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1.
From the derivative of the statistical mechanical definition of the number density (the first Yvon equation), we derive an infinite set of sum rules that must be satisfied by the density profile and the pair correlation function of a liquid-vapour system with pairwise central interactions. For a particular class of approximate pair correlation functions, the sum rules reduce to equations linking the pressure and temperature with the densities of the two bulk phases. Good agreement with experimental data is obtained. 相似文献
2.
We compute the third-order correction to the heavy-quark current correlation function due to the emission and absorption of an ultrasoft gluon. Our result supplies a missing contribution to top-quark pair production near threshold and the determination of the bottom quark mass from QCD sum rules. 相似文献
3.
A.S. Deakin V. Elias A.H. Fariborz Ying Xue Fang Shi T.G. Steele 《The European Physical Journal C - Particles and Fields》1998,4(4):693-704
There is a need to go beyond the narrow resonance approximation for QCD sum-rule channels which are likely to exhibit sensitivity
to broad resonance structures. We discuss how the first two Laplace sum rules are altered when one goes beyond the narrow
resonance approximation to include possible subcontinuum resonances with nonzero widths. We show that the corresponding first
two finite energy sum rules are insensitive to the widths of such resonances, provided their peaks are symmetric and entirely
below the continuum threshold. We also discuss the reduced sensitivity of the first two finite energy sum rules to higher
dimensional condensates, and show these sum rules to be insensitive to dimension condensates containing at least one pair. We extract the direct single-instanton contribution to the sum rule for the longitudinal component of the axial-vector correlation function from the known single-instanton contribution
to the lowest Laplace sum rule for the pseudoscalar channel. Finally, we demonstrate how inclusion of this instanton contribution
to the finite-energy sum rule leads to both a lighter quark mass and to more phenomenologically reasonable higher-mass-resonance
contributions within the pseudoscalar channel.
Received: 15 September 1997 / Revised version: 15 November 1997 / Published online: 26 February 1998 相似文献
4.
Summary The asymptotic behaviours of particle correlation functions and the related sum rules are discussed for a layered classical
plasma withe
2/r interactions in the fluid state, in dependence on the number of layers. These properties derive from consistency conditions
imposed by screening on the hierarchical equations, as already treated by A. Alastuey and P. A. Martin (J. Stat. Phys.,39, 405 (1985)) for various Coulomb fluids. The main results concern i) the type of clustering of correlations needed for the
validity of multipolar sum rules at various orders, ii) the proof that the pair correlation function in a finite multilayer
may carry an electric dipole moment and the calculation of its partioning among the layers, and iii) the dimensionality crossover
in an infinitely extended or periodically repeated multiplayer with varying interlayer spacing and wave vector. 相似文献
5.
6.
Ladislav ?amaj 《Journal of statistical physics》2009,137(1):1-17
This paper concerns the equilibrium bulk charge and current density correlation functions in quantum media, conductors and
dielectrics, fully coupled to the radiation (the retarded regime). A sequence of static and time-dependent sum rules, which
fix the values of certain moments of the charge and current density correlation functions, is obtained by using Rytov’s fluctuational
electrodynamics. A technique is developed to extract the classical and purely quantum-mechanical parts of these sum rules.
The sum rules are critically tested in the classical limit and on the jellium model. A comparison is made with microscopic
approaches to systems of particles interacting through Coulomb forces only (the non-retarded regime). In contrast with microscopic
results, the current-current density correlation function is found to be integrable in space, in both classical and quantum
regimes. 相似文献
7.
This paper is a continuation of the previous study (Šamaj in J. Stat. Phys. 137:1–17, 2009), where a sequence of sum rules for the equilibrium charge and current density correlation functions in an infinite (bulk)
quantum media coupled to the radiation was derived by using Rytov’s fluctuational electrodynamics. Here, we extend the previous
results to inhomogeneous situations, in particular to the three-dimensional interface geometry of two joint semi-infinite
media. The sum rules derived for the charge-charge density correlations represent a generalization of the previous ones, related
to the interface dipole moment and to the long-ranged tail of the surface charge density correlation function along the interface
of a conductor in contact with an inert (not fluctuating) dielectric wall, to two fluctuating semi-infinite media of any kind.
The charge-current and current-current sum rules obtained here are, to our knowledge, new. The current-current sum rules indicate
a breaking of the directional invariance of the diagonal current-current correlations by the interface. The sum rules are
expressed explicitly in the classical high-temperature limit (the static case) and for the jellium model (the time-dependent
case). 相似文献
8.
A. H.M. Zaheri S. Srivastava K. Tankeshwar 《The European Physical Journal B - Condensed Matter and Complex Systems》2008,61(4):465-473
Expressions for zeroth, second and fourth sum rules of longitudinal and bulk
stress auto correlation functions have been derived for binary fluid mixtures.
Longitudinal and bulk viscosities of an Ar–Kr mixture have been calculated using
Mori's memory function formalism coupled with the sum rules of longitudinal and
bulk stress auto correlation functions.
The results obtained are compared with the molecular dynamics
simulation. Mass dependence of the longitudinal and bulk viscosities has
been studied for different compositions
of an isotopic mixture at different densities and temperatures. For very large mass ratio, the
longitudinal and bulk viscosities of the isotopic mixture are more dependent on mole fraction than on mass. 相似文献
9.
W. Brenig 《Zeitschrift für Physik A Hadrons and Nuclei》1962,169(1):219-223
An equation for the time dependent pair correlation resp. its Fourier transform, the response function, is derived within the framework ofLandau's theory of Fermi liquids. The conditions for the validity of the optical sum rule are investigated. An “elastic” sum rule relating the response function to the compressibility is formulated and its proof indicated. 相似文献
10.
M. J. Lavelle 《Zeitschrift fur Physik C Particles and Fields》1985,29(2):203-208
We consider light cone sum rules for a vertex function involving a pion state. These incorporate radiative corrections, continuum effects and power corrections; the latter depend on the non-asymptotic form of a higher twist component of the pion wave function. We derive restrictions on this component from sum rules for two-point functions and propose a model wave function for it. Finally we analyse our vertex sum rules in the light of this information and find results for the lowest twist component in good agreement with those already obtained from two-point function sum rules with derivative currents. 相似文献
11.
C. Deutsch 《Physics letters. A》1975,53(2):183-184
An effective Coulomb interaction taking into account the diffraction effects is used to sum the series of bubbles diagrams building up the short-range part of the pair correlation function. 相似文献
12.
TheW boson pair production by electron and positron of same helicity is computed. The restrictions due to the tree unitarity are exhibited in three sum rules and we have shown how the gauge theories satisfy the sum rules. A simple way to isolate heavy lepton contributions is presented. 相似文献
13.
B. Jancovici 《Journal of statistical physics》1982,29(2):263-280
The equilibrium structure of classical Coulomb systems bounded by a plane hard wall is studied near that wall. A general sum rule is derived for the asymptotic form of the charge-charge correlation function along the wall. The exact results which can be obtained for the two-dimensional one-component plasma provide a test for this new sum rule, as well as for other already known sum rules or their generalizations.This laboratory is associated with the Centre National de la Recherche Scientifique. 相似文献
14.
A new high frequency kinetic sum rule for classical simple fluids is obtained. It involves only the static pair- and triplet-correlation functions; its self part and the local limit depend only on the pair correlation function. 相似文献
15.
The expression for the fourth frequency moment of current correlation function in a two-component fluid is derived. This result is used to obtain certain exact sum rules, in the long-wavelength limit, for charge current correlations in fused salts. 相似文献
16.
17.
M.J. Lavelle 《Nuclear Physics B》1985,260(2):323-332
We consider light-cone sum rules for vertex functions involving baryon-meson couplings. These sum rules relate the non-pertubative, and experimentally known, coupling constants to the moments of the wave function of the proton state. Our results for these moments are consistent with those obtained from QCD sum rules for two-point functions. 相似文献
18.
Sum rules are derived for the quantum wave functions of the Hadamard billiard in arbitrary dimensions. This billiard is a strongly chaotic (Anosov) system which consists of a point particle moving freely on a D-dimensional compact manifold (orbifold) of constant negative curvature. The sum rules express a general (two-point)correlation function of the quantum mechanical wave functions in terms of a sum over the orbits of the corresponding classical system. By taking the trace of the orbit sum rule or pre-trace formula, one obtains the Selberg trace formula. The sum rules are applied in two dimensions to a compact Riemann surface of genus two, and in three dimensions to the only non-arithmetic tetrahedron existing in hyperbolic 3-space. It is shown that the quantum wave functions can be computed from classical orbits. Conversely, we demonstrate that the structure of classical orbits can be extracted from the quantum mechanical energy levels and wave functions (inverse quantum chaology). 相似文献
19.
20.
ABSTRACTIn this work, we compare four inhomogeneous square-well fluid models, only distinct in the approximation on the pair correlation function present in the attractive free energy term of the density functional theory (DFT). Various criteria can be considered to select or validate an approximation, depending on fundamental interests or for a specified application. Here the considered criteria of selection were the verification of sum rules, and the prediction of both the adsorbed quantity and the density profiles. Even if a model satisfies one of these criteria, it may fail to describe others, so they can be considered supplementary to each other and in no case redundant. According to this study, one can attach more importance to any of these criteria depending on the specific objectives intended for the model development and purpose. They can serve as references in the development of new DFT models, eventually with other criteria, according to the objective of the work and the accuracy desired. 相似文献