Berlin 2024 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 41: Statistical Physics: General

DY 41.5: Talk

Thursday, March 21, 2024, 10:30–10:45, BH-N 128

Finite-size excess-entropy scaling for simple liquids — •Mauricio Sevilla, Atreyee Banerje, and Robinson Cortes-Huerto — Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany

Integral equations in statistical mechanics play a crucial role in connecting thermodynamics to microscopic properties of simple liquids. In computer simulations, these integral equations manifest explicit and implicit size effects that arise from systems with a fixed number of particles and periodic boundary conditions, respectively. The excess entropy is of particular interest in the theory of liquids and glasses. However, often, in the computation of the two-body excess-entropy s₂ finite-size effects are overlooked and simulations are treated as if they were in the Grand Canonical ensemble. In this talk, we introduce and validate a finite-size two-body excess-entropy integral equation. Through analytical arguments and computer simulations of prototypical simple liquids, we demonstrate that the excess entropy s₂ displays a finite-size scaling with the inverse of the linear size of the simulation box. To valid our expression and given that the self-diffusivity coefficient D^* also exhibits a similar finite-size scaling, we establish that the empirical relation D^*=Aexp(α s₂) also depends on the simulation box size. Extrapolating this relation to the thermodynamic limit, we report values for A and α with excellent agreement with the literature. Finally, we find a power law relation between the scaling coefficients for D^*(L) and s₂(L), suggesting a constant viscosity-to-entropy ratio.

Keywords: Finite-Size Scaling; Excess-Entropy; Theory of Liquids; Integral Equations; Computer Simulations