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6,800 | Suppose that you have an abstract for a scientific paper: we study the effect of decoherence on the sub - planck scale structures of the vibrational wave packet of a molecule .
the time evolution of these wave packets is investigated under the influence of a photonic or phononic environment .
we determine the master equation describing the reduced dynamics of the wave - packet and analyze the sensitivity of the sub - planck structures against decoherence in the case of a hydrogen iodide ( hi ) molecule . .
And you have already written the first three sentences of the full article: recent progress of controlled femtosecond pulses has advanced greatly the technology during the last few years @xcite .
a new field of molecular optics has emerged where lasers are used to manipulate the internal and external degrees of freedom of molecules , to deflect beams of molecules , to control molecular dynamics , and to align molecules @xcite .
many investigations have focused on the vibrational motion of diatomic molecules ..
Please generate the next two sentences of the article | the single bond between the atoms acts as a spring and supports harmonic oscillations for small amplitudes , but the bond can break ( dissociate ) when stretched too much
. these phenomena usually occur at time scales between few picoseconds and few hundred femtoseconds . with ultrashort pulses one can now prepare a molecular wave packet and |
6,801 | Suppose that you have an abstract for a scientific paper: we present an in - depth analysis of the experimental estimation of cross sections in surface enhanced raman scattering ( sers ) by vibrational pumping .
the paper highlights the advantages and disadvantages of the technique , pinpoints the main aspects and limitations , and provides the underlying physical concepts to interpret the experimental results .
examples for several commonly used sers probes are given , and a discussion on future possible developments is also presented . .
And you have already written the first three sentences of the full article: in the last decade surface enhanced raman scattering ( sers)@xcite has made rapid progress towards applications . with a sensitivity rivaling fluorescence in some cases , and a much higher structural specificity , sers is a highly attractive technique , being developed simultaneously with the field of plasmonics .
progress towards different uses of sers in practical applications has been steady .
new substrates including : arrays of inverted pyramids@xcite , silver pillar and torroid arrays@xcite , adaptive silver films@xcite , and metallic nano - shells@xcite , have been demonstrated ..
Please generate the next two sentences of the article | in addition , many molecules relevant to a myriad of applications such as glucose@xcite , proteins@xcite , dna@xcite , a wide range of medicinal drugs@xcite , and substances for forensic science@xcite , have been characterized . on the other hand ,
the understanding of some fundamental aspects of the phenomenon is still incomplete , and in some cases controversial . |
6,802 | Suppose that you have an abstract for a scientific paper: we present several results on the geometry of the quantum projective plane .
they include : explicit generators for the k - theory and the k - homology ; a real calculus with a hodge star operator ; anti - selfdual connections on line bundles with explicit computation of the corresponding ` classical ' characteristic classes ( via fredholm modules ) ; complete diagonalization of gauged laplacians on these line bundles ; ` quantum ' characteristic classes via equivariant k - theory and @xmath0-indices . .
And you have already written the first three sentences of the full article: quantum spaces are revealing rich geometrical structures and are the subject of intense research activities . in this paper
we present a construction of monopoles on the quantum projective plane @xmath1 . by a monopole
we mean a line bundle over @xmath1 , that is to say a ` rank 1 ' ( in a sense to be made precise ) finitely generated projective module over the coordinate algebra @xmath2 , endowed with a connection having anti - selfdual curvature ; these are described in sect ..
Please generate the next two sentences of the article | [ se : mono ] .
necessary for the anti - selfduality was a differential calculus and a hodge star operators on forms . in sect . |
6,803 | Suppose that you have an abstract for a scientific paper: we present jhk photometry and spectroscopy of rx j0019.8 + 2156 .
the spectrum appears to be dominated by the accretion disc to at least 2.4 @xmath0 m , over any other source of emission .
we find paschen , brackett and he ii lines strongly in emission , but no he i. there are satellite lines approximately 850 km s@xmath1 either side of the strongest , unblended hydrogen lines .
these satellite lines may be the spectral signature of jets from the accretion disc .
accretion , accretion disks ism : jets and outflows stars : emission - line x - rays : stars infrared : stars stars : individual : rx j0019.8 + 2156 .
And you have already written the first three sentences of the full article: the ` supersoft ' x - ray sources form a new and exciting but inhomogeneous class of x - ray objects . though a few members of the class were known before rosat , it is this observatory which has characterised the class as objects with temperatures of 15 80 ev and luminosities approaching the eddington limit for a solar mass object , i.e. @xmath2 @xmath3 erg s@xmath1 .
the model which best fits the observations has a white dwarf steadily or cyclically burning hydrogen - rich material accreted onto its surface at @xmath4 m@xmath5 yr@xmath1 ( van den heuvel et al .
@xcite ) ..
Please generate the next two sentences of the article | van den heuvel et al .
( @xcite ) theorise that this material may be supplied by a near main - sequence a / f companion star , more massive than the white dwarf and in a close binary orbit , which is overflowing its roche lobe . |
6,804 | Suppose that you have an abstract for a scientific paper: we investigate the effects of discontinuous mass loss in recurrent outburst events on the long term evolution of cataclysmic variables ( cvs ) .
similarly we consider the effects of frictional angular momentum loss ( faml ) , i.e. interaction of the expanding nova envelope with the secondary .
the bondi
hoyle accretion model is used to parameterize faml in terms of the expansion velocity @xmath0 of the nova envelope at the location of the secondary ; we find that small @xmath0 causes strong faml .
numerical calculations of cv evolution over a wide range of parameters demonstrate the equivalence of a discontinuous sequence of nova cycles and the corresponding mean evolution ( replacing envelope ejection by a continuous wind ) , even close to mass transfer instability .
a formal stability analysis of discontinuous mass transfer confirms this , independent of details of the faml model .
faml is a consequential angular momentum loss which amplifies the mass transfer rate driven by systemic angular momentum losses such as magnetic braking .
we show that for a given @xmath0 and white dwarf mass the amplification increases with secondary mass and is significant only close to the largest secondary mass consistent with mass transfer stability .
the amplification factor is independent of the envelope mass ejected during the outburst , whereas the mass transfer amplitude induced by individual nova outbursts is proportional to it . in sequences calculated with nova model parameters taken from prialnik & kovetz @xcite faml amplification
is negligible , but the outburst amplitude in systems below the period gap with a white dwarf mass @xmath1 is larger than a factor of 10 . the mass transfer rate in such systems is smaller than @xmath2/yr for @xmath3 myr ( @xmath4 of the nova cycle ) after the outburst .
this offers an explanation for intrinsically unusually faint cvs below the period gap .
= = = = = = = = # 1 # 1 # 1 # 1 @mathgroup@group @mathgroup@normal@groupeurmn....
And you have already written the first three sentences of the full article: cataclysmic variables ( cvs ) are short period binary systems in which a roche lobe filling low mass main sequence secondary transfers mass to a white dwarf ( wd ) primary .
the transferred matter accretes onto the wd either through a disc or a stream and slowly builds up a hydrogen rich surface layer on the wd . with continuing accretion the pressure at the bottom of this layer increases , and
hydrogen burning eventually starts ..
Please generate the next two sentences of the article | the thermodynamic conditions at ignition determine how the burning proceeds ( e.g. fujimoto 1982 ) .
if the degeneracy is very high , a thermonuclear runaway occurs , leading to a violent outburst terminated by the ejection of all or most of the accumulated envelope . |
6,805 | Suppose that you have an abstract for a scientific paper: we prove that the kane - mele - hubbard model with purely imaginary next - nearest - neighbor hoppings has a particle - hole symmetry at half - filling .
such a symmetry has interesting consequences including the absence of charge and spin currents along open edges , and the absence of the sign problem in the determinant quantum monte - carlo simulations .
consequentially , the interplay between band topology and strong correlations can be studied at high numeric precisions .
the process that the topological band insulator evolves into the antiferromagnetic mott insulator as increasing interaction strength is studied by calculating both the bulk and edge electronic properties . in agreement with previous theory analyses ,
the numeric simulations show that the kane - mele - hubbard model exhibits three phases as increasing correlation effects : the topological band insulating phase with stable helical edges , the bulk paramagnetic phase with unstable edges , and the bulk antiferromagnetic phase . .
And you have already written the first three sentences of the full article: the precise quantization of the hall conductance in the integer quantum hall states is protected by the non - trivial topology of band structures .
this topological property is characterized by the thouless - kohmoto - nightingale - den nijs ( tknn ) number , or the chern number @xcite , which takes non - zero values only when time - reversal symmetry is broken . in recent years
, tremendous progress has been achieved in a new class of topologically non - trivial band insulators in the presence of time - reversal symmetry , which are termed as topological insulators @xcite ..
Please generate the next two sentences of the article | topological insulators exist in both two ( 2d ) and three dimensions ( 3d ) , which are characterized by the @xmath0 topological index .
these topological states have robust gapless helical edge modes with odd number of channels in 2d @xcite , and odd number of surface dirac cones in 3d @xcite . |
6,806 | Suppose that you have an abstract for a scientific paper: x - ray techniques have been used for more than a century to study the atomic and electronic structure in virtually any type of material .
the advent of correlated electron systems , in particular complex oxides , brought about new scientific challenges and opportunities for the advancement of conventional x - ray methods . in this context , the need for new approaches capable of selectively sensing new forms of orders involving all degrees of freedom charge , orbital , spin , and lattice paved the way for the emergence and success of resonant x - ray scattering , which has become an increasingly popular and powerful tool for the study of electronic ordering phenomena in solids . here
we review the recent resonant x - ray scattering breakthroughs in the copper oxide high - temperature superconductors , in particular regarding the phenomenon of charge order a broken - symmetry state occurring when valence electrons self - organize into periodic structures . after a brief historical perspective on charge order , we outline the milestones in the development of resonant x - ray scattering , as well as the basic theoretical formalism underlying its unique capabilities .
the rest of the review will focus on the recent contributions of resonant scattering to the tremendous advancements in our description and understanding of charge order . to conclude
, we propose a series of present and upcoming challenges , and discuss the future outlook for this technique .
charge - density - wave ; charge order ; resonant soft x - ray scattering ; high-@xmath0 cuprates ; superconductivity . .
And you have already written the first three sentences of the full article: over the years , transition metal oxides have represented a traditional platform for strongly correlated electron physics , which has nowadays become a field of its own , encompassing several classes of compounds with one common denominator : the localized character of the low - energy electronic wavefunctions ( with @xmath1 or @xmath2 orbital character ) and the corresponding prominence of coulomb interactions in driving the electronic properties of these materials . in conventional metals or semiconductors , the fermiology is essentially determined by the lowering of the total kinetic energy which becomes possible when a periodic potential supports the delocalization of the local orbitals into extended wavefunctions with a well - defined momentum and a correspondigly homogeneous distribution of the charge density . in correlated electron systems , the on - site coulomb repulsion between two electrons in the same @xmath1 or @xmath2 orbital can overcome the kinetic energy part of the hamiltonian , inducing the electronic system to find new ways to lower its total energy , often by spontaneous breaking of the native symmetries of the lattice ( translational and/or point group symmetry ) .
this tendency leads to the emergence of a rich variety of symmetry - broken electronic phases , and represents a distinctive trademark of strongly correlated systems , spanning across families of compounds otherwise very different from a chemical standpoint @xcite . within the extended class of correlated electron systems ,
copper oxides represent a unique breed due to the mixed character of the electronic bands , frustrated by the conflicting interplay between the o-@xmath3 states promoting itinerancy and electron hopping and the cu-@xmath4 states which hinder charge fluctuations and are conducive to mott - hubbard physics and an insulating , antiferromagnetic ( af ) ground state @xcite ..
Please generate the next two sentences of the article | this delicate balance can be tuned and controlled by carrier doping , resulting in a phase diagram of astonishing richness and complexity , yet to be fully understood @xcite .
antiferromagnetism has been long known as the ground state in charge - transfer insulating undoped copper oxides @xcite , while unconventional superconductivity was discovered in 1986 @xcite . to date , several broken symmetries have been detected in the cuprates , which can be categorized into zero - momentum ( @xmath5 ) and finite - momentum ( @xmath6 ) orders , breaking rotational and translational symmetry , respectively . |
6,807 | Suppose that you have an abstract for a scientific paper: we present distance estimates for eleven peculiar virgo cluster spiral galaxies based on measurements of the stellar kinematics of their central 2 kpc .
stellar circular velocities were obtained using two - integral dynamical models .
distances were obtained by comparing , at each radius , the stellar circular velocities with synthetic h@xmath0 rotation curves derived from nir tully - fisher relations .
the results show that most of our galaxies are located within 4 mpc of the core of the cluster .
three of these galaxies , previously classified as low rotator galaxies " or with truncated / compact " h@xmath0 radial distributions , have stellar kinematics - based distances that are discrepant with hi - based distances by at least 60% , and are likely to be located within the virial radius of the cluster .
these discrepancies appear due to very truncated gas distributions plus non - circular gas motions or gas motions not in the plane of the stellar disk , perhaps as the result of gravitational interactions .
our results show that environmental effects can significantly reduce the measured hi linewidths for some disturbed cluster galaxies , thus affecting the accurate determination of distances based on gas kinematics methods . .
And you have already written the first three sentences of the full article: for many years , the tully - fisher relation ( tully & fisher , 1977 ) has been used to estimate distances to the virgo cluster .
these studies were based on optical or near infrared photometry ( gavazzi 1999 ) , together with gas kinematics from hi linewidths ( e.g. , yasuda 1997 ) or h@xmath0 rotation curves ( rubin 1999 ) .
these techniques have been useful in the determination of distances to individual galaxies within the cluster , allowing attempts to determine its 3-d structure ( i.e. yasuda 1997 , gavazzi 1999 , and more recently solanes 2002 ) ..
Please generate the next two sentences of the article | recent results show that there is a population of galaxies in virgo with hi line
widths narrower than those expected from the mean tully - fisher relation derived for the cluster . |
6,808 | Suppose that you have an abstract for a scientific paper: we propose several new schedules for strassen - winograd s matrix multiplication algorithm , they reduce the extra memory allocation requirements by three different means : by introducing a few pre - additions , by overwriting the input matrices , or by using a first recursive level of classical multiplication . in particular , we show two fully in - place schedules : one having the same number of operations , if the input matrices can be overwritten ; the other one , slightly increasing the constant of the leading term of the complexity , if the input matrices are read - only . many of these schedules have been found by an implementation of an exhaustive search algorithm based on a pebble game .
* keywords : * matrix multiplication , strassen - winograd s algorithm , memory placement . .
And you have already written the first three sentences of the full article: strassen s algorithm @xcite was the first sub - cubic algorithm for matrix multiplication .
its improvement by winograd @xcite led to a highly practical algorithm .
the best asymptotic complexity for this computation has been successively improved since then , down to @xmath0 in @xcite ( see @xcite for a review ) , but strassen - winograd s still remains one of the most practicable ..
Please generate the next two sentences of the article | former studies on how to turn this algorithm into practice can be found in @xcite and references therein for numerical computation and in @xcite for computations over a finite field .
+ in this paper , we propose new schedules of the algorithm , that reduce the extra memory allocation , by three different means : by introducing a few pre - additions , by overwriting the input matrices , or by using a first recursive level of classical multiplication . |
6,809 | Suppose that you have an abstract for a scientific paper: we use the new results of the hegra detector on the tev @xmath0ray emission from mkn 501 to set upper limits on the energy density of the cosmic infrared background ( cirb ) .
contrary to previous interpretations of the @xmath0ray spectrum of mkn 421 as showing an intergalactic absorption cutoff at 5 tev , the observed spectrum of mkn 501 extends beyond 10 tev and appears to be unattenuated by @xmath1 collisions with the low - energy cirb photons .
the upper limits on the cirb intensity derived both assuming an _ a priori _ shape for the cirb spectrum and without model - dependent assumptions
are thus quite strong and come almost in conflict with the observational evaluations based on deep surveys of extragalactic sources in the near- and mid - ir .
if spectra at tev energies for extragalactic @xmath2-ray sources like this for mkn 501 will be confirmed with improved statistics , we may be forced to conclude that the process of @xmath1 interaction in the intergalactic space is more complex than expected and the average intergalactic magnetic field extremely weak ( @xmath3 ) . .
And you have already written the first three sentences of the full article: cosmic history from the decoupling ( @xmath4 ) to the epoch of lighting of the first luminous sources ( at redshifts @xmath5 to 5 ) is one of the biggest unknowns of present day observational cosmology .
high redshifts and dust extinction during early active phases both degrade the energetic optical uv photons emitted by massive stars , decaying particles , or more exotic energy sources , to the infrared wavelengths . a fundamental information on the total energy budget associated with astrophysical processes occurring at high redshifts is then provided by observations of the cosmic background at infrared wavelengths ( cirb ) .
unfortunately , the infrared domain presents various levels of difficulty to the observational astronomer , because of the huge backgrounds from the earth s atmosphere , the interplanetary dust ( ipd ) , and diffuse dust in the milky way , in addition to the background produced by the telescope itself . also the sensitivity and stability of infrared detectors are far poorer than those used in the optical ..
Please generate the next two sentences of the article | because of all this , the detection and characterization of the diffuse background flux of low - energy photons coming from primeval structures has been exceedingly difficult so far .
even dedicated experiments exploiting cooled platforms outside the atmosphere , among which the most important is dirbe on cobe ( @xcite ) , have failed so far to detect significant signals from the cirb above the intense foregrounds . |
6,810 | Suppose that you have an abstract for a scientific paper: polarizable dipoles , such as atoms , molecules or nanoparticles , subject to laser radiation , may attract or repel each other . we derive a general formalism in which such laser - induced dipole - dipole interactions ( liddi ) in any geometry and for any laser strength are described in terms of the resonant dipole - dipole interaction ( rddi ) between dipoles dressed by the laser .
this approach provides a simple route towards the analysis of liddi in a general geometry .
our general results reveal liddi effects due to nonlinear dipolar response to the laser , previously unaccounted for .
the origin of these nonlinear effects is discussed .
our general formalism is illustrated for liddi between atoms in a cavity . .
And you have already written the first three sentences of the full article: electromagnetic fields are the main tool in the control and manipulation of the motion of polarizable dipoles , such as atoms and molecules , which are key objects in physics and chemistry .
optical traps @xcite and laser cooling @xcite are widely used to induce external mechanical forces on individual dipoles , whereas interactions between atoms are often tuned with the help of external magnetic or electric fields @xcite . in this work ,
we address laser - induced dipole - dipole interactions ( liddi ) by establishing their relation to resonant inter - dipolar interaction ( excitation exchange ) in any confined geometry ..
Please generate the next two sentences of the article | polarizable dipoles subject to static electric fields interact via the electrostatic dipole - dipole interaction that scales in free space as @xmath0 , @xmath1 being the inter - dipolar distance .
a dynamic analog is obtained when a laser field , far - detuned from the dipolar resonant frequency , illuminates the ( induced ) dipoles . in the retarded regime , |
6,811 | Suppose that you have an abstract for a scientific paper: agile - sd is one of the latest versions of loss - based congestion control algorithm ( cca ) , which has been proposed to improve the total performance of tcp over high - speed and short - distance networks .
it has introduced a new mechanism , called agility factor mechanism ( afm ) , which shortens the epoch time to reduce the sensitivity to packet losses and in turn to increase the average throughput .
agile - sd has only been tested via simulation , however , it has not been mathematically proven or evaluated .
the contribution of this paper is twofold : first , a new mathematical model for the throughput of newreno and agile - sd is proposed .
this model is designed using the well - known markov chains to validate the correctness of agile - sd and to show the impact of buffer size , multiplicative decrease factor and maximum limit of agility factor ( @xmath0 ) on the total performance .
second , an automated algorithm configuration and parameter tuning ( aacpt ) technique is employed to optimize and automate the configuration of @xmath0 .
further , the numerical results for both newreno and agile - sd are compared to the simulation results in which the validity of the proposed model is confirmed .
moreover , the output of aacpt is exploited to formulate a new equation which calculates the optimal @xmath0 from a given @xmath1 in order to conserve the standard interface of tcp .
this equation increases the scalability of agile - sd and improves its total performance .
addtoresetfootnotepage agile - sd , transmission control protocol , congestion control , markov chains , average throughput . .
And you have already written the first three sentences of the full article: of the most predominant protocols of the internet is the transmission control protocol ( tcp ) , which provides a high level of reliability on end - to - end connections .
it regulates the transmission rate between the two ends of a connection based on the changes of the underlying network . in other words , it estimates the condition of the connection and adjusts its congestion window ( _ cwnd _ ) accordingly . in order to enhance the total performance of tcp over high - speed networks , many congestion control algorithms ( ccas )
have been proposed in the literature such as scalable tcp @xcite , hs - tcp @xcite , h - tcp @xcite , bic @xcite , tcp africa @xcite , tcp compound @xcite , fusion @xcite , yeah @xcite , tcp illinois @xcite , cubic , @xcite and hcc @xcite ..
Please generate the next two sentences of the article | the main three approaches , which are employed by these ccas , are either loss - based , delay - based or loss - delay - based approach @xcite .
the delay - based approach relies on the variation of delay resulted by big buffers and/or long rtts , which are presented in high - bdp networks . |
6,812 | Suppose that you have an abstract for a scientific paper: we present a 2.5d mhd simulation of a magnetic flux rope ( fr ) propagating in the heliosphere and investigate the cause of the observed sharp plasma @xmath0 transition .
specifically , we consider a strong internal magnetic field and an explosive fast start , such that the plasma @xmath0 is significantly lower in the fr than the sheath region that is formed ahead .
this leads to an unusual fr morphology in the first stage of propagation , while the more traditional view ( e.g. from space weather simulations like enlil ) of a ` pancake ' shaped fr is observed as it approaches 1au .
we investigate how an equipartition line , defined by a magnetic weber number , surrounding a core region of a propagating fr can demarcate a boundary layer where there is a sharp transition in the plasma @xmath0 .
the substructure affects the distribution of toroidal flux , with the majority of the flux remaining in a small core region which maintains a quasi - cylindrical structure .
quantitatively , we investigate a locus of points where the kinetic energy density of the relative inflow field is equal to the energy density of the transverse magnetic field ( i.e. effective tension force ) .
the simulation provides compelling evidence that at all heliocentric distances the distribution of toroidal magnetic flux away from the fr axis is not linear ; with @xmath1 of the toroidal flux occurring within @xmath2 of the distance from the fr axis .
thus our simulation displays evidence that the competing ideas of a pancaking structure observed remotely can coexist with a quasi - cylindrical magnetic structure seen in situ . .
And you have already written the first three sentences of the full article: coronal mass ejections ( cmes ) are large scale transient eruptions from the sun that travel into the heliosphere .
the impact of these transients onto earth are the dominant source of the most severe space weather incidents @xcite .
the velocity and magnetic field vectors within a cme are often considered the primary properties of interest for estimating their space weather effects ..
Please generate the next two sentences of the article | cmes also play a significant role in removing magnetic helicity which is generated as the sun evolves ( e.g. * ? ? ?
it has also been shown to provide a significant contribution in modulating the open solar flux over a solar cycle ( e.g. * ? ? ? * ) . |
6,813 | Suppose that you have an abstract for a scientific paper: we present new spherically symmetric , dyonic soliton and black hole solutions of the @xmath0 einstein - yang - mills equations in four - dimensional asymptotically anti - de sitter space - time .
the gauge field has nontrivial electric and magnetic components and is described by @xmath1 magnetic gauge field functions and @xmath1 electric gauge field functions .
we explore the phase space of solutions in detail for @xmath2 and @xmath3 gauge groups .
combinations of the electric gauge field functions are monotonic and have no zeros ; in general the magnetic gauge field functions may have zeros .
the phase space of solutions is extremely rich , and we find solutions in which the magnetic gauge field functions have more than fifty zeros . of particular interest
are solutions for which the magnetic gauge field functions have no zeros , which exist when the negative cosmological constant has sufficiently large magnitude .
we conjecture that at least some of these nodeless solutions may be stable under linear , spherically symmetric , perturbations . .
And you have already written the first three sentences of the full article: the study of soliton and black hole solutions of the einstein - yang - mills ( eym ) equations has been an active subject for some twenty - five years , triggered by the discovery of regular , static , spherically symmetric , solitons @xcite and `` coloured '' black holes @xcite in @xmath2 eym in four - dimensional asymptotically flat space - time . in these configurations ,
the nonabelian gauge field is purely magnetic @xcite and described by a single function @xmath4 of the radial coordinate @xmath5 .
numerical investigations @xcite show that @xmath4 must have at least one zero , and this is has also been proven analytically @xcite ..
Please generate the next two sentences of the article | both the particle - like and black hole solutions arise at discrete points in the phase space of parameters , and can be indexed by @xmath6 , the number of zeros of @xmath4 .
the @xmath2 solitons and black holes have no magnetic charge at infinity . |
6,814 | Suppose that you have an abstract for a scientific paper: we demonstrate that at relatively low mass accretion rates , black hole candidate ( bhc ) x - ray binaries ( xrbs ) should enter ` jet - dominated ' states , in which the majority of the liberated accretion power is in the form of a ( radiatively inefficient ) jet and not dissipated as x - rays in the accretion flow .
this result follows from the empirically established non - linear relation between radio and x - ray power from low / hard state bhc xrbs , which we assume also to hold for neutron star ( ns ) xrbs .
conservative estimates of the jet power indicate that all bhc xrbs in ` quiescence ' should be in this jet - dominated regime . in combination with an additional empirical result , namely that bhc xrbs are more ` radio loud ' than ns xrbs , we find that in quiescence ns xrbs should be up to two orders of magnitude more luminous in x - rays than bhc xrbs , without requiring any significant advection of energy into a black hole .
this ratio is as observed , and such observations should therefore no longer be considered as direct evidence for the existence of black hole event horizons .
furthermore , even if bhcs do contain black holes with event horizons , this work demonstrates that there is no requirement for the advection of significant amounts of accretion energy across the horizon .
binaries : close radio continuum : stars ism : jets and outflows stars : neutron black hole physics .
And you have already written the first three sentences of the full article: proving the existence of black holes remains a key goal of observational high energy astrophysics .
while dynamical evidence ( e.g. charles 1998 ) convincingly demonstrates the existence of compact accreting objects in binary systems which have masses in excess of the highest theoretical limit for a neutron star ( @xmath0 ) , and are therefore strong black hole candidates ( bhcs ) , we can not rule out the possibility that some as - yet - unconsidered state of matter may provide an alternative explanation . as an alternative approach , in recent years
much attention has been focussed on finding evidence for black hole event horizons ..
Please generate the next two sentences of the article | one promising and actively pursued route has been a comparison of the x - ray luminosities of bhc and neutron star ( ns ) x - ray binaries ( xrbs ) in ` quiescence ' . in such states ,
black hole accretion could be advection dominated and considerably fainter than neutron stars . |
6,815 | Suppose that you have an abstract for a scientific paper: qcd in 1 + 1 dimensions is examined in the limit of a large number of colors and flavors .
the hamiltonian matrix is given in a fock space spanned by t hooft meson states and , for the case of zero fermion mass , a submatrix is diagonalized numerically to give the low - lying spectrum as a function of @xmath0 .
pair creation effects generate bound states which are complicated mixtures of components of different meson number .
there are a number of nontrivial zero modes ; in the massive part of the spectrum some states tend to a well - defined @xmath1 limit while others become unstable and disappear . the masses of most states remain remarkably constant over a large range of @xmath0 . .
And you have already written the first three sentences of the full article: since its inception , the large @xmath2 expansion @xcite @xcite has afforded a host of valuable insights into @xmath3 dynamics beyond standard perturbation theory in the coupling constant . besides providing a solvable example of a nonabelian gauge theory in the case of one space dimension @xcite
, it has been significant e.g. in clarifying the relation between the skyrme model and @xmath3 and in qualitatively explaining the zweig rule @xcite . on the other hand ,
the number of colors @xmath2 is not the only parameter of @xmath3 which can be regarded as large ..
Please generate the next two sentences of the article | the same procedure may also be applied to the number of flavors @xmath4 . in the real world , especially at higher energies , where the heavy quarks contribute to the dynamics , the effective @xmath0 ratio becomes larger than unity .
thus it seems natural to investigate in what way the presence of a large number of flavors modifies the large @xmath2 picture and how those parts of large @xmath2 phenomenology which appear to be successes survive the modification . |
6,816 | Suppose that you have an abstract for a scientific paper: in the paper , we investigate correlation between broad - line and radio variations for broad - line radio galaxy 3c 120 . by the z - transformed discrete correlation function method and the model - independent flux randomization / random subset selection ( fr / rss ) monte carlo method
, we find that the broad h@xmath0 line variations lead the 15 ghz variations .
the fr / rss method shows that the h@xmath0 line variations lead the radio variations by a factor of @xmath1 yr .
this time lag can be used to locate the position of emitting region of radio outbursts in jet , on the order of @xmath2 5 light - years , from the central engine .
this distance is much larger than the size of broad - line region .
the large separation of the radio outburst emitting region from the broad - line region will observably influence the gamma - ray emission in 3c 120 . .
And you have already written the first three sentences of the full article: according to the reverberation mapping model ( e.g. * ? ? ? * ) , the broad emission line variations follow the ionizing continuum variations through the photoionization process . the variation correlations between broad - lines and continua
were observed with time lags in type 1 active galactic nuclei ( agns , see e.g. * ? ? ?
* ; * ? ? ?.
Please generate the next two sentences of the article | * ; * ? ? ?
the disturbances from the central engine in agns are transported with ionizing continua to broad - lines . |
6,817 | Suppose that you have an abstract for a scientific paper: the oscillation periods of the interlayer exchange coupling are investigated when two magnetic layers are separated by a metallic superlattice of two distinct non - magnetic materials . in spite of the conventional behaviour of the coupling as a function of the spacer thickness , new periods arise when the coupling is looked upon as a function of the number of cells of the superlattice .
the new periodicity results from the deformation of the corresponding fermi surface , which is explicitly related to a few controllable parameters , allowing the oscillation periods to be tuned . psbox .
And you have already written the first three sentences of the full article: oscillatory interlayer exchange coupling in metallic magnetic multilayers causes the magnetizations of neighbouring magnetic layers separated by non - magnetic spacers to be spontaneously aligned ferromagnetically or antiferromagnetically depending on the thickness of the spacer material .
this phenomenon has been intensively studied both experimentally and theoretically over the last few years @xcite .
the relation between the periods , by far the most investigated feature of the oscillations , and the electronic structure of multilayered systems is a fundamental aspect of the mechanism responsible for the origin of this phenomenon ..
Please generate the next two sentences of the article | in fact , the periods were originally shown to be dependent on the shape of the spacer fermi surface , where two distinct criteria were proposed for determining the periods with which the interlayer coupling oscillates @xcite . within the quantum well
theory the wave vectors yielding the effective oscillation periods correspond to extremal radii of the fermi surface in the direction perpendicular to the layers , or in other words to half the caliper measurements @xcite . on the other hand , in the rkky theory adapted to the layered geometry , |
6,818 | Suppose that you have an abstract for a scientific paper: the theory and experiments concerned with the electron - ion thermal relaxation and melting of overheated crystal lattice constitute the subject of this paper .
the physical model includes two - temperature equation of state , many - body interatomic potential , the electron - ion energy exchange , electron thermal conductivity , and optical properties of solid , liquid , and two phase solid - liquid mixture .
two - temperature hydrodynamics and molecular dynamics codes are used . an experimental setup with pump - probe technique
is used to follow evolution of an irradiated target with a short time step 100 fs between the probe femtosecond laser pulses .
accuracy of measurements of reflection coefficient and phase of reflected probe light are 1% and @xmath0 , respectively .
it is found that , _
firstly _ , the electron - electron collisions make a minor contribution to a light absorbtion in solid al at moderate intensities ; _ secondly _ , the phase shift of a reflected probe results from heating of ion subsystem and kinetics of melting of al crystal during @xmath1 where @xmath2 is time delay between the pump and probe pulses measured from the maximum of the pump ; _ thirdly _ the optical response of au to a pump shows a marked contrast to that of al on account of excitation of _ d_-electrons .
femtosecond laser ablation , pump - probe , optics of hot al and au .
And you have already written the first three sentences of the full article: figures [ fig:1],[fig:2 ] show diagrams of processes in pump femtosecond laser pulse ( fslp ) action on metal .
the three time slices `` ei '' , @xmath3 and @xmath4 in fig .
[ fig:1 ] correspond to the following non - equilibrium processes : ( e - i ) the electron - ion thermal relaxation , ( m ) the melting of an overheated crystal lattice , and ( c ) the cavitation decay of a metastable state ..
Please generate the next two sentences of the article | duration of fslp @xmath5 is shorter than characteristic times of these three processes .
they have very various time scales from subpicoseconds to nanoseconds . |
6,819 | Suppose that you have an abstract for a scientific paper: an increase in energy production from renewable energy sources is viewed as a crucial achievement in most industrialized countries .
the higher variability of power production via renewables leads to a rise in ancillary service costs over the power system , in particular costs within the electricity balancing markets , mainly due to an increased number of extreme price spikes .
this study focuses on forecasting the behavior of price and volumes of the italian balancing market in the presence of an increased share of renewable energy sources .
starting from configurations of load and power production , which guarantee a stable performance , we implement fluctuations in the load and in renewables ; in particular we artificially increase the contribution of renewables as compared to conventional power sources to cover the total load .
we then forecast the amount of provided energy in the balancing market and its fluctuations , which are induced by production and consumption . within an approach of agent based modeling
we estimate the resulting energy prices and costs .
while their average values turn out to be only slightly affected by an increased contribution from renewables , the probability for extreme price events is shown to increase along with undesired peaks in the costs .
renewable energy , electricity markets , statistical physics , agent based modeling .
And you have already written the first three sentences of the full article: the increasing environmental awareness , together with the progressive reduction of production and installation costs@xcite , leads to a considerable growth in the amount of renewable energy sources ( res ) that is installed worldwide .
moreover , the increasing propensity to reduce greenhouse gas emissions requires an increment of the energy produced by clean , accessible energy sources such as wind and photovoltaic ( pv ) generation . despite the great advantages of these energy sources , their intrinsic variability in power production badly fits to the very hierarchical structure and the strictly dispatch rules of actual power systems .
the limited accuracy of the prediction of their energy production profiles makes the management of these intermittent power sources difficult and limits the amount of res generation that the power system can tolerate ..
Please generate the next two sentences of the article | after the network liberalization over the last 15 years , the system balancing in real time is performed via the electricity balancing market ( ebm ) , which is a subphase of the ancillary services market ( asm ) .
this market phase shall ensure the correct balanced state over the system at the transmission level , providing the security of the supply at the lowest possible costs . |
6,820 | Suppose that you have an abstract for a scientific paper: the big bounce ( bb ) transition within a flat friedmann - robertson - walker model is analyzed in the setting of loop geometry underlying the loop cosmology .
we solve the constraint of the theory at the classical level to identify physical phase space and find the lie algebra of the dirac observables .
we express energy density of matter and geometrical functions in terms of the observables .
it is the modification of classical theory by the loop geometry that is responsible for bb .
the classical energy scale specific to bb depends on a parameter that should be fixed either by cosmological data or determined theoretically at quantum level , otherwise the energy scale stays unknown . .
And you have already written the first three sentences of the full article: it is commonly believed that the cosmological _ singularity _ problem @xcite may be resolved in a theory which unifies gravity and quantum physics .
recent analyses done within the _ loop _ quantum cosmology ( lqc ) concerning homogeneous isotropic universes of the friedmann - robertson - walker ( frw ) type , strongly suggest that the evolution of these universes does not suffer from the classical singularity . strong _
quantum _ effects at the planck scale cause that classical big bang is replaced by quantum big bounce ( bb ) @xcite ..
Please generate the next two sentences of the article | the resolution of the cosmic singularity problem offered by lqc requires the existence of a fundamental _ length _ , which effectively implies the discreteness of quantum geometry .
however , the _ size _ of this length has not been determined satisfactory yet , i.e. derived within lqc . |
6,821 | Suppose that you have an abstract for a scientific paper: we present a numerical investigation of the coronal evolution of a coronal mass ejection ( cme ) on 2005 august 22 using a 3-d thermodynamics magnetohydrodynamic model , the swmf .
the source region of the eruption was anemone active region ( ar ) 10798 , which emerged inside a coronal hole .
we validate our modeled corona by producing synthetic extreme ultraviolet ( euv ) images , which we compare to eit images .
we initiate the cme with an out - of - equilibrium flux rope with an orientation and chirality chosen in agreement with observations of a h@xmath0 filament . during the eruption , one footpoint of the flux rope reconnects with streamer magnetic field lines and with open field lines from the adjacent coronal hole .
it yields an eruption which has a mix of closed and open twisted field lines due to interchange reconnection and only one footpoint line - tied to the source region .
even with the large - scale reconnection , we find no evidence of strong rotation of the cme as it propagates .
we study the cme deflection and find that the effect of the lorentz force is a deflection of the cme by about 3@xmath1 / r@xmath2 towards the east during the first 30 minutes of the propagation .
we also produce coronagraphic and euv images of the cme , which we compare with real images , identifying a dimming region associated with the reconnection process .
we discuss the implication of our results for the arrival at earth of cmes originating from the limb and for models to explain the presence of open field lines in magnetic clouds . .
And you have already written the first three sentences of the full article: coronal mass ejections ( cmes ) are one of the leading causes of space weather , especially when they have organized southward directed magnetic field .
therefore , it is of great importance for space weather forecasting to understand how their direction of propagation and their orientation at 1 au relate to properties on the solar disk ( location of source region , orientation of the polarity inversion line , etc ... ) .
the deflection of cmes in the latitudinal direction has been observed and reported since the launch of the first space coronagraphs in the 1970s and 1980s ..
Please generate the next two sentences of the article | for example , @xcite reported an average deflection of 2.2@xmath1 towards the equator for 29 cmes during solar minimum ( 19731974 ) , while they found no systematic deflection for 19 cmes during solar maximum ( 1980 ) . with the launch of the _ solar - terrestrial relations observatory _ ( stereo ) in 2006 , there has been a renewed focus on the deflection of cmes in the corona and the heliosphere , thanks to stereoscopic measurements from the two spacecraft ( e.g. , see : * ? ? ? * ; * ? ? ? * ; * ? ? ? * ) .
the presence of coronal holes is known to affect the direction of propagation of cmes @xcite . |
6,822 | Suppose that you have an abstract for a scientific paper: in composite higgs models light fermionic top partners often play an important role in obtaining a 126 gev higgs mass .
the presence of these top partners implies that coloured vector mesons , or massive gluon partners , most likely exist .
since the coupling between the top partners and gluon partners can be large there are then sizeable two - loop contributions to the composite higgs mass .
we compute the radiative correction to the higgs mass from a gluon partner in the minimal composite higgs model and show that the higgs mass is in fact reduced .
this allows the top partner masses to be increased , easing the tension between having a light composite higgs and heavy top partners . .
And you have already written the first three sentences of the full article: the recent discovery of the higgs boson at the large hadron collider ( lhc ) @xcite confirms that the higgs mechanism is responsible for spontaneously breaking electroweak symmetry in the standard model ( sm ) .
however , the question of whether the higgs sector is natural or not remains to be answered .
the two most appealing solutions for stabilising the weak scale are supersymmetry ( see ref ..
Please generate the next two sentences of the article | @xcite for a review ) and compositeness @xcite .
both are now constrained by measurements of the higgs mass and its couplings , which have led to consequences for the spectrum of exotic states predicted in these two scenarios . in supersymmetric models |
6,823 | Suppose that you have an abstract for a scientific paper: we present the suzaku results of @xmath0 carinae in the 550 kev range conducted twice around the apastron in 2005 august for 50 ks and in 2006 february for 20 ks .
the x - ray imaging spectrometer ( xis ) produced hard ( 512 kev ) band spectra , resolving k shell lines from highly ionized fe and ni .
the hard x - ray detector yielded a significant detection in the super - hard ( 1550 kev ) band , which is uncontaminated by near - by sources .
we constrained the temperature of the optically - thin thermal plasma emission dominant in the hard band as 34 kev using the k - shell line features with the xis .
we found significant excess emission above the thermal emission in the super - hard band with the pin , confirming the previous integral isgri report .
the entire 550 kev spectra were fitted by a combination of a thermal plasma model plus a flat power - law or a very hot thermal bremsstrahlung model for the excess emission .
no significant change of the excess emission was found at different epochs within the systematic and statistical uncertainties and no flare - like flux amplification was seen in the hard band , indicating that the excess emission is a steady phenomenon .
we argue that the super - hard emission is attributable to the inverse compton of stellar uv photons by non - thermal electrons or to the thermal bremsstrahlung of very hot plasma , and not to the bremsstrahlung by non - thermal electrons colliding with cold ambient matter . .
And you have already written the first three sentences of the full article: lcccccccc number & sequence & & & & orbital + & number & date & time & date & time & xis & hxd & phase@xmath1 + first & 100012010 & 2005 - 08 - 29 & 01:48 & 2005 - 08 - 30 & 01:30 & 50 & 53 & 1.39 + second & 100045010 & 2006 - 02 - 03 & 09:59 & 2006 - 02 - 03 & 22:45 & 21 & 17 & 1.47 + colliding wind binaries ( cwbs ) , a binary system comprised of two early - type stars with stellar winds at high mass loss rates and velocities , are the brightest class of stellar hard x - ray emitters .
theoretical interpretations are given for their luminous hard x - rays as the thermal emission from high - temperature plasma produced by strong shocks due to the colliding winds @xcite .
the interpretation is supported by the x - ray modulation observed along the orbital motion in some cwbs @xcite ..
Please generate the next two sentences of the article | cwbs are also expected to be an agent of cosmic particle acceleration , which is evidenced by the presence of non - thermal radio emission from e.g. , wr140 @xcite .
charged particles with an energy distribution deviating from the maxwellian distribution give rise to the x - ray emission harder than the thermal emission dominant below 10 kev , thus the presence and the process of particle acceleration in cwbs can be best studied in the super - hard x - ray band . for convenience |
6,824 | Suppose that you have an abstract for a scientific paper: the percolation threshold for flow or conduction through voids surrounding randomly placed spheres is rigorously calculated . with large scale monte carlo simulations
, we give a rigorous continuum treatment to the geometry of the impenetrable spheres and the spaces between them . to properly exploit finite size scaling , we examine multiple systems of differing sizes , with suitable averaging over disorder , and extrapolate to the thermodynamic limit .
an order parameter based on the statistical sampling of stochastically driven dynamical excursions and amenable to finite size scaling analysis is defined , calculated for various system sizes , and used to determine the critical volume fraction @xmath0 and the correlation length exponent @xmath1 . .
And you have already written the first three sentences of the full article: notwithstanding simple underlying physics , percolation transition are _ bona fide _ second order phase transitions , with all of usual the hallmarks of singular behavior at a critical point @xcite .
percolation transitions , phase transitions mediated by a disordering influence such as the random removal of sites or bonds on a regular lattice geometry , are amenable to numerical study in the context of monte carlo calculations used to treat disorder .
however , while the critical behavior in discrete systems may be characterized to a high level of precision in this manner , there are salient examples of percolation phenomena which can not be reduced to discrete lattices . in realistic porous media ,.
Please generate the next two sentences of the article | the flow of liquid on a macroscopic basis typically entails the passage of liquid around irregularly shaped granules which comprise the material and represent barriers to fluid flow . for the movement of fluid or charge in porous materials ,
there is a dichotomy for volume concentrations of barrier particles above and below a critical concentration @xmath2 . |
6,825 | Suppose that you have an abstract for a scientific paper: the crystal structure of the thermoelectric material tin selenide has been investigated with angle - dispersive synchrotron x - ray powder diffraction under hydrostatic pressure up to 27 gpa . with increasing pressure ,
a continuous evolution of the crystal structure from the ges type to the higher - symmetry tli type was observed , with a critical pressure of 10.5(3 ) gpa . the orthorhombic high - pressure modification , @xmath0-snse , is closely related to the pseudo - tetragonal high - temperature modification at ambient pressure .
the similarity between the changes of the crystal structure at elevated temperatures and at high pressures suggests the possibility that strained thin films of snse may provide a route to overcoming the problem of the limited thermal stability of @xmath1-snse at high temperatures . .
And you have already written the first three sentences of the full article: the central challenge in finding or engineering thermoelectric materials suitable for thermal energy conversion beyond niche applications remains to combine good electrical properties and a very low thermal conductivity in a single material .
very recently , the compound snse has been reported to exhibit exceptionally good thermoelectric properties at high temperatures above @xmath2800 k , including a very low thermal conductivity @xcite .
nanostructuring of materials has been pursued extensively in recent years as a possible route towards achieving a sufficiently low thermal conductivity @xcite , but the discovery of extremely low thermal conductivity in bulk snse has markedly improved the prospects of obtaining bulk thermoelectrics suitable for general commercial applications . as snse consists only of earth - abundant elements of comparatively low toxicity , it represents also an important advance in avoiding toxic and rare elements like lead and tellurium in thermoelectric materials . at ambient conditions.
Please generate the next two sentences of the article | , snse adopts a layered orthorhombic crystal structure ( ges structure type ; space group @xmath3 , no .
62 ) as illustrated in fig . |
6,826 | Suppose that you have an abstract for a scientific paper: we adopt the general formalism for analyzing evolution of gaussian states of quantized fields in time - dependent backgrounds in the schrodinger picture ( presented in detail in @xcite ) to study the example of a spatially uniform electric field background ( in a time - dependent gauge ) which is kept turned on for a finite duration of time . in particular , we study the _ time - dependent _ particle content , defined in terms of the concept of instantaneous eigenstates , and describe how it captures the time evolution of the quantized field modes .
the actual particle creation process occurs over a relatively short interval in time , and the particle content saturates rather quickly .
we also compare the _ power spectrum _ of the field modes , computed in the asymptotic limit , with the corresponding situation in a cosmological de sitter background .
particle creation under the influence of a spiked electric field localized in time , as a particular limiting case of the above general model , is also considered . .
And you have already written the first three sentences of the full article: the schwinger effect , involving pair creation by a classical electromagnetic field out of the vacuum , is a well - known representative example of quantum field theory in an external classical background @xcite . the usual treatment , in the case of a spatially uniform and constant ( in time ) electric field , proceeds by evaluating the gauge - invariant effective action which is directly related with the transition amplitude between asymptotically defined _ in - out _ vacuum states @xcite .
the real part of the effective lagrangian describes vacuum polarization by the electric background , and can be added to the classical electromagnetic lagrangian to compute the modified equations of motion for the background incorporating back - reaction at the semiclassical level .
the imaginary part encodes information about particle creation , or more precisely , provides a direct measure of the asymptotic particle content in the _ in _ vacuum with respect to the _ out _ vacuum state . an alternative route to deriving this result is based on a particular choice for the gauge in which the vector potential is time - dependent ..
Please generate the next two sentences of the article | the field modes can be treated as a bunch of quantized time - dependent oscillators , and sensible vacuum states can be defined in the asymptotic regions @xcite .
these states are however in - equivalent due to the non - trivial time dependence of the vector potential though the electric field is constant with the consequence that a positive frequency mode defined at early times evolves into a combination of positive and negative frequency modes with respect to late times . |
6,827 | Suppose that you have an abstract for a scientific paper: motivated by the compactification process of the space of connections in loop quantum gravity literature .
a description of the space of @xmath0-connections using the tangent groupoid is given .
as the tangent groupoid parameter is away from zero , the @xmath0-connections are ( strictly ) deformation quantised to noncommuting elements using @xmath1-algebraic formalism .
the approach provides a mean to obtaining a semi - classical limit in loop quantum gravity . .
And you have already written the first three sentences of the full article: in ashtekar s theory of gravity , a @xmath2-connection captures the extrinsic curvature of a space - like leaf in a time - transversal foliation , and the intrinsic geometry of the leaf is given by a tetrad @xcite .
it is shown that the einstein - hilbert functional and einstein equations can be written in terms of @xmath2-connections and tetrads , thus these variables together recast einstein s theory of gravity . by rewriting einstein s gravity with the connection variables and tetrad variables
, one could attempt to quantise gravity via the hamiltonian formalism , and obtain a theory of quantum gravity @xcite.
Please generate the next two sentences of the article | . the reader may refer to thiemann s introductory @xcite .
this article offers an alternative view of the space of connections to ones that appear in other loop quantum gravity literatures , and proposes a semi - classical limit using strict @xmath1-algebraic deformation quantisation formalism @xcite . to take the connections as dynamic variables in a quantum theory , |
6,828 | Suppose that you have an abstract for a scientific paper: we compare recent results from x - ray , strong lensing , weak lensing , and optical observations with numerical simulations of the merging galaxy cluster 1e 0657 - 56 .
x - ray observations reveal a bullet - like subcluster with a prominent bow shock , which gives an estimate for the merger velocity of 4700 km s@xmath0 , while lensing results show that the positions of the total mass peaks are consistent with the centroids of the collisionless galaxies ( and inconsistent with the x - ray brightness peaks ) .
previous studies , based on older observational datasets , have placed upper limits on the self - interaction cross - section of dark matter per unit mass , @xmath1 , using simplified analytic techniques . in this work , we take advantage of new , higher - quality observational datasets by running full n - body simulations of 1e 0657 - 56 that include the effects of self - interacting dark matter , and comparing the results with observations . furthermore , the recent data allow for a new independent method of constraining @xmath1 , based on the non - observation of an offset between the bullet subcluster mass peak and galaxy centroid .
this new method places an upper limit ( 68% confidence ) of @xmath2 @xmath3 g@xmath0 .
if we make the assumption that the subcluster and the main cluster had equal mass - to - light ratios prior to the merger , we derive our most stringent constraint of @xmath4 @xmath3 g@xmath0 , which comes from the consistency of the subcluster s observed mass - to - light ratio with the main cluster s , and with the universal cluster value , ruling out the possibility of a large fraction of dark matter particles being scattered away due to collisions .
our limit is a slight improvement over the previous result from analytic estimates , and rules out most of the @xmath5 @xmath3 g@xmath0 range invoked to explain inconsistencies between the standard collisionless cold dark matter model and observations . .
And you have already written the first three sentences of the full article: the nature of dark matter , which accounts for the majority of the mass in the universe , is one of the major outstanding problems of modern astrophysics .
although it is often assumed that dark matter is collisionless , there is no a priori reason to believe that this is the case , and it has been noted by other authors that a non - zero self - interaction cross - section can have important astrophysical implications ( e.g. , spergel & steinhardt 2000 ) . in particular , self - interacting dark matter ( sidm ) has been invoked to alleviate some apparent problems with the standard cold dark matter ( cdm ) model , such as the non - observation of cuspy mass profiles in galaxies ( e.g. , moore 1994 ; flores & primack 1994 ; cf .
navarro et al ..
Please generate the next two sentences of the article | 1997 ; moore et al .
1999b ) and the overprediction of the number of small sub - halos within larger systems ( e.g. , klypin et al . 1999 |
6,829 | Suppose that you have an abstract for a scientific paper: motivated by recent studies that reported the successful synthesis of monolayer mg(oh)@xmath0 [ suslu _ et al .
_ , sci . rep .
* 6 * , 20525 ( 2016 ) ] and hexagonal ( _ h_-)aln [ tsipas _ et al_. , appl .
. lett . * 103 * , 251605 ( 2013 ) ] , we investigate structural , electronic , and optical properties of vertically stacked @xmath1-aln and mg(oh)@xmath0 , through _ ab initio _ density - functional theory ( dft ) , many - body quasi - particle calculations within the gw approximation , and the bethe - salpeter equation ( bse ) . it is obtained that the bilayer heterostructure prefers the @xmath2 stacking having direct band gap at the @xmath3 with type - ii band alignment in which the valance band maximum and conduction band minimum originate from different layer . regarding the optical properties ,
the imaginary part of the dielectric function of the individual layers and hetero - bilayer are investigated .
the hetero - bilayer possesses excitonic peaks which appear only after the construction of the hetero - bilayer .
the lowest three exciton peaks are detailedly analyzed by means of band decomposed charge density and the oscillator strength .
furthermore , the wave function calculation shows that the first peak of the hetero - bilayer originates from spatially indirect exciton where the electron and hole localized at @xmath1-aln and mg(oh)@xmath0 , respectively , which is important for the light harvesting applications . .
And you have already written the first three sentences of the full article: after the discovery of graphene@xcite , interest in atomically thin materials@xcite has grown rapidly due to their extraordinary physical properties.@xcite in the last decade , several 2d materials have been synthesized and theoretically predicted , such as silicene,@xcite germanene,@xcite stanene,@xcite transition metal dichalcogenides ( tmds such as mos@xmath0 , ws@xmath0),@xcite and iii - v binary compounds ( e.g. @xmath1-bn , @xmath1-aln).@xcite beside the single crystal of 2d materials , recently emerging field is their vertically stacked heterostructures.@xcite because of the van der waals type weak interlayer interaction , the synthesis of heterostructures is not restricted with the lattice matching of the each layers .
this provides a wide variety of combinations of layers which exhibit different electronic and optical properties.@xcite stable hexagonal crystalline structure of aln was first theoretically predicted by sahin _
et al_.@xcite and experimentally synthesized by tsipas _ _ et al.__@xcite they found that , differing from its bulk structure which is an insulator , monolayer @xmath1-aln is a semiconductor with the indirect band gap where the valance band maximum and conduction band minimum at the k and @xmath3 points , respectively ..
Please generate the next two sentences of the article | _ et al.__@xcite investigated properties of defects , such as vacancies , antisites , and impurities , in @xmath1-aln . it was reported that n vacancies and si impurities lead to the breaking of the planar symmetry and cause significant changes in the electronic properties .
_ et al.__@xcite calculated the magnetic properties of bare and transition - metal ( tm ) doped aln nanosheets by using first - principles calculations . |
6,830 | Suppose that you have an abstract for a scientific paper: we show that closest substring , one of the most important problems in the field of biological sequence analysis , is @xmath0$]-hard when parameterized by the number @xmath1 of input strings ( and remains so , even over a binary alphabet ) .
this problem is therefore unlikely to be solvable in time @xmath2 for any function @xmath3 of @xmath1 and constant @xmath4 independent of @xmath1 .
the problem can therefore be expected to be intractable , in any practical sense , for @xmath5 .
our result supports the intuition that closest substring is computationally much harder than the special case of closest string , although both problems are @xmath6-complete .
we also prove @xmath0$]-hardness for other parameterizations in the case of unbounded alphabet size .
our @xmath0$]-hardness result for closest substring generalizes to consensus patterns , a problem of similar significance in computational biology . .
And you have already written the first three sentences of the full article: motif search problems are of central importance for sequence analysis in computational molecular biology .
these problems have applications in fields such as genetic drug target identification or signal finding ( see @xcite and the references cited therein for more details and further applications ) .
two core problems in this context are closest substring @xcite and consensus patterns @xcite : * input : * @xmath1 strings @xmath7 over alphabet @xmath8 and non - negative integers @xmath9 and @xmath10 ..
Please generate the next two sentences of the article | + + * question in case of closest substring : * is there a string @xmath11 of length @xmath10 , and for @xmath12 , a substring @xmath13 of length @xmath10 such that , for all @xmath14 , @xmath15 ? ( here @xmath16 denotes the hamming distance between @xmath11 and @xmath17 . ) + + * question in case of consensus patterns : * is there a string @xmath11 of length @xmath10 , and for @xmath12 , a substring @xmath13 of length @xmath10 such that , @xmath18 ? + what is currently known about these two problems is summarized as follows . *
the closest substring problem . * 1 . |
6,831 | Suppose that you have an abstract for a scientific paper: in a coupled cavity qed network model , we study the transition from a localized superfluid like state to a delocalized mott insulator like state , triggered by losses . without cavity losses ,
the transition never takes place .
further , if one measures the quantum correlations between the polaritons via the negativity , we find a critical cavity damping constant , above which the negativity displays a single peak in the same time region where the transition takes place .
additionally , we identify two regions in the parameter space , where below the critical damping , oscillations of the initial localized state are observed along with a multipeaked negativity , while above the critical value , the oscillations die out and the transition is witnessed by a neat single peaked negativity . .
And you have already written the first three sentences of the full article: quantum phase transitions(qpt ) , as opposed to the classical transitions , driven by quantum rather than thermal fluctuations , occur at absolute zero and are induced by the change of some coupling constant or physical parameter .
these phenomena have captured the attention of many researchers during the last decade . in cavity qed networks , the trade off between the mott insulator ( mi ) and superfluid ( sf )
phases have been specially studied . in the present context ,.
Please generate the next two sentences of the article | these are not truly `` phases '' in the thermodynamic sense , since in our model , we deal only with few cavities . however , it has been shown that even small systems , containing a reduced number of cavities display the superfluid - mott transition @xcite .
the importance of this transition is that it enables the system to go from a delocalized state ( mi ) , with the excitations equally distributed throughout the system , to the state where the excitations move freely ( sf ) , and more importantly , all the excitations could be localized in just one cavity . in the literature , |
6,832 | Suppose that you have an abstract for a scientific paper: measurements of [ ci ] , @xmath0=21 @xmath1 and @xmath0=43 @xmath2 emission from quiescent , starburst and active galaxy centers reveal a distinct pattern characterized by relatively strong [ ci ] emission .
the [ ci ] to @xmath1 emission ratio increases with central [ ci ] luminosity .
it is lowest in quiescent and mild starburst centers and highest for strong starburst centers and active nuclei .
c@xmath3 abundances are close to , or even exceed , co abundances .
the emission is characteristic of warm and dense gas rather than either hot tenuous or cold very dense gas .
the relative intensities of co , [ ci ] , [ cii ] and far - infrared emission suggest that the dominant excitation mechanism in galaxy centers may be different from that in photon - dominated regions ( pdrs ) . .
And you have already written the first three sentences of the full article: carbon monoxide ( co ) , the most common molecule after @xmath4 , is routinely detected in external galaxies .
when exposed to photons of energy greater than 11.1 ev , co is readily photodissociated into atomic carbon and oxygen . as the c@xmath3 ionization potential is only 11.3 ev
, i.e. quite close to the co dissociation energy , neutral carbon may be quickly ionized ..
Please generate the next two sentences of the article | because carbon monoxide , its isotopes , as well as neutral and ionized carbon respond differently to ambient conditions , observations of the relative emission strengths of @xmath2 , @xmath1 , c@xmath3 and c@xmath5 provide significant information on the physical condition of cloud complexes from which the emission arises .
even though far - infrared continuum and [ cii ] lines are much more efficient coolants overall , co and [ ci ] lines are especially important for the temperature balance of cool and dense molecular gas . |
6,833 | Suppose that you have an abstract for a scientific paper: the origin , propagation , and mechanisms of acceleration of the ultra - high energy cosmic rays ( uhecrs ) are not yet well understood . aiming for a better interpretation of the available experimental data ,
these data have to be confronted with theoretical models .
a realistic simulation of the propagation of uhecrs in the universe should take into account all the relevant energy loss processes due to the interaction with astrophysical backgrounds , as well as the intervening cosmic magnetic fields .
cosmological effects , such as the redshift dependence of the photon backgrounds and the adiabatic expansion of the universe can play an important role in the aforementioned processes . here
we present results of simulations of the propagation of uhecr through the large scale structure of the universe considering cosmological and magnetic field effects simultaneously .
[ firstpage ] ultra - high energy cosmic rays , large scale structure of the universe , propagation of uhecrs .
And you have already written the first three sentences of the full article: during their propagation to earth , ultra - high energy cosmic rays ( uhecrs ) can suffer different interaction processes and be deflected by the pervasive cosmic magnetic fields , which directly affects the spectrum and chemical composition observables of these particles .
therefore , to address the question concerning the origin and nature of uhecrs , one has to simulate their propagation taking into account all the relevant interaction and energy loss processes , as well as the effects of cosmic magnetic fields .
if uhecrs have an extragalactic origin , the intervening cosmic magnetic fields can play an important role on propagation , and increase the trajectory length of the particles in such a way that cosmological effects , such as the adiabatic expansion of the universe and the redshift evolution of the photon backgrounds , can have a relevant contribution to the energy losses ..
Please generate the next two sentences of the article | weak magnetic fields should only slightly increase the trajectory length for nearby sources , but should have considerable effects for distant sources . depending on the model of extragalactic magnetic field ( egmf )
used this increase in path length causes larger deflections . by propagating uhecrs through the large scale structure of the universe ( lss ) obtained from magnetohydrodynamical ( mhd ) simulations , dolag _ et al . _ |
6,834 | Suppose that you have an abstract for a scientific paper: the formation of conducting channels of ti@xmath0o@xmath1 inside tio@xmath2-based memristors is believed to be the origin for the change in electric resistivity of these devices .
while the properties of the bulk materials are reasonably known , the interface between them has not been studied up to now mostly due to their different crystalline structures . in this work we present a way to match the interfaces between tio@xmath2 and ti@xmath0o@xmath1 and subsequently the band offset between these materials
is obtained from density functional theory based calculations .
the results show that while the valence band is located at the ti@xmath0o@xmath1 , the conduction band is found at the tio@xmath2 structure , resulting into a type ii interface . in this case
, the ti@xmath0o@xmath1 would act as a donor to the tio@xmath2 matrix . .
And you have already written the first three sentences of the full article: the memristor is an electronic device predicted by l. chua in 1971@xcite and experimentally obtained a few years ago.@xcite these devices are characterized by distinct resistance states which could be used to store information as they show very fast switching and high retention times.@xcite there are reports of a wide range of materials ( particularly metal oxides ) which show this memristive effect.@xcite although the switching mechanism , and the origin of the different resistance states has not been completely elucidated , it is generally believed that the presence of oxygen deficient phases plays a major role in the memristive effect.@xcite within the possible materials , tio@xmath2 is one of the most studied ones.@xcite inside memristive devices , ti@xmath0o@xmath1 channels immersed in the tio@xmath2-based matrix have been observed , and the formation of such structures is believed to be largely responsible for the change in resistivity.@xcite while tio@xmath2 is known to be a wide gap semiconductor ( experimental band gap @xmath3 ev@xcite ) ti@xmath0o@xmath1 presents three phases with different electronic transport properties .
the low temperature ( @xmath4 140 k ) and intermediate temperature phases ( 140 k @xmath5 150 k ) are semiconductors while the high temperature phase ( @xmath6 150 k ) is metallic.@xcite the differences between those phases is mainly due to small atomic displacements which do not lead to significant changes in the unit cell . despite the large amount of theoretical work on either tio@xmath2 rutile @xcite and ti@xmath0o@xmath1,@xcite the band alignment of these two materials
is not known up to now , mainly because of the difficulty in building a supercell containing the ti@xmath0o@xmath1-tio@xmath2 interface - the two materials present very different unit cells , making the match between them very difficult ..
Please generate the next two sentences of the article | this information could be very useful to the understanding of the atomic level mechanism of the memristor , given that the ti@xmath0o@xmath1-tio@xmath2 interface spans a great part of the device length after the formation of the conducting channels .
as the total energy is given with respect to an arbitrary reference energy in periodic calculations , a common reference should be determined for all the structures involved in this work.@xcite in fact , the knowledge of this common reference is necessary to find the offset between the valence band of different materials . |
6,835 | Suppose that you have an abstract for a scientific paper: the kinematics of newly - formed star clusters are interesting both as a probe of the state of the gas clouds from which the stars form , and because they influence planet formation , stellar mass segregation , cluster disruption , and other processes controlled in part by dynamical interactions in young clusters . however , to date
there have been no attempts to use simulations of star cluster formation to investigate how the kinematics of young stars change in response to variations in the properties of their parent molecular clouds . in this letter
we report the results of turbulent self - gravitating simulations of cluster formation in which we consider both clouds in virial balance and those undergoing global collapse .
we find that stars in these simulations generally have velocity dispersions smaller than that of the gas by a factor of @xmath0 , independent of the dynamical state of the parent cloud , so that subvirial stellar velocity dispersions arise naturally even in virialized molecular clouds .
the simulated clusters also show large - scale stellar velocity gradients of @xmath1 km s@xmath2 pc@xmath2 and strong correlations between the centroid velocities of stars and gas , both of which are observed in young clusters .
we conclude that star clusters should display subvirial velocity dispersions , large - scale velocity gradients , and strong gas - star velocity correlations regardless of whether their parent clouds are in virial balance , and , conversely , that observations of these features can not be used to infer the dynamical state of the parent gas clouds . .
And you have already written the first three sentences of the full article: the majority of stars form in clusters of 100 or more members @xcite .
the dynamics and distribution of stars within clusters have important ramifications for planet formation , stellar multiplicity , mass segregation , cluster disruption , and any other property of stars and planets that can be influenced by interactions between stars in the dense environment of a young cluster .
for example , @xcite show that close encounters with neighboring stars can disrupt the outer parts of planetary systems ( however , see @xcite ) . at an earlier stage ,.
Please generate the next two sentences of the article | protoplanetary disks in dense clusters are subject to dynamical disruption ( e.g. @xcite ) , photoevaporation ( e.g. @xcite ) , and contamination with short - lived radio - nuclides ( e.g. * ? ? ?
* ; * ? ? ? |
6,836 | Suppose that you have an abstract for a scientific paper: the actual potential of the next generation of gamma ray telescopes in improving the existing tests of an effective quantum gravity scale from the study of the propagation delay for gamma rays of different energies coming from a distant astrophysical source is discussed .
it is shown that the existence of a cosmological gamma ray horizon , will impose very demanding conditions on the observations of the telescopes to try to test a quantum gravity scale close to the planck mass .
, , lorentz invariance , @xmath0-rays , quantum gravity , cherenkov telescopes , gamma ray horizon 95.85.pw , 95.30.sf .
And you have already written the first three sentences of the full article: imaging cherenkov telescopes have proven to be the most successful tool developed so far to explore the cosmic gamma rays of energies above few hundred gev .
a pioneering generation of installations has been able to detect a handful of sources and start a whole program of very exciting physics studies . now
a second generation of more elaborated telescopes is under construction and will provide soon with new observations ..
Please generate the next two sentences of the article | one of the main characteristics of these new telescopes is the ability to detect lower energy gamma rays , which could fill the observational gap between 10 and 300 gev .
one of the most interesting results in fundamental physics from the existing telescopes is a limit , given by the whipple collaboration @xcite , on the quantum gravity scale to be larger than @xmath1 gev ( about 1/250th of the planck mass ) at the 95 % confidence level . in that study , |
6,837 | Suppose that you have an abstract for a scientific paper: we draw attention on a particular configuration of supersymmetric particle masses , motivated by naturalness and flavour considerations .
all its relevant phenomenological properties for the lhc are described in terms of a few physical parameters , irrespective of the underlying theoretical model .
this allows a simple characterization of its main features , useful to define a strategy for its discovery .
= 1 1.0 cm * s - particles at their naturalness limits * 1.0 cm riccardo barbieri@xmath0 and duccio pappadopulo@xmath1 + _
@xmath0 scuola normale superiore and infn , piazza dei cavalieri 7 , 56126 pisa , italy _
+ _ @xmath1 institut de thorie des phnomnes physiques , epfl , ch1015 lausanne , switzerland_1.0 cm .
And you have already written the first three sentences of the full article: supersymmetric particles have been so far elusive . nor we have seen any indirect signal of them in flavour physics , giving rise to the so - called _ supersymmetric flavour problem_. assuming that s - particles at the fermi scale indeed exist , is there any message in this ?
on one side , the discovery potential of the lhc in its full strength appears large enough to render this question not so urgent : if s - particles are there , they will be seen . on the other side ,
any orientation towards a specifically motivated configuration of s - particle masses and , possibly , of corresponding signals would clearly be valuable ..
Please generate the next two sentences of the article | this would be especially true in the case of particular configurations that appear to have received relatively little attention in the otherwise vast literature on phenomenological supersymmetry .
we argue in the following that there is one such case , based on naturalness and on the supersymmetric flavour problem . |
6,838 | Suppose that you have an abstract for a scientific paper: it is well known that no time - independent galactic cosmic ray ( gcr ) flux model can account for the observed linear relationship of be and b abundances with metallicity . in this contribution
we solve the time - dependent cr propagation equation using simple analytic time dependences for the cr spectrum at the source , the galactic cr escape - length and gas density evolution .
the cr fluxes so obtained are used to study the early evolution of the libeb abundances in the galaxy . .
And you have already written the first three sentences of the full article: recent observations of unevolved halo stars have confirmed the surprising linear relationship of the be and b abundances with [ fe / h ] ( @xcite , @xcite ) .
this primary behaviour of be and b can not be understood on the basis of the standard model ( sm ) of libeb production in the interstellar medium ( ism ) from gcr spallation .
this is because in the sm the libeb production rates are proportional to the global metallicity of the ism , so that a secondary behaviour with [ fe / h ] is expected ..
Please generate the next two sentences of the article | however , the sm assumes a _ gcr flux constant in time _ and equal to that currently oberved at the earth .
there are many reasons to believe that the gcr flux was different in early epochs . in this contribution we solve the time - dependent propagation equation of crs in the galaxy in a simple and parametrized way to test whether the sm can be compatible with observations when the hypothesis of the cr flux constancy in time is relaxed . |
6,839 | Suppose that you have an abstract for a scientific paper: the persistence phenomenon is studied in the japanese financial market by using a novel mapping of the time evolution of the values of shares quoted on the nikkei index onto ising spins .
the method is applied to historical end of day data from the japanese stock market during 2002 . by studying the time dependence of the spins , we find clear evidence for a double - power law decay of the proportion of shares that remain either above or below starting values chosen at random
. the results are consistent with a recent analysis of the data from the london ftse100 market .
the slopes of the power - laws are also in agreement .
we estimate a long time persistence exponent for the underlying japanese financial market to be 0.5 . .
And you have already written the first three sentences of the full article: in its most generic form , the persistence problem is concerned with the fraction of space which persists in its initial @xmath0 state up to some later time @xmath1 .
it is a classic problem which falls into the general class of so - called first passage problems [ 1 ] and has been extensively studied over the past decade or so for model spin systems by physicists [ 2 - 6 ] .
persistence has been investigated at both zero [ 2 - 5 ] and non - zero [ 6 ] temperatures ..
Please generate the next two sentences of the article | typically , in the non - equilibrium dynamics of spin systems at zero - temperature [ 2 - 5 ] , the system is prepared initially in a random state and the fraction of spins , @xmath2 , that persists in the same state as at @xmath3 up to some later time @xmath1 is monitored . at a finite temperature , on the other hand , one is interested in the global persistence behaviour and one monitors the change in the sign of the magnetization in a collection of non - interacting systems [ 6 ] .
it is now well established that the persistence probability decays algebraically [ 2 - 6 ] @xmath4 where @xmath5 is the non - trivial persistence exponent . |
6,840 | Suppose that you have an abstract for a scientific paper: two types of gaussian processes , namely the gaussian field with generalized cauchy covariance ( gfgcc ) and the gaussian sheet with generalized cauchy covariance ( gsgcc ) are considered .
some of the basic properties and the asymptotic properties of the spectral densities of these random fields are studied .
the associated self - similar random fields obtained by applying the lamperti transformation to gfgcc and gsgcc are studied .
@xmath0faculty of engineering , multimedia university , jalan multimedia , cyberjaya , 63100 , selangor darul ehsan , malaysia .
@xmath1faculty of information technology , multimedia university , jalan multimedia , cyberjaya , 63100 , selangor darul ehsan , malaysia . .
And you have already written the first three sentences of the full article: generalization of some well - known stochastic processes indexed by a single parameter to processes indexed by two parameters has attracted considerable interest recently .
for example , houdre and villa @xcite generalized fractional brownian motion parametrized by a single hurst index to the bifractional brownian motion characterized by two indices
. another example is provided by the multidimensional stationary gaussian fields with generalized cauchy covariance indexed by two parameters introduced by gneiting and schlather @xcite ..
Please generate the next two sentences of the article | these processes can be regarded as extension of the gaussian processes with cauchy covariance used in geostatistics . for simplicity , we call such processes the gaussian field with generalized cauchy covariance ( gfgcc ) . here
we would like to point out that one should not confuse such a process with a stable process with cauchy marginals . in general |
6,841 | Suppose that you have an abstract for a scientific paper: this correspondence presents an iterative geometric mean decomposition ( igmd ) algorithm for multiple - input - multiple - output ( mimo ) wireless communications .
in contrast to the existing gmd algorithms , the proposed igmd does not require the explicit computation of the geometric mean of positive singular values of the channel matrix , and hence substantially reduces the required hardware complexity .
the proposed igmd has a regular structure and can be easily adapted to solve problems with different dimensions .
we show that the proposed igmd is guaranteed to converge to the perfect gmd under certain sufficient condition .
three different constructions of the proposed algorithm are proposed and compared through computer simulations .
numerical results show that the proposed algorithm quickly attains comparable performance to that of the true gmd within only a few iterations . geometric mean decomposition ( gmd ) , mimo , qr , vblast , tomlinson - harashima precoding ( thp ) .
And you have already written the first three sentences of the full article: -input - multiple - output ( mimo ) communications @xcite have continued to be one of the key technologies of the next generation wireless systems due to their potential of providing higher data rate and better reliability compared to the conventional single - input - single - output ( siso ) systems .
when the channel state information ( csi ) is available at both the transmitter and receiver , it is well known that the closed - loop gain can be further acquired by jointly designing the precoder and the equalizer . among these closed - loop transceiver design schemes , singular - value - decomposition
( svd)-based linear transceiver decomposes the mimo channel into multiple parallel subchannels and is known to achieve the channel capacity if proper power allocation @xcite is applied ..
Please generate the next two sentences of the article | however , due to the variation of the signal - to - noise - ratio ( snr ) in each subchannel , the bit error rate ( ber ) performance is dominated by the subchannel with the worst snr .
consequently , without sophisticated bit - allocation schemes , fundamental trade - off between the ber and capacity can not be avoided in this type of design @xcite . |
6,842 | Suppose that you have an abstract for a scientific paper: noise in optical telecom fibers is an important limitation on optical quantum data transmission .
unfortunately , the classically successful amplifiers ( such as edfa ) can not be used in quantum communication because of the no - cloning theorem .
we propose a simple method to reduce quantum noise : the insertion of phase - shifters and/or beam - splitters at regular distance intervals into a fiber .
we analyze in detail the case of qubits encoded into polarization states of low - intensity light , which is of central importance to various quantum information tasks , such as quantum cryptography and communication .
we discuss the experimental feasibility of our scheme and propose a simple experiment to test our method . .
And you have already written the first three sentences of the full article: quantum communication ( qc ) has recently emerged as a subject of much interest , due to its applications in distributed quantum computation and quantum cryptography @xcite . in qc ,
non - orthogonal quantum signals are typically transmitted through telecom fibers .
reducing noise in telecom fibers is crucial for qc applications , because the very weak signals carried by polarization states are usually employed ..
Please generate the next two sentences of the article | ideally , a single photon in a superposition of two pulses separated in time with a controlled phase difference ( i.e. , @xmath0 ) may be used . however ,
on - demand single - photon sources remain an important technological challenge . currently , weak coherent states are often employed as approximate single photon signals . |
6,843 | Suppose that you have an abstract for a scientific paper: it is shown that a momentum - boost technique applied to the extended kohn - sham scheme enables the computational determination of the mott insulating transition .
self - consistent solutions are given for correlated electron systems by the first - principles calculation defined by the multi - reference density functional theory , in which the effective short - range interaction can be determined by the fluctuation reference method .
an extension of the harriman construction is made for the twisted boundary condition in order to define the momentum - boost technique in the first - principles manner .
for an effectively half - filled - band system , the momentum - boost method tells that the period of a metallic ground state by the lda calculation is shortened to the least period of the insulating phase , indicating occurrence of the mott insulating transition . .
And you have already written the first three sentences of the full article: detection of the mott insulating transition is a desirable function for the first - principles calculations , which has been demanded for years .
a recently developed multi - reference density functional theory with the fluctuation reference method defines a self - consistent first - principles calculation , in which a short - range correlation effect is explicitly included.@xcite this technique is a generalization of the kohn - sham scheme of the electronic structure calculation.@xcite incorporation of the effective many - body system to determine the total energy and the single - particle charge density of the electronic state became possible through 1 ) introduction of a fluctuation - counting term and 2 ) the reformulation of the exchange correlation energy functional as a residual exchange correlation energy functional .
the effective hamiltonian appearing in the theory is a kind of the hubbard model@xcite or the anderson model@xcite ..
Please generate the next two sentences of the article | the lda+u hamiltonian@xcite is derived as an approximation for the residual exchange correlation functional.@xcite in this short paper , i show a technique to determine the mott insulating phase in this first - principles calculation .
the method is an application of the momentum boost technique known in the literature.@xcite to introduce the momentum boost method in the density functional theory , one needs to show the n representability . |
6,844 | Suppose that you have an abstract for a scientific paper: we introduce the `` exponential linear unit '' ( elu ) which speeds up learning in deep neural networks and leads to higher classification accuracies . like rectified linear units
( relus ) , leaky relus ( lrelus ) and parametrized relus ( prelus ) , elus alleviate the vanishing gradient problem via the identity for positive values .
however elus have improved learning characteristics compared to the units with other activation functions .
in contrast to relus , elus have negative values which allows them to push mean unit activations closer to zero like batch normalization but with lower computational complexity .
mean shifts toward zero speed up learning by bringing the normal gradient closer to the unit natural gradient because of a reduced bias shift effect .
while lrelus and prelus have negative values , too , they do not ensure a noise - robust deactivation state .
elus saturate to a negative value with smaller inputs and thereby decrease the forward propagated variation and information .
therefore elus code the degree of presence of particular phenomena in the input , while they do not quantitatively model the degree of their absence . in experiments ,
elus lead not only to faster learning , but also to significantly better generalization performance than relus and lrelus on networks with more than 5 layers . on cifar-100 elus networks
significantly outperform relu networks with batch normalization while batch normalization does not improve elu networks .
elu networks are among the top 10 reported cifar-10 results and yield the best published result on cifar-100 , without resorting to multi - view evaluation or model averaging . on imagenet , elu networks considerably speed up learning compared to a relu network with the same architecture , obtaining less than 10% classification error for a single crop , single model network . .
And you have already written the first three sentences of the full article: currently the most popular activation function for neural networks is the rectified linear unit ( relu ) , which was first proposed for restricted boltzmann machines @xcite and then successfully used for neural networks @xcite .
the relu activation function is the identity for positive arguments and zero otherwise .
besides producing sparse codes , the main advantage of relus is that they alleviate the vanishing gradient problem @xcite since the derivative of 1 for positive values is not contractive @xcite ..
Please generate the next two sentences of the article | however relus are non - negative and , therefore , have a mean activation larger than zero .
units that have a non - zero mean activation act as bias for the next layer . |
6,845 | Suppose that you have an abstract for a scientific paper: we report the discovery of a radio - loud flat - spectrum qso at z=5.47 with properties similar to those of the _ egret _ @xmath0-ray blazars .
this source is the brightest radio qso at z@xmath15 , with a pc - scale radio jet and a black hole mass estimate @xmath2 .
it appears to be the most distant blazar discovered to date .
high energy observations of this source can provide powerful probes of the background radiation in the early universe . .
And you have already written the first three sentences of the full article: agn classification is still somewhat heuristic , but in the unified model , blazars are believed to be sources viewed close to the axis of a powerful relativistic jet ( * ? ? ? * and references therein ) .
they thus have compact flat spectrum radio counterparts , with apparent superluminal motion at vlbi scales .
optically , the sources are often variable , exhibit significant polarization and show either broad emission lines ( flat spectrum radio quasar ) or continuum - dominated ( bl lac ) spectra ..
Please generate the next two sentences of the article | perhaps the most interesting consequence of the jet / line - of - sight alignment is the observability of a compton scattered component at x - ray to gev or ( for nearby sources ) tev energies .
the interaction of the high energy jet particles and radiation with surrounding photon fields allows unique probes of the extragalactic background light ( ebl ) . |
6,846 | Suppose that you have an abstract for a scientific paper: we study the symmetry and strength of the superconducting pairing in a two - orbital model for iron pnictides using the salve boson mean - field theory .
we show that the nearest - neighbor biquadratic interaction @xmath0 inflences the superconducting pairing phase diagram by promoting the @xmath1 @xmath2 and the @xmath3 @xmath4 channels .
the resulting phase diagram consists of several competing pairing channels , including an isotropic @xmath5 @xmath4 channel , an anisotropic @xmath1 @xmath2 channel , and two @xmath6 pairing channels .
we have investigated the evolution of superconducting states with electron doping , and find that with the biquadratic interaction various pairing channels may dominate at different doping concentrations .
we show that this is crucial in understanding the doping evolution of superconducting gap anisotropy observed in some angle resolved photoemission spectrum measurements . .
And you have already written the first three sentences of the full article: in iron pnictides , the superconductivity @xcite emerges near an antiferromagnetically ordered state @xcite in the phase diagram .
this implies a strong interplay between the superconductivity and magnetism in these materials .
it has been observed that the parent compounds of iron pnictides have a @xmath7 antiferromagnetic order , which could arise either within a weak - coupling approach invoking a fermi surface nesting,@xcite or from a strong - coupling approach whose starting point is a local moment @xmath8 model.@xcite in the strong - coupling approach , the @xmath7 antiferromagnetic order can arise from a @xmath9 model for sufficiently large @xmath10 ..
Please generate the next two sentences of the article | but the strong anisotropic magnetic excitations in the paramagnetic phase observed from inelastic neutron scattering measurements prompts the necessity and importance of including a biquadratic exchange interaction @xmath11 between the nearest - neighbor ( n.n . )
pair of spins.@xcite from the theoretical perspective , the emergence of the biquadratic interaction is natural when the system contains multiple orbitals and when the correlations are strong in the metallic ground state : the low - energy effective hamiltonian in the spin sector should consist of not only two - spin heisenberg interactions , such as @xmath12 and @xmath10 heisenberg exchange between n.n . |
6,847 | Suppose that you have an abstract for a scientific paper: this paper develops a simplified model for sexual replication within the quasispecies formalism .
we assume that the genomes of the replicating organisms are two - chromosomed and diploid , and that the fitness is determined by the number of chromosomes that are identical to a given master sequence .
we also assume that there is a cost to sexual replication , given by a characteristic time @xmath0 during which haploid cells seek out a mate with which to recombine . if the mating strategy is such that only viable haploids can mate , then when @xmath1 , it is possible to show that sexual replication will always outcompete asexual replication . however , as @xmath0 increases , sexual replication only becomes advantageous at progressively higher mutation rates .
once the time cost for sex reaches a critical threshold , the selective advantage for sexual replication disappears entirely .
the results of this paper suggest that sexual replication is not advantageous in small populations per se , but rather in populations with low replication rates . in this regime ,
the cost for sex is sufficiently low that the selective advantage obtained through recombination leads to the dominance of the strategy .
in fact , at a given replication rate and for a fixed environment volume , sexual replication is selected for in high populations because of the reduced time spent finding a reproductive partner . .
And you have already written the first three sentences of the full article: sexual reproduction is the observed mode of reproduction for nearly all multicellular organisms . as such
, the evolution of sex has been one of the central outstanding questions in evolutionary biology .
one of the biological explanations for the existence of sex is that it provides a natural mechanism for diploid organisms to eliminate deleterious mutations from a population @xcite ..
Please generate the next two sentences of the article | the idea is that , by reproducing via a haploid intermediate , it is possible for haploids without defective genes to recombine with one another , thereby preventing the accumulation of deleterious mutations .
other explanations that have been advanced are that sex leads to greater variability in a population , making the population more adaptable in adverse conditions . |
6,848 | Suppose that you have an abstract for a scientific paper: charged lepton transverse momenta in the drell yan processes play an important role at the lhc in precision measurements of the standard model parameters , such as the @xmath0-boson mass and width , their charge asymmetries and @xmath1 .
therefore , their distributions should be described as accurate as possible by the monte carlo event generators . in this paper
we discuss the problem of matching the hard - process kinematics of the monte carlo generator with the parton - shower kinematics of the 6.4 generator while interfacing these two programs .
we show that improper assignment of the quark and antiquark effective momenta in the lo matrix element computations may affect considerably the predicted lepton transverse momenta and even completely reverse their charge asymmetries at the lhc .
we propose two matching schemes in which the nlo qcd distributions of the leptonic kinematical variables can be well reproduced by the lo generator . * charge asymmetries of lepton transverse momenta in drell
yan processes at the lhc * * m. w. krasny@xmath2 and w. paczek@xmath3 * + _ to be submitted to acta physica polonica b _
@xmath4the work is partly supported by the program of the french polish co - operation between in2p3 and copin no . 05 - 116 , and by the polish national centre of science grant no .
dec-2011/03/b / st2/00220 . .
And you have already written the first three sentences of the full article: distributions of transverse momenta of charged leptons ( @xmath5 ) produced in drell yan ( dy ) processes are important observables in hadron collider experiments .
their sensitivity to the values of the standard model ( sm ) parameters and to the polarisation of @xmath0 and @xmath6 bosons produced in the dy process can be used in precision tests of the standard model ( sm ) and in searches for new physics .
the measurement of the sm parameters : @xmath0-boson mass ( @xmath7 ) , its charge asymmetry ( @xmath8 ) and width ( @xmath9 ) at the lhc was investigated in refs ..
Please generate the next two sentences of the article | it was shown that in order to reach a precision at the level of @xmath10mev , the @xmath5 distributions must be controlled experimentally to a comparable accuracy .
since the monte carlo ( mc ) event generators are indispensable tools to derive the values of the sm parameters from the measured distributions , they must predict these distributions to even higher precision . |
6,849 | Suppose that you have an abstract for a scientific paper: cross sections , kinetic energy and angular distributions of fragments with charge 6@xmath0z@xmath028 emitted in @xmath1kr+@xmath2c at 5.5 mev / a reactions were measured at the ganil facility using the indra apparatus .
this experiment aims to investigate the influence of the neutron enrichment on the decay mechanism of excited nuclei .
data are discussed in comparison with predictions of transition state and hauser - feshbach models . .
And you have already written the first three sentences of the full article: nuclei under extreme conditions ( temperature , spin , neutron to proton ratio n / z , density ) have been the focus of experimental and theoretical investigations .
the fusion process between heavy ions colliding at incident energies around the coulomb barrier is well suited to study hot and rotating compound nuclei .
these excited nuclei decay through a variety of channels such as neutrons , light charged particles , fission and production of intermediate mass fragments ( imf s ) with charge z@xmath33 ..
Please generate the next two sentences of the article | the neutron enrichment of the compound nuclei is expected to influence the competition between these decay modes . in this contribution
we present new data on the production of fragments with 6@xmath0z@xmath028 formed in @xmath1kr+@xmath2ca fusion reactions at 5.5 mev / a incident energy . |
6,850 | Suppose that you have an abstract for a scientific paper: the pan - starrs1 @xmath0 survey has produced photometry and astrometry covering the 30,000 square degrees @xmath1 .
this article describes the photometric and astrometric calibration of this survey . .
And you have already written the first three sentences of the full article: this is the fifth in a series of seven papers describing the pan - starrs1 surveys , the data reduction techiques and the resulting data products .
this paper ( paper v ) describes the final calibration process , and the resulting photometric and astrometric quality .
* paper i ) provides an overview of the pan - starrs system , the design and execution of the surveys , the resulting image and catalog data products , a discussion of the overall data quality and basic characteristics , and a brief summary of important results ..
Please generate the next two sentences of the article | * paper ii ) describes how the various data processing stages are organised and implemented in the imaging processing pipeline ( ipp ) , including details of the the processing database which is a critical element in the ipp infrastructure .
* paper iii ) describes the details of the pixel processing algorithms , including detrending , warping , and adding ( to create stacked images ) and subtracting ( to create difference images ) and resulting image products and their properties . |
6,851 | Suppose that you have an abstract for a scientific paper: we present theoretical investigation on the high - frequency collective dynamics in liquids and glasses at microscopic length scales and terahertz frequency region based on the mode - coupling theory for ideal liquid - glass transition .
we focus on recently investigated issues from inelastic - x - ray - scattering and computer - simulation studies for dynamic structure factors and longitudinal and transversal current spectra : the anomalous dispersion of the high - frequency sound velocity and the nature of the low - frequency excitation called the boson peak .
it will be discussed how the sound mode interferes with other low - lying modes present in the system .
thereby , we provide a systematic explanation of the anomalous sound - velocity dispersion in systems ranging from high temperature liquid down to deep inside the glass state in terms of the contributions from the structural - relaxation processes and from vibrational excitations called the anomalous - oscillation peak ( aop ) . a possibility of observing negative dispersion the _ decrease _ of the sound velocity upon increase of the wave number
is argued when the sound - velocity dispersion is dominated by the contribution from the vibrational dynamics .
we also show that the low - frequency excitation , observable in both of the glass - state longitudinal and transversal current spectra at the same resonance frequency , is the manifestation of the aop . as a consequence of the presence of the aop in the transversal current spectra
, it is predicted that the transversal sound velocity also exhibits the anomalous dispersion .
these results of the theory are demonstrated for a model of the lennard - jones system . .
And you have already written the first three sentences of the full article: the study of high - frequency collective dynamics in liquids and glasses at microscopic length scales and terahertz frequency region has been a subject of intense investigations in the past decade . in particular , recent development of the inelastic x - ray scattering ( ixs )
technique has renewed the interest in a long - standing issue of sound propagation @xcite .
it is now generally accepted that a well - defined sound - like oscillatory mode called the high - frequency or fast sound is supported in liquids outside the strict hydrodynamic region , down to wavelengths of a few interparticle distances , but with a sound velocity larger than the hydrodynamic value ..
Please generate the next two sentences of the article | traditionally , such increase of the sound velocity upon increase of the wave number called the anomalous or positive dispersion has been interpreted within the so - called viscoelastic model @xcite . in this model ,
relevant memory kernel in the zwanzig - mori or memory - function equation for the dynamics structure factor @xmath0 is modeled by an exponential function with a single time constant @xmath1 reflecting structural relaxation in liquids . |
6,852 | Suppose that you have an abstract for a scientific paper: we report on very high energy @xmath0-observations with the magic telescope of the pulsar psr b1951 + 32 and its associated nebula , ctb 80 .
our data constrain the cutoff energy of the pulsar to be less than @xmath1gev , assuming the pulsed @xmath0-ray emission to be exponentially cut off .
the upper limit on the flux of pulsed @xmath0-ray emission above @xmath2gev is @xmath3photons @xmath4 sec@xmath5 , and the upper limit on the flux of steady emission above @xmath6gev is @xmath7photons @xmath4 sec@xmath5 .
we discuss our results in the framework of recent model predictions and other studies . .
And you have already written the first three sentences of the full article: it is currently believed that pulsars are among the few objects in our galaxy that are candidate sources of ultrarelativistic charged cosmic rays .
relativistic particles within the magnetosphere emit @xmath0-rays at energies up to several gev in various processes such as curvature radiation , synchrotron radiation and inverse compton ( ic ) scattering .
thus , observations in the multi - gev @xmath0-ray domain allow one to study the acceleration sites in the magnetosphere of a pulsar . predicted sites where particle acceleration can take place are , for example , above the polar cap of the neutron star ( e.g. *.
Please generate the next two sentences of the article | * ; * ? ? ?
* ) and in the so - called outer gap of the magnetosphere ( e.g. * ? ? ? |
6,853 | Suppose that you have an abstract for a scientific paper: we describe the design and performance of a series of fast , precise current sensing noise thermometers .
the thermometers have been fabricated with a range of resistances from 1.290 @xmath0 down to 0.2 m@xmath0 .
this results in either a thermometer that has been optimised for speed , taking advantage of the improvements in superconducting quantum interference device ( squid ) noise and bandwidth , or a thermometer optimised for ultra - low temperature measurement , minimising the system noise temperature . with a single temperature calibration point
, we show that noise thermometers can be used for accurate measurements over a wide range of temperatures below 4 k. comparisons with a melting curve thermometer , a calibrated germanium thermometer and a pulsed platinum nuclear magnetic resonance thermometer are presented . for the 1.290 @xmath0 resistance we measure a 1 % precision in just 100 ms , and
have shown this to be independent of temperature .
example.eps gsave newpath 20 20 moveto 20 220 lineto 220 220 lineto 220 20 lineto closepath 2 setlinewidth gsave .4 setgray fill grestore stroke grestore .
And you have already written the first three sentences of the full article: there is a rapidly expanding use of low temperature platforms ( @xmath1 k ) , for fundamental science , sensitive instrumentation , and new technologies of potentially significant commercial impact .
the availability of commercial `` push button '' cryogen - free dilution refrigerators is a key game - changing recent development , in which european companies have played the leading role .
the availability of cryogen - free commercial platforms to 1 mk is a future prospect @xcite ..
Please generate the next two sentences of the article | precise measurement of the thermodynamic temperature of these low temperature platforms is crucial for their operation .
however , despite the sophisticated nature of the cooling technology , reliable and convenient thermometers are unavailable . in the temperature range below 1 |
6,854 | Suppose that you have an abstract for a scientific paper: the rotation of the disk of the large magellanic cloud ( lmc ) is derived from the radial velocities of 422 carbon stars ( kunkel , irwin , & demers 1997 , a&as , 122 , 463 ) .
new aspects of this analysis include the propagation of uncertainties in the lmc proper motion with a monte carlo , and a self - consistent modeling of the rotation curve and disk kinematics .
the lmc rotation curve reaches a maximum circular velocity of 72 @xmath0 7 km s@xmath1 at @xmath2 kpc and then declines .
the rotation curve is well fit by a truncated , finite - thickness exponential disk model with no dark halo , implying a total mass of 5.3 @xmath0 1.0 @xmath3 @xmath4 @xmath5 .
the velocity dispersion in concentric radial bins from @xmath6 to 5.6 kpc decreases from 22 to 15 km s@xmath1 , then increases to @xmath720 km s@xmath1 at larger radii .
constant - thickness disk models in virial equilibrium can not be reconciled with the data even if the effects of lmc or galactic dark halos are included .
if the disk is virialized , the scale height rises from @xmath8 = 0.3 to 1.6 kpc over the range of @xmath9 = 0.5 to 5.6 kpc . thus the lmc disk is flared .
we model the velocity dispersion at large radii ( @xmath10 6 kpc ) as a maximal flared disk under the influence of the galactic dark halo , which favors a mean density for the latter of @xmath11 @xmath5 pc@xmath12 at the lmc distance . lmc stellar kinematics play an important role in elucidating the nature of machos , a dark population inferred from lmc microlensing .
we have constructed a truncated and flared maximal disk model for the lmc which is kinematically based .
our model does not include a nonvirialized component such as tidal debris .
the instantaneous probability of microlensing from lmc stars in our model is @xmath13 , where @xmath14 is the disk inclination .
our upper limit on the self - lensing optical depth is in good agreement with that obtained from less sophisticated models , and is an order of magnitude too small to....
And you have already written the first three sentences of the full article: if the galactic dark halo were composed entirely of massive compact halo objects ( machos ) , the instantaneous probablity of microlensing ( the `` optical depth '' ) towards the large magellanic cloud ( lmc ) would have been @xmath15 ( pacznski 1986 ) .
the most recent observational result for machos with masses up to about 1 @xmath5 is @xmath16 , which comes from an analysis of 5.7 years of lmc microlensing survey data ( alcock et al .
thus an all - macho galactic dark halo is ruled out . however , the observed optical depth is significantly higher than the estimate for known galactic and lmc stellar populations , @xmath17 ( alcock et al ..
Please generate the next two sentences of the article | the excess lmc microlensing signal may be telling us the macho fraction of the galactic dark halo or revealing gaps in our understanding of the essential structure of the lmc and galaxy .
critical discussions of the microlensing optical depth from known stellar populations have developed along two lines . |
6,855 | Suppose that you have an abstract for a scientific paper: it is suggested that the motion of pedestrians can be described as if they would be subject to ` social forces ' .
these ` forces ' are not directly exerted by the pedestrians personal environment , but they are a measure for the internal motivations of the individuals to perform certain actions ( movements ) .
the corresponding force concept is discussed in more detail and can be also applied to the description of other behaviors . in the presented model of pedestrian behavior
several force terms are essential : first , a term describing the acceleration towards the desired velocity of motion .
second , terms reflecting that a pedestrian keeps a certain distance to other pedestrians and borders .
third , a term modeling attractive effects .
the resulting equations of motion are nonlinearly coupled langevin equations .
computer simulations of crowds of interacting pedestrians show that the social force model is capable of describing the self - organization of several observed collective effects of pedestrian behavior very realistically . .
And you have already written the first three sentences of the full article: during the last two decades models of pedestrian behavior have found notable interest for several reasons . first , there are some striking analogies with gases @xcite and fluids @xcite .
second , all model quantities like places @xmath0 and velocities @xmath1 of pedestrians @xmath2 are measurable and , therefore , comparable with empirical data .
third , there already exists a considerable amount of data material like flow measurements or ( video ) films @xcite ..
Please generate the next two sentences of the article | fourth , pedestrian models can provide valuable tools for designing and planning pedestrian areas , subway or railroad stations , big buildings , shopping malls , etc . @xcite . in the 1970s
henderson @xcite has compared measurements of pedestrian flows with navier - stokes equations with considerable success . |
6,856 | Suppose that you have an abstract for a scientific paper: we show that the security proof of the bennett 1992 protocol over loss - free channel in ( k. tamaki , m. koashi , and n. imoto , phys .
rev .
lett . * 90 * , 167904 ( 2003 ) ) can be adapted to accommodate loss .
we assumed that bob s detectors discriminate between single photon states on one hand and vacuum state or multi - photon states on the other hand . .
And you have already written the first three sentences of the full article: quantum key distribution ( qkd ) is one of the most interesting topics in quantum information processing , which allows the sender ( alice ) and the receiver ( bob ) to share a secret key with negligibly leakage of information to an eavesdropper ( eve ) .
this task is accomplished by making use of the properties of quantum mechanics , such as no - cloning theorem @xcite , indistinguishability of nonorthogonal quantum states , entanglement , and so on @xcite . the b92 protocol @xcite , where only two nonorthogonal states are used , is thought to be secure due to the fact that eve can not clone and distinguish the states deterministically .
although the qualitative reason of the security is simple , it is quite hard to show the quantitative security against so - called coherent attack , which is the most general attack allowed by quantum mechanics . in @xcite ,.
Please generate the next two sentences of the article | the security of the bb84 protocol @xcite is proven by showing the relationship between qkd and other important protocols in quantum information , such as the entanglement distillation protocol ( edp ) @xcite and the calderbank - shor - steane ( css ) quantum error correcting codes @xcite . recently in @xcite ,
the unconditional security of the b92 protocol has been proved by relating the b92 protocol to an entanglement distillation protocol ( edp ) @xcite initiated by local filtering @xcite . |
6,857 | Suppose that you have an abstract for a scientific paper: entanglement generated from polar molecules of two - dimensional rotation is investigated in a static electric field .
the electric field modulates the rotational properties of molecules , leading to distinctive entanglement .
the concurrence is used to estimate the degree of entanglement . when the electric field is applied parallel or perpendicular to the intermolecular direction ,
the concurrences reveal two overlapping features .
such a pronounced signature corresponds to the coexistence of all bell - like states .
the characteristics of bell - like states and overlapping concurrences are kept independent of the modulation of dipole - field and dipole - dipole interactions . on the contrary ,
the bell - like states fail to coexist in other field directions , reflecting nonoverlapping concurrences .
furthermore , the thermal effect on the entanglement is analyzed for the bell - like states .
dissimilar suppressed concurrences occur due to different energy structures for the two specific field directions . .
And you have already written the first three sentences of the full article: exploring entanglement has attracted considerable interest in various physical systems , ranging from atoms and photons to solid - state materials @xcite .
entanglement describes a phenomenon in which two or more subsystems are linked through direct or indirect interactions .
this a quantum phenomenon has become an essential ingredient in quantum information processing @xcite . among various architectures ,.
Please generate the next two sentences of the article | a bipartite system is a fundamental unit to exploit the nature of entanglement .
fascinating properties have been extracted from a variety of bipartite systems . |
6,858 | Suppose that you have an abstract for a scientific paper: in this paper , we find a bound for the number of the positive solutions to the titled equation , improving a result of togb . as a consequence , we prove a conjecture of togb in a few cases . .
And you have already written the first three sentences of the full article: cassels @xcite was challenged to determine when the sum of three consecutive cubes equals a square .
he @xcite reduced the problem to finding integral points on the elliptic curve @xmath0 . using the arithmetic of certain quartic number fields
, he obtained that the integral points on the above elliptic curve were @xmath1 , @xmath2 , @xmath3 , and @xmath4 . using the classical work of ljunggren @xcite and its generalizations ( see @xcite , @xcite , @xcite , and @xcite ) , luca and walsh @xcite considered the problem of finding the number of positive integer solutions to the diophantine equation @xmath5 , where @xmath6 is a positive integer ..
Please generate the next two sentences of the article | they proved that the number of positive integer solutions to @xmath5 is at most @xmath7 , where @xmath8 is the number of distinct prime factors of @xmath9 . in @xcite ,
chen considered the case where @xmath9 is a prime number greater than @xmath10 . |
6,859 | Suppose that you have an abstract for a scientific paper: this continuation of the derivation of general beam - referenced stage - two spin - correlation functions is for the analysis of top - antitop pair - production at the tevatron and at the large hadron collider .
both the gluon - production and the quark - production contributions are included for the charged - lepton - plus - jets reaction @xmath0 or @xmath1 .
there is a simple 4-angle beam - referenced spin - correlation function for determination of the relative sign of or for measurement of a possible non - trivial phase between the two dominant @xmath2 helicity amplitudes for the @xmath3 decay mode .
there is an analogous function and tests for @xmath4 decay .
this signature requires use of the @xmath5 energy of the hadronically decaying w - boson , or the kinematically equivalent cosine of the polar - angle of @xmath6 emission in the anti - top ( top ) decay frame .
spinors and their outer - products are constructed so that the helicity - amplitude phase convention of jacob & wick can be used throughout for the fixing of the signs associated with this large w - boson longitudinal - transverse interference effect .
= -5 mm * use of w - boson longitudinal - transverse interference in top quark spin - correlation functions : ii * + charles a. nelson , jeffrey j. berger , and joshua r. wickman + _ department of physics , state university of new york at binghamton + binghamton , n.y . 13902 _ + .
And you have already written the first three sentences of the full article: this continuation of a previous paper [ 1 ] on the derivation of general beam - referenced stage - two spin - correlation functions is for the analysis of top - antitop pair - production [ 2,3 ] at the tevatron and at the large hadron collider [ 4 ] .
each second at the large hadron collider there will be a top - antitop pair produced when the planned @xmath7 is reached .
this should provide an almost ideal laboratory " for both investigating top - quark physics itself , and for simultaneously improved empirical mastery of reaction backgrounds and detector systematics / performance . as in the previous paper , which we denote as i " , the helicity formalism [ 5 ].
Please generate the next two sentences of the article | is used for a simple and transparent treatment of all relative phase effects .
we use this formalism for investigating the large effects of w - boson longitudinal - transverse interference in top - antitop pair - production for the charged - lepton plus jets channel , the di - lepton plus jets channel , and the all - jets channel . in i " , only the quark - production contribution was included ; it is the dominant contribution at the tevatron . on the other hand at the large hadron collider , the gluon - production contribution dominates . to leading order in @xmath8 , |
6,860 | Suppose that you have an abstract for a scientific paper: the origin of magnetic fields in clusters of galaxies is still an unsolved problem , which is largely due to our poor understanding of initial seed magnetic fields .
if the seed magnetic fields have primordial origins , it is likely that large - scale pervasive magnetic fields were present before the formation of the large - scale structure . on the other hand ,
if they were ejected from astrophysical bodies , they were highly localized in space at the time of injection . in this paper , using turbulence dynamo models for high magnetic prandtl number fluids , we find constraints on the seed magnetic fields .
the hydrodynamic reynolds number based on the spitzer viscosity in the intracluster medium ( icm ) is believed to be less than @xmath0 , while the magnetic reynolds number can be much larger than that . in this case , if the seed magnetic fields have primordial origins , they should be stronger than @xmath1 g , which is very close to the upper limit of @xmath2 g set by the cosmic microwave background ( cmb ) observations .
on the other hand , if the seed magnetic fields were ejected from astrophysical bodies , any seed magnetic fields stronger than @xmath2 g can safely magnetize the intracluster medium .
therefore , it is less likely that primordial magnetic fields are the direct origin of present - day magnetic fields in the icm . .
And you have already written the first three sentences of the full article: observations have it that magnetic fields of order @xmath3 g are present in clusters of galaxies ( see , for example , kronberg 1994 ; zweibel & heiles 1997 ; carilli & taylor 2002 ; widrow 2002 ; govoni & feretti 2004 ; vogt & enlin 2005 ; ferrari et al . 2008 ; ryu et al .
2012 ) . no physical effect ,
e.g. a battery effect , seems to produce such strong magnetic fields directly ..
Please generate the next two sentences of the article | therefore , it is natural to assume that weak seed magnetic fields were produced at some time and they have been amplified later to current strengths . according to this point of view ,
the origin of cosmic magnetism now involves two separate issues : generation of the initial seed magnetic fields and their amplification . in this paper |
6,861 | Suppose that you have an abstract for a scientific paper: consider the standard linear regression model @xmath0 with given design matrix @xmath1 ( @xmath2 ) , unknown parameter @xmath3 ( @xmath4 ) and unobserved error vector @xmath5 ( @xmath6 ) with i.i.d
. centered gaussian components .
motivated by an application in economics , we compare the ranks @xmath7 of the errors @xmath8 with the ranks @xmath9 of the residuals @xmath10 , where @xmath11 with the least squares estimator @xmath12 .
exact and approximate formulae are given for the rank distortions @xmath13 .
[ [ key - words ] ] key words : + + + + + + + + + + leverage , rank distortion . .
And you have already written the first three sentences of the full article: this paper is motivated by a recent consulting case in which a company wants to evaluate the performance of its @xmath14 offices at different locations . the performance of office no .
@xmath15 is quantified by a certain measure @xmath16 of costs per unit , but it is clear that it is influenced by various covariables @xmath17 describing , for instance , regional factors which can not be altered by the offices .
the idea is to eliminate these effects via a ( linear ) regression model , assuming that @xmath18 for some unknown handycap function @xmath19 of the covariable vectors @xmath20 , and @xmath8 are the corrected costs per unit of the @xmath15-th office ..
Please generate the next two sentences of the article | now the proposal is to use a linear model for the regression function @xmath19 and to estimate it via least squares or least absolute deviations .
that means , we determine a regression function @xmath21 within a given model @xmath22 such that @xmath23 becomes minimal , where @xmath24 is the residual of the fitted regression function @xmath21 . |
6,862 | Suppose that you have an abstract for a scientific paper: in this work we investigate the quantum noise properties of polarization vortices in connection with an intensity based clauser - horne - shimony - holt inequality for their spin - orbit separability .
we evaluate the inequality for different input quantum states and the corresponding intensity fluctuations .
the roles played by coherence and photon number squeezing provide a suitable framework for characterizing pure state spin - orbit entanglement .
structural inseparability of the spin - orbit mode requires coherence , an issue concerning either classical or quantum descriptions . in both cases
, it can be witnessed by violation of this intensity based chsh inequality . however , in the quantum domain , entanglement requires both coherence and reduced photon number fluctuations . .
And you have already written the first three sentences of the full article: as a major resource for quantum information processing , entangled states have been intensively studied in a wide variety of quantum systems . from the mathematical point of view ,
when pure states are considered , they correspond to state vectors of a combined system that can not be factorized as a tensor product of vectors belonging to the hilbert spaces of the individual subsystems . in the general case ,
mixed entangled states can not be written as a convex combination of projectors on factorized vectors . from the physical point of view.
Please generate the next two sentences of the article | , these states exhibit strong correlations when the individual systems are locally measured in different ( non orthogonal ) bases , as in the well known setting for the clauser - horn - shimony - holt ( chsh ) inequality @xcite .
for example , in photonic systems it has been tested with polarization entangled photon pairs @xcite . |
6,863 | Suppose that you have an abstract for a scientific paper: we study , using molecular dynamics techniques , how boundary conditions affect the process of fragmentation of finite , highly excited , lennard - jones systems .
we analyze the behavior of the caloric curves ( cc ) , the associated thermal response functions ( trf ) and cluster mass distributions for constrained and unconstrained hot drops .
it is shown that the resulting cc s for the constrained case differ from the one in the unconstrained case , mainly in the presence of a `` vapor branch '' .
this branch is absent in the free expanding case even at high energies .
this effect is traced to the role played by the collective expansion motion . on the other hand
, we found that the recently proposed characteristic features of a first order phase transition taking place in a finite isolated system , i.e. abnormally large kinetic energy fluctuations and a negative branch in the trf , are present for the constrained ( dilute ) as well the unconstrained case .
the microscopic origin of this behavior is also analyzed . .
And you have already written the first three sentences of the full article: the possibility of getting information about the thermodynamics of nuclear matter from the analysis of intermediate energies heavy ion collisions has triggered a lot of interest in this field .
starting from the pioneering work of the purdue group , when for the first time a power law was used to fit the mass spectra resulting from highly excited nuclear systems and thus suggesting that a critical phenomena was taking place , it has open the study of a rather new branch of thermodynamics i.e the study of phase transitions ( liquid - vapor ) in finite systems@xcite .
one of the most challenging features that nuclear multi - fragmentation phenomena presents , is that signals of phase transitions of different orders can be extracted from experimental data . on one hand.
Please generate the next two sentences of the article | , the analogy between the nuclear force and a van der waals interaction suggests that the nuclear equation of state should reproduce the main features that characterize a liquid - gas phase transition .
different indications of this kind of transition have been reported @xcite . on the other , signatures of a second order phase transition or critical behavior |
6,864 | Suppose that you have an abstract for a scientific paper: we present neutron diffraction , dielectric permittivity and photoconductivity measurements , evidencing that lead - magnesium niobate experiences a diffuse phase transformation between the spherical glass and quadrupole glass phases , in the temperature interval between 400 k and 500 k , with the quadrupole phase possessing extremely high magnitudes of dielectric permittivity .
our analysis shows that the integral diffuse scattering intensity may serve as an order parameter for this transformation .
our experimental dielectric permittivity data support this choice .
these data are important for the aplications desiring giant dielectric responses , in a wide temperature intervals and not related to electron s excitations . .
And you have already written the first three sentences of the full article: lead magnesium niobate pbmg@xmath0nb@xmath1o@xmath2 ( pmn ) is a canonical relaxor material characterized by an extremely large magnitude of dielectric permittivity over a broad temperature range and having logarithmically - wide frequency dispersion @xcite that is strongly demanded in many valuable applications .
for example , this is important to produce small - size capacitors robust to the temperature change .
dilution of pmn with ferroelectrics led to the discovery of one of the best piezoelectrics ever found , which have now extremely wide applications , in all brunches of life , science and technology @xcite . at the same time , the understanding of the main property of relaxors , which is the colossal dielectric response , is still debated @xcite ..
Please generate the next two sentences of the article | the source for the main properties of relaxors is usually related to the temperature growth of the polar nano regions ( pnr s ) on cooling @xcite .
it is believed that pnr s start their development , at a temperature called the burns temperature of @xmath3 , and increase their strength on cooling @xcite . |
6,865 | Suppose that you have an abstract for a scientific paper: determining the ultimate classical information carrying capacity of electromagnetic waves requires quantum - mechanical analysis to properly account for the bosonic nature of these waves .
recent work has established capacity theorems for bosonic single - user and broadcast channels , under the presumption of two minimum output entropy conjectures . despite considerable accumulated evidence that supports the validity of these conjectures , they have yet to be proven . in this paper
, it is shown that the second conjecture suffices to prove the classical capacity of the bosonic wiretap channel , which in turn would also prove the quantum capacity of the lossy bosonic channel .
the preceding minimum output entropy conjectures are then shown to be simple consequences of an entropy photon - number inequality ( epni ) , which is a conjectured quantum - mechanical analog of the entropy power inequality ( epi ) form classical information theory . .
And you have already written the first three sentences of the full article: the performance of communication systems that rely on electromagnetic wave propagation are ultimately limited by noise of quantum - mechanical origin . moreover ,
high - sensitivity photodetection systems have long been close to this noise limit . hence determining the ultimate capacities of lasercom channels
is of immediate relevance ..
Please generate the next two sentences of the article | the most famous channel capacity formula is shannon s result for the classical additive white gaussian noise channel . for a complex - valued channel model in which we transmit @xmath0 and receive @xmath1 , where @xmath2 is the channel s transmissivity and @xmath3 is a zero - mean , isotropic , complex - valued gaussian random variable that is independent of @xmath0 , shannon s capacity is @xmath4\,\mbox { nats / use } , \label{shannon}\ ] ] with @xmath5 and @xmath6 . in the quantum version of this channel model
, we control the state of an electromagnetic mode with photon annihilation operator @xmath7 at the transmitter , and receive another mode with photon annihilation operator @xmath8 , where @xmath9 is the annihilation operator of a noise mode that is in a zero - mean , isotropic , complex - valued gaussian state . for lasercom , if quantum measurements corresponding to ideal optical homodyne or heterodyne detection are employed at the receiver , this quantum channel reduces to a real - valued ( homodyne ) or complex - valued ( heterodyne ) additive gaussian noise channel , from which the following capacity formulas ( in nats / use ) follow : @xmath10 \label{homodyne}\\[.06 in ] c_{\rm heterodyne } & = & \ln[1 + \eta\bar{n}/((1-\eta)n+1 ) ] . |
6,866 | Suppose that you have an abstract for a scientific paper: in this paper we present the mass functions in the substellar regime of three young open clusters , ic 348 , @xmath0 orionis and pleiades , as derived using the data from the 2 micron all sky survey ( 2mass ) catalogue which has a limiting magnitude of @xmath1 , and the latest version of the guide star catalogue ( gsc ) which has a limiting magnitude of @xmath2 21 . based on recent evolutionary models for low mass stars ,
we have formulated the selection criteria for stars with masses below @xmath3 . using a statistical approach to correct for the background contamination , we derive the mass function of objects with masses ranging from 0.5@xmath4 down to the substellar domain , well below the hydrogen burning mass limit .
the lowest mass bins in our analysis are 0.025 , 0.045 and 0.055 m@xmath5 for ic 348 , @xmath0 orionis and pleiades , respectively .
the resultant slopes of the mass functions are 0.8 @xmath6 0.2 for ic 348 , 1.2 @xmath6 0.2 for @xmath0 orionis and 0.5 @xmath6 0.2 for pleiades , which are consistent with the previous results .
the contribution of objects below 0.5 m@xmath5 to the total mass of the cluster is @xmath740% , and the contribution of objects below 0.08 m@xmath5 to the total mass is @xmath74% . .
And you have already written the first three sentences of the full article: the initial mass function ( imf ) of stars is one of the most fundamental and crucial ingredients in models of galaxy formation and stellar evolution .
it determines several key parameters in stellar populations , such as the yield of heavy elements , the mass - to - light ratio , luminosity evolution over time , and the energy input into the interstellar medium .
the determination of the imf is therefore of great astrophysical importance ..
Please generate the next two sentences of the article | the imf of low - mass stars is of special interest in this context , since they contain a major fraction of the stellar mass , and have been hypothesized to contain a significant fraction of the total mass in the universe ( see , e.g. , fukugita , hogan and peebles , 1998 ) . in this paper
we mainly deal with objects having masses less than 0.5@xmath8 , the lowest mass of the detectable objects being as low as 0.025@xmath8 . |
6,867 | Suppose that you have an abstract for a scientific paper: all available photometric and spectroscopic observations were collected and used as the basis of a detailed analysis of the close binary i m mon .
the orbital period of the binary was refined to 1.19024249(0.00000014 ) .
the roche equipotentials , fractional luminosities ( in _ b , v _ and _ h@xmath0 _ - bands ) and fractional radii for the component stars in addition to mass ratio @xmath1 , inclination @xmath2 of the orbit and the effective temperature @xmath3 of the secondary cooler less massive component were obtained by the analysis of light curves .
i m mon is classified to be a detached binary system in contrast to the contact configuration estimations in the literature .
the absolute parameters of i m mon were derived by the simultaneous solutions of light and radial velocity curves as m@xmath4 m@xmath5 and 3.32(0.16 ) m@xmath5 , r@xmath6 r@xmath5 and 2.36(0.03 ) r@xmath5 , @xmath7 k and 14500(550 ) k implying spectral types of b4 and b6.5 zams stars for the primary and secondary components respectively .
the modelling of the high resolution spectrum revealed the rotational velocities of the component stars as v@xmath8 kms@xmath9 and v@xmath10 kms@xmath9 .
the photometric distance of 353(59 ) pc was found more precise and reliable than hipparcos distance of 341(85 ) pc .
an evolutionary age of 11.5(1.5 ) myr was obtained for i m mon .
kinematical and dynamical analysis support the membership of the young thin - disk population system i m mon to the ori ob1a association dynamically .
finally , we derived the distance , age and metallicity information of ori ob1a sub - group using the information of i m mon parameters . .
And you have already written the first three sentences of the full article: young stellar associations ( @xmath11 50 myr ) and open clusters have a crucial importance in advancing our understanding of star formation and the first stages of stellar evolution . since the galactic acceleration does not have a chance to affect the kinematical properties of these young stellar groups , the stellar content of an association is preserved .
consequently one can obtain kinematical , dynamical and chemical properties of these young stellar groups by studying their secure members .
today nearby associations within the solar neighbourhood have been very well identified ..
Please generate the next two sentences of the article | their stellar content of each association has been precisely determined up to a magnitude limit of @xmath1210.5 mag using astrometric data of the hipparcos satellite ( i.e. * ? ? ?
* ; * ? ? ? |
6,868 | Suppose that you have an abstract for a scientific paper: optical birefringence and light absorption measurements reveal four regimes for the thermotropic behavior of a nematogen liquid ( 7cb ) upon sequential filling of parallel - aligned capillaries of 12 nm diameter in a monolithic , mesoporous silica membrane .
no molecular reorientation is observed for the first adsorbed monolayer . in the film - condensed state ( up to 1 nm thickness ) a weak , continuous paranematic - to - nematic ( p - n ) transition is found , which is shifted by 10 k below the discontinuous bulk transition at t@xmath0305 k. the capillary - condensed state exhibits a more pronounced , albeit still continuous p - n reordering , located 4 k below t@xmath1 . . .
And you have already written the first three sentences of the full article: liquid crystals spatially confined on the nanometer scale exhibit structural and thermodynamical properties which differ markedly from their bulk counterparts .
both the collective orientational ( isotropic - to - nematic ) and translational ( smectic ) transitions have turned out to be significantly by finite size , quenched disorder and interfacial ( solid - liquid ) interactions introduced by the confining solid walls or the pore topology @xcite . for example
, the first - order discontinuous isotropic - to - nematic transition of rod - like liquid crystals condensed in pores a few nanometers across goes to a critical point , above which , strictly speaking , it disappears ..
Please generate the next two sentences of the article | then the transition is rendered continuous with a paranematic high - temperature phase , where even at highest temperatures the pore walls ( anchoring fields ) induce a residual collective orientational , paranematic order and no isotropic liquid is observable @xcite .
this sensitivity of liquid crystalline phase transitions stimulated a plethora of experimental studies . |
6,869 | Suppose that you have an abstract for a scientific paper: consider a manifold endowed with the action of a lie group .
we study the relation between the cohomology of the cartan complex and the equivariant cohomology by using the equivariant de rham complex developed by getzler , and we show that the cohomology of the cartan complex lies on the @xmath0 row of the second page of a spectral sequence converging to the equivariant cohomology .
we use this result to generalize a result of witten on the equivalence of absence of anomalies in gauged wzw actions on compact lie groups to the existence of equivariant extension of the wzw term , to the case on which the gauge group is the special linear group with real coefficients . .
And you have already written the first three sentences of the full article: in certain situations , geometrical information of manifolds might be encoded in differential forms . in the presence of symmetries of the manifold via the action of a lie group ,
the behavior of these differential forms under the group action may lead to a better understanding of the manifold itself . in some well known instances of actions of compact lie groups ,
the action is of a particular type whenever the differential form may be extended to an equivariant one in the cartan model of equivariant cohomology @xcite ; this is the case for example in hamiltonian actions on symplectic manifolds @xcite , in hamiltonian actions on exact courant algebroids @xcite or in gauged wzw actions which are anomaly free @xcite and its generalizations @xcite ..
Please generate the next two sentences of the article | when the lie group is not compact , the cartan complex associated to the action in general does not compute the equivariant cohomology of the manifold , and therefore many of the results that hold for compact lie groups may not hold for the non - compact case .
but since the cartan model is very well suited for studying the infinitesimal behavior of the differential forms with respect to the action of the lie algebra , it would be worthwhile knowing more about the relation between the cohomology of the cartan complex and the equivariant cohomology . in this paper |
6,870 | Suppose that you have an abstract for a scientific paper: we analyze charge tunneling statistics and current noise in a superconducting single - electron transistor in a regime where the josephson - quasiparticle cycle is the dominant mechanism of transport . due to the interplay between coulomb blockade and josephson coherence ,
the probability distribution for tunneling events strongly deviates from a poissonian and displays a pronounced even
odd asymmetry in the number of transmitted charges .
the interplay between charging and coherence is reflected also in the zero - frequency current noise which is significantly quenched when the quasi - particle tunneling rates are comparable to the coherent cooper - pair oscillation frequency . furthermore the finite frequency spectrum shows a strong enhancement near the resonant transition frequency for josephson tunneling . .
And you have already written the first three sentences of the full article: shot noise in a mesoscopic conductor is a consequence of the stochastic character of electron tunneling and of the discreteness of charge . unlike thermal noise , shot noise describes the non - equilibrium fluctuations of current
; therefore , the study of current fluctuations can provide further understanding of properties related to correlation mechanisms , internal energy scales or the carrier statistics which can not be obtained by measuring the average current @xcite .
a well studied example of physical processes where electron correlations play a dominant role is the phenomenon of coulomb blockade . in a system of small tunneling junctions , due to the large electrostatic energy ( as compared to temperature or voltages ) ,.
Please generate the next two sentences of the article | the electronic charge is transported one by one .
this effect leads to many remarkable features in transport properties and has been a subject of extensive study for the last decades @xcite . as an example |
6,871 | Suppose that you have an abstract for a scientific paper: a tree @xmath0 , in an edge - colored graph @xmath1 , is called _ a rainbow tree _ if no two edges of @xmath0 are assigned the same color .
a _
@xmath2-rainbow coloring _ of @xmath1 is an edge coloring of @xmath1 having the property that for every set @xmath3 of @xmath2 vertices of @xmath1 , there exists a rainbow tree @xmath0 in @xmath1 such that @xmath4 .
the minimum number of colors needed in a @xmath2-rainbow coloring of @xmath1 is the _
@xmath2-rainbow index of @xmath1 _ , denoted by @xmath5 . in this paper , we consider @xmath6-rainbow index @xmath7 of @xmath1 . we first show that for connected graph @xmath1 with minimum degree @xmath8 , the tight upper bound of @xmath7 is @xmath9)+4 $ ] , where @xmath10 is the connected @xmath11-dominating set of @xmath1 .
and then we determine a tight upper bound for @xmath12 and a better bound for @xmath13-free graphs .
finally , we obtain a sharp bound for @xmath6-rainbow index of general graphs .
* keywords * : @xmath6-rainbow index ; rainbow tree ; connected @xmath11-dominating set . .
And you have already written the first three sentences of the full article: all graphs considered in this paper are simple , connected and undirected .
we follow the terminology and notation of bondy and murty @xcite .
an edge - colored graph @xmath1 is _ rainbow connected _ if any two vertices are connected by a path whose edges have distinct colors ..
Please generate the next two sentences of the article | the _ rainbow connection number _ @xmath14 of @xmath1 , introduced by chartrand et al .
@xcite , is the minimum number of colors that results in a rainbow connected graph @xmath1 . |
6,872 | Suppose that you have an abstract for a scientific paper: we present a detailed analysis of @xmath0 quiescent , luminous red galaxies ( lrgs ) selected from sloan digital sky survey ( sdss ) data release seven ( dr7 ) spanning a redshift range of @xmath1 .
these galaxies are co - added into four equal bins of velocity dispersion and luminosity to produce high signal to noise spectra ( @xmath2 ) , thus facilitating accurate measurements of the standard lick absorption
line indices . in particular , we have carefully corrected and calibrated these indices onto the commonly used lick / ids system , thus allowing us to compare these data with other measurements in the literature , and derive realistic ages , metallicities ( @xmath3 $ ] ) and @xmath4-element abundance ratios ( @xmath5 $ ] ) for these galaxies using simple stellar population ( ssp ) models .
we use these data to study the relationship of these galaxy parameters with redshift , and find little evidence for evolution in metallicity or @xmath4elements ( especially for our intermediate mass samples ) .
this demonstrates that our subsamples are consistent with pure passive evolving ( i.e. no chemical evolution ) and represent a homogeneous population over this redshift range .
we also present the age
redshift relation for these lrgs and clearly see a decrease in their age with redshift ( @xmath6gyrs over the redshift range studied here ) which is fully consistent with the cosmological lookback times in a concordance @xmath7cdm universe .
we also see that our most massive sample of lrgs is the youngest compared to the lower mass galaxies .
we provide these data now to help future cosmological and galaxy evolution studies of lrgs , and provide in the appendices of this paper the required methodology and information to calibrate sdss spectra onto the lick / ids system .
[ firstpage ] methods : observational galaxies : elliptical galaxies : abundances galaxies : evolution galaxies : fundamental parameters .
And you have already written the first three sentences of the full article: the formation and evolution of massive elliptical ( passive ) galaxies in the universe is interesting for both studies of galaxy evolution and cosmology . in the former case ,
such galaxies present an observational challenge for hierarchical models of structure formation , as some form of feedback is required to suppress on - going star formation in such massive systems ( see @xcite and references therein ) .
for cosmology , such massive ellipticals can be used to directly constrain cosmological parameters ( e.g. , as standard candles ; @xcite ) and provide efficient tracers of the large scale structure ( lss ) in the universe @xcite . moreover ,.
Please generate the next two sentences of the article | the ( relative ) ages of massive ellipticals , as a function of redshift , offers the possibility of directly constraining the hubble parameter , thus providing vital information on the expansion history of the universe and therefore , the equation of state of dark energy ( see @xcite for a discussion of the underlying concept , and @xcite ; @xcite and @xcite for observational constraints obtained from using this technique ) . in this paper , we revisit the techniques used to constrain cosmological parameters through the age redshift relationship of passive ( elliptical ) , massive galaxies . in detail
, we present a new analysis of the ages of luminous red galaxies ( lrgs ; @xcite ) , as selected from the sloan digital sky survey ( sdss ; @xcite ) . |
6,873 | Suppose that you have an abstract for a scientific paper: the availability of the double - differential charged - current neutrino cross section , measured by the miniboone collaboration using a carbon target , allows for a systematic comparison of nuclear effects in quasi - elastic electron and neutrino scattering .
the results of theoretical studies based on the impulse approximation scheme and state - of - the - art models of the nuclear spectral functions suggest that the electron cross section and the flux averaged neutrino cross sections corresponding to the same target and seemingly comparable kinematical conditions can not be described within the same theoretical scheme using the value of the nucleon axial mass obtained from deuterium measurements .
i analyze the assumptions underlying the treatment of electron scattering data , and argue that the development of a new _ paradigm _ , suitable for application to processes in which the lepton kinematics is not fully determined , will be required .
lepton - nucleus interaction , charged current neutrino interactions , nucleon axial form factor .
And you have already written the first three sentences of the full article: the data set of charged current quasi elastic ( ccqe ) events recently released by the miniboone collaboration @xcite provides an unprecedented opportunity to carry out a systematic study of the double differential cross section of the process , _ + ^12 - 5mu c ^- + x , averaged over the neutrino flux . the charged current elastic neutrino - nucleon process is described in terms of three form factors .
the proton @xmath0 and neutron @xmath1 vector form factors , @xmath2 and @xmath3 ( @xmath4 , @xmath5 being the four - momentum transfer ) , have been precisely measured up to large values of @xmath6 in electron - proton and electron - deuteron scattering experiments , respectively ( for a recent review , see , e.g. , ref.@xcite ) .
the @xmath6-dependence of the nucleon axial form factor @xmath7 , whose value at @xmath8 can be extracted from neutron @xmath9-decay measurements , is generally assumed to be of dipole form and parametrized in terms of the so called axial mass @xmath10 : f_a(q^2 ) = g_a ( 1 + q^2/m_a^2 ) ^-2 ..
Please generate the next two sentences of the article | the world average of the measured values of the axial mass , mainly obtained from low statistics experiments carried out using deuterium targets , turns out to be @xmath11 gev @xcite , while the analyses performed by the k2k @xcite and miniboone @xcite collaborations using oxygen and carbon targets , respectively , yield @xmath12 .
it would be tempting to interpret the large value of @xmath10 reported by miniboonne and k2k as an _ effective _ axial mass , modified by nuclear effects not included in the oversimplified fermi gas model employed in data analysis . |
6,874 | Suppose that you have an abstract for a scientific paper: we consider new series expansions for variants of the so - termed ordinary geometric square series generating functions originally defined in the recent article titled `` _ _ square series generating function transformations _ _ '' ( arxiv : 1609.02803 ) . whereas the original square series transformations article adapts known generating function transformations to construct integral representations for these square series functions enumerating the square powers of @xmath0 for some fixed non - zero @xmath1 with @xmath2 , we study the expansions of these special series through power series generated by jacobi - type continued fractions , or j - fractions
. we prove new exact expansions of the @xmath3 convergents to these continued fraction series and show that the limiting case of these convergent generating functions exists as @xmath4 .
we also prove new infinite @xmath1-series representations of special square series expansions involving square - power terms of the series parameter @xmath1 , the @xmath1-pochhammer symbol , and double sums over the @xmath1-binomial coefficients .
applications of the new results we prove within the article include new @xmath1-series representations for the ordinary generating functions of the special sequences , @xmath5 , and @xmath6 , as well as parallels to the examples of the new integral representations for theta functions , series expansions of infinite products and partition function generating functions , and related unilateral special function series cited in the first square series transformations article . : _ square series ; @xmath1-series ; j - fraction ; continued fraction ; sum of squares functions ; sum of divisors function ; theta function ; ordinary generating function . _ : _ 05a15 ; 11y65 ; 11b65 ; 40a15 . _ .
And you have already written the first three sentences of the full article: _ jacobi - type continued fractions _ , or _
j - fractions _ , correspond to power series defined by infinite continued fraction expansions of the form @xmath7 for some sequences @xmath8 and @xmath9 , and some ( typically formal ) series variable @xmath10 @xcite @xcite .
the formal series enumerated by special cases of the truncated and infinite j - fraction series of this form include _ ordinary _ ( as opposed to typically closed - form _ exponential _ ) _ generating functions _ for many one and two - index combinatorial sequences including the generalized factorial functions studied in the references and in the results from flajolet s articles ..
Please generate the next two sentences of the article | the references provide infinite formal continued fraction series for the typically divergent ordinary generating functions of many special sequences , factorial functions , and combinatorial triangles arising in applications @xcite . [ [ j - fraction - expansions - of - ordinary - square - series - generating - functions ] ] j - fraction expansions of ordinary square series generating functions ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ in this article , we consider a @xmath1-series - related variant of the j - fractions in enumerating the square - power terms of @xmath0 , which we have discovered computationally ( see @xcite for integral representations ) .
in particular , for non - zero @xmath11 such that @xmath12 , we define the following jacobi - type j - fraction , @xmath13}(q , z)$ ] , for the ordinary square series generating function defined in @xcite as follows : @xmath14}(q , z ) & = \cfrac{1}{1-qz-\cfrac{q^2(q^2 - 1 ) z^2}{1-q(q^4+q^2 - 1)z- \cfrac{q^8 ( q^4 - 1 ) z^2}{1-q^3(q^6+q^4 - 1)z-\cfrac{q^{14}(q^6 - 1 ) z^2}{\cdots . } } } } \end{aligned}\ ] ] [ def_ciq_abiq_phqz_qhqz ] we define the component sequence functions , @xmath15}(q)$ ] and @xmath16}(q)$ ] , as follows for @xmath17 : @xmath18}(q ) & : = \begin{cases } q^{2h-3 } \cdot \left(q^{2h } + q^{2h-2 } - 1\right ) & \text { if $ h \geq 2 $ ; } \\ q & \text { if $ h = 1 $ ; } \\ 1 & \text { if $ h = 0 $ , } \end{cases } \\ \label{eqn_abhq_subseq_def } \operatorname{ab}_h^{[\sq]}(q ) & : = \begin{cases } q^{6h-10 } \cdot \left(q^{2h-2 } - 1\right ) & \text { if $ h \geq 2 $ ; } \\ 0 & \text { otherwise . } \end{cases } \end{aligned}\ ] ] we then define the @xmath3 convergent functions , @xmath19 , recursively through the component numerator and denominator functions given by , as @xmath20 . |
6,875 | Suppose that you have an abstract for a scientific paper: we study the production of charmonia and charmed hadrons in nucleus - nucleus collisions at sps , rhic , and lhc energies within the framework of the statistical hadronization model .
results from this model are compared to the measured yields and centrality dependence of @xmath0 production at sps and rhic energies .
we explore and contrast the centrality dependence of the production of mesons with open and hidden charm at sps , rhic and lhc .
the sensitivity of the results to various input parameters is analyzed in detail for rhic energy .
, , , statistical hadronization , open and hidden charm hadrons , @xmath0 suppression or enhancement 25.75.-q , 25.75.nq , 25.75.dw .
And you have already written the first three sentences of the full article: the concept of a possible thermal origin of charmonia was initially introduced @xcite to explain the measurement of the j/@xmath1/hadron ratio in nuclear collisions .
because of their large mass and small production cross section at thermal energies charm quarks are , however , not likely to be thermally produced .
on the other hand , significant production of charm quark pairs takes place in initial hard collisions ..
Please generate the next two sentences of the article | this led to the idea of statistical hadronization of charm quarks @xcite , which has sparked an intense activity in this field @xcite . at about the same time
an independent effort @xcite based on a kinetic model has been developed to study charm production in heavy ion collisions at collider energies . |
6,876 | Suppose that you have an abstract for a scientific paper: in social networks of human individuals , social relationships do not necessarily last forever as they can either fade gradually with time , resulting in `` link aging '' , or terminate abruptly , causing `` link deletion '' , as even old friendships may cease . in this paper
, we study a social network formation model where we introduce several ways by which a link termination takes place .
if we adopt the link aging , we get a more modular structure with more homogeneously distributed link weights within communities than when link deletion is used . by investigating distributions and relations of various network characteristics , we find that the empirical findings are better reproduced with the link deletion model .
this indicates that link deletion plays a more prominent role in organizing social networks than link aging . .
And you have already written the first three sentences of the full article: interdisciplinary efforts in network science have considerably deepened our understanding about the structure and dynamics of the society @xcite .
this active development of the field is largely attributed to the huge amount of digital information that has become available due to rapid development of the information and communication technology ( ict ) .
many empirical studies have been conducted on social networks including those based on email @xcite , mobile phone call ( mpc ) @xcite , short - message communication , social networking services ( sns ) @xcite , and scientific collaborations @xcite . among these.
Please generate the next two sentences of the article | , mpc data sets play a special role because mobile phones are frequently used in our daily life and the coverage of the service is almost 100% for adults in large part of the world . as a matter of fact , an analysis of the mpc data set @xcite has been successful in validating the `` strength of weak ties '' hypothesis proposed by granovetter @xcite , stating that if the tie between two persons is strong , then the overlap between their neighbors will be large .
this has far - reaching consequences for the overall structure of the social network : it suggests that the network consists of strongly wired communities connected by weak ties . |
6,877 | Suppose that you have an abstract for a scientific paper: we discuss the spiral spin density wave model and its application to explain properties of underdoped la@xmath0sr@xmath1cuo@xmath2 .
we argue that the spiral picture is theoretically well justified in the context of the extended @xmath3 model , and then show that it can explain a number of observed features , such as the location and symmetry of the incommensurate peaks in elastic neutron scattering , as well as the in - plane resistivity anisotropy .
a consistent description of the low doping region ( below 10% or so ) emerges from the spiral formulation , in which the holes show no tendency towards any type of charge order and the physics is purely spin driven .
address= institute of theoretical physics , swiss federal institute of technology ( epfl ) , + ch-1015 lausanne , switzerland address = school of physics , university of new south wales , sydney 2052 , australia .
And you have already written the first three sentences of the full article: a popular scenario to explain the complex physics of the high - temperature superconductors is based on the idea that the ground state of these materials exhibits some form of charge ordering tendency ( charge stripes , checkerboard order , etc . )
@xcite , which , in turn , can lead to incommensurate magnetism ( spin stripes ) . from the outset we state that we do not subscribe to this point of view . in order to illustrate the direction of our efforts
, we will take as an example the la cuprate family , of which the most studied representative is la@xmath0sr@xmath1cuo@xmath2 ( lsco ) ( @xmath4 is the hole doping ) ..
Please generate the next two sentences of the article | this compound is commonly believed to show `` dynamic '' charge order near the special doping value @xmath5 , while static order ( although quite weak ) has been observed with additional nd co - doping , or upon the substitution la@xmath6ba . however
the rest of the lsco phase diagram at low doping @xmath7 does not exhibit any charge order @xcite making it rather hard to accept the universal concept that holes in antiferromagnets fundamentally tend to segregate into charge stripes or similar structures . |
6,878 | Suppose that you have an abstract for a scientific paper: an interplay of an exotic quantum holonomy and exceptional points is examined in one - dimensional bose systems .
the eigenenergy anholonomy , in which hermitian adiabatic cycle induces nontrivial change in eigenenergies , can be interpreted as a manifestation of eigenenergy s riemann surface structure , where the branch points are identified as the exceptional points which are degeneracy points in the complexified parameter space .
it is also shown that the exceptional points are the divergent points of the non - abelian gauge connection for the gauge theoretical formulation of the eigenspace anholonomy .
this helps us to evaluate anti - path - ordered exponentials of the gauge connection to obtain gauge covariant quantities . .
And you have already written the first three sentences of the full article: a variation of a classical external parameter of a quantum system offers a way to manipulate quantum states . almost since the dawn of the quantum theory , it has been recognized that the slow variation of the parameter ensures the adiabatic time evolution , where the quantum state can be pinned to an eigenspace of system s hamiltonian @xcite .
later , the concept of quantum holonomy has been developed for adiabatic cycles on quantum systems . among them , the phase holonomy , where an adiabatic cycle induces a nontrivial change in the phase of a quantum state @xcite , is a textbook result nowadays @xcite .
recently , the quantum holonomy of exotic kind has been recognized in that an adiabatic cycle can induce changes both in the eigenvalue and the eigenspace of a stationary state @xcite ..
Please generate the next two sentences of the article | such changes are also referred to as eigenenergy and eigenspace anholonomies @xcite .
spectral degeneracies are crucial for the quantum holonomy . the phase holonomy is associated with a spectral degeneracy point , where a structure mathematically identical to the magnetic monopole resides , in the parameter space @xcite . as for the exotic quantum holonomy |
6,879 | Suppose that you have an abstract for a scientific paper: we report _ ab initio _ calculations of the melting curve and hugoniot of molybdenum for the pressure range @xmath0 gpa , using density functional theory ( dft ) in the projector augmented wave ( paw ) implementation .
we use the `` reference coexistence '' technique to overcome uncertainties inherent in earlier dft calculations of the melting curve of mo .
our calculated melting curve agrees well with experiment at ambient pressure and is consistent with shock data at high pressure , but does not agree with the high pressure melting curve from static compression experiments .
our calculated @xmath1 and @xmath2 hugoniot relations agree well with shock measurements .
we use calculations of phonon dispersion relations as a function of pressure to eliminate some possible interpretations of the solid - solid phase transition observed in shock experiments on mo . .
And you have already written the first three sentences of the full article: the melting curves of transition metals at pressures up to the megabar region are highly controversial , particularly for b.c.c
diamond anvil cell ( dac ) measurements find that the melting temperature @xmath3 increases by only a few hundred k over the range 1 - 100 gpa @xcite , while shock experiments indicate an increase of several thousand k over this range @xcite .
there have been several _ ab initio _.
Please generate the next two sentences of the article | calculations on transition - metal @xmath3(p ) curves , and the predictions agree more closely with the shock data than with the dac data @xcite .
a challenging case is molybdenum , where there are very large differences between dac and shock data @xcite , and where the shock data reveal _ two _ transitions , the one at high pressure ( @xmath4 380 gpa ) being attributed to melting , and the one at low pressure ( @xmath4 210 gpa ) to a transition from b.c.c . to an unidentified structure @xcite . |
6,880 | Suppose that you have an abstract for a scientific paper: we discuss the renormalization of the @xmath0 vector meson propagator within resonance chiral theory at one loop . using the particular form of the interaction lagrangian
we show that additional poles of the renormalized propagator corresponding to @xmath1 degrees of freedom can be generated .
we give a concrete example of such an effect . .
And you have already written the first three sentences of the full article: non - perturbative investigation of the qcd dynamics in the low energy region by means of the effective lagrangian approach has made considerable progress recently . in the very low energy region ( @xmath2 ) the chiral perturbation theory ( @xmath3pt ) @xcite based on the spontaneously broken chiral symmetry @xmath4 grew into a very successful model - independent tool for description of the green functions ( gf ) of quark currents and related low - energy phenomenology .
@xmath3pt is organized as a rigorously defined simultaneous perturbative expansion in small momenta and light quark masses .
recent calculations are performed at the next - to - next - to - leading order @xmath5 @xcite . in the intermediate energy region ( @xmath6 ) , however , the situation is less satisfactory ..
Please generate the next two sentences of the article | the set of relevant degrees of freedom includes now the low lying resonances and because there is no mass gap existing in the spectrum , the effective theory in this region can not be constructed as a straightforward extension of the @xmath3pt low energy expansion . on the other hand , the considerations based on the large @xmath7 expansions together with high - energy constraints derived from perturbative qcd and operator product expansion ( ope ) allow to introduce another type of effective lagrangian description , corresponding to the leading order in @xmath8 and reflecting the basic features of qcd in the @xmath9 limit .
namely , the spectrum consisting of an infinite tower of free stable mesonic resonances exchanged in each channel requires infinite number of resonance fields in the @xmath10 symmetric lagrangian with interaction vertices suppressed by an appropriate power of @xmath11and ( since the @xmath12 expansion is correlated with semiclassical expansion ) only tree graphs have to be taken into account in the leading order . an approximation to this general picture consisting in limiting the number of resonance field to one in each channel and matching the resulting theory in the high energy region with ope is known as resonance chiral theory ( r@xmath3 t ) @xcite . |
6,881 | Suppose that you have an abstract for a scientific paper: outer radius variations play an important role disc structure and evolution .
we consider theoretical and observational consequences of such variations in cataclysmic binaries and low - mass x - ray binaries .
we find that the action of tidal torques must be important well inside the tidal radius .
we also conclude that it is doubtful that the tidal - thermal instability is responsible for the superoutburst / superhump phenomena . , accretion , accretion discs , binaries : close , cataclysmic variables , x - ray binaries 97.10.gz , 97.30.qt , 97.80.gm , 97.80.jp .
And you have already written the first three sentences of the full article: dwarf novae are a subclass of cataclysmic variables undergoing outbursts lasting ( at least ) a few days during which their brightness increases by several magnitudes ( see e.g. * ? ? ?
* for a review ) .
these outbursts are widely believed to be due to a thermal / viscous disc instability ( see * ? ? ? * for a review ) ..
Please generate the next two sentences of the article | the weakest point of this model aside from the assumption that angular momentum transport is due to viscosity ( i.e. is a local phenomenon accompanied by energy dissipation ) described by the @xmath0-prescription , is the approximate treatment of 2d effects at the disc edge .
there is in particular a debate about the outcome of the disc reaching the radius at which the 3:1 resonance occurs ( this may happen for low secondary to primary mass - ratios ) . |
6,882 | Suppose that you have an abstract for a scientific paper: a standard form of analysis for linguistic typology is the universal implication .
these implications state facts about the range of extant languages , such as `` if objects come after verbs , then adjectives come after nouns . ''
such implications are typically discovered by painstaking hand analysis over a small sample of languages .
we propose a computational model for assisting at this process .
our model is able to discover both well - known implications as well as some novel implications that deserve further study .
moreover , through a careful application of hierarchical analysis , we are able to cope with the well - known sampling problem : languages are not independent . .
And you have already written the first three sentences of the full article: linguistic typology aims to distinguish between logically possible languages and actually observed languages .
a fundamental building block for such an understanding is the _ universal implication _
these are short statements that restrict the space of languages in a concrete way ( for instance `` object - verb ordering implies adjective - noun ordering '' ) ; , and provide excellent introductions to linguistic typology ..
Please generate the next two sentences of the article | we present a statistical model for automatically discovering such implications from a large typological database @xcite .
analyses of universal implications are typically performed by linguists , inspecting an array of @xmath0-@xmath1 languages and a few pairs of features . |
6,883 | Suppose that you have an abstract for a scientific paper: measurement induced non - locality was introduced by luo and fu as a measure of non - locality in a bipartite state . in this paper
we will discuss monogamy property of measurement induced non - locality for some three and four qubit classes of states .
unlike discord , we find quite surprising result in this situation .
both the generalized ghz and w states satisfy monogamy relations in the three qubit case , however , in general there are violations of monogamy relations in both the ghz - class and w - class states . in case of four qubit system , monogamy holds for most of the states in the generic class .
four qubit ghz does not satisfy monogamy relation , but w - state does .
we will also extend our results of generalized w - class to n - qubit . .
And you have already written the first three sentences of the full article: non - locality is in the heart of quantum world . from bell
s theorem@xcite , it is understood that no local hidden variable theory could replace quantum theory as a theory of physical world .
the existence of entangled states in composite quantum systems assures the non - local behavior of quantum theory ..
Please generate the next two sentences of the article | generally , violation of bell s inequality is taken as the signature of non - locality .
entangled states play an important role to show the violation of bell s inequality . |
6,884 | Suppose that you have an abstract for a scientific paper: the hydrodynamic description of probabilistic ballistic annihilation , for which no conservation laws hold , is an intricate problem with hard sphere - like dynamics for which no exact solution exists .
we consequently focus on simplified approaches , the maxwell and very hard particles ( vhp ) models , which allows us to compute analytically upper and lower bounds for several quantities .
the purpose is to test the possibility of describing such a far from equilibrium dynamics with simplified kinetic models .
the motivation is also in turn to assess the relevance of some singular features appearing within the original model and the approximations invoked to study it .
the scaling exponents are first obtained from the ( simplified ) boltzmann equation , and are confronted against monte carlo simulation ( dsmc technique ) .
then , the chapman - enskog method is used to obtain constitutive relations and transport coefficients .
the corresponding navier - stokes equations for the hydrodynamic fields are derived for both maxwell and vhp models .
we finally perform a linear stability analysis around the homogeneous solution , which illustrates the importance of dissipation in the possible development of spatial inhomogeneities . .
And you have already written the first three sentences of the full article: the possibility to describe in terms of hydrodynamic equations the evolution of a system where some physical quantities are not conserved is a challenging problem of non - equilibrium statistical mechanics .
several questions have to be faced as for example the validity of the underlying ( and in practice approximate ) kinetic theory , the choice of the hydrodynamical fields that are supposed to describe the relevant excitations in the problem , or the consistency of the method itself that is used to deduce the coarse - grained description from the kinetic theory .
much attention has been recently paid to such questions , mainly in the field of granular gas dynamics ( see e.g @xcite ) . in such systems ,.
Please generate the next two sentences of the article | the kinetic energy is not conserved , while the linear momentum and number of particles are . however , even for low dissipation , the derivation of the hydrodynamic relations , based on a hard - sphere - like boltzmann equation is not a simple task and several approximations have to be invoked @xcite .
these difficulties lead to consider some simpler models by choosing ad - hoc collision term in the boltzmann equation . |
6,885 | Suppose that you have an abstract for a scientific paper: we perform numerical simulations of the su(2 ) boltzmann - vlasov equation including both hard elastic particle collisions and soft interactions mediated by classical yang - mills fields . using this technique
we calculate the momentum - space broadening of high - energy jets in real - time for both locally isotropic and anisotropic plasmas . in both cases
we introduce a separation scale which separates hard and soft interactions and demonstrate that our results for jet broadening are independent of the precise separation scale chosen . for an isotropic plasma
this allows us to calculate the jet transport coefficient @xmath0 including hard and soft non - equilibrium dynamics . for an anisotropic plasma
the jet transport coefficient becomes a tensor with @xmath1 .
we find that for weakly - coupled anisotropic plasmas the fields develop unstable modes , forming configurations where @xmath2 and @xmath3 which lead to @xmath4 .
we study whether the effect is strong enough to explain the experimental observation that high - energy jets traversing the plasma perpendicular to the beam axis experience much stronger broadening in rapidity , @xmath5 , than in azimuth , @xmath6 . .
And you have already written the first three sentences of the full article: high transverse momentum jets produced in heavy - ion collisions represent a valuable tool for studies of the properties of the hot parton plasma produced in the central rapidity region @xcite .
this is due to the fact that jets couple to the plasma causing the jet to broaden in momentum space and to lose energy .
the magnitude of momentum - space broadening and energy loss experienced by a parton depends on whether or not one assumes the matter to be hadronic or partonic in nature ..
Please generate the next two sentences of the article | hence , it is one of the primary observables to ascertain experimentally whether or not the plasma has been produced . at very high energies
it is expected that hard bremsstrahlung processes dominate the light quark or gluon energy loss @xcite ; however , at intermediate energies the inclusion of both collisional and radiative processes is necessary in order to make phenomenological predictions . |
6,886 | Suppose that you have an abstract for a scientific paper: it is shown that for the n - neighbor and k - state cellular automata , the class ii , class iii and class iv patterns coexist at least in the range @xmath0 . the mechanism which determines the difference between the pattern classes at a fixed @xmath1
is found , and it is studied quantitatively by introducing a new parameter @xmath2 . using the parameter f and @xmath1 , the phase diagram of cellular automata is obtained for 5-neighbor and 4-state cellular automata .
+ pacs : 89.75.-k complex systems .
And you have already written the first three sentences of the full article: cellular automata ( ca ) has been one of the most studied fields in the research of complex systems .
various patterns has been generated by choosing the rule tables .
wolfram@xcite has classified these patterns into four rough categories : class i ( homogeneous ) , class ii ( periodic ) , class iii ( chaos ) and class iv ( edge of chaos ) ..
Please generate the next two sentences of the article | the class iv patterns have been the most interesting target for the study of ca , because it provides us with an example of the self - organization in a simple system and it is argued that the possibility of computation is realized by the complexity at the edge of chaos@xcite . + a more detailed classification of ca , has been carried out mainly for the elementary cellular automata ( 3-neighbor and 2-state ca)@xcite , in which the pattern is studied quite accurately for each rule table .
however the number of rule table in n - neighbor and k - state cellular automata grows like @xmath3 . |
6,887 | Suppose that you have an abstract for a scientific paper: the squeezing spectrum of the resonance fluorescence is studied for a coherently driven four - level atom in the y - type configuration .
it is found that the squeezing properties of the fluorescence radiation are modified significantly when quantum interference of the spontaneous decays channels is included .
we show a considerable enhancement of steady - state squeezing in spectral components for strong and off - resonant driving fields . the squeezing may be increased in both the inner and outer sidebands of the spectrum depending upon the choice of parameters .
we also show that the interference can degrade the spectral squeezing by increasing the decay rates of atomic transitions . an analytical description using dressed states
is provided to explain the numerical results
. + + keywords : resonance fluorescence ; squeezing ; quantum interference .
And you have already written the first three sentences of the full article: squeezing of the radiation field is one of the distinct features of the quantum theory of light @xcite . squeezed states of light , being nonclassical in origin @xcite , have a reduced variance in one of the quadrature components of the electric field .
it is well known that the resonance fluorescence from a driven atomic system can serve as a source of squeezed radiation .
theoretical investigations on two - level and three - level atoms demonstrated squeezing either in the total variance of phase quadratures or in the frequency ( spectral ) components of the fluorescence radiation @xcite . for a driven two - level atom , walls and zller first predicted that squeezing can occur in the in - phase / out - of - phase quadrature component of the fluorescent light [ 4a ] ..
Please generate the next two sentences of the article | the noise spectrum was shown to exhibit single- and two - mode squeezing in the weak- and strong - excitation regimes @xcite .
some experimental evidences of squeezing have also been reported in the phase - dependent spectra of two - level atoms @xcite . |
6,888 | Suppose that you have an abstract for a scientific paper: the structure of the moduli space of @xmath0 supersymmetric gauge theories is analyzed from an algebraic geometric viewpoint .
the connection between the fundamental fields of the ultraviolet theory , and the gauge invariant composite fields of the infrared theory is explained in detail .
the results are then used to prove an anomaly matching theorem .
the theorem is used to study anomaly matching for supersymmetric qcd , and can explain all the known anomaly matching results for this case .
c # 1lie ( # 1 ) # 1 ^-1 ( ( # 1 ) ) # 1#2- # 2pt .
And you have already written the first three sentences of the full article: one important constraint on the moduli space of vacua of supersymmetric gauge theories @xcite is that the massless fermions in the low energy theory should have the same flavor anomalies as the fundamental fields , i.e.the t hooft consistency conditions should be satisfied @xcite . these conditions are considered a particularly stringent test on the spectrum of massless fermions , which is usually obtained from symmetry arguments and renormalization group flows .
it is found that for some theories the classical moduli space @xmath1 or a suitable quantum modified version @xmath2 of it satisfies t hooft consistency conditions at every point .
other theories fail t hooft s test at some vacua , and it is believed that in the infrared , these theories correspond to the weak coupling sector of a dual theory with a different gauge group and matter content @xcite . in this paper , sufficient conditions on the fundamental chiral field content @xmath3 for a theory to satisfy the t hooft conditions is established ..
Please generate the next two sentences of the article | this is usually done by first finding a basic set of gauge invariants @xmath4 and the constraints among them , then checking point by point the matching of flavor anomalies between the fundamental fields and the composites at each point on the moduli space .
this procedure involves tedious calculations , and does not offer a systematic approach to the problem of determining whether @xmath1 ( or a suitable quantum modified version of it ) gives the right description of the infrared sector or not . |
6,889 | Suppose that you have an abstract for a scientific paper: we consider a thought experiment where the preparation of a macroscopically massive or charged particle in a quantum superposition and the associated dynamics of a distant test particle apparently allow for superluminal communication .
we give a solution to the paradox which is based on the following fundamental principle : any local experiment , discriminating a coherent superposition from an incoherent statistical mixture , necessarily requires a minimum time proportional to the mass ( or charge ) of the system . for a charged particle , we consider two examples of such experiments , and show that they are both consistent with the previous limitation . in the first
, the measurement requires to accelerate the charge , that can entangle with the emitted photons . in the second
, the limitation can be ascribed to the quantum vacuum fluctuations of the electromagnetic field . on the other hand , when applied to massive particles our result provides an indirect evidence for the existence of gravitational vacuum fluctuations and for the possibility of entangling a particle with quantum gravitational radiation . .
And you have already written the first three sentences of the full article: the existence of coherent superpositions is a fundamental postulate of quantum mechanics but , apparently , implies very counterintuitive consequences when extended to macroscopic systems .
this problem , already pointed out since the beginning of quantum theory through the famous schrdinger cat paradox @xcite , has been the subject of a large scientific debate which is still open and very active .
nowadays there is no doubt about the existence of quantum superpositions ..
Please generate the next two sentences of the article | indeed this effect has been demonstrated in a number of experiments involving microscopic systems ( photons @xcite , electrons @xcite , neutrons @xcite , atoms @xcite , molecules @xcite , _ etc . _ ) .
however , at least in principle , the standard theory of quantum mechanics is valid at any scale and does not put any limit on the size of the system : if you can delocalize a molecule then nothing should forbid you to delocalize a cat , apart from technical difficulties . |
6,890 | Suppose that you have an abstract for a scientific paper: we study phase entrainment of kuramoto oscillators under different conditions on the interaction range and the natural frequencies . in the first part
the oscillators are entrained by a pacemaker acting like an impurity or a defect .
we analytically derive the entrainment frequency for arbitrary interaction range and the entrainment threshold for all - to - all couplings . for intermediate couplings
our numerical results show a reentrance of the synchronization transition as a function of the coupling range . the origin of this reentrance can be traced back to the normalization of the coupling strength . in the second part
we consider a system of oscillators with an initial gradient in their natural frequencies , extended over a one - dimensional chain or a two - dimensional lattice . here
it is the oscillator with the highest natural frequency that becomes the pacemaker of the ensemble , sending out circular waves in oscillator - phase space .
no asymmetric coupling between the oscillators is needed for this dynamical induction of the pacemaker property nor need it be distinguished by a gap in the natural frequency . .
And you have already written the first three sentences of the full article: synchronization in the sense of coordinated behavior in time is essential for any efficient organization of systems , natural as well as artificial ones . in artificial systems like factories the sequence of production processes
should be synchronized in a way that time - and space consuming storage of input or intermediate products is avoided .
the same applies to natural systems like networks of cells which obviously perform very efficiently in fulfilling a variety of functions and tasks . in a more special sense.
Please generate the next two sentences of the article | , the synchronized behavior refers to oscillators with almost identical individual units , in particular to phase oscillators with continuous interactions as described by the kuramoto model @xcite .
these sets of limit - cycle oscillators describe synchronization phenomena in a wide range of applications @xcite . |
6,891 | Suppose that you have an abstract for a scientific paper: we present new optical spectroscopic and archival spitzer irac photometric observations of a b - type star in the smc cluster ngc 346 , ngc 346:kwbbe 200 .
we detect numerous fe ii , [ o i ] , and [ fe ii ] lines , as well as strong p - cygni profile h i emission lines in its optical spectrum .
the star s near - ir color and optical to ir sed clearly indicate the presence of an infrared excess , consistent with the presence of gas and warm , t @xmath0800 k , circumstellar dust . based on a crude estimate of the star s luminosity and the observed spectroscopic line profile morphologies , we find that the star is likely to be a b - type supergiant .
we suggest that ngc 346:kwbbe 200 is a newly discovered b[e ] supergiant star , and represents the fifth such object to be identified in the smc . .
And you have already written the first three sentences of the full article: massive ob stars play an important role in astrophysics ; their winds and ejecta shape the morphology and ionization structure of their local environment , and provide a source of heavy elements which serve as the building blocks of planetary systems .
b[e ] stars comprise a heterogeneous group of massive stars which all exhibit similar observational properties , yet range in evolutionary age from the pre- to post - main sequence @xcite .
b[e ] supergiants ( b[e]sgs ) represent one sub - class of the b[e ] phenomenon and are notable in that at least some share similar photometric , spectroscopic , and rotational velocity properties as luminous blue variables ( lbvs ) @xcite , which suggests b[e]sgs might be precursors to lbvs ..
Please generate the next two sentences of the article | b - type stars which exhibit strong h i balmer emission , forbidden and low excitation emission lines , commonly fe ii , [ fe ii ] , and [ o i ] , and evidence of warm ( t@xmath0 1000 k ) dust are assigned the classification of b[e ] @xcite .
b[e]sgs are known to exhibit a hybrid spectrum characterized by broad uv resonance absorption lines and a wealth of narrow emission lines @xcite . |
6,892 | Suppose that you have an abstract for a scientific paper: the structural properties and the band structures of the charge
transfer insulating oxides sro , mgo and srtio@xmath0 are computed both within density functional theory in the local density approximation ( lda ) and in the hedin s gw scheme for self - energy corrections , by using a model dielectric function , which approximately includes local field and dynamical effects .
the deep valence states are shifted to higher binding energies by the gw method , in very good agreement with photoemission spectra . since in all these oxides
the direct gaps at high - symmetry points of the brillouin zone may be strongly sensitive to the actual value of the lattice parameter @xmath1 , already at the lda level , self - energy corrections are computed both at the theoretical and the experimental @xmath1 . for mgo and sro , the values of the transition energies between the valence and the conduction bands is improved by gw corrections , while for srtio@xmath0 they are overestimated .
the results are discussed in relation to the importance of local field effects and to the nature of the electronic states in these insulating oxides . .
And you have already written the first three sentences of the full article: aside from being the major constituent of the outer crust of the earth , oxides are of considerable interest for their wide applications in various technological fields such as electrochemistry , catalysis or microelectronics.@xcite .
they present very diverse electronic ground states which range from superconducting , metallic , semi conducting ( intrinsic , charge density or spin density like ) to insulating .
> from a theoretical point of view , a proper description of their electronic properties is still an active research subject . on the one hand ,.
Please generate the next two sentences of the article | several transition metal oxides require an inclusion of many - body effects beyond the available effective one - electron approaches , such as the density functional theory ( dft ) or the _ ab initio _ hartree - fock ( hf ) method . on the other hand , even for insulating charge transfer oxides , such as mgo and sro , whose electronic ground state is well accounted for in a one - electron picture , the calculation of quasiparticle ( qp ) energies within the dft or the hf method gives rather poor results .
indeed , one has to face the so - called energy band gap problem @xcite . indeed , when using the kohn - sham eigenvalues of the highest occupied and the lowest empty states , the resulting gap usually underestimates the experimental data . |
6,893 | Suppose that you have an abstract for a scientific paper: the strength of the non - adiabatic spin torque is currently under strong debate , as its value differs by orders of magnitude as well in theoretical predictions as in measurements . here
, a measurement scheme is presented that allows to determine the strength of the non - adiabatic spin torque accurately and directly .
analytical and numerical calculations show that the scheme allows to separate the displacement due to the oersted field and is robust against uncertainties of the exact current direction .
a spin - polarized current flowing through a ferromagnetic sample interacts with the magnetization and exerts a torque on the local magnetic moments . for conduction
electron spins that follow the local magnetization adiabatically it has been shown that the interaction via spin transfer can be described by adding a current - dependent term to the landau - lifshitz - gilbert equation.@xcite this equation has been extended by an additional term that takes the non - adiabatic influence of the itinerant spins into account.@xcite theoretically , several mechanisms have been proposed as the origin of the non - adiabatic spin torque , leading to different orders of magnitude for its strength.@xcite thus a precise measurement of the non - adiabatic spin torque is necessary to give insight into its microscopic origin .
a determination of its strength is further important for a reliable prediction of the current - driven domain - wall velocity.@xcite currently measured values of the non - adiabatic spin torque for permalloy differ by one order of magnitude,@xcite thus the strength of the non - adiabatic spin torque is under strong debate . in these experiments the observed motion of a domain wall
was compared with micromagnetic simulations to determine the non - adiabatic spin torque .
this analysis is highly susceptible to surface roughness and oersted fields . due to its high symmetry and spacial confinement
a vortex in a micro- or nanostructured magnetic thin - film element is a promising....
And you have already written the first three sentences of the full article: for an analytical investigation the motion of the vortex is commonly described employing the thiele equation.@xcite this equation is exact for the steady state motion of a non - deformable magnetization pattern . however
, this assumption holds true only for the small vortex core . due to the spacial restriction the vortex has to deform while the core is moving .
this yields a small modification of the thiele equation that is especially important for current - driven vortex motion in view of the non - adiabatic spin torque . with the magnetization @xmath59 and the magnetic field.
Please generate the next two sentences of the article | @xmath60 a general version of the thiele equation reads@xcite @xmath61 ( \vec h \cdot \vec m)\\ & - \frac{m_s \mu_0}{\gamma } \int dv \ ,
\sin(\theta ) ( \vec \nabla \theta \times \vec \nabla \phi ) \times ( \vec v + b_j \vec j)\\ & - \frac{m_s \mu_0}{\gamma } \int dv \ , ( \vec \nabla \theta \vec \nabla \theta + \sin^2(\theta ) \vec \nabla \phi \vec \nabla \phi ) ( \alpha \vec v + \xi b_j \vec j ) \end{split } \label{eq_thile_start}\ ] ] with the saturation magnetization @xmath62 , the gyromagnetic ratio @xmath30 , the current density @xmath63 , the gilbert damping @xmath9 , the non - adiabaticity parameter @xmath10 , and the coupling constant @xmath64 between current and magnetization . @xmath65 and @xmath66 are the out - of - plane and in - plane angle of the magnetization , respectively . |
6,894 | Suppose that you have an abstract for a scientific paper: the unprecedented quality of recent colour - magnitude diagrams of resolved stellar populations in nearby galaxies requires state - of - the - art techniques to infer the star formation histories which gave rise to the observed distributions .
we have developed a maximum likelihood technique , which coupled to a variational calculus allows us to make a robust , non - parametric reconstruction of the evolution of the star formation rate .
a full bayesian analysis is also applied to assess whether the best solutions found are also good fits to the data . applying this new method to wfpc2 observations of five dsph galaxies of the local group
, we find a wide variety of star formation histories , with no particular epoch being dominant . in the case of the solar neighbourhood observed by hipparcos
we infer , with an unprecedented resolution of 50 myr , its star formation history over the past 3 gyr .
the surprising regularity of star formation episodes separated by some 0.5 gyr could be interpreted as the result of interactions with two spiral arms or the galactic bar .
these bursts possibly trigger the formation of massive star clusters which slowly dissolve into the galactic field . .
And you have already written the first three sentences of the full article: the history of the star formation rate in galaxies is one of the main ingredients required to understand their formation and evolution . whilst the roberts time scale for gas consumption by star formation gives a rough idea of the evolution of the stellar and gas content , more elaborate models ( as summarised , e.g. by sandage , 1986 )
can reproduce a wide variety of observables , from the evolution of the bulge - to - disc ratio in the hubble sequence to the integrated colours as a function of redshift . however , in sharp contrast with these global views where the star formation rate sfr(t ) is a monotone function of time , current bottom - up hierarchical scenarios of structure formation predict far more complicated histories , where star formation episodes are related to , if not driven by , halo mergers .
the star formation history is , in this context , a more or less faithful reproduction of the merger history , rich in both strong and minor events at redshifts @xmath0 or so ..
Please generate the next two sentences of the article | while it is possible to understand some of the observed properties of high redshift galaxies in this framework , a far more direct test can be achieved with the fossil record of the star formation history itself : the colour - magnitude diagrams ( cmds ) of the resolved stellar populations in nearby galaxies .
progress in this field has been steady , driven both by ground - based wide - field surveys and by deep , high - resolution , narrow - field hst studies , reaching well below the main sequence turn off point in many satellites of the local group ( see aparicio 1998 , mateo 1998 for recent reviews ) . |
6,895 | Suppose that you have an abstract for a scientific paper: we study the finite temperature transition in qcd with three flavors of equal masses using the r and rhmc algorithm on lattices with temporal extent @xmath0 and @xmath1 . for the transition temperature in the continuum limit
we find @xmath2 for the light pseudo - scalar mass corresponding to the end point of the 1st order transition region . when comparing the results obtained with the r and rhmc algorithms for p4fat3 action we see no significant step - size errors down to a lightest pseudo - scalar mass of @xmath3 . .
And you have already written the first three sentences of the full article: lattice qcd has established the existence of a transition from hadron gas to a new state of strongly interacting matter where quarks and gluons are no longer confined inside hadrons and which is usually called the quark gluon plasma @xcite .
the nature of this transition depends on the quark content and quark masses . for infinite or very large quark masses
the transition is a 1st order deconfining transition . in the opposite case of zero quark masses.
Please generate the next two sentences of the article | one may have a 2nd order chiral phase transition for 2 flavors or a 1st order chiral phase transition for 3 flavors . for intermediate masses
the transition is just a rapid crossover , meaning that thermodynamic quantities change very rapidly in a narrow temperature interval . |
6,896 | Suppose that you have an abstract for a scientific paper: we study static bps black hole horizons in four dimensional @xmath0 gauged supergravity coupled to @xmath1-vector multiplets and with an arbitrary cubic prepotential .
we work in a symplectically covariant formalism which allows for both electric and magnetic gauging parameters as well as dyonic background charges and obtain the general solution to the bps equations for horizons of the form @xmath2 . in particular
this means we solve for the scalar fields as well as the metric of these black holes as a function of the gauging parameters and background charges . when the special khler manifold is a symmetric space , our solution is completely explicit and the entropy is related to the familiar quartic invariant . for more general models
our solution is implicit up to a set of holomorphic quadratic equations .
for particular models which have known embeddings in m - theory , we derive new horizon geometries with dyonic charges and numerically construct black hole solutions . these correspond to m2-branes wrapped on a riemann surface in a local calabi - yau five - fold with internal spin . nick halmagyi + 0.5 cm laboratoire de physique thorique et hautes energies , + universit pierre et marie curie , cnrs umr 7589 , + f-75252 paris cedex 05 , france + 0.5 cm [email protected] + _ dedicated to the loving memory of sue halmagyi _ .
And you have already written the first three sentences of the full article: four dimensional @xmath0 gauged supergravity coupled to @xmath1-vector multiplets admits regular , static , bps black holes which are asympotic to @xmath3 . for very particular choices of prepotential ,
gauging parameters and background charges , there exists a remarkable analytic solution @xcite due to cacciatori and klemm ( ck ) .
these solutions can have spherical , flat or hyperbolic horizon geometries - hypermultiplets and there is also a rich solution space @xcite but in the current work we will restrict our focus to vector - multiplets ..
Please generate the next two sentences of the article | there has been some futher study of these ck solutions as well as related non - bps @xmath3 black holes @xcite ] and can be interpreted in m - theory as m2-branes wrapped on riemann surfaces @xcite .
to understand the structure of these new black holes we find it quite useful to compare with the much better understood , asymptotically flat , single - center , bps black holes in @xmath0 ungauged supergravity @xcite . |
6,897 | Suppose that you have an abstract for a scientific paper: edge - on spiral galaxies offer a unique perspective on disks .
one can accurately determine the height distribution of stars and ism and the line - of - sight integration allows for the study of faint structures .
the spitzer irac camera is an ideal instrument to study both the ism and stellar structure in nearby galaxies ; two of its channels trace the old stellar disk with little extinction and the 8 micron channel is dominated by the smallest dust grains ( polycyclic aromatic hydrocarbons , pahs ) . @xcite probed the link between the appearance of dust lanes and the disk stability . in a sample of bulge - less disks
they show how in massive disks the ism collapses into the characteristic thin dust lane .
less massive disks are gravitationally stable and their dust morphology is fractured .
the transition occurs at 120 km / s for bulgeless disks . here
we report on our results of our spitzer / irac survey of nearby edge - on spirals and its first results on the nir tully - fischer relation , and ism disk stability . .
And you have already written the first three sentences of the full article: for 32 edge - on spiral galaxies , spanning hubble type and mass , we fit the edge - on infinite disk model by @xcite on the irac mocaics : @xmath0 .
we applied stellar dominated 3.6 and 4.5 @xmath1 m channels and the pah emission at 8.0 @xmath1 m , with the stellar contribution subtracted ( using the prescription from * ? ? ? * ) .
the data is from our dedicated go program ( go 20268 ) and the _ spitzer _ archive ..
Please generate the next two sentences of the article | our program aims to populate the lower range of disk masses . from the fit
we obtain the scale - length ( @xmath2 ) , the scale - height ( @xmath3 ) , and the face - on central surface brightness ( @xmath4 ) . |
6,898 | Suppose that you have an abstract for a scientific paper: the structure and dynamics of atomic oxygen adsorbed on ag(410 ) and ag(210 ) surfaces has been investigated using density functional theory .
our results show that the adsorption configuration in which o adatoms decorate the upper side of the ( 110 ) steps forming o ag o rows is particularly stable for both surfaces . on ag(210 ) , this arrangement is more stable than other configurations at all the investigated coverages . on ag(410 ) , adsorption on the terrace and at the step edge are almost degenerate , the former being slightly preferred at low coverage while the latter is stabilized by increasing the coverage .
these findings are substantiated by a comparison between the vibrational modes , calculated within density - functional perturbation theory , and the hreel spectrum which has been recently measured in these systems . .
And you have already written the first three sentences of the full article: the interaction of oxygen with silver surfaces has been intensively studied because of the key role of silver in many important industrial oxidation reactions such as , for example , partial oxidation of methanol to formaldehyde or ethylene epoxidation.@xcite these reactions occur very efficiently when ag powders are employed as a catalyst .
since the particles which compose these powders are affected by many surface defects of different nature and with different concentrations , their chemistry can be extremely different from that of perfect low - miller - index surfaces .
indeed the presence of various inequivalent adsorption sites suggests that atomic and molecular oxygen can adsorb forming species of different chemical nature ..
Please generate the next two sentences of the article | the microscopic characterization of such adsorbed species is a fundamental issue to understand the catalytic activity of ag powders .
a large amount of experimental and theoretical results clearly indicates that steps , kinks , and other surface imperfections play a crucial role in surface chemistry . |
6,899 | Suppose that you have an abstract for a scientific paper: given a @xmath0-graph @xmath1 , let @xmath2 denote the maximum value of the minimum co - degree of a @xmath0-graph on @xmath3 vertices which does not contain a copy of @xmath1 .
let @xmath4 denote the fano plane , which is the @xmath0-graph @xmath5 .
mubayi @xcite proved that @xmath6 and conjectured that @xmath7 for sufficiently large @xmath3 . using a very sophisticated quasi - randomness argument , keevash @xcite proved mubayi s conjecture .
here we give a simple proof of mubayi s conjecture by using a class of @xmath0-graphs that we call rings .
we also determine the turn density of the family of rings . .
And you have already written the first three sentences of the full article: for a family @xmath8 of @xmath9-graphs , let @xmath10 denote the maximum number of edges in an @xmath3-vertex @xmath9-graph which contains no member of @xmath8 . determining @xmath10 is a fundamental question in graph theory which becomes extremely difficult when @xmath11 .
let @xmath12 and call this value the _ turn density _ of @xmath8 ( as has been pointed out many times , it is easy to show that this limit exists ) . when @xmath8 consists of a single graph @xmath1 , we write @xmath13 for @xmath14 .
let @xmath15 denote the complete @xmath0-graph on four vertices ..
Please generate the next two sentences of the article | over 70 years ago , turn famously conjectured that @xmath16 , but this conjecture is still unproved @xcite .
in fact , when @xmath11 there are very few @xmath9-graphs for which the turn density is known ( see @xcite for a detailed account ) . despite this general difficulty , there is a special @xmath0-graph called the _ fano plane _ for which much is known . |
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