Towards the Theory of Cosmological Phase Transitions

TL;DR

The paper analyzes the electroweak phase transition at finite temperature, deriving and examining the finite-temperature potential $V(\phi,T)$ and the bubble nucleation dynamics through the action $S_3$ and rate $S_3/T$. It shows that no dangerous linear terms arise in the effective potential after careful higher-order accounting, but the cubic term is reduced by a factor of $2/3$ due to infrared screening, weakening the transition in the minimal Standard Model and challenging baryogenesis scenarios. Bubble formation is dominated by critical bubbles with $S_3/T\sim130$–$140$ for a strongly first-order transition, while subcritical bubbles are only relevant for extremely weak transitions. The bubble wall propagation through the hot plasma is generally non-relativistic and thick across several parameter regimes, with density enhancements and damping slowing the wall further; the results motivate exploring extensions of the Standard Model to realize a sufficiently strong first-order transition for successful baryogenesis.

Abstract

We discuss recent progress (and controversies) in the theory of finite temperature phase transitions. This includes the structure of the effective potential at a finite temperature, the infrared problem in quantum statistics of gauge fields, the theory of formation of critical and subcritical bubbles and the theory of bubble wall propagation.