Deconfinement and Chiral Symmetry Restoration in a Strong Magnetic Background

TL;DR

This paper investigates how strong magnetic fields influence deconfinement and chiral symmetry restoration in QCD using a Polyakov-loop extended Nambu-Jona Lasinio model, finding that these transitions remain closely linked even at very high magnetic fields.

Contribution

The study introduces a Polyakov-loop dependent coupling in the NJL model to analyze the entanglement of QCD phase transitions under strong magnetic fields, providing new insights into their behavior.

Findings

Deconfinement and chiral crossovers are entangled at high magnetic fields.

The measured split between the transitions is approximately 2% at eB=30 m_pi^2.

The role of the 8-quark term on the crossover entanglement is briefly analyzed.

Abstract

We perform a model study of deconfinement and chiral symmetry restoration in a strong magnetic background. We use a Nambu-Jona Lasinio model with the Polyakov loop, taking into account a possible dependence of the coupling on the Polyakov loop expectation value, as suggested by the recent literature. Our main result is that, within this model, the deconfinement and chiral crossovers of QCD in strong magnetic field are entangled even at the largest value of $eB$ considered here, namely $eB=30 m_\pi^2$ (that is, $B \approx 6\times 10^{15}$ Tesla). The amount of split that we measure is, at this value of $eB$, of the order of 2%. We also study briefly the role of the 8-quark term on the entanglement of the two crossovers. We then compare the phase diagram of this model with previous results, as well as with available Lattice data.