those of rich clusters of galaxies but have relatively higher temperatures .
similarly , the nw component has x - ray bolometric luminosity similar to that of isolated groups but with much higher temperature .
it is , therefore , possible that all the components of the cluster have been heated by the ongoing mergers .
the ne subcluster is the most massive and luminous constituent and other subclusters are found to be gravitationally bound to it .
the w component is most probably either a clump of gas stripped off the sw due to ram pressure or a separate subcluster that has merged or is merging with the sw .
no x - ray cavities are seen associated with the wide angle tailed ( wat ) radio source near the centre of the sw subcluster .
minimum energy pressure in the radio emission - peaks of the wat galaxy is comparable with the external thermal pressure .
the radio spectrum of the wat suggests a spectral age of @xmath010myr . .
And you have already written the first three sentences of the full article: clusters of galaxies , the largest gravitationally - bound structures , are believed to form hierarchically in a sequence of cosmic structure formation where smaller groups of galaxies merge to form larger and richer systems ( geller & beers 1982 ; dressler & shectman 1988 ; girardi et al .
1997 ; kriessler & beers 1997 ; jones & forman 1999 ; schuecker et al . 2001 ; burgett et al .
the intra - group or intra - cluster medium ( icm ) of these clusters contains a hot ( t@xmath1k ) and tenuous ( n@xmath2 @xmath3 ) plasma which emits in x - rays mainly through bremsstrahlung and line emission ( kellogg et al ..
Please generate the next two sentences of the article | 1972 ; mitchell et al .
1979 ; also see reviews by sarazin 1988 ; mcnamara & nulsen 2007 ) . |
5,960 | Suppose that you have an abstract for a scientific paper: an intriguing discrepancy emerging in the concordance model of cosmology is the tension between the locally measured value of the hubble rate , and the ` global ' value inferred from the cosmic microwave background ( cmb ) .
this could be due to systematic uncertainties when measuring @xmath0 locally , or it could be that we live in a highly unlikely hubble bubble , or other exotic scenarios .
we point out that the global @xmath0 can be found by extrapolating @xmath1 data points at high-@xmath2 down to @xmath3 . by doing this in a bayesian non - parametric way we can find a model - independent value for @xmath0 .
we apply this to 19 measurements based on differential age of passively evolving galaxies as cosmic chronometers . using gaussian processes
, we find @xmath4 km s@xmath5 mpc@xmath5 @xmath6 , in agreement with the cmb value , but reinforcing the tension with the local value .
an analysis of possible sources of systematic errors shows that the stellar population synthesis model adopted may change the results significantly , being the main concern for subsequent studies .
forecasts for future data show that distant @xmath1 measurements can be a robust method to determine @xmath0 , where a focus in precision and a careful assessment of systematic errors are required .
[ firstpage ] cosmological parameters cosmology : observations cosmology : theory dark energy large - scale structure of universe
cosmology : distance scale .
And you have already written the first three sentences of the full article: there is a strong tension , recently quantified by @xcite , between the value of the hubble constant @xmath0 derived by _
planck _ @xcite from anisotropies in the cosmic microwave background ( cmb ) : @xmath7 km
s@xmath5 mpc@xmath5 , and the value from local measurements : @xmath8 km s@xmath5 mpc@xmath5 @xcite . while the latter measurement is based on local measurements , the former infers a global value for the hubble constant within a cosmological model ..
Please generate the next two sentences of the article | there remains disagreement about the local value of @xmath0 depending on the distance indicator used to measure it , which hints the discrepancy with _
planck _ could be the result of systematic errors . |
5,961 | Suppose that you have an abstract for a scientific paper: we quantify the degree of inhomogeneity in the luminous red galaxy ( lrg ) distribution from the sdss dr7 as a function of length scales by measuring the shannon entropy in independent and regular cubic voxels of increasing grid sizes .
we also analyze the data by carrying out measurements in overlapping spheres and find that it suppresses inhomogeneities by a factor of @xmath0 to @xmath1 on different length scales . despite the differences observed in the degree of inhomogeneity both the methods show a decrease in inhomogeneity with increasing length scales which eventually settle down to a plateau at @xmath2 . considering the minuscule values of inhomogeneity at the plateaus and their expected variations we conclude that the lrg distribution becomes homogeneous at @xmath3 and beyond .
we also use the kullback - leibler divergence as an alternative measure of inhomogeneity which reaffirms our findings .
we show that the method presented here can effectively capture the inhomogeneity in a truly inhomogeneous distribution at all length scales .
we analyze a set of monte carlo simulations with certain periodicity in their spatial distributions and find periodic variations in their inhomogeneity which helps us to identify the underlying regularities present in such distributions and quantify the scale of their periodicity .
we do not find any underlying regularities in the lrg distribution within the length scales probed .
[ firstpage ] methods : numerical - galaxies : statistics - cosmology : theory - large scale structure of the universe . .
And you have already written the first three sentences of the full article: statistical homogeneity and isotropy of the universe on sufficiently large scales is a crucial assumption which simplifies the study of large scale structure of the universe and cosmology as a whole .
this assumption which is known as the cosmological principle is one of the fundamental pillars of modern cosmology .
one can not derive this principle in a strictly mathematical sense and can only verify this by analyzing various cosmological observations and comparing them with the theoretical predictions based on it ..
Please generate the next two sentences of the article | so far the most compelling evidence of isotropy comes from the near uniform temperature of the cmbr over the full sky @xcite .
this is further supported by multitude of evidences such as the isotropy in angular distributions of radio sources @xcite , isotropy in the x - ray background @xcite , isotropy of gamma - ray bursts @xcite , isotropy in the distribution of galaxies @xcite , isotropy in the distribution of supernovae @xcite and isotropy in the distribution of neutral hydrogen @xcite . but merely having isotropy around us does not guarantee homogeneity of the universe . |
5,962 | Suppose that you have an abstract for a scientific paper: rotating massive stars at @xmath0 and @xmath1 lose a great part of their initial mass through stellar winds .
the chemical composition of the rotationally enhanced winds of very low @xmath2 stars is very peculiar .
the winds show large cno enhancements by factors of @xmath3 to @xmath4 , together with large excesses of @xmath5c and @xmath6o and moderate amounts of na and al .
the excesses of primary n are particularly striking . when these ejecta from the rotationally enhanced winds are diluted with the supernova ejecta from the corresponding co cores , we find [ c / fe ] , [ n / fe],[o / fe ] abundance ratios very similar to those observed in the c rich extremely metal poor stars ( cemp ) .
we show that rotating agb stars and rotating massive stars have about the same effects on the cno enhancements .
abundances of s - process elements and the @xmath7c/@xmath5c ratio could help us to distinguish between contributions from agb and massive stars . on the whole
, we emphasize the dominant effects of rotation for the chemical yields of extremely metal poor stars . .
And you have already written the first three sentences of the full article: many intriguing and fascinating results were shown during this conference , which certainly require some revision of our classical understanding of the evolution of the first stellar generations in the universe .
let us briefly recall a few of them here : * the measured abundances of many elements at very low metallicity present a very small scatter ( cayrel et al .
this might indicate that already at this low metallicity , stars are formed from a well mixed reservoir composed of ejecta from stars of different initial masses ..
Please generate the next two sentences of the article | * at least down to a metallicity of [ fe / h ] equal to -4 , there is no sign of enrichments by pair instability supernovae ( see the contribution by heger in this volume ) . * the n / o ratios observed at the surface of halo stars by israelian et al .
( @xcite ) and spite et al . |
5,963 | Suppose that you have an abstract for a scientific paper: we review the results from our studies , and previous published work , on the spatially resolved physical properties of a sample of hii / bcd galaxies , as obtained mainly from integral - field unit spectroscopy with gemini / gmos and vlt / vimos .
we confirm that , within observational uncertainties , our sample galaxies show nearly spatially constant chemical abundances , similar to other low - mass starburst galaxies . they also show he ii @xmath04686 emission with properties being suggestive of a mix of excitation sources , with wolf - rayet stars being excluded as the primary one .
finally , in this contribution we include a list of all hii / bcd galaxies studied thus far with integral - field unit spectroscopy . .
And you have already written the first three sentences of the full article: the concept of _ compact galaxies _ was introduced by zwicky @xcite , who has described them as galaxies barely distinguishable from stars " on the palomar sky survey plates . the term blue compact dwarf ( bcd )
galaxies @xcite identify those objects that show low luminosity , small linear dimensions , strong emission lines superposed on a blue continuum , and spectral properties that indicate low chemical abundances .
bcds form a subset of hii galaxies , a large number of which have been identified on objective prism surveys by @xcite , @xcite , @xcite and @xcite by the presence of strong emission lines , similar to giant hii regions ( ghiirs ) in our galaxy . here.
Please generate the next two sentences of the article | , we will refer to hii / bcd galaxies as objects with a metallicity 7.0@xmath112+log(o / h)@xmath18.4 ( e.g. , @xcite ) , low luminosity ( m@xmath2 @xmath3 -18 ) and gas - rich objects ( e.g. , @xcite ) undergoing vigorous starburst activity in a relatively small physical size ( @xmath41 kpc ) .
the star - forming component , in these objects , typically contains multiple knots of star - formation with unresolved ensembles of young star clusters ( e.g. , @xcite , @xcite ) . |
5,964 | Suppose that you have an abstract for a scientific paper: to significantly improve the frequency references used in radio - astronomy and precision measurements in atomic physics , we provide frequency dissemination through a coherent optical fiber link , that will be also part of a forthcoming european network of optical links .
on the frequency transfer , we obtained a frequency instability of at in terms of allan deviation on a measurement bandwidth , and an accuracy of .
the ultimate link performance has been evaluated by doubling the link to , demonstrating a new characterization technique based on the double round - trip on a single fiber .
the arming of a second fiber is avoided : this is beneficial to long hauls realizations in view of a continental fiber network for frequency and time metrology . the observed noise power spectrum is seldom found in the literature ; hence
, the expression of the allan deviation is theoretically derived and the results confirm the expectations . .
And you have already written the first three sentences of the full article: coherent optical fiber links are the most precise technique to transfer time and frequency signals or to compare remote frequency standards , @xcite as they improve by more than four orders of magnitude the resolution of current satellite techniques @xcite .
thus , they are a key technology both for science and metrology , allowing for different outstanding applications . + presently , optical links are the only viable method for optical clocks comparison .
this is a prerequisite for an effective secondary representation of the second in the international system of units @xcite , as recommended by the confrence gnrale des poids et mesures , and for the possible redefinition of the second itself ..
Please generate the next two sentences of the article | + even cs fountains , presently the best realizations of the si second , could benefit from optical fiber links as an alternative to satellite techniques @xcite .
in fact , optical links would reduce by a factor 20 the measuring time needed to compare primary standards at their accuracy level . |
5,965 | Suppose that you have an abstract for a scientific paper: the nonlinear dynamics of a warped accretion disc is investigated in the important case of a thin keplerian disc with negligible viscosity and self - gravity .
a one - dimensional evolutionary equation is formally derived that describes the primary nonlinear and dispersive effects on propagating bending waves other than parametric instabilities .
it has the form of a derivative nonlinear schrdinger equation with coefficients that are obtained explicitly for a particular model of a disc .
the properties of this equation are analysed in some detail and illustrative numerical solutions are presented .
the nonlinear and dispersive effects both depend on the compressibility of the gas through its adiabatic index @xmath0 . in the physically realistic case @xmath1 ,
nonlinearity does not lead to the steepening of bending waves but instead enhances their linear dispersion . in the opposite case @xmath2
, nonlinearity leads to wave steepening and solitary waves are supported .
the effects of a small effective viscosity , which may suppress parametric instabilities , are also considered .
this analysis may provide a useful point of comparison between theory and numerical simulations of warped accretion discs .
[ firstpage ] accretion , accretion discs hydrodynamics waves . .
And you have already written the first three sentences of the full article: the existence of warped accretion discs , in which the orbital plane of the gas varies slowly with radius and possibly with time , is suggested by both observational evidence and theoretical reasoning . of the observational results ,
perhaps the best examples are certain x - ray binary stars , including her x-1 , in which the x - ray source appears to be periodically occulted by a precessing warped disc ( e.g. @xcite ; @xcite ) , and a few active galactic nuclei , including ngc 4258 , in which the warped shape of the disc is revealed by maser emission ( e.g. @xcite ; @xcite ) .
theoretical arguments indicate that a fluid disc will be warped by an external torque if it is misaligned with the equatorial plane of a spinning black hole or magnetized star at its centre ( @xcite ; @xcite ; @xcite ) , or with the orbital plane of a binary companion , planet or other satellite ( @xcite ) . even in an initially aligned system ,.
Please generate the next two sentences of the article | the disc may develop a warp through a linear instability of the coplanar state , depending on tidal , radiation or magnetic forces ( @xcite ; @xcite ; @xcite ) .
interpreting the behaviour of warped discs is an important and challenging problem in astrophysical fluid dynamics . |
5,966 | Suppose that you have an abstract for a scientific paper: the initial shear field , characterized by a primordial perturbation potential , plays a crucial role in the formation of large scale structures .
hence , considerable analytic work has been based on the joint distribution of its eigenvalues , associated with gaussian statistics .
in addition , directly related morphological quantities such as ellipticity or prolateness are essential tools in understanding the formation and structural properties of halos , voids , sheets and filaments , their relation with the local environment , and the geometrical and dynamical classification of the cosmic web . to date , most analytic work has been focused on doroshkevich s unconditional formulae for the eigenvalues of the linear tidal field , which neglect the fact that halos ( voids ) may correspond to maxima ( minima ) of the density field .
i present here new formulae for the constrained eigenvalues of the initial shear field associated with gaussian statistics , which include the fact that those eigenvalues are related to regions where the source of the displacement is positive ( negative ) : this is achieved by requiring the hessian matrix of the displacement field to be positive ( negative ) definite .
the new conditional formulae naturally reduce to doroshkevich s unconditional relations , in the limit of no correlation between the potential and the density fields . as a direct application
, i derive the individual conditional distributions of eigenvalues and point out the connection with previous literature .
finally , i outline other possible theoretically- or observationally - oriented uses , ranging from studies of halo and void triaxial formation , development of structure - finding algorithms for the morphology and topology of the cosmic web , till an accurate mapping of the gravitational potential environment of galaxies from current and future generation galaxy redshift surveys .
[ firstpage ] methods : analytical , statistical cosmology : theory , large - scale structure of universe ....
And you have already written the first three sentences of the full article: the large - scale spatial distribution of dark matter , as revealed from numerical simulations , shows a characteristic anisotropic web - like structure .
this _ cosmic web _ , which arises through the gravitational clustering of matter , is mainly due to the effects of the tidal field : in fact , the competition between cosmic expansion , the trace , and the traceless part of the tidal field imprints anisotropies in the large - scale matter distribution in much the same way that gravity and radiation pressure imprints baryonic acoustic oscillations ( bao ) on the cosmic microwave background ( cmb ) sky ( hu & sugiyama 1995 ; lee & springel 2010 ) . hence , the initial shear field plays a crucial role in the formation of large scale structures , and a number of studies in the literature have been devoted to this subject among the plethora of papers , see for example the classic works by zeldovich ( 1970 ) , icke ( 1973 ) , peebles ( 1980 ) , white ( 1984 ) , bardeen et al .
( 1986 ) , kaiser ( 1986 ) , bertschinger ( 1987 ) , bond & myers ( 1996 ) , bond , kofman & pogosyan ( 1996 ) and van de weygaert & bertschinger ( 1996 ) ..
Please generate the next two sentences of the article | in addition , if the cosmic web originates from primordial tidal effects and its degree of anisotropy increases with the evolution of the universe , then studying this initial field is crucial in understanding the subsequent nonlinear evolution of cosmic structures ( springel et al . 2005 ; shandarin et al .
2006 ; desjacques 2008 ; desjacques & smith 2008 ; pogosyan et al . 2009 ) , the alignment of shape and angular momentum of halos ( west 1989 ; catelan et al . 2001 |
5,967 | Suppose that you have an abstract for a scientific paper: we examine the properties of an atom laser produced by outcoupling from a bose - einstein condensate with squeezed light .
we model the multimode dynamics of the output field and show that a significant amount of squeezing can be transfered from an optical mode to a propagating atom laser beam .
we use this to demonstrate that two - mode squeezing can be used to produce twin atom laser beams with continuous variable entanglement in amplitude and phase . .
And you have already written the first three sentences of the full article: the experimental demonstration of bose - einstein condensates ( bec ) @xcite has lead to the development of atom lasers by outcoupling atoms from trapped becs by either a radio frequency transition or a raman transition to change the internal state of the atom to one that is either untrapped or anti - trapped @xcite .
atom lasers are coherent matter waves with spectral fluxes many orders of magnitude higher than thermal sources of atoms .
the coherence of these sources will enable an increase in the sensitivity of interferometric measurements @xcite ..
Please generate the next two sentences of the article | although current experiments usually operate in parameter regimes limited by technical noise , the fundamental limit on these measurements will be caused by the shot noise of the atomic field , which will be intrinsic to all interferometers without a non - classical atomic source .
sensitivity is increased in optical interferometry by ` squeezing ' the quantum state of the optical field , where the quantum fluctuations in one quadrature are reduced compared to a coherent state , while the fluctuations in the conjugate quadrature are increased . in the context of atom optics , |
5,968 | Suppose that you have an abstract for a scientific paper: we describe fluctuating two - dimensional metallic antiferromagnets by transforming to a rotating reference frame in which the electron spin polarization is measured by its projections along the local antiferromagnetic order .
this leads to a gauge - theoretic description of an ` algebraic charge liquid ' involving spinless fermions and a spin @xmath0 complex scalar .
we propose a phenomenological effective lattice hamiltonian which describes the binding of these particles into gauge - neutral , electron - like excitations , and describe its implications for the electron spectral function across the entire brillouin zone .
we discuss connections of our results to photoemission experiments in the pseudogap regime of the cuprate superconductors . .
And you have already written the first three sentences of the full article: an understanding of the nature of the electron spectral function in the underdoped ` pseudogap ' regime has emerged as one of the central problems in the study of the cuprate superconductors .
a wealth of data has appeared in photoemission studies , some of which @xcite has been interpreted using a model of `` fermi arcs '' across the brillouin zone diagonals ; other studies @xcite have indicated the presence of pocket fermi surfaces in the same region of the brillouin zone .
scanning tunnelling microscopy ( stm ) studies @xcite also indicate a fermi arc of excitations which appears to end abruptly at the magnetic brillouin zone boundary associated with two sublattice nel order ..
Please generate the next two sentences of the article | another issue of interest in experiments has been the angular dependence of the electronic excitation gap energy in the superconducting state .
a ` dichotomy ' has been noted @xcite between the behavior of the gap near the nodal points on the brillouin zone diagonals , and the antinodal points along the principle axes of the brillouin zone . |
5,969 | Suppose that you have an abstract for a scientific paper: we theoretically and numerically analyze x - ray scattering from asymmetric - top molecules three - dimensionally aligned using elliptically polarized laser light .
a rigid - rotor model is assumed .
the principal axes of the polarizability tensor are assumed to coincide with the principal axes of the moment of inertia tensor .
several symmetries in the hamiltonian are identified and exploited to enhance the efficiency of solving the time - dependent schrdinger equation for each rotational state initially populated in a thermal ensemble . using a phase - retrieval algorithm ,
the feasibility of structure reconstruction from a quasi - adiabatically - aligned sample is illustrated for the organic molecule naphthalene .
the spatial resolution achievable strongly depends on the laser parameters , the initial rotational temperature , and the x - ray pulse duration .
we demonstrate that for a laser peak intensity of 5 tw/@xmath0 , a laser pulse duration of 100 ps , a rotational temperature of 10 mk , and an x - ray pulse duration of 1 ps , the molecular structure may be probed at a resolution of 1 . .
And you have already written the first three sentences of the full article: x - ray diffraction is a powerful method for investigating structures of molecules .
x - ray crystallography has become the standard tool for identifying the structure of large molecules and proteins @xcite .
recent developments in x - ray sources have opened new opportunities @xcite for imaging membrane proteins and other macromolecules that can not be crystallized @xcite ..
Please generate the next two sentences of the article | one possibility is single - molecule imaging , where one molecule at a time is probed by an intense x - ray pulse @xcite , which subjects the molecule to severe damage @xcite .
a series of diffraction patterns has to be collected and classified according to the molecular orientation to get full structural information from randomly oriented molecules @xcite . |
5,970 | Suppose that you have an abstract for a scientific paper: we discuss several problems concerning domain walls in the spin @xmath0 ising model at zero temperature in a magnetic field , @xmath1 , applied in the @xmath2 direction .
some results are also given for the planar ( @xmath3-@xmath4 ) model in a transverse field .
we treat the quantum problem in one dimension by perturbation theory at small @xmath5 and numerically over a large range of @xmath5 .
we obtain the spin density profile by fixing the spins at opposite ends of the chain to have opposite signs of @xmath6 .
one dimension is special in that there the quantum width of the wall is proportional to the size @xmath7 of the system .
we also study the quantitative features of the ` particle ' band which extends up to energies of order @xmath5 above the ground state . except for the planar limit
, this particle band is well separated from excitations having energy @xmath8 involving creation of more walls . at large @xmath0
this particle band develops energy gaps and the lowest sub - band has tunnel splittings of order @xmath9 .
this scale of energy gives rise to anomalous scaling with respect to a ) finite size , b ) temperature , or c ) random potentials .
the intrinsic width of the domain wall and the pinning energy are also defined and calculated in certain limiting cases .
the general conclusion is that quantum effects prevent the wall from being sharp and in higher dimension would prevent sudden excursions in the configuration of the wall . .
And you have already written the first three sentences of the full article: recently , there has been a growing interest in the study of interfaces with non - trivial geometry .
such interfaces arise in a variety of situations including domain walls in random magnets,@xcite fluid invasion in porous media@xcite , spreading on heterogeneous surfaces@xcite , membranes and vesicles in biology,@xcite and epitaxial growth in materials science.@xcite in connection with such problems it is natural to ask whether quantum effects play a significant role . for static properties
it is well established that in nonrandom systems , such as a spin @xmath0 antiferromagnet , with only a nearest neighbor exchange interaction , @xmath10 , there are various regimes . near the critical temperature at @xmath11 ,.
Please generate the next two sentences of the article | thermal fluctuations are dominant . in the ordered phase ,
as long as @xmath12 , quantum effects due to the finiteness of @xmath0 are unimportant . for @xmath13 |
5,971 | Suppose that you have an abstract for a scientific paper: using the multi - wavelength images and the photospheric magnetograms from the _ solar dynamics observatory _ , we study the flare which was associated by the only one coronal mass ejection ( cme ) in active region ( ar ) 12192 . the eruption of a filament caused a blowout jet , and then an m4.0 class flare occurred .
this flare was located at the edge of ar instead of in the core region .
the flare was close to the apparently open " fields , appearing as extreme - ultraviolet structures that fan out rapidly . due to the interaction between flare materials and
open " fields , the flare became an eruptive flare , leading to the cme .
then at the same site of the first eruption , another small filament erupted . with the high spatial and temporal resolution h@xmath0 data from the new vacuum solar telescope at the _ fuxian solar observatory _ , we investigate the interaction between the second filament and the nearby open " lines .
the filament reconnected with the
open " lines , forming a new system . to our knowledge
, the detailed process of this kind of interaction is reported for the first time .
then the new system rotated due to the untwisting motion of the filament , implying that the twist was transferred from the closed filament system to the open " system .
in addition , the twist seemed to propagate from the lower atmosphere to the upper layers , and was eventually spread by the cme to the interplanetary space . .
And you have already written the first three sentences of the full article: solar jets which are small - scale plasma ejections along open field lines or the legs of large - scale coronal loops have been extensively investigated ( e.g. , schmieder et al .
1988 ; shibata et al .
1994 ; zhang et al ..
Please generate the next two sentences of the article | 2000 ; liu & kurokawa 2004 ; cirtain et al .
2007 ; jiang et al . 2007 |
5,972 | Suppose that you have an abstract for a scientific paper: passive remote sensing techniques have become more and more popular for detection and characterization purposes .
the advantage of using the global navigation satellite systems ( gnss ) are the well known signals emitted and the availability in most areas on earth . in the present paper , l - band signals ( including gnss signals )
are considered for oceanographic purposes .
the main interest in this contribution is the analysis of the signal reflected by an evolving sea surface using time - frequency transforms .
the features which occur in this domain are examined in relation to the physical phenomena : interaction of the electromagnetic waves with the moving sea surface .
* qualitative analysis of the time - frequency signature induced by a reflected l - band signal from time evolving sea surfaces * arnaud coatanhay and alexandre baussard + _ ^1^ensta bretagne / lab - sticc ( umr cnrs 6285 ) , brest , france + ( dated : december 17 , 2013 ) _ .
And you have already written the first three sentences of the full article: for a decade , the passive remote sensing techniques based upon electromagnetic sources of opportunity have become more and more popular for detection and characterization purposes .
the most significant reason for this enthusiasm lies in the fact that the passive systems take advantage of the numerous existing electromagnetic emitting sources to come up with new approaches for remote sensing or surveillance applications . as a matter of fact , among all the possible sources of opportunity ,
the global navigation satellite systems gnss ( gps , galileo , glonass , ... ) appear among the most relevant solutions since the electromagnetic signals emitted ( in l - band ) are reliable , available all over the world , deterministic and perfectly known ( for direct paths ) ..
Please generate the next two sentences of the article | it is worth noting that the use of gnss signals for passive observation has been applied to a significant extent to the field of oceanography since the year 2000 . indeed
, several studies have been carried out to estimate oceanographic parameters using the reflected gnss signals measured from ground - based systems , see for example @xcite , or airborne systems , see for example @xcite . |
5,973 | Suppose that you have an abstract for a scientific paper: in this paper , we study a class of fractional optimal control problems .
a necessary condition for the existence of an optimal control is provided in @xcite and references therein .
it is commonly given as the existence of a solution of a fractional pontryagin s system and the proof is based on the introduction of a lagrange multiplier .
assuming an additional condition on these problems , we suggest a new presentation of this result with a proof using only classical mathematical tools adapted to the fractional case : _ calculus of variations _ , _ gronwall s lemma _ , _ cauchy - lipschitz theorem _ and _ stability under perturbations of differential equations_. in this paper , we furthermore provide a way in order to transit from a classical optimal control problem to its fractional version via the stanislavsky s formalism .
we also solve a strict fractional example allowing to test numerical schemes .
finally , we state a fractional noether s theorem giving the existence of an explicit constant of motion for fractional pontryagin s systems admitting a symmetry . * * optimal control ; fractional calculus ; noether s theorem . *
* 26a33 ; 49j15 . .
And you have already written the first three sentences of the full article: the control theory is the analysis of controlled dynamical systems .
these systems are varied : they can be differential , stochastic or discrete .
the optimal control theory concerns the determination of a control optimizing a certain cost ..
Please generate the next two sentences of the article | consequently , this theory is strongly connected to the 18@xmath0 century classical mechanic ( variational principles , euler - lagrange equations , etc . , see @xcite ) .
since the second world war , this theory has a considerable development and one can find applications in many domains : celestial mechanic @xcite , biology @xcite , hydroelectricity @xcite , economy @xcite , etc . |
5,974 | Suppose that you have an abstract for a scientific paper: we present new radial velocities for 87 globular clusters around the elliptical galaxy ngc 4472 , and combine these with our previously published data to create a data set of velocities for 144 globular clusters around ngc 4472 .
we utilize this data set to analyze the kinematics of the ngc 4472 globular cluster system .
the new data confirms our previous discovery that the metal - poor clusters have significantly higher velocity dispersion than the metal - rich clusters in ngc 4472 .
we also find very little or no rotation in the more spatially concentrated metal - rich population , with a resulting upper limit for this population of @xmath0 at a @xmath1 confidence level .
the very small angular momentum in the metal - rich population requires efficient angular momentum transport during the formation of this population which is spatially concentrated and chemically enriched .
such angular momentum transfer can be provided by galaxy mergers , but has not been achieved in other extant models of elliptical galaxy formation that include dark matter halos .
we also calculate the velocity dispersion as a function of radius , and show that it is consistent with roughly isotropic orbits for the clusters and the mass distribution of ngc 4472 inferred from x - ray observations of the hot gas around the galaxy . .
And you have already written the first three sentences of the full article: although early - type galaxies make up much of the stellar mass in the local universe ( e.g. fukugita , peebles , & hogan 1998 , coppi & zepf 2000 ) , there is no consensus on when or how they formed .
the possibilities range from monolithic collapse at high redshift to formation via galaxy mergers over a range of redshifts .
many of the integrated properties of elliptical galaxies can be accounted for by both scenarios , making it difficult to determine the formation histories of these galaxies ..
Please generate the next two sentences of the article | for example , one of the salient observational features of the population of early - type galaxies is that their color - magnitude and mg@xmath2 relations have small scatter .
however , both early collapse models ( e.g. kodama & arimoto 1997 ) and hierarchical merging models ( e.g. kauffmann & charlot 1998 ) have been shown to be consistent with the observed correlations . both mergers and collapse models can also be made consistent with current observations of galaxies at high redshift . |
5,975 | Suppose that you have an abstract for a scientific paper: we show experimentally and theoretically that localized pulses can be generated from an electrically biased @xmath0 m multi - transverse mode vertical - cavity surface - emitting laser .
the device is passively mode - locked using optical feedback from a distant resonant saturable absorber mirror and it is operated below threshold .
we observe multistability between the off solution and a large variety of pulsating solutions with different number and arrangements of pulses per round - trip , thus indicating that the mode - locked pulses are localized , i.e. mutually independent .
we show that a modulation of the bias current allows controlling the number of the pulses travelling within the cavity , thus suggesting that our system can be operated as an arbitrary pattern generator of 10 ps pulses and 1 w peak power .
mode - locking , broad - area lasers , vcsels .
And you have already written the first three sentences of the full article: ode - locking ( ml ) is a fascinating phenomenon that allows the generation of ultrashort pulses from a laser @xcite and that is still a subject of intense research .
passive ml ( pml ) is arguably the most successful approach and it is achieved by combining two elements , a laser amplifier which provides gain and a saturable absorber ( sa ) acting as a pulse shortening element , see @xcite for a review . pulsed emission with a fundamental period corresponding to the cavity round - trip time arises from the different dynamical properties of the sa and the amplifier , which open a short window for amplification around the pulse @xcite .
ml has led to the shortest and most intense optical pulses ever generated and pulses in the femtosecond range are produced by dye @xcite and solid state lasers @xcite ..
Please generate the next two sentences of the article | large output powers in the watt range are commonly achieved from coupled vecsels - sesam @xcite configurations . on the other hand ,
the large gain of semiconductor materials allows building sub - millimeter monolithic pml lasers . |
5,976 | Suppose that you have an abstract for a scientific paper: we show that for every complete riemannian surface @xmath0 diffeomorphic to a sphere with @xmath1 holes there exists a morse function @xmath2 , which is constant on each connected component of the boundary of @xmath0 and has fibers of length no more than @xmath3 .
we also show that on every 2-sphere there exists a simple closed curve of length @xmath4 subdividing the sphere into two discs of area @xmath5 .
[ theorem]definition [ theorem]lemma [ theorem]proposition [ theorem]corollary .
And you have already written the first three sentences of the full article: let @xmath0 be a reiamannian 2-sphere . denote the area of @xmath0 by @xmath6 .
in this paper we consider the problem of slicing @xmath0 by short curves .
we start with the following isoperimetric problem : when is it possible to subdivide @xmath0 into two regions of relatively large area by a short simple closed curve ?.
Please generate the next two sentences of the article | papasoglu @xcite used besicovitch inequality to show that there exists a simple closed curve of length @xmath7 subdividing @xmath0 into two regions of area @xmath8 .
a similar result was independently proved by balacheff and sabourau @xcite using a variation of gromov s filling argument . |
5,977 | Suppose that you have an abstract for a scientific paper: few - particle dynamics in a three - well potential are investigated numerically .
it is shown that periodically shaking the potential can considerably increase the fidelity of emerging spatial quantum superpositions .
such noon - states are important for quantum interferometry .
if the two particles initially sit in the middle well , the probability to return to this state can distinguish pure quantum dynamics from statistical mixtures .
the numeric implementation of decoherence via particle losses shows clear differences from the pure quantum behaviour .
a three - well lattice could be an ideal system for experimental realisations . .
And you have already written the first three sentences of the full article: double - well lattices @xcite provide an interesting , experimentally accessible tool to investigate quantum effects for atom numbers even down to less than six atoms @xcite .
three - well lattices and four - well lattices could be realised either by using subwavelength lattices @xcite or by adjusting the technique used in refs .
@xcite by using more lasers . the number of particles in one of the two wells of a double - well lattice can easily be measured by averaging over all double wells @xcite . for a single three - well potential , transport and interaction blockade of cold bosonic atoms.
Please generate the next two sentences of the article | have been discussed in ref .
@xcite . in a single three - well potential , few particle dynamics could be observed by using the single - site addressability of refs . |
5,978 | Suppose that you have an abstract for a scientific paper: we identify 4 unusually bright ( h@xmath0<25.5 ) galaxies from hst and spitzer candels data with probable redshifts _ _ z__@xmath17 - 9 .
these identifications include the brightest - known galaxies to date at @xmath2 . as @xmath3-band observations are not available over the full candels program to perform a standard lyman - break selection of @xmath4 galaxies , we employ an alternate strategy using deep spitzer / irac data .
we identify [email protected] - 9.1 galaxies by selecting _ _ z__@xmath56 galaxies from the hst candels data that show quite red irac [ 3.6]@xmath6[4.5 ] colors , indicating strong [ oiii]+h@xmath7 lines in the 4.5@xmath8 m band .
this selection strategy was validated using a modest sample for which we have deep y - band coverage , and subsequently used to select the brightest @xmath9 sources . applying the irac criteria to all hst - selected optical - dropout galaxies over the full @xmath1900 arcmin@xmath10 of the candels survey revealed four unusually bright @xmath11 , 7.6 , 7.9 and 8.6 candidates .
the median [ 3.6]@xmath6[4.5 ] color of our selected @xmath11 - 9.1 sample is consistent with rest - frame [ oiii]+h@xmath7 ews of @xmath11500@xmath12 in the [ 4.5 ] band .
keck / mosfire spectroscopy has been independently reported for two of our selected sources , showing ly@xmath13 at redshifts of [email protected] and 8.683@xmath15 , respectively .
we present similar keck / mosfire spectroscopy for a third selected galaxy with a probable 4.7@xmath16 ly@xmath13 line at @[email protected] .
all three have h@xmath18-band magnitudes of @xmath125 mag and are @xmath10.5 mag more luminous ( @xmath19 ) than any previously discovered _ _
z__@xmath18 galaxy , with important implications for the uv lf .
our 3 brightest , highest redshift @xmath20>7 galaxies all lie within the candels egs field , providing a dramatic illustration of the potential impact of field - to - field variance . .
And you have already written the first three sentences of the full article: the first galaxies are believed to have formed within the first 300 - 400 myr of the universe and great strides have been made towards identifying objects within this era . since the installation of the wide field camera 3 ( wfc3 ) instrument on the hubble space telescope ( hst ) , an increasing number of candidates have been identified by means of their photometric properties , with @xmath5700 probable galaxies identified at @xmath217 - 8 ( @xcite : see also @xcite ; @xcite ; @xcite ; @xcite ; @xcite ; @xcite ; @xcite ; @xcite ) and another 10 - 15 candidates identified even further out at @xmath219 - 11 ( e.g. , @xcite ; @xcite ; @xcite ; @xcite ; @xcite ; @xcite ; @xcite ; @xcite ) .
one of the most interesting questions to investigate with these large samples is the build - up and evolution of galaxies .
while these issues have long been explored in the context of fainter galaxies through the evolution of the @xmath22 lf , less progress has been made in the study of the most luminous galaxies due to the large volumes that must be probed to effectively quantify their evolution ..
Please generate the next two sentences of the article | the entire enterprise of finding especially bright galaxies at @xmath9 has been limited by the availability of sufficiently deep , multi - wavelength near - infrared data over wide areas of the sky .
the most noteworthy such data sets are the ukidss uds program ( lawrence et al . |
5,979 | Suppose that you have an abstract for a scientific paper: we show that existing proofs of factorization imply the cancellation of certain multiladder contributions that gotsman , levin , and maor had suggested would invalidate the basic factorization theorem in qcd .
no modifications of the original argument are necessary , although the details of the example offer useful insight into the mechanisms of factorization .
= 6.5 in = -0.5 in epsf.tex ( # 1 width # 2)=#2 .
And you have already written the first three sentences of the full article: factorization theorems are at the heart of the theory of high - energy inclusive processes involving a large momentum transfer .
examples include the inclusive production in hadron - hadron collisions of new , heavy particles , such as the higgs boson or the supersymmetric partners of the currently known particles .
these theorems apply to _ inclusive _ cross sections for the production of a set @xmath0 of heavy particles or of a system of jets with a total mass @xmath1 , @xmath2 the theorem assumes that @xmath0 is defined in such a way that all final states that differ by the emission of soft hadrons and by the collinear rearrangement of momenta between outgoing light hadrons are summed over ..
Please generate the next two sentences of the article | it is important here that @xmath1 be large .
one usually assumes that @xmath1 is of the order of the @xmath3 invariant mass @xmath4 . for @xmath5 , |
5,980 | Suppose that you have an abstract for a scientific paper: we study the properties of dipolar fermions trapped in one - dimensional bichromatic optical lattices and show the existence of fractional topological states in the presence of strong dipole - dipole interactions .
we find some interesting connections between fractional topological states in one - dimensional superlattices and the fractional quantum hall states : ( i ) the one - dimensional fractional topological states for systems at filling factor @xmath0 have @xmath1-fold degeneracy , ( ii ) the quasihole excitations fulfill the same counting rule as that of fractional quantum hall states , and ( iii ) the total chern number of @xmath1-fold degenerate states is a nonzero integer .
the existence of crystalline order in our system is also consistent with the thin - torus limit of the fractional quantum hall state on a torus .
the possible experimental realization in cold atomic systems offers a new platform for the study of fractional topological phases in one - dimensional superlattice systems . _
introduction.- _ fractional quantum hall ( fqh ) effects have attracted intensive studies in the past decades as an important subject in condensed matter physics .
the traditional fqh states were realized in two - dimensional ( 2d ) electron gases within a strong external magnetic field .
in addition to 2d electron gases , great effort has been made to study quantum hall effects in some other physical systems , for example , lattice systems without a magnetic field and cold atomic systems .
effective landau levels can be realized in cold atomic systems in the presence of a rapidly rotating trap @xcite or a laser - induced gauge field @xcite . because of the existence of long - range interaction , the dipolar fermi gas is a good candidate to realize fqh states .
the fqh effects in a 2d dipolar fermi gas with either isotropic @xcite or anisotropic dipole - dipole interaction ( ddi ) @xcite have been studied recently .
as most of the previous studies on topological nontrivial states focus on....
And you have already written the first three sentences of the full article: in the supplemental material , we give details for exact diagonalization of hamiltonian ( 1 ) considered in the main text .
the hamiltonian is given by @xmath88 with @xmath27 .
under the periodic boundary condition , we can transform the hamiltonian from the real space to the momentum space through a fourier transformation . for @xmath27 , there are 3 sites in each unit cell and the single - particle energy spectrum are composed of 3 bands . for convenience ,.
Please generate the next two sentences of the article | we use @xmath89 , @xmath90 , and @xmath91 to represent the annihilation operator at different sites in a unit cell , respectively . to represent it in momentum space
, we make the fourier transformation @xmath92 where @xmath93 , @xmath94 , @xmath95 and m is the index of the unit cell . |
5,981 | Suppose that you have an abstract for a scientific paper: we introduce a three - dimensional model for jamming and glasses , and prove that the fraction of frozen particles is discontinuous at the directed - percolation critical density . in agreement with the accepted scenario for jamming- and glass - transitions ,
this is a mixed - order transition ; the discontinuity is accompanied by diverging length- and time - scales .
because one - dimensional directed - percolation paths comprise the backbone of frozen particles , the unfrozen rattlers may use the third dimension to travel between their cages .
thus the dynamics are diffusive on long - times even above the critical density for jamming . .
And you have already written the first three sentences of the full article: glassiness and jamming in grains and colloids entails mechanical solid - like behavior accompanied by divergent relaxation times , apparently without spatial order @xcite .
a rather simple way to theoretically study such non - equilibrium transitions is by lattice models in which disorder and slow ( or nonexistent ) dynamics arise naturally from the underlying static or dynamic local rules of the models @xcite .
thus , a promising approach for describing the glass and jamming transitions has evolved in recent years around _ kinetically - constrained models _.
Please generate the next two sentences of the article | @xcite . the first such model due to fredrickson and andersen ( fa ) @xcite considers non - interacting spins on an ordered lattice such that each spin can flip only if at least some number @xmath0 of its neighbors are up .
kob and andersen ( ka ) later suggested the corresponding lattice - gas model @xcite . |
5,982 | Suppose that you have an abstract for a scientific paper: in order to investigate various decay channels of the higgs boson @xmath0 or the hypothetical dilaton , we consider a neutral particle @xmath1 with zero spin and arbitrary @xmath2 parity .
this particle can decay into two off - mass - shell @xmath3 bosons ( @xmath4 and @xmath5 ) decaying to identical fermion - antifermion pairs ( @xmath6 ) : @xmath7 .
we derive analytical formulas for the fully differential width of this decay and for the fully differential width of @xmath8 ( @xmath9 stands for @xmath10 , @xmath11 , or @xmath12 ) .
integration of these formulas yields some standard model histogram distributions of the decay @xmath8 which are compared with corresponding monte carlo simulated distributions obtained by atlas and with atlas experimental data . .
And you have already written the first three sentences of the full article: the boson @xmath0 discovered @xcite in 2012 by the cms and atlas collaborations was reported to have a mass about 125 gev and some decay modes predicted for the standard model ( sm ) higgs boson .
since that time , the observed particle , called the higgs boson , has been intensively studied ( see , for example , papers @xcite ) .
a main goal of experiments on the higgs boson physics has been to prove or disprove the hypothesis that @xmath0 is the sm higgs boson ..
Please generate the next two sentences of the article | apart from the decay channels , the sm predicts that @xmath0 has @xmath13 .
the followed thorough analysis has fine - tuned the mass of @xmath0 , which is @xmath14 gev according to ref . |
5,983 | Suppose that you have an abstract for a scientific paper: the structure of the nucleon and the first radial excitation of the nucleon , the roper , @xmath0 , is studied within the formalism of light - front holography .
the nucleon elastic form factors and @xmath1 transition form factors are calculated under the assumption of the dominance of the valence quark degrees of freedom .
contrary to the previous studies , the bare parameters of the model associated with the valence quark are fixed by the empirical data for large momentum transfer ( @xmath2 ) assuming that the corrections to the three - quark picture ( meson cloud contributions ) are suppressed .
the @xmath1 transition form factors are then calculated without any adjustable parameters .
our estimates are compared with results from models based on valence quarks and others .
the model compares well with the @xmath1 transition form factor data , suggesting that meson cloud effects are not large , except in the region @xmath3 gev@xmath4 .
in particular , the meson cloud contributions for the pauli form factor are small . .
And you have already written the first three sentences of the full article: within the nucleon excited states ( @xmath5 ) the @xmath0 resonance , also known as roper , plays a special role .
contrarily to the @xmath6 and other nucleon excitations , the roper was not identified as a bump in a reaction cross - section but was instead found in the analysis of phase - shifts @xcite .
nowadays there is evidence that the roper should be identified as the first radial excitation of the nucleon quark core , although meson excitations are also important for the internal structure.
Please generate the next two sentences of the article | . calculations based on valence quark degrees of freedom are consistent with the @xmath1 transition form factors for large @xmath2 ( @xmath7 gev@xmath4 ) @xcite .
however , estimates based exclusively on quark degrees of freedom fail to describe the small @xmath2 data ( @xmath8 gev@xmath4 ) @xcite . |
5,984 | Suppose that you have an abstract for a scientific paper: in this paper we construct the 5 parameter _ generating solution _ of @xmath0 bps regular supergravity black holes as a five parameter solution of the @xmath1 @xmath2 model .
our solution has a simpler form with respect to previous constructions already appeared in the literature and moreover , through the embedding @xmath3 ^ 3\subset su(3,3)\subset e_{7(7)}$ ] discussed in previous papers , the action of the @xmath4duality group is well defined .
this allows to reproduce via @xmath4duality rotations any other solution , like those corresponding to r
r black holes whose microscopic description is given by intersecting d branes .
= cmss10 = cmss10 at 7pt # 1#2#3#4 ( ) = cmss10 = cmss10 at 7pt # 1#2\{#1;#2 } = cmss10 = cmss10 at 7pt c = [ ] = = | # 1 sissa ref 55/99/ep swat/227 * the generating solution of regular n=8 bps black holes * m. bertolini@xmath5 , p. fr@xmath6 and m. trigiante@xmath7 _ @xmath5international school for advanced studies isas - sissa and infn + sezione di trieste , via beirut 2 - 4 , 34013 trieste , italy _
_ @xmath6dipartimento di fisica teorica , universit di torino and infn + sezione di torino , via p. giuria 1 , 10125 torino , italy _ _ @xmath7department of physics , university of wales swansea , singleton park + swansea sa2 8pp , united kingdom _
e - mail : [email protected] , [email protected] , [email protected] ' '' '' width 3.cm 0.2 cm supported in part by eec under tmr contracts erbfmrx ct960045 and erbfmrx .
And you have already written the first three sentences of the full article: after the advent of d - branes @xcite there has been a renewed interest in the study of supergravity black @xmath8-branes , in particular those preserving a fraction of the original supersymmetry .
this is due to their identification with the bps saturated non perturbative states of superstring theory @xcite which has promoted them from classical solutions of the low energy theory to solutions of the whole quantum theory .
therefore they represent an important tool in probing the non perturbative regime of superstring theories ..
Please generate the next two sentences of the article | of particular interest are the regular ones , namely those having a non vanishing bekenstein hawking entropy .
in this paper we deal with bps static black hole solutions of @xmath9 supergravity preserving 1/8 of the original @xmath0 supersymmetry , completing a program started in @xcite and continued in @xcite . |
5,985 | Suppose that you have an abstract for a scientific paper: we study the s - wave interaction of mesons with baryons in the strangeness @xmath0 sector in a coupled channel unitary approach .
the basic dynamics is drawn from the lowest order meson baryon chiral lagrangians .
small modifications inspired by models with explicit vector meson exchange in the @xmath1channel are also considered .
in addition the @xmath2 channel is included and shown to have an important repercussion in the results , particularly in the @xmath3 sector .
the @xmath4 resonance is dynamically generated and appears as a pole in the second riemann sheet with its mass , width and branching ratios in fair agreement with experiment .
a @xmath5 resonance also appears as a pole at the right position although with a very large width , coming essentially from the coupling to the @xmath2 channel , in qualitative agreement with experiment . .
And you have already written the first three sentences of the full article: the introduction of effective chiral lagrangians to account for the basic symmetries of qcd and its application through @xmath6 to the study of meson meson interaction @xcite or meson baryon interaction @xcite has brought new light into these problems and allowed a systematic approach . yet , @xmath6 is constrained to the low energy region , where it has had a remarkable success , but makes unaffordable the study of the intermediate energy region where resonances appear . in recent years , however , the combination of the information of the chiral lagrangians , together with the use of nonperturbative schemes , have allowed one to make prediction beyond those of the chiral perturbation expansion .
the main idea that has allowed the extension of @xmath6 to higher energies is the inclusion of unitarity in coupled channels . within the framework of chiral dynamics
, the combination of unitarity in coupled channels together with a reordering of the chiral expansion , provides a faster convergence and a larger convergence radius of a new chiral expansion , such that the lowest energy resonances are generated within those schemes ..
Please generate the next two sentences of the article | a pioneering work along this direction was made in @xcite where the lippmann schwinger equation in coupled channels was used to deal with the meson baryon interaction in the region of the @xmath4 and @xmath7 resonances .
similar lines , using the bethe salpeter equation in the meson meson interaction , were followed in @xcite and a more elaborated framework was subsequently developed using the inverse amplitude method ( iam ) @xcite and the n / d method @xcite . |
5,986 | Suppose that you have an abstract for a scientific paper: we propose a new method for the coulomb wave function correction including the momentum resolution for charged hadron pairs and apply it to the precise data on @xmath0 correlations obtained in @xmath1 reaction at 70 gev / c .
it is found that interaction regions of this reaction ( assuming gaussian source function ) are @xmath2 and @xmath3 fm for the thicknesses of the target @xmath4 and @xmath5 microns , respectively .
the physical picture of the source size obtained in this way is discussed .
= -1 cm = 0 cm = 0 cm = 23.7 cm = 16 cm * 1 .
introduction.*recently we have obtained the new formulae for the coulomb wave function correction for charged hadron pairs @xcite . in particular
we have applied them ( in @xcite ) to data on @xmath0 correlation obtained in @xmath6 reaction at 70 gev / c @xcite ( which were originally corrected by usual gamow factor only ) . however , as it was pointed out to us by one of the author of @xcite , we did not take into account their published finite momentum resolution @xcite .
in fact , our formulae can not be applied directly to experimental data in which such momentum resolution is accounted for .
therefore in the present letter we would like to extend our method for the coulomb wave correction provided in @xcite to include also the momentum resolution case and to re - analyse data of @xcite and also to analyse the new , preliminary data of @xcite obtained with two kinds of thickness of ta target : 8 microns ( 8 mkm ) and 1.4 microns ( 1.4 mkm ) .
+ in the next paragraph we first reconstruct ( for the sake of completeness ) the analysis performed in ref .
@xcite and then , in the third paragraph , we propose our new method for the coulomb wave correction including this time also the momentum resolution .
the final part contains our concluding remarks .
+ * 2 . reconstruction of the analysis of @xmath0 correlation data performed by using the gamow factor with momentum resolution.*it has been stressed in @xcite that relative momenta of @xmath0....
And you have already written the first three sentences of the full article: fig . 1 . : : flow chart of the present procedure for gamow factor and/or coulomb wave function , which includes momentum resolution by generating the gaussian random numbers . fig . 2 . : : results of @xmath64 fit for 8 mkm target of @xmath66 reaction with @xmath31 mev / c by eq .
( [ eqn : a6 ] ) .
3 . : : results of the @xmath64 fit for ref ..
Please generate the next two sentences of the article | @xcite of @xmath66 reaction with @xmath31 mev / c by eq .
( [ eqn : a9 ] ) . |
5,987 | Suppose that you have an abstract for a scientific paper: nonlinear supercoherent states , which are eigenstates of nonlinear deformations of the kornbluth - zypman annihilation operator for the supersymmetric harmonic oscillator , will be studied .
they turn out to be expressed in terms of nonlinear coherent states , associated to the corresponding deformations of the standard annihilation operator .
we will discuss as well the heisenberg uncertainty relation for a special particular case , in order to compare our results with those obtained for the kornbluth - zypman linear supercoherent states .
as the supersymmetric harmonic oscillator executes an evolution loop , such that the evolution operator becomes the identity at a certain time , thus the linear and nonlinear supercoherent states turn out to be cyclic and the corresponding geometric phases will be evaluated . .
And you have already written the first three sentences of the full article: in quantum field theory , supersymmetry ( susy ) generates transformations between boson and fermion , supplying us with a global framework to describe both kinds of particles using the same supersymmetric multiplet @xcite .
witten was the first people who considered the simplest supersymmetric system composed of a particle of spin @xmath0 moving in one dimension @xcite , defining thus the algebra that the charge operators ( also called supercharges ) must meet and the way in which the supersymmetric hamiltonian is expressed in terms of them .
these algebraic relations define what nowadays is called supersymmetric quantum mechanic ( susy qm ) ..
Please generate the next two sentences of the article | one of the simplest systems realizing susy qm is the so - called supersymmetric harmonic oscillator .
it has been employed to illustrate how supersymmetry works , and it has been used also to introduce the supercoherent states , a supersymmetric generalization of the standard coherent states @xcite . in order to perform the supercoherent states analysis , it is important to study the algebraic commutation relations between the hamiltonian @xmath1 and the creation @xmath2 and annihilation operators @xmath3 of the system . |
5,988 | Suppose that you have an abstract for a scientific paper: zero temperature crossover from superfluidity to superconductivity with carrier density increasing is studied for a two - dimensional system in the @xmath0-wave and @xmath1-wave pairing channels .
it was assumed that the particle attraction correlation length depends on carrier density @xmath2 as @xmath3 .
such a dependence was found experimentally for the radius of magnetic correlations in @xmath4 .
the short range coulomb repulsion was also taken into account .
it is shown that the behavior of the system with doping is fundamentally different from the case with @xmath5 .
in particular , similarly to the @xmath1-wave case , the crossover in the @xmath0-channel takes place only if the coupling is larger of some minimal value , otherwise the cooper pairing scenario takes place at any small carrier density .
the relevance of the model to the high - temperature superconductors is discussed . : 74.20.-z , 74.62.dh , 74.72.-h _ keywords _ : symmetry , @xmath0-wave , @xmath1-wave , effects of doping .
And you have already written the first three sentences of the full article: the problem of the crossover from superfluidity to superconductivity with charge carrier density or coupling constant changing has a long history @xcite .
the interest to this phenomena has arisen again after the discovery of high - temperature superconductors ( htscs ) in 1986 @xcite .
it was already known upon that time that the superfluidity of composite bosons transforms into the superconductivity of overlapped cooper pairs with chemical doping in the case of the s - wave pairing ..
Please generate the next two sentences of the article | now , in the s - wave pairing case the problem is quite well explored for the 3d systems @xcite and , particularly for the quasi-2d case @xcite . for the 2d case this problem was studied at @xmath6 ( when a long - range superconducting is still possible in a 2d system @xcite ) for the case of local attraction ( see , for example @xcite ) and for the phonon - exchange model @xcite .
most of these problems are reviewed in @xcite . |
5,989 | Suppose that you have an abstract for a scientific paper: graphical functions are single - valued complex functions which arise from feynman amplitudes .
we study their properties and use their connection to multiple polylogarithms to calculate feynman periods . for the zig - zag and two more families of @xmath0 periods we give exact results modulo products .
these periods are proved to be expressible as integer linear combinations of single - valued multiple polylogarithms evaluated at one . for the larger family of constructible graphs we give an algorithm that allows one to calculate their periods by computer algebra .
the theory of graphical functions is used in @xcite to prove the zig - zag conjecture . .
And you have already written the first three sentences of the full article: in four dimensional @xmath0 theory the period map assigns positive real numbers to 4-regular internally 6-connected graphs @xcite .
the periods determine the contributions of primitive logarithmically divergent graphs to the beta function of the underlying quantum field theory .
although periods are originally associated to sub - divergence free four - pointgraphs , it is convenient to complete the graph by adding an extra vertex ( henceforth labeled @xmath1 ) and gluing this vertex to the four external ( half-)edges of the graph . as a remnant of conformal symmetry one can consider the completed graph as an equivalence class of four - point graphs ( obtained by opening up a vertex ) with the same period ( see figure 1 ) ..
Please generate the next two sentences of the article | figure 1 : completed ( @xmath2 ) and uncompleted ( @xmath3 ) zig - zag graphs with five and six loops .
2ex the structure of @xmath0 periods were first studied systematically by broadhurst and kreimer in 1995 @xcite when they found by exact numerical methods that up to seven loops ( the number of independent cycles in the four - point graph ) many periods are multiple zeta values ( mzvs ) , i.e. rational linear combinations of multiple zeta sums @xmath4 multiple zeta values span a @xmath5 vector space @xmath6 which is conjectured to be graded by the weight @xmath7 |
5,990 | Suppose that you have an abstract for a scientific paper: we introduce a measurement scheme that utilizes a single ion as a local field probe . the ion is confined in a segmented paul trap and shuttled around to reach different probing sites . by the use of a single atom probe , it becomes possible characterizing fields with spatial resolution of a few nm within an extensive region of millimeters .
we demonstrate the scheme by accurately investigating the electric fields providing the confinement for the ion . for this
we present all theoretical and practical methods necessary to generate these potentials .
we find sub - percent agreement between measured and calculated electric field values . .
And you have already written the first three sentences of the full article: the concept to realize and investigate quantum processes with single ions in paul traps was subject to an impressive development over the last years .
as for quantum information with single to a few ions , there has hardly been an experimental challenge that could withstand this development , consider for instance high fidelity quantum gates @xcite , multi - qubit entanglement @xcite , and error correction @xcite .
there has been a recent development in ion trap technology that was primarily initiated by the necessity and possibility to scale up the established techniques to process larger numbers of ions ..
Please generate the next two sentences of the article | this idea how to scale up an ion trap computer is to create multiple trap potentials , each keeping only a small , processable number of ions @xcite .
time dependent potentials can then be used to shuttle the ions between different sections . to generate such spatially separated potentials , |
5,991 | Suppose that you have an abstract for a scientific paper: the use of type ia supernovae as cosmological tools has reinforced the need to better understand these objects and their light curves .
the light curves of type ia supernovae are powered by the nuclear decay of @xmath0 . the late time light curves can provide insight into the behavior of the decay products and their effect of the shape of the curves . we present the optical light curves of six normal " type ia supernovae , obtained at late times with template image subtraction , and the fits of these light curves to supernova energy deposition models . .
And you have already written the first three sentences of the full article: type ia supernovae ( sne ia ) are thought to be the thermonuclear explosion of a white dwarf .
the light curves of sne ia are powered by deposition in the sn ejecta of the @xmath1-ray and positron products of the @xmath2 decay @xcite . the extreme brightness and seemingly uniform light curves of sne
ia make them good candidates for use as standard candle distance indicators . in more recent years , it has been shown that type ia supernovae do not have uniform light curve magnitudes , shape or spectra ..
Please generate the next two sentences of the article | the light curves can , however , be normalized to account for this inhomogeneity , thus allowing these objects to be used at standard candle distance indicators ( e.g. * ? ? ?
* ; * ? ? ? |
5,992 | Suppose that you have an abstract for a scientific paper: we analyze the spin flip loss for ultracold neutrons in magnetic bottles of the type used in experiments aiming at a precise measurement of the neutron lifetime , extending the one - dimensional field model used previously by steyerl @xmath0 [ phys .
rev .
c @xmath1 , 065501 ( 2012 ) ] to two dimensions for cylindrical multipole fields .
we also develop a general analysis applicable to three dimensions . here
we apply it to multipole fields and to the bowl - type field configuration used for the los alamos ucn@xmath2 experiment . in all cases
considered the spin flip loss calculated exceeds the majorana estimate by many orders of magnitude but can be suppressed sufficiently by applying a holding field of appropriate magnitude to allow high - precision neutron lifetime measurements , provided other possible sources of systematic error are under control . .
And you have already written the first three sentences of the full article: the neutron lifetime @xmath3 is an important parameter in nuclear physics , particle physics , and cosmology .
@xmath3 can be combined with the neutron @xmath4-decay ( @xmath5 ) correlation coefficients to determine the universal weak interaction vector and axial - vector coupling constants whose values allow searches for semi - leptonic scalar and tensor currents beyond the standard model @xcite .
a @xmath3 of reliable precision is also needed for calculations of the neutrino flux expected from solar and reactor sources , including detection efficiencies @xcite , as well as in big bang nucleosynthesis calculations . at present ,.
Please generate the next two sentences of the article | we are confronted by an apparent discrepancy of about three standard deviations between the average @xmath3 from ultracold neutron ( ucn ) storage experiments and the @xmath3 from cold neutron beam experiments .
it is the leading source of uncertainty in predictions of the primordial abundance of @xmath6he @xcite . for reviews of @xmath3 experiments |
5,993 | Suppose that you have an abstract for a scientific paper: this paper extends results obtained by @xcite for the annealed ising model coupled to two - dimensional causal dynamical triangulations .
we employ the fortuin - kasteleyn ( fk ) representation in order to determine a region in the quadrant of parameters @xmath0 where the critical curve for the annealed model is possibly located .
this is done by outlining a region where the model has a unique infinite - volume gibbs measure , and a region where the finite - volume gibbs measure does not have weak limit ( in fact , does not exist if the volume is large enough ) .
we also improve the region of subcritical behaviour of the model , and provide a better approximation of the free energy . + + * 2000 msc . * 60f05 , 60j60 , 60j80 . + * keywords : * causal dynamical triangulation ( cdt ) , ising model , partition function , gibbs measure , transfer matrix , fk representation * critical region for an ising model coupled to causal dynamical triangulations * _ j. cerda - hernndez_@xmath1 @xmath2 institute of mathematics , statistics and scientic computation , + university of campinas - unicamp , + rua srgio buarque de holanda 651 , cep 13083 - 859 , campinas , sp , brazil .
+ e - mail : [email protected] . .
And you have already written the first three sentences of the full article: models of planar random geometry appear in physics in the context of two - dimensional quantum gravity and provide an interplay between mathematical physics and probability theory .
causal dynamical triangulation ( cdt ) and its predecessor dynamical triangulation ( dt ) , introduced by ambjrn and loll ( see @xcite ) , constitute attemps to provide a meaning to the formal expressions appearing in the path integral quantization of gravity ( see @xcite , @xcite for an overview ) .
the idea is to approximate the path integral by changing integration with respect to continuous random geometry by integration with respect to dts or cdts . as a result ,.
Please generate the next two sentences of the article | the path integral with respect to continuous random geometries is replaced by a weighted sum over discrete geometries , where the weights are defined by the discrete form of the original action . in this paper
we adopt the framework of cdts coupled with an ising spin system . putting a spin system on the collection of all causal triangulations |
5,994 | Suppose that you have an abstract for a scientific paper: the equation of motion for the expectation value of a scalar quantum field does not have the local form that is commonly assumed in studies of inflationary cosmology .
we have recently argued that the true , temporally non - local equation of motion does not possess a time - derivative expansion and that the conversion of inflaton energy into particles is not , in principle , described by the friction term estimated from linear response theory .
here , we use numerical methods to investigate whether this obstacle to deriving a local equation of motion is purely formal , or of some quantitative importance . using a simple scalar - field model , we find that , although the non - equilibrium evolution can exhibit significant damping , this damping is not well described by the local equation of motion obtained from linear response theory .
it is possible that linear response theory does not apply to the situation we study only because thermalization turns out to be slow , but we argue that that the large discrepancies we observe indicate a failure of the local approximation at a more fundamental level . .
And you have already written the first three sentences of the full article: the dynamics of a classical inflaton field is commonly assumed to be governed by a local equation of motion of the form @xmath0 where the friction term @xmath1 represents the dissipative mechanism through which inflaton energy is converted into particles . in particular , in ` warm inflation ' scenarios @xcite , this term is taken to be large enough for a significant fraction of the energy to be dissipated during inflation .
assuming that the classical inflaton @xmath2 is the expectation value of quantum scalar field @xmath3 , its equation of motion can be derived straightforwardly from a suitable quantum field theory , and it is _ not _ of the form ( [ localeom ] ) .
for example , if @xmath2 couples to a scalar quantum field @xmath4 through an interaction @xmath5 , one obtains a term @xmath6 in the equation of motion , and the expectation value depends on @xmath2 through the effective mass of the @xmath4 particles , @xmath7 ..
Please generate the next two sentences of the article | the field @xmath4 here might be the quantum part of @xmath3 ( that is , @xmath8 , with @xmath9 ) or it might be an independent field . in any case
, the expectation value @xmath10 is a highly _ nonlocal _ quantity : it depends in a complicated way on the entire history of @xmath2 , in contrast to the local equation ( [ localeom ] ) , where @xmath2 , @xmath11 and @xmath12 are all evaluated at a single time @xmath13 . |
5,995 | Suppose that you have an abstract for a scientific paper: the discovery of luminous quasars at redshift @xmath0 indicates the presence of supermassive black holes ( smbhs ) of mass @xmath1 when the universe was less than one billion years old .
this finding presents several challenges for theoretical models , because whether such massive objects can form so early in the @xmath2-cold dark matter ( @xmath2cdm ) cosmology , the leading theory for cosmic structure formation , is an open question .
furthermore , whether the formation process requires exotic physics such as super - eddington accretion remains undecided . here , we present the first multi - scale simulations that , together with a self - regulated model for the smbh growth , produce a luminous quasar at @xmath3 in the @xmath2cdm paradigm .
we follow the hierarchical assembly history of the most massive halo in a @xmath4 volume , and find that this halo of @xmath5 forming at @xmath3 after several major mergers is able to reproduce a number of observed properties of sdss j1148 + 5251 , the most distant quasar detected at @xmath6 @xcite . moreover , the smbhs grow through gas accretion below the eddington limit in a self - regulated manner owing to feedback .
we find that the progenitors experience vigorous star formation ( up to @xmath7 ) preceding the major quasar phase such that the stellar mass of the quasar host reaches @xmath8 at @xmath9 , consistent with observations of significant metal enrichment in sdss j1148 + 5251 .
the merger remnant thus obeys similar @xmath10 scaling relation observed locally as a consequence of coeval growth and evolution of the smbh and its host galaxy .
our results provide a viable formation mechanism for @xmath0 quasars in the standard @xmath2cdm cosmology , and demonstrate a common , merger - driven origin for the rarest quasars and the fundamental @xmath10 correlation in a hierarchical universe . .
And you have already written the first three sentences of the full article: quasars rank among the most luminous objects in the universe and are believed to be powered by smbhs ( e.g. , @xcite ) .
they constrain the formation and evolution of galaxies and smbhs throughout cosmic time .
the similarity between the cosmic star formation history ( e.g. , @xcite ) and the evolution of quasar abundances ( e.g. , @xcite ) suggests an intriguing link between galaxy formation and black hole growth ..
Please generate the next two sentences of the article | this is strengthened by tight correlations measured locally between the masses of the black holes and the global properties of the spheroid components of their hosts , such as their luminosities and masses ( @xcite ) , light concentration ( @xcite ) , and velocity dispersions ( @xcite ) .
distant , highly luminous quasars are important cosmological probes for studying the first generation of galaxies , the star formation history and metal enrichment in the early universe , the growth of the first supermassive black holes ( smbhs ) , the role of feedback from quasars and black holes in galaxy evolution , and the epoch of reionization . the sloan digital sky survey ( sdss , @xcite ) has contributed significantly to the discovery of high redshift quasars . |
5,996 | Suppose that you have an abstract for a scientific paper: transport of carriers in two dimensional graphene at high electric fields is investigated by combining semi - analytical and monte - carlo methods .
a semi - analytical high - field transport model based on the high rate of optical phonon emission provides useful estimates of the saturation currents in graphene . for developing a more accurate picture ,
the non - equilibrium ( hot ) phonon effect and the role of electron - electron scattering were studied using monte carlo simulations .
monte carlo simulations indicate that the hot phonon effect plays a dominant role in current saturation , and electron - electron scattering strongly thermalizes the hot carrier population in graphene .
we also find that electron - electron scattering removes negative differential resistance in graphene .
transient phenomenon as such as velocity overshoot can be used to speed up graphene - based high speed electronic devices by shrinking the channel length below 80 nm if electrostatic control can be exercised in the absence of a band gap .
= 1 .
And you have already written the first three sentences of the full article: monolayer graphene has attracted great amount of interest due to its novel electronic properties @xcite .
it has perfect two - dimensional ( 2d ) geometry and a linear band structure near dirac points . since its discovery ,
a substantial body of work has been done on charge transport properties in graphene @xcite ..
Please generate the next two sentences of the article | electron mobility as high as @xmath0 120,000 @xmath1/v@xmath2s at @xmath0 240 k has been measured in suspended graphene @xcite . at high field bias , epitaxial graphene field effect transistors ( fets ) on sic substrates
have exhibited high current drives , exceeding ~ 3 ma/@xmath3 m @xcite . |
5,997 | Suppose that you have an abstract for a scientific paper: the environment in which a population evolves can have a crucial impact on selection .
we study evolutionary dynamics in finite populations of fixed size in a changing environment .
the population dynamics are driven by birth and death events .
the rates of these events may vary in time depending on the state of the environment , which follows an independent markov process .
we develop a general theory for the fixation probability of a mutant in a population of wild - types , and for mean unconditional and conditional fixation times .
we apply our theory to evolutionary games for which the payoff structure varies in time .
the mutant can exploit the environmental noise ; a dynamic environment that switches between two states can lead to a probability of fixation that is higher than in any of the individual environmental states .
we provide an intuitive interpretation of this surprising effect .
we also investigate stationary distributions when mutations are present in the dynamics . in this regime , we find two approximations of the stationary measure .
one works well for rapid switching , the other for slowly fluctuating environments .
[ firstpage ] * keywords : * evolutionary dynamics , fluctuating environments , stochastic processes .
And you have already written the first three sentences of the full article: evolutionary dynamics describes the change of populations over time subject to spontaneous mutation , selection , and other random events @xcite .
different phenotypes in the population can emerge spontaneously by mutation , i.e. through errors during reproduction of wild - types .
in many cases , wild - type and mutant individuals are characterised by heritable differences in behavioural traits or strategies @xcite ..
Please generate the next two sentences of the article | selection acts on different phenotypes and changes the population composition .
changes in the state of the environment can alter these selective pressures over time . |
5,998 | Suppose that you have an abstract for a scientific paper: in this paper , a new decoding scheme for low - density parity - check ( ldpc ) codes using the concept of simple product code structure is proposed based on combining two independently received soft - decision data for the same codeword .
ldpc codes act as horizontal codes of the product codes and simple algebraic codes are used as vertical codes to help decoding of the ldpc codes .
the decoding capability of the proposed decoding scheme is defined and analyzed using the parity - check matrices of vertical codes and especially the _ combined - decodability _ is derived for the case of single parity - check ( spc ) and hamming codes being used as vertical codes .
it is also shown that the proposed decoding scheme achieves much better error - correcting capability in high signal to noise ratio ( snr ) region with low additional decoding complexity , compared with a conventional decoding scheme .
b. shin : new decoding scheme for ldpc codes based on simple product code structure combined - decodability , decoding , hamming codes , low - density parity - check ( ldpc ) codes , product codes , single parity - check ( spc ) codes . .
And you have already written the first three sentences of the full article: , extremely low error probability has been required in many application areas such as wireless communication systems without feedback and data storage systems . low - density parity - check ( ldpc ) codes@xcite,@xcite have become one of promising error - correcting codes in these areas due to their near capacity - approaching performance . however , since finite - length ldpc codes show a serious error - floor problem@xcite in high signal to noise ratio ( snr ) region , it may be difficult to achieve an extremely good error correction performance .
many researches on the iterative decoding of ldpc codes ( e.g. @xcite -@xcite ) have been made to achieve good error correction performance by improving only the decoding algorithm while not changing the code structure .
however , the requirement for the performance and complexity of decoder is getting more strict ..
Please generate the next two sentences of the article | thus , more powerful decoding schemes for ldpc codes are required . in this paper
, we propose a decoding scheme for ldpc codes using simple product code structure to improve the error correction performance together with error floor . |
5,999 | Suppose that you have an abstract for a scientific paper: we investigate the magnetic properties of small transition metal clusters using a simple statistical model , which requires some input data from _ ab initio _ spin - density functional calculations . in our study , we consider a thermodynamically equilibrated ensemble of clusters with different structures , spin multiplicities , and ground state energies .
we calculate the physical properties of this system by weighting the individual configurations according to the boltzmann statistics .
we find that presence of isomers with very similar ground state energies , yet very different magnetic properties , gives rise to a rich magnetic behaviour of the system which differs significantly from what would be expected for single configurations .
we apply the present model to determine the magnetic susceptibility of a cluster ensemble of langevin paramagnets .
our results show that some of the anomalies in the magnetic behaviour of transition metal clusters might be understood in the framework of our model which is , of course , limited by the extremely high computational effort needed to obtain the input data . .
And you have already written the first three sentences of the full article: the magnetic properties of small transition metal clusters have been of growing interest in the past few years .
however , there has not been any study about the dependence on temperature so far . as shown in a large variety of papers ( e.g. refs . ) small clusters exhibit , unlike the bulk , smooth structural transformations , which one might call _ isomer hopping _ , and which occur between pure solid and fluid phases over a relatively wide temperature range , in a so - called coexistence phase . in the following
we will be concerned with the effect of those properties on the magnetic behaviour of clusters ..
Please generate the next two sentences of the article | the basic idea is that a cluster of a specific size might have two or more structures with different magnetic moments and that these structures or _ isomer states _
occur with their statistical probability . |
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