Monte Carlo simulation results for critical Casimir forces

TL;DR

This paper introduces a Monte Carlo simulation method to determine universal scaling functions of critical Casimir forces in confined critical media, with results aligning well with experimental data.

Contribution

A novel Monte Carlo integration scheme for calculating free energy differences to determine critical Casimir forces in lattice models.

Findings

Results agree with experimental data for binary liquid mixtures.

Results agree with experimental data for 4He.

Method effectively characterizes temperature and geometry dependence.

Abstract

The confinement of critical fluctuations in soft media induces critical Casimir forces acting on the confining surfaces. The temperature and geometry dependences of such forces are characterized by universal scaling functions. A novel approach is presented to determine them for films via Monte Carlo simulations of lattice models. The method is based on an integration scheme of free energy differences. Our results for the Ising and the XY universality class compare favourably with corresponding experimental results for wetting layers of classical binary liquid mixtures and of 4He, respectively.