The NJL model of dense three-flavor matter with axial anomaly: the low temperature critical point and BEC-BCS diquark crossover

TL;DR

This paper explores the phase structure of dense three-flavor quark matter using the NJL model, revealing a low-temperature critical point and a BEC-BCS crossover driven by the axial anomaly.

Contribution

It demonstrates the emergence of a low-temperature critical point and BEC-BCS crossover in the NJL model with axial anomaly, extending previous Ginzburg-Landau predictions.

Findings

Identification of a low-temperature critical point in the phase diagram.

Observation of BEC of diquark molecules at intermediate densities.

Evidence of a BEC-BCS crossover with increasing chemical potential.

Abstract

We study the QCD phase structure in the three-flavor Nambu-Jona-Lasinio model, incorporating the interplay between the chiral and diquark condensates induced by the axial anomaly. We demonstrate that for an appropriate range of parameters of the model, the interplay leads to the low temperature critical point in the phase structure predicted by a previous Ginzburg-Landau analysis. We also show that a Bose-Einstein condensate (BEC) of diquark molecules emerges in the intermediate density region, and as a result, a BEC-BCS crossover is realized with increasing quark chemical potential.