Microscopic Description of Critical Bubbles

TL;DR

This paper uses holography to microscopically analyze critical bubbles in first-order phase transitions within a strongly coupled gauge theory, computing surface tension and nucleation rates.

Contribution

It provides a fully microscopic holographic description of critical bubbles, comparing results with effective actions and highlighting the importance of surface tension constraints.

Findings

Holographic solutions match microscopic results when derived from the theory.

Significant discrepancies occur when using only the equation of state and dimensional analysis.

Imposing a surface tension constraint resolves discrepancies.

Abstract

First-order phase transitions occur through the nucleation of critical bubbles of the stable phase within the metastable phase. Using holography, we present a fully microscopic description of these bubbles in a strongly coupled, four-dimensional gauge theory at finite temperature. In the gravitational dual, these bubbles correspond to static, inhomogeneous and unstable black-brane solutions with a localized deformation on the horizon. We construct these solutions across the entire metastable branch and compute the surface tension and the nucleation rate. We then compare these microscopic results with those obtained from a two-derivative effective action for the order parameter in two different scenarios. When the effective action is derived from the microscopic theory via holography, we find remarkable agreement. However, when the effective action is constrained only by the equation of state and dimensional analysis, significant discrepancies emerge. These discrepancies can be resolved if an additional constraint related to the surface tension is imposed.