Chiral vortical effect for vector fields

TL;DR

This paper investigates the photonic chiral vortical effect in rotating media, comparing two theoretical approaches and resolving a previous discrepancy by introducing a small mass to the vector field.

Contribution

It demonstrates that adding an infinitesimal mass to the vector field reconciles two different methods of calculating the chiral vortical effect for photons.

Findings

Introduction of a small mass aligns the two evaluation methods.

Infrared regularization details are crucial for accurate results.

Implications for theoretical understanding and potential experiments.

Abstract

We consider photonic vortical effect, i.e. the difference of the flows of left- and right-handed photons along the vector of angular velocity in rotating photonic medium. Two alternative frameworks to evaluate the effect are considered, both of which have already been tried in the literature. First, the standard thermal fied theory and, alternatively, Hawking-radiation-type derivation. In our earlier attempt to compare the two approaches, we found a crucial factor of two difference. Here we revisit the problem, paying more attention to details of infrared regularizations. We find out that introduction of an infinitesimal mass of the vector field brings the two ways of evaluating the chiral vortical effect into agreement with each other. Some implications, both on the theoretical and phenomenological sides, are mentioned.