Dispersion forces and duality

TL;DR

This paper introduces a symmetry principle based on electric-magnetic duality and demonstrates its invariance in dispersion forces within macroscopic quantum electrodynamics, unifying various Casimir and van der Waals interactions.

Contribution

It formulates a duality invariance principle for dispersion forces, extending the symmetry to macroscopic quantum electrodynamics and force calculations.

Findings

Casimir forces are duality invariant in free space.

Casimir-Polder and van der Waals forces maintain duality invariance.

Green tensor behavior under duality transformation is characterized.

Abstract

We formulate a symmetry principle on the basis of the duality of electric and magnetic fields and apply it to dispersion forces. Within the context of macroscopic quantum electrodynamics, we rigorously establish duality invariance for the free electromagnetic field in the presence of causal magnetoelectrics. Dispersion forces are given in terms of the Green tensor for the electromagnetic field and the atomic response functions. After discussing the behavior of the Green tensor under a duality transformation, we are able to show that Casimir forces on bodies in free space as well as local-field corrected Casimir-Polder and van der Waals forces are duality invariant.