Cosmological Phase Transition of Spontaneous Confinement

TL;DR

This paper investigates the dynamics of cosmological confinement transitions in nearly conformal theories, highlighting how a dilaton effective theory can predict transition rates and their implications for gravitational wave signals.

Contribution

It introduces a method to compute transition rates in conformal theories using dilaton effective theory and explores how RG fixed points influence transition speed and gravitational wave signals.

Findings

Transition rates can be computed via dilaton effective theory.

Two RG fixed points can accelerate the phase transition.

Weaker gravitational wave signals are associated with faster transitions.

Abstract

The dynamics of a cosmological (de)confinement phase transition is studied in nearly conformally invariant field theories, where confinement is predominantly spontaneously generated and associated with a light "dilaton" field. We show how the leading contribution to the transition rate can be computed within the dilaton effective theory. In the context of Composite Higgs theories, we demonstrate that a simple scenario involving two renormalization-group fixed points can make the transition proceed much more rapidly than in the minimal scenario, thereby avoiding excessive dilution of matter abundances generated before the transition. The implications for gravitational wave phenomenology are discussed. In general, we find that more (less) rapid phase transitions are associated with weaker (stronger) gravitational wave signals. The various possible features of the strongly coupled composite Higgs phase transition discussed here can be concretely modeled at weak coupling within the AdS/CFT dual Randall-Sundrum extra-dimensional description, which offers important insights into the nature of the transition and its theoretical control. These aspects will be presented in a companion paper.