5,023 research outputs found
The Diffusion Equation on a Hypersphere
We study the diffusion equation on the surface of a 4D sphere and obtain a
Kubo formula for the diffusion coefficient
Sine-Gordon theory for the equation of state of classical hard-core Coulomb systems. II. High-temperature expansion
We perform a high-temperature expansion of the grand potential of the
restrictive primitive model of electrolytes in the frame of the extended
sine-Gordon theory exposed in the companion paper. We recover a result already
obtained by Stell an Lebowitz (J. Chem. Phys., 49, 3706 (1968)) by means of
diagrammatic expansions
Liquid-Vapor Transition and Critical Behavior of The Ultrasoft Restricted Primitive Model of Polyelectrolytes : a Monte Carlo Study
We present a Monte-Carlo study of the liquid-vapor transition and the
critical behavior of a model of polyelectrolytes with soft gaussian charge
distributions introduced recently by Coslovich, Hansen, and Kahl [J. Chem.
Phys. \textbf{134}, 244514 (2011)]. A finite size study involving four
different volumes in the grand canonical ensemble yields a precise
determination of the critical temperature, chemical potential, and density of
the model. Attempts to determine the nature of the criticality and to obtain
reliable values for the critical exponents are not conclusive.Comment: 14 pages, 4 figure
Exact Renormalization Group : A New Method for Blocking the Action
We consider the exact renormalization group for a non-canonical scalar field
theory in which the field is coupled to the external source in a special non
linear way. The Wilsonian action and the average effective action are then
simply related by a Legendre transformation up to a trivial quadratic form. An
exact mapping between canonical and non-canonical theories is obtained as well
as the relations between their flows. An application to the theory of liquids
is sketched
Monte Carlo simulations of the screening potential of the Yukawa one-component plasma
A Monte Carlo scheme to sample the screening potential H(r) of Yukawa plasmas
notably at short distances is presented. This scheme is based on an importance
sampling technique. Comparisons with former results for the Coulombic
one-component plasma are given. Our Monte Carlo simulations yield an accurate
estimate of H(r) as well for short range and long range interparticle
distances.Comment: to be published in Journal of Physics A: Mathematical and Genera
Statistical field theory for simple fluids: the collective variables representation
An alternative representation of an exact statistical field theory for simple
fluids, based on the method of collective variables, is presented. The results
obtained are examined from the point of another version of theory that was
developed recently by performing a Hubbard-Stratonovich transformation of the
configurational Boltzmann factor [J.-M. Caillol, Mol. Phys. 101 (2003) 1617].
The analytical expressions for the pressure and the free energy are derived in
two-loop approximation for both versions of theory and it is shown that they
are indeed equivalent.The results yield a new type approximation within an
untested approximation scheme
Transport Coefficients of the Yukawa One Component Plasma
We present equilibrium molecular-dynamics computations of the thermal
conductivity and the two viscosities of the Yukawa one-component plasma. The
simulations were performed within periodic boundary conditions and Ewald sums
were implemented for the potentials, the forces, and for all the currents which
enter the Kubo formulas. For large values of the screening parameter, our
estimates of the shear viscosity and the thermal conductivity are in good
agreement with the predictions of the Chapman-Enskog theory.Comment: 11 pages, 2 figure
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