Fermi-Einstein condensation in dense QCD-like theories

TL;DR

This paper explores how centre symmetry influences dense QCD-like theories, revealing a novel Fermi Einstein condensation phenomenon driven by centre sector transitions, with implications for cold, dense matter states.

Contribution

It introduces an effective SU(3) quark model incorporating centre sector transitions and demonstrates the occurrence of Fermi Einstein condensation at low temperatures and intermediate chemical potentials.

Findings

Centre transitions occur under extreme conditions in the Schwinger model.

Confinement phase diagram is mapped as a function of temperature and chemical potential.

Fermi Einstein condensation is proposed as a new state of cold, dense matter.

Abstract

While pure Yang-Mills theory feature the centre symmetry, this symmetry is explicitly broken by the presence of dynamical matter. We study the impact of the centre symmetry in such QCD-like theories. In the analytically solvable Schwinger model, centre transitions take place even under extreme conditions, temperature and/or density, and we show that they are key to the solution of the Silver-Blaze problem. We then develop an effective SU(3) quark model which confines quarks by virtue of centre sector transitions. The phase diagram by confinement is obtained as a function of the temperature and the chemical potential. We show that at low temperatures and intermediate values for the chemical potential the centre dressed quarks undergo condensation due to Bose like statistics. This is the Fermi Einstein condensation. To corroborate the existence of centre sector transitions in gauge theories with matter, we study (at vanishing chemical potential) the interface tension in the three-dimensional Z2 gauge theory with Ising matter, the distribution of the Polyakov line in the four-dimensional SU(2)-Higgs model and devise a new type of order parameter which is designed to detect centre sector transitions. Our analytical and numerical findings lead us to conjecture a new state of cold, but dense matter in the hadronic phase for which Fermi Einstein condensation is realised.