On the Feigel Effect: Extraction of Momentum from Vacuum?

TL;DR

This paper develops a Green-function formalism for electromagnetic fields in magnetoelectric media, predicting that electromagnetic momentum can be extracted from the vacuum, similar to the Casimir energy, without external field induction.

Contribution

It introduces a generalized formalism for vacuum momentum extraction in magnetoelectric materials, differing from prior work by assuming natural ME coupling rather than externally induced fields.

Findings

Predicts electromagnetic momentum extraction from vacuum in ME media

Shows the effect via Green-function formalism and mode analysis

Aligns with Feigel's concept but with different assumptions

Abstract

The Green-function formalism for the electromagnetic field in a magnetoelectric (ME) medium is constructed, as a generalization of conventional Casimir theory. Zero temperature is assumed. It is shown how the formalism predicts electromagnetic momentum to be extracted from the vacuum field, just analogous to how energy is extracted in the Casimir case. The possibility of extracting momentum from vacuum was discussed recently by Feigel [Phys. Rev. Lett. 92, 020404 (2004)]. By contrast to Feigel's approach, we assume that the ME coupling occurs naturally, and is not produced by external strong fields. We also find the same effect qualitatively via another route, by considering one single electromagnetic mode.