Bose-Einstein condensation in dense quark matter

TL;DR

This paper investigates Bose-Einstein condensation of charged pions in dense quark matter using an effective field theory, analyzing how condensates and quasiparticle masses vary with temperature and chemical potential.

Contribution

It applies the 2PI $1/N$-expansion to determine pion and chiral condensates in QCD at finite isospin chemical potential, providing new insights into phase transitions.

Findings

Bose condensation occurs for chemical potentials above the pion mass at zero temperature.

Chiral condensate vanishes for any finite isospin chemical potential in the chiral limit.

The study maps condensate behavior across temperature and chemical potential.

Abstract

We consider the problem of Bose condensation of charged pions in QCD at finite isospin chemical potential $\mu_I$ using the O(4)-symmetric linear sigma model as an effective field theory for two-flavor QCD. Using the 2PI $1/N$-expansion, we determine the quasiparticle masses as well as the pion and chiral condensates as a function of the temperature and isospin chemical potential in the chiral limit and at the physical point. At T=0, Bose condensation takes place for chemical potentials larger than $m_{\pi}$. In the chiral limit, the chiral condensate vanishes for any finite value of $\mu_I$.