# The Supercooled Universe

## TL;DR

This paper explores how supercooling driven by strongly-coupled theories in the early universe affects cosmological phenomena, including relic abundances, dark matter, axions, and gravitational waves.

## Contribution

It demonstrates the role of QCD effects in ending supercooling and analyzes implications for relic densities, dark matter, axion parameters, and gravitational wave signals.

## Key findings

- QCD effects can trigger the end of supercooling.
- Supercooling influences relic abundances and dark matter.
- Enhanced gravitational wave signals are possible.

## Abstract

Strongly-coupled theories at the TeV can naturally drive a long period of supercooling in the early universe. Trapped into the deconfined phase, the universe could inflate and cool down till the temperature reaches the QCD strong scale. We show how at these low temperatures QCD effects are important and could trigger the exit from the long supercooling era. We also study the implications on relic abundances. In particular, the latent heat released at the end of supercooling could be the reason for the similarities between dark matter and baryon energy densities. The axion abundance could also be significantly affected, allowing for larger values of the axion decay constant. Finally, we discuss how a long supercooling epoch could lead to an enhanced gravitational wave signal.