The phase structure of two color QCD and charged pion condensation phenomenon

TL;DR

This paper explores the phase structure of dense two-color quark matter, revealing dualities that connect various phases and demonstrating how chiral imbalance can induce charged pion condensation relevant to neutron star conditions.

Contribution

It uncovers duality symmetries in the phase diagram of two-color QCD and shows how these relate to three-color cases, providing a new understanding of phase relationships.

Findings

Identifies three dualities linking different phases in two-color QCD.

Demonstrates that phase diagrams are highly symmetric due to dualities.

Shows chiral imbalance induces charged pion condensation in neutron star matter.

Abstract

The phase structure of dense quark matter in the two color case has been investigated with nonzero baryon $\mu_B$, isospin $\mu_I$ and chiral isospin $\mu_{I5}$ chemical potentials. %in the framework of Nambu--Jona-Lasinio model with quark-antiquark and quark-quark interaction channels. It has been shown in the mean-field approximation that there exist three dualities, one of them between phases with spontaneous chiral symmetry breaking and condensation of charged pions, found in the three color case. The other two dual symmetries between the phase with condensation of charged pions and the phase with diquark condensation and between chiral symmetry breaking and diquark condensation phenomena. It has been demonstrated that due to the duality properties the phase diagram is extremely symmetric and the whole phase diagram in two color case can be obtained just by dualities from the phase structure of three color case. This shows that the dualities are rather usefull tool. It is shown that chiral imbalance generates charged pion condensation phenomenon in conditions of matter in neutron stars, i. e. electrically neutral and $\beta$-equilibrated dense quark matter. And that diquark condensation does not prohibit the generation of the charged PC phase by chiral imbalance at least in the two color case.