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J. -M. Caillol

Publications and source records attributed to J. -M. Caillol.

10 recordsLinked to original sources
arXiv2020

A symplectic integrator for molecular dynamics on a hypersphere

We present a reversible and symplectic algorithm called ROLL, for integrating the equations of motion in molecular dynamics simulations of simple fluids on a hypersphere $\mathcal{S}^d$ of arbitrary dimension $d$. It is derived in the framework of geometric algebra and shown to be mathematically equivalent to algorithm RATTLE. An application to molecular dynamics simulation of the one component plasma is briefly discussed.

physics.comp-ph↗
arXiv2014

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.

cond-mat.stat-mech↗
arXiv2007

Crossover behavior in fluids with Coulomb interactions

According to extensive experimental findings, the Ginzburg temperature $t_{G}$ for ionic fluids differs substantially from that of nonionic fluids [Schröer W., Weigärtner H. 2004 {\it Pure Appl. Chem.} {\bf 76} 19]. A theoretical investigation of this outcome is proposed here by a mean field analysis of the interplay of short and long range interactions on the value of $t_{G}$. We consider a quite general continuous charge-asymmetric model made of charged hard spheres with additional short-range interactions (without electrostatic interactions the model belongs to the same universality class as the 3D Ising model). The effective Landau-Ginzburg Hamiltonian of the full system near its gas-liquid critical point is derived from which the Ginzburg temperature is calculated as a function of the ionicity. The results obtained in this way for $t_{G}$ are in good qualitative and sufficient quantitative agreement with available experimental data.

cond-mat.soft↗
arXiv2004

New mean field theories for the liquid-vapor transition of charged hard spheres

The phase behavior of the primitive model of electrolytes is studied in the framework of various mean field approximations obtained recently by means of methods pertaining to statistical field theory (CAILLOL, J.-M., 2004, \textit{J. Stat. Phys.}, \textbf{115}, 1461). The role of the regularization of the Coulomb potential at short distances is discussed in details and the link with more traditional approximations of the theory of liquids is discussed. The values computed for the critical temperatures, chemical potentials, and densities are compared with available Monte Carlo data and other theoretical predictions.

cond-mat.stat-mech↗
arXiv2003

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.

cond-mat.stat-mech↗
arXiv2002

Critical behavior of the restricted primitive model revisited

Reassessment of the critical temperature and density of the restricted primitive model of an ionic fluid by Monte Carlo simulations performed for system sizes with linear dimension up to $L/σ=34$ and sampling of $\sim 10^9$ trial moves leads to $T^*_c=0.04917 \pm 0.00002$ and $ρ_c^* =0.080 \pm 0.005$. Finite size scaling analysis based in the Bruce-Wilding procedure gives critical exponents in agreement with those of the 3d Ising universality class. An analysis similar to that proposed by Orkoulas et al [Phys. Rev. E 63, 051507 (2001)], not relying on an a priori knowledge of the universality class, leads to an unaccurate estimate of $T_c^*$ and to unexpected behavior of the specific heat and value of the critical exponent ratio $γ/ν$.

cond-mat.stat-mech↗
arXiv2001

The density functional theory of classical fluids revisited

We reconsider the density functional theory of nonuniform classical fluids from the point of view of convex analysis. From the observation that the logarithm of the grand-partition function $\log Ξ[ϕ]$ is a convex functional of the external potential $ϕ$ it is shown that the Kohn-Sham free energy ${\cal A}[ρ]$ is a convex functional of the density $ρ$. $\log Ξ[ϕ]$ and ${\cal A}[ρ]$ constitute a pair of Legendre transforms and each of these functionals can therefore be obtained as the solution of a variational principle. The convexity ensures the unicity of the solution in both cases. The variational principle which gives $\log Ξ[ϕ]$ as the maximum of a functional of $ρ$ is precisely that considered in the density functional theory while the dual principle, which gives ${\cal A}[ρ]$ as the maximum of a functional of $ϕ$ seems to be a new result.

cond-mat.stat-mech↗
arXiv2001

Sine-Gordon theory for the equation of state of classical hard-core Coulomb systems. I Low fugacity expansion

We present an exact field theoretical representation of the statistical mechanics of classical hard-core Coulomb systems. This approach generalizes the usual sine-Gordon theory valid for point-like charges or lattice systems to continuous Coulomb fluids with additional short-range interactions. This formalism is applied to derive the equation of state of the restricted primitive model of electrolytes in the low fugacity regime up to order $ρ^{5/2}$ ($ρ$ number density). We recover the results obtained by Haga by means of Mayer graphs expansions.

cond-mat.stat-mech↗