Chiral current induced by torsional Weyl anomaly

TL;DR

This paper demonstrates that torsion in Dirac and Weyl semimetals can induce novel chiral currents via Weyl anomaly, offering a potential experimental approach to explore theoretical controversies in Weyl anomaly.

Contribution

It reveals a new mechanism where torsion induces chiral currents in Weyl semimetals through Weyl anomaly, linking theoretical physics with experimental possibilities.

Findings

Torsion induces chiral currents in Weyl semimetals.

The effect can be observed near boundaries or in conformally flat spaces.

Experimental measurement could clarify Weyl anomaly controversies.

Abstract

Torsion can be realized as dislocation in the crystal lattice of material. It is particularly interesting if the material has fermions in the spectrum, such as graphene, topological insulators, Dirac and Weyl semimetals, as it's transport properties can be affected by the torsion. In this paper, we find that, due to Weyl anomaly, torsion in Dirac and Weyl semimetals can induce novel chiral currents, either near a boundary or in a ``conformally flat space''. We briefly discuss how to measure this interesting effect in experiment. It is remarkable that these experiments can help to clarify the theoretical controversy of whether an imaginary Pontryagin density could appear in the Weyl anomaly.