The influence of a repulsive vector coupling in magnetized quark matter

TL;DR

This paper studies how a repulsive vector coupling affects magnetized quark matter, revealing its role in modifying phase transitions, the critical end point, and oscillations under strong magnetic fields at low temperatures.

Contribution

It introduces the impact of a repulsive vector interaction on the phase diagram and transition patterns of magnetized quark matter, highlighting effects on the critical end point and oscillations.

Findings

High magnetic fields increase the density coexistence region when $G_V=0$.

A repulsive vector interaction reduces the coexistence region at high $G_V$ and zero magnetic field.

The vector interaction enhances de Haas-van Alphen oscillations at low temperatures.

Abstract

We consider two flavor magnetized quark matter in the presence of a repulsive vector coupling ($G_V$) devoting special attention to the low temperature region of the phase diagram to show how this type of interaction counterbalances the effects produced by a strong magnetic field. The most important effects occur at intermediate and low temperatures affecting the location of the critical end point as well as the region of first order chiral transitions. When $G_V=0$ the presence of high magnetic fields ($eB \ge 10 m_\pi^2$) increases the density coexistence region with respect to the case when $B$ and $G_V$ are absent while a decrease of this region is observed at high $G_V$ values and vanishing magnetic fields. Another interesting aspect observed at the low temperature region is that the usual decrease of the coexistence chemical value (Inverse Magnetic Catalysis) at $G_V=0$ is highly affected by the presence of the vector interaction which acts in the opposite way. Our investigation also shows that the presence of a repulsive vector interaction enhances the de Haas-van Alphen oscillations which, for very low temperatures, take place at $eB \lesssim 6 m_\pi^2$. We observe that the presence of a magnetic field, together with a repulsive vector interaction, gives rise to a complex transition pattern since $B$ favors the appearance of multiple solutions to the gap equation whereas $G_V$ turns some metastable solutions into stable ones allowing for a cascade of transitions to occur.