Chiral Casimir Forces: Repulsive, Enhanced, Tunable

TL;DR

This paper proposes a universal method to achieve and control repulsive Casimir forces using optically active or gyrotropic media, challenging the traditional belief that such forces are always attractive between symmetric bodies.

Contribution

It identifies a loophole in the no-go theorem and introduces a novel approach to realize tunable repulsive Casimir forces with external field modulation.

Findings

Repulsive Casimir forces can be achieved with specific media.

The sign and strength of Casimir forces are tunable.

External fields can modulate the Casimir interactions.

Abstract

Both theoretical interest and practical significance attach to the sign and strength of Casimir forces. A famous, discouraging no-go theorem states that "The Casimir force between two bodies with reflection symmetry is always attractive." Here we identify a loophole in the reasoning, and propose a universal way to realize repulsive Casimir forces. We show that the sign and strength of Casimir forces can be adjusted by inserting optically active or gyrotropic media between bodies, and modulated by external fields.