Chiral torsional effect

TL;DR

This paper introduces a novel nondissipative transport phenomenon called the chiral torsional effect, where axial currents arise due to background gravity with torsion, with potential observations in condensed matter systems.

Contribution

It proposes the chiral torsional effect as a new nondissipative transport phenomenon and derives its response in a model of massless Dirac fermions, linking it to the chiral vortical effect.

Findings

Derived the axial current response to torsion in Dirac fermions.

Identified the chiral vortical effect as a special case of the chiral torsional effect.

Suggested possible observation in Weyl/Dirac semimetals and superfluid ^3He-A.

Abstract

We propose the new nondissipative transport effect - the appearance of axial current of thermal quasiparticles in the presence of background gravity with torsion. For the non-interacting model of massless Dirac fermions the response of the axial current to torsion is derived. The chiral vortical effect appears to be the particular case of the chiral torsional effect. The proposed effect may be observed in the condensed matter systems with emergent relativistic invariance (Weyl/Dirac semimetals and the $^3$He-A superfluid).