Anomalous Geometric Spin Hall Effect of Light?

TL;DR

This paper explores the geometric spin Hall effect of light (GSHEL) focusing on momentum flux, revealing differences based on energy-momentum tensor types and proposing an experiment to test the effect's physical implications.

Contribution

It introduces a new perspective on GSHEL by analyzing momentum flux and proposes an experimental scheme to determine the more accurate energy-momentum tensor for light.

Findings

Centroid shift of momentum flux doubles that of energy flux with symmetric tensor.

For canonical tensor, momentum and energy flux centroid shifts are equal.

Orbital angular momentum increases centroid displacement of momentum flux to twice that of energy flux.

Abstract

The geometric spin Hall effect of light (GSHEL), similar to the spin Hall effect of light, is also a spin-dependent shift of the centroid of light beam's intensity (energy flux), but it is a purely geometric effect that does not depend on a particular light-matter interaction. In this paper, we discuss the GSHEL with respect to momentum instead of energy flux, and find out that in the case of the symmetric energy-momentum tensor, the shift of the centroid of momentum flux is double that of energy flux. Interestingly, for the canonical energy-momentum tensor, the centroid shift of momentum flux agrees with that of energy flux. If we consider the effect of orbital angular momentum, however, the centroid displacement of momentum flux is twice that of energy flux for both energy-momentum tensors. To tell which energy-momentum tensor of light field would be more "correct", we propose a experimental scheme to test the GSHEL of momentum flux through the mechanical effect of light.