Revisiting the Abraham-Minkowski Dilemma

TL;DR

This paper revisits the Abraham-Minkowski dilemma on light momentum in media, showing that under ideal conditions, the Abraham momentum can be unambiguously determined, with implications for quantum optics and moving media.

Contribution

It clarifies the conditions under which the Abraham momentum is uniquely determined and discusses the fundamental role of Minkowski momentum in quantum optics of moving media.

Findings

In the absence of absorption, Abraham momentum is unambiguously determined.

Effective medium formalism limits internal state information, affecting the dilemma.

Minkowski momentum plays a fundamental role in quantum optics of moving media.

Abstract

Here, the Abraham-Minkowski controversy on the correct definition of the light momentum in a macroscopic medium is revisited with the purpose to highlight that an effective medium formalism necessarily restricts the available information on the internal state of a system, and that this is ultimately the reason why the dilemma has no universal solution. Despite these difficulties, it is demonstrated that in the limit of no material absorption and under steady-state conditions, the time-averaged light (kinetic) momentum may be unambiguously determined by the Abraham result, both for bodies at rest and for circulatory flows of matter. The implications of these findings are discussed in the context of quantum optics of moving media, and we examine in detail the fundamental role of the Minkowski momentum in such a context.