BEC-BCS crossover in a cold and magnetized two color NJL model

Abstract

The BEC-BCS crossover for a Nambu--Jona-Lasinio (NJL) model with diquark interactions is studied in the presence of an external magnetic field. Particular attention is paid to different regularization schemes used in the literature. A thorough comparison of results is performed for the case of a cold and magnetized two-color NJL model. According to our results, the critical chemical potential for the BEC transition exhibits a clear inverse magnetic catalysis effect for magnetic fields in the range $1\ensuremath{\lesssim}eB/{m}_{\ensuremath{\pi}}^{2}\ensuremath{\lesssim}20$. As for the BEC-BCS crossover, the corresponding critical chemical potential is very weakly sensitive to magnetic fields up to $eB\ensuremath{\sim}9{m}_{\ensuremath{\pi}}^{2}$, showing a much smaller inverse magnetic catalysis as compared to the BEC transition, and displays a strong magnetic catalysis from this point on.