Stability of Axion-Saxion wormholes

TL;DR

This paper analyzes the perturbative stability of Euclidean axion wormholes, demonstrating their stability through dual formulations and considering the effects of additional scalar fields.

Contribution

It provides a direct derivation of the quadratic action for perturbations and shows stability in both dual descriptions, including with a massless dilaton.

Findings

Axion wormholes are perturbatively stable.

Stability holds even with a massless dilaton or saxion.

Dual formulations yield equivalent stability results.

Abstract

We reconsider the perturbative stability of Euclidean axion wormholes. The quadratic action that governs linear perturbations is derived directly in Euclidean gravity. We demonstrate explicitly that a stability analysis in which one treats the axion as a normal two-form gauge field is equivalent to one performed in the Hodge-dual formulation, where one considers the axion as a scalar with a wrong-sign kinetic term. Both analyses indicate that axion wormholes are perturbatively stable, even in the presence of a massless dilaton, or saxion, field that couples to the axion.