Repulsive Casimir forces and the role of surface modes

TL;DR

This paper investigates how surface modes influence Casimir repulsion in layered systems, emphasizing their critical role at short distances through theoretical modeling and analysis.

Contribution

It introduces a detailed analysis of surface modes in layered dielectric systems and their impact on Casimir repulsion, extending understanding beyond previous experimental studies.

Findings

Surface modes are crucial at short separations for Casimir repulsion.

A toy plasma model illustrates the contribution of surface modes across all distances.

Surface modes significantly influence the magnitude and behavior of Casimir forces.

Abstract

The Casimir repulsion between a metal and a dielectric suspended in a liquid has been thoroughly studied in recent experiments. In the present paper we consider surface modes in three layered systems modeled by dielectric functions guaranteeing repulsion. It is shown that surface modes play a decisive role in this phenomenon at short separations. For a toy plasma model we find the contribution of the surface modes at all distances.