Detecting quark matter in the early universe by gravitational waves

TL;DR

This paper explores the possibility that a first order QCD phase transition at high chemical potential in the early universe could produce detectable gravitational waves, challenging the standard crossover assumption.

Contribution

It investigates the implications of a high chemical potential first order QCD transition on gravitational wave signals and other cosmological phenomena, aligning with current observations.

Findings

Potential gravitational wave signatures from a first order QCD transition.

Implications for dark matter power spectrum and black hole formation.

Possible origins of extragalactic magnetic fields.

Abstract

For large baryochemical potential, strongly interacting matter might undergo a first order phase transition at temperatures T ~ 100-200 MeV. Within standard cosmology, however, the chemical potential is assumed to be very small leading to a crossover. We discuss implications of a first order QCD transition at high chemical potential being consistent with current observations. In this contribution we concentrate on effects on the gravitational wave spectrum. There are other interesting cosmological signals as a modification of the power spectrum of dark matter, the production of stellar black holes, and the seeds for the extragalactic magnetic fields which we briefly address also.