Generalized plasma-like permittivity and thermal Casimir force between real metals

TL;DR

This paper demonstrates that using a generalized plasma-like permittivity in the Lifshitz theory resolves thermodynamic inconsistencies and accurately describes the thermal Casimir force between real metals, addressing issues with the Drude model.

Contribution

The study introduces a generalized plasma-like permittivity that ensures thermodynamic consistency in Lifshitz theory for real metals, unlike the traditional Drude dielectric function.

Findings

Lifshitz theory with Drude dielectric function is thermodynamically inconsistent.

Generalized plasma-like permittivity aligns with thermodynamics.

The approach accurately describes the thermal Casimir force between real metals.

Abstract

The physical reasons why the Drude dielectric function is not compatible with the Lifshitz formula, as opposed to the generalized plasma-like permittivity, are presented. Essentially, the problem is connected with the finite size of metal plates. It is shown that the Lifshitz theory combined with the generalized plasma-like permittivity is thermodynamically consistent.