The Role of Microstate Degeneracy in Phase Transitions: Gravitational Waves from Bubble Entanglement

TL;DR

This paper explores how high microstate degeneracy in vacuum bubbles during phase transitions influences their quantum dynamics and results in unique gravitational wave signatures, challenging classical assumptions.

Contribution

It demonstrates that microstate degeneracy affects bubble merger dynamics and gravitational wave production, introducing a quantum perspective to cosmological phase transitions.

Findings

Degeneracy enhances transition rates.

Quantum entanglement impacts bubble merger dynamics.

Distinct gravitational wave features arise from microstate effects.

Abstract

Vacuum bubbles, formed in first order phase transitions, have important implications for cosmology. In particular, they source gravitational waves. Usually, it is assumed that, once bubbles are materialized, their state, further evolution and mergers are well-described classically. This paper will show that this intuition breaks down for bubbles which possess high microstate degeneracy. This is generic when the phase transition breaks spontaneously a symmetry. First, the degeneracy enhances the transition rate. Furthermore, the internal quantum state of the bubbles profoundly affects the classical dynamics of their mergers. A bubble, no matter how macroscopic, is born in a maximally entangled quantum state. This state can be viewed as a symmetric superposition of many different would-be classical bubbles. The inner entanglement is largely maintained up until their mergers. The resulting true quantum dynamics of the merger is macroscopically different from any type of classical mergers. These differences are imprinted as macroscopic features in the resulting classical gravitational waves. In this way, the inner microstate entanglement of merging bubbles provides a qualitatively new source of gravitational waves. This phenomenon is quantified and compared with the swift memory burden effect in black hole mergers.