An anomalous propulsion mechanism

TL;DR

This paper investigates a novel propulsion mechanism where chiral fermions emitted from a rotating shell generate thrust, with the effect influenced by the formation of an ergosphere, potentially explaining astrophysical phenomena like pulsar kicks.

Contribution

It introduces a new anomaly-driven propulsion mechanism involving chiral fermions and analyzes its dependence on shell parameters and ergosphere formation.

Findings

The propulsion effect is sensitive to the formation of an ergosphere.

Emission of fermions is driven by chiral and mixed anomalies.

Potential implications for astrophysical phenomena such as pulsar kicks.

Abstract

We consider a gas of free chiral fermions trapped inside a uniform rotating spherical shell. Once the shell becomes transparent the fermions are emitted along the axis of rotation due to the chiral and mixed anomaly. In return, owing to momentum conservation, the shell is propelled forward. We study the dependence of the magnitude of this effect on the shell parameters in a controlled setting and find that it is sensitive to the formation of an ergosphere around the rotating shell. A brief discussion on a possible relation to pulsar kicks is provided.