The specific heat of thin films near the lambda-transition: A Monte Carlo study of an improved three-dimensional lattice model

TL;DR

This study uses Monte Carlo simulations of an improved three-dimensional lattice model to analyze the finite size scaling of specific heat in thin films near the lambda-transition, providing insights relevant to 4He experiments.

Contribution

It introduces a detailed Monte Carlo analysis of the specific heat in thin films near the lambda-transition using an improved lattice model with boundary conditions mimicking real films.

Findings

Finite size scaling functions require 1/L_0 corrections for accurate collapse.

Results align with experimental data on 4He thin films.

Comparison with field theory and previous simulations validates the approach.

Abstract

We study the finite size scaling behaviour of the specific heat of thin films in the neighbourhood of the lambda-transition. To this end we have simulated the improved two-component phi^4 model on the simple cubic lattice. We employ free boundary conditions in the short direction to mimic the vanishing order parameter at the boundaries of a 4He film. Most of our simulations are performed for the thicknesses L_0=8,16 and 32 of the film. It turns out that one has to take into account corrections proportional 1/L_0 to obtain a good collapse of the finite size scaling functions obtained from different L_0. Our results are compared with those obtained from experiments on thin films of 4He near the lambda-transition, from field theory and from previous Monte Carlo simulations.