Vortex Fluctuations in the Critical Casimir Effect of Superfluid and Superconducting Films

TL;DR

This paper investigates the critical Casimir forces in superfluid and superconducting films using vortex-loop renormalization, revealing significant forces near the critical temperature that could be experimentally observed as voltage differences.

Contribution

It applies vortex-loop renormalization techniques to calculate Casimir forces in superfluid and superconducting films, extending understanding to temperatures below Tc.

Findings

Casimir force becomes significant when vortex loops are comparable to film thickness

Results align well with perturbative theories for T > Tc

Predicted voltage differences in superconducting films are experimentally detectable

Abstract

Vortex-loop renormalization techniques are used to calculate the magnitude of the critical Casimir forces in superfluid films. The force is found to become appreciable when size of the thermal vortex loops is comparable to the film thickness, and the results for T < Tc are found to match very well with perturbative renormalization theories that have only been carried out for T > Tc. When applied to a high-Tc superconducting film connected to a bulk sample, the Casimir force causes a voltage difference to appear between the film and bulk, and estimates show that this may be readily measurable.