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Exact Relation (exact + relation)

Distribution by Scientific Domains
Physics and Astronomy75%

Selected Abstracts

S-matrix, vertex operators and correlation functions of Liouville theory

FORTSCHRITTE DER PHYSIK/PROGRESS OF PHYSICS, Issue 6-7 2004
G. Jorjadze
We investigate the S-matrix of Liouville theory on the basis of exact relation between exponentials of the in - and out -fields. The vertex operators for negative integer exponentials are constructed by regularising procedure. Their vacuum matrix elements are calculated using Dotsenko-Fateev integrals. The result is continued analytically to the generic case. The obtained correlation function coincides with the suggested 3-point function of Dorn and Otto for positive exponentials only. [source]

AN OBTRUSIVE REMARK ON CAPITAL AND COMPARATIVE STATICS

METROECONOMICA, Issue 1 2009
Gaetano Bloise
ABSTRACT We present a simple comparative statics analysis of steady-state equilibria in overlapping generations economies with capital accumulation. We regard comparative statics as paradoxical whenever an exogenous increase in saving propensity induces a decrease (an increase) in consumption at the steady state when interest rate is positive (negative). It is shown that there is an exact relation between paradoxical comparative statics and a perverse intersection of properly identified curves of demand for and supply of capital in value. The demand curve for capital in value coincides with that of neo-Ricardian analysis. We relate our conclusions to some old and recent issues in capital theory. [source]

Interband transmission in armchair graphene ribbons with a step-like profile of potential energy: Relevance to Klein's tunneling

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 11-12 2009
Lyuba Malysheva
Abstract Three principal results concerning graphene-based wires and their ambipolar behavior are presented. First, it is the exact expression of the transmission coefficient for armchair graphene wires described by the tight-binding Hamiltonian with the step-like change U of site energies. Second, the exact relation between the energy of incident electrons or holes and potential U at which there is no backscattering for the given mode of the transverse motion. Third, the range of relevance of Klein's formula describing the motion of relativistic particles in the same potential profile is established. Analysis of newly derived results shows that physics of interband transitions at constant energy in graphene wires is richer than it was believed. [source]

Sum rules and exact relations for quantal Coulomb systems

CONTRIBUTIONS TO PLASMA PHYSICS, Issue 5-6 2003
V.M. Adamyan
Abstract A complex response function describing a reaction of a multi-particle system to a weak alternating external field is the boundary value of a Nevanlinna class function (i.e. a holomorphic function with non-negative imaginary part in the upper half-plane). Attempts of direct calculations of response functions based on standard approximations of the kinetic theory for real Coulomb condensed systems often result in considerable discrepancies with experiments and computer simulations. At the same time a relatively simple approach using only the exact values of leading asymptotic terms of the response function permits to restrict essentially a subset of Nevanlinna class functions containing this response function, and in this way to obtain sufficient data to explain and predict experimental results. Mathematical details of this approach are demonstrated on an example with the response function being the (external) dynamic electrical conductivity of cold dense hydrogen-like plasmas. In particular, the exact values of the leading terms of asymptotic expansions of the conductivity are calculated. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]