Universality versus material dependence of fluctuation forces between metallic wires

TL;DR

This paper investigates the Casimir forces between metallic wires and plates, revealing conditions under which these forces are universal or material-dependent, especially concerning plasma and Drude models.

Contribution

It provides a detailed analysis of how the Casimir interaction varies with material models and separation distances, highlighting unexpected independence from conductivity at certain scales.

Findings

At large separations, plasma interactions are universal and independent of material details.

Interactions involving Drude wires depend on dc conductivity at large distances.

Numerical results show the proximity approximation becomes accurate at small separations.

Abstract

We calculate the Casimir interaction between two parallel wires and between a wire and a metall plate. The dielectric properties of the objects are described by the plasma, Drude and perfect metal models. We find that at asymptotically large separation interactions involving plasma wires and/or plates are independent of the material properties, but depend on the dc conductivity $\sigma$ for Drude wires. Counterintuitively, at intermediate separations the interaction involving Drude wires can become independent of $\sigma$. At smaller separations, we compute the interaction numerically and observe an approach to the proximity approximation.