Repulsive Casimir force in Bose-Einstein Condensate

TL;DR

This paper investigates the Casimir effect in a Bose-Einstein condensate system, revealing that certain boundary conditions lead to a repulsive Casimir force, contrasting with the typically attractive force observed under other conditions.

Contribution

It demonstrates that Zaremba and anti-periodic boundary conditions produce a repulsive Casimir force in a Bose gas, a novel finding compared to traditional boundary conditions.

Findings

Casimir force is repulsive under Zaremba and anti-periodic boundary conditions.

Force decays as a power law below condensation temperature.

Force decays exponentially above condensation temperature.

Abstract

We study the Casimir effect for a three dimensional system of ideal free massive Bose gas in a slab geometry with Zaremba and anti-periodic boundary conditions. It is found that for these type of boundary conditions the resulting Casimir force is repulsive in nature, in contrast with usual periodic, Dirichlet or Neumann boundary condition where the Casimir force is attractive (Martin P. A. and Zagrebnov V. A., Europhys. Lett., 73 (2006) 15.). Casimir forces in these boundary conditions also maintain a power law decay function below condensation temperature and exponential decay function above the condensation temperature albeit with a positive sign, identifying the repulsive nature of the force.