Finite temperature Casimir effect of a Lorentz-violating scalar with higher order derivatives

TL;DR

This paper analyzes the finite temperature Casimir effect for a Lorentz-violating scalar field with higher derivatives, deriving analytic expressions for energy and pressure under various boundary conditions, orientations, and limits.

Contribution

It introduces a novel analysis of the Casimir effect incorporating Lorentz violation via higher derivatives and provides explicit formulas for different physical scenarios.

Findings

Derived analytic expressions for Casimir energy and pressure.

Explored effects of Lorentz violation direction on Casimir forces.

Analyzed asymptotic behaviors in small distance, high temperature, and large mass limits.

Abstract

In this work I study the finite temperature Casimir effect caused by a complex and massive scalar field that breaks Lorentz invariance in a CPT-even, aether-like manner. The Lorentz invariance breaking is caused by a constant space-like vector directly coupled to higher order field derivatives. This vector needs to be space-like in order to avoid non-causality problems that will arise with a time-like vector. I investigate the two scenarios of the scalar field satisfying either Dirichlet or mixed boundary conditions on a pair of flat parallel plates. I use the generalized zeta function technique that enables me to obtain the Helmholtz free energy and the Casimir pressure when the Casimir plates are in thermal equilibrium with a heat reservoir at finite temperature. I investigate two different directions of the unit vector, parallel and perpendicular to the plates. I examine both scenarios for both types of boundary conditions and, in both cases and for the two different boundary conditions, I obtain simple analytic expressions of the Casimir energy and pressure in the three asymptotic limits of small plate distance, high temperature, and large mass, examining all combinations of boundary conditions, unit vector direction, and asymptotic limits.