Critical fluctuations of a confined binary mixture

TL;DR

This paper investigates the critical fluctuations in a confined binary mixture by mapping it to the Ising model and analyzing the critical Casimir force behavior near the capillary condensation line.

Contribution

It applies the density-matrix renormalization group to study the critical Casimir force in a 2D Ising strip with surface fields, revealing new behavior across the condensation line.

Findings

Critical Casimir force varies significantly across the capillary condensation line.

Most attractive force occurs near the critical temperature T_C.

Force behavior depends on reservoir composition relative to the critical composition.

Abstract

Exploiting the mapping between a binary mixture and the Ising model we have analyzed the critical fluctuations by means of the density-matrix renormalization group technique. The calculations have been carried out for a two-dimensional Ising strip subject to equal strong surface fields. It was found that the critical Casimir force displays significantly different behavior on opposite sides of the capillary condensation line, especially below the critical temperature. It can be concluded that in a real binary mixtures the most attractive force appears at temperatures near T_C and at reservoir compositions slightly away from the critical composition.