# Chiral sound waves in strained Weyl semimetals

## TL;DR

This paper predicts a new type of unidirectional, gapless sound wave in strained Weyl semimetals, driven by elastic pseudo-magnetic fields and related to the chiral anomaly, with potential for long-distance propagation.

## Contribution

It introduces the concept of chiral sound waves in strained Weyl semimetals, linking elastic fields to chiral anomaly effects and proposing an experimental detection method.

## Key findings

- Chiral sound waves are supported in strained Weyl semimetals.
- These waves propagate unidirectionally along elastic magnetic fields.
- Potential for long-distance propagation due to weak damping.

## Abstract

We show that a strained wire of a Weyl semimetal supports a new type of gapless excitation, the chiral sound wave (CSW). It is a longitudinal charge density wave analog to the chiral magnetic wave predicted in the quark-gluon plasma but driven by an elastic axial pseudo-magnetic field. It involves the axial-axial-axial contribution to the chiral anomaly which couples the chiral charge density to the elastic axial gauge field. The chiral sound is unidirectional: it propagates along the elastic magnetic field and not in the opposite direction. The CSW may propagate for long distances as it does not couple directly to quickly dissipating electromagnetic plasmons, while its damping is controlled by the slow chirality flip rate. We propose an experimental setup to directly detect the chiral sound, which is excited by mechanical vibrations of the crystal lattice in the GHz frequency range. Our findings contribute to a new trend, the chiral acoustics, in strained Weyl semimetals.