1,523 research outputs found

    Two-dimensional two-component plasma with adsorbing impurities

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    We study the behavior of the two-dimensional two-component plasma in the presence of some adsorbing impurities. Using a solvable model, we find analytic expressions for the thermodynamic properties of the plasma such as the nn-body densities, the grand potential, and the pressure. We specialize in the case where there are one or two adsorbing point impurities in the plasma, and in the case where there are one or two parallel adsorbing lines. In the former case we study the effective interaction between the impurities, due to the charge redistribution around them. The latter case is a model for electrodes with adsorbing sticky sites on their surface

    Statistical Behavior Of Domain Systems

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    We study the statistical behavior of two out of equilibrium systems. The first one is a quasi one-dimensional gas with two species of particles under the action of an external field which drives each species in opposite directions. The second one is a one-dimensional spin system with nearest neighbor interactions also under the influence of an external driving force. Both systems show a dynamical scaling with domain formation. The statistical behavior of these domains is compared with models based on the coalescing random walk and the interacting random walk. We find that the scaling domain size distribution of the gas and the spin systems is well fitted by the Wigner surmise, which lead us to explore a possible connection between these systems and the circular orthogonal ensemble of random matrices. However, the study of the correlation function of the domain edges, show that the statistical behavior of the domains in both gas and spin systems, is not completely well described by circular orthogonal ensemble, nor it is by other models proposed such as the coalescing random walk and the interacting random walk. Nevertheless, we find that a simple model of independent intervals describe more closely the statistical behavior of the domains formed in these systems.Comment: v2: minor change

    Non-linear screening of spherical and cylindrical colloids: the case of 1:2 and 2:1 electrolytes

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    From a multiple scale analysis, we find an analytic solution of spherical and cylindrical Poisson-Boltzmann theory for both a 1:2 (monovalent co-ions, divalent counter-ions) and a 2:1 (reversed situation) electrolyte. Our approach consists in an expansion in powers of rescaled curvature 1/(κa)1/(\kappa a), where aa is the colloidal radius and 1/κ1/\kappa the Debye length of the electrolytic solution. A systematic comparison with the full numerical solution of the problem shows that for cylinders and spheres, our results are accurate as soon as κa>1\kappa a>1. We also report an unusual overshooting effect where the colloidal effective charge is larger than the bare one.Comment: 9 pages, 11 figure

    Guest charges in an electrolyte: renormalized charge, long- and short-distance behavior of the electric potential and density profile

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    We complement a recent exact study by L. Samaj on the properties of a guest charge QQ immersed in a two-dimensional electrolyte with charges +1/−1+1/-1. In particular, we are interested in the behavior of the density profiles and electric potential created by the charge and the electrolyte, and in the determination of the renormalized charge which is obtained from the long-distance asymptotics of the electric potential. In Samaj's previous work, exact results for arbitrary coulombic coupling β\beta were obtained for a system where all the charges are points, provided βQ<2\beta Q<2 and β<2\beta < 2. Here, we first focus on the mean field situation which we believe describes correctly the limit β→0\beta\to 0 but βQ\beta Q large. In this limit we can study the case when the guest charge is a hard disk and its charge is above the collapse value βQ>2\beta Q>2. We compare our results for the renormalized charge with the exact predictions and we test on a solid ground some conjectures of the previous study. Our study shows that the exact formulas obtained by Samaj for the renormalized charge are not valid for βQ>2\beta Q>2, contrary to a hypothesis put forward by Samaj. We also determine the short-distance asymptotics of the density profiles of the coions and counterions near the guest charge, for arbitrary coulombic coupling. We show that the coion density profile exhibit a change of behavior if the guest charge becomes large enough (βQ≥2−β\beta Q\geq 2-\beta). This is interpreted as a first step of the counterion condensation (for large coulombic coupling), the second step taking place at the usual Manning--Oosawa threshold βQ=2\beta Q=2

    A Generalization of the Stillinger-Lovett Sum Rules for the Two-Dimensional Jellium

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    In the equilibrium statistical mechanics of classical Coulomb fluids, the long-range tail of the Coulomb potential gives rise to the Stillinger-Lovett sum rules for the charge correlation functions. For the jellium model of mobile particles of charge qq immersed in a neutralizing background, the fixing of one of the qq-charges induces a screening cloud of the charge density whose zeroth and second moments are determined just by the Stillinger-Lovett sum rules. In this paper, we generalize these sum rules to the screening cloud induced around a pointlike guest charge ZqZ q immersed in the bulk interior of the 2D jellium with the coupling constant Γ=βq2\Gamma=\beta q^2 (β\beta is the inverse temperature), in the whole region of the thermodynamic stability of the guest charge Z>−2/ΓZ>-2/\Gamma. The derivation is based on a mapping technique of the 2D jellium at the coupling Γ\Gamma = (even positive integer) onto a discrete 1D anticommuting-field theory; we assume that the final results remain valid for all real values of Γ\Gamma corresponding to the fluid regime. The generalized sum rules reproduce for arbitrary coupling Γ\Gamma the standard Z=1 and the trivial Z=0 results. They are also checked in the Debye-H\"uckel limit Γ→0\Gamma\to 0 and at the free-fermion point Γ=2\Gamma=2. The generalized second-moment sum rule provides some exact information about possible sign oscillations of the induced charge density in space.Comment: 16 page

    Expanded Vandermonde powers and sum rules for the two-dimensional one-component plasma

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    The two-dimensional one-component plasma (2dOCP) is a system of NN mobile particles of the same charge qq on a surface with a neutralising background. The Boltzmann factor of the 2dOCP at temperature TT can be expressed as a Vandermonde determinant to the power Γ=q2/(kBT)\Gamma=q^{2}/(k_B T). Recent advances in the theory of symmetric and anti-symmetric Jack polymonials provide an efficient way to expand this power of the Vandermonde in their monomial basis, allowing the computation of several thermodynamic and structural properties of the 2dOCP for NN values up to 14 and Γ\Gamma equal to 4, 6 and 8. In this work, we explore two applications of this formalism to study the moments of the pair correlation function of the 2dOCP on a sphere, and the distribution of radial linear statistics of the 2dOCP in the plane

    Onsager-Manning-Oosawa condensation phenomenon and the effect of salt

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    Making use of results pertaining to Painleve III type equations, we revisit the celebrated Onsager-Manning-Oosawa condensation phenomenon for charged stiff linear polymers, in the mean-field approximation with salt. We obtain analytically the associated critical line charge density, and show that it is severely affected by finite salt effects, whereas previous results focused on the no salt limit. In addition, we obtain explicit expressions for the condensate thickness and the electric potential. The case of asymmetric electrolytes is also briefly addressed.Comment: to appear in Phys. Rev. Let
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