Effective description of axion defects

TL;DR

This paper explores the unique electromagnetic effects of axion strings and domain walls, modeling them with Nambu-Goto-type objects and extending to axionic p-branes, highlighting the role of gauge fields and Goldstone modes.

Contribution

It introduces a unified model for axion defects incorporating gauge fields and generalizes to higher-dimensional axionic p-branes with worldvolume gauge fields.

Findings

Reproduction of electromagnetic effects in a Nambu-Goto-type framework

Extension to axionic p-branes with gauge fields as Goldstone modes

Insights into the coupling of gauge fields with axion defects

Abstract

Axion strings and domain walls exhibit a number of novel effects in the presence of gauge fields, in particular the electromagnetic field. It is shown how these effects are reproduced in a model of Nambu-Goto-type strings and open or closed membranes coupled to gauge fields. The generalization to `axionic p-branes' is considered and it is shown how worldvolume gauge fields that arise in certain cases can be interpreted as Goldstone fields.