Bound diquarks and their Bose-Einstein condensation in strongly coupled quark matter

TL;DR

This paper investigates how diquark molecules form and undergo Bose-Einstein condensation in strongly coupled three-flavor quark matter, revealing conditions for their stability and phase transitions at finite temperature and chemical potential.

Contribution

It introduces a quark model to identify diquark excitations and analyzes their stability and BEC formation across the phase diagram of quark matter.

Findings

Bound diquark molecules appear at small chemical potentials.

Bose-Einstein condensation occurs with sufficiently strong attractive interactions.

Diquark stability depends on the coupling strength and temperature.

Abstract

We explore the formation of diquark molecules and their Bose-Einstein condensation (BEC) in the phase diagram of three-flavor quark matter at nonzero temperature, T, and quark chemical potential, mu. Using a quark model with a four-fermion interaction, we identify possible diquark excitations as poles of the microscopically computed diquark propagator. The quark masses are obtained by solving a dynamical equation for the chiral condensate and are found to determine the stability of the diquark excitations. The stability of diquark excitations is investigated in the T-mu plane for different values of the diquark coupling strength. We find that bound diquark molecules appear at small quark chemical potentials at intermediate coupling and that BEC of non-strange diquark molecules occurs if the attractive interaction between quarks is sufficiently strong.