Dressed Polyakov loop and phase diagram of hot quark matter under magnetic field

TL;DR

This study investigates how strong magnetic fields influence the phase transitions of hot quark matter, using an extended Nambu-Jona Lasinio model to analyze the deconfinement and chiral crossovers and their splitting.

Contribution

It introduces the dressed Polyakov loop as a sensitive probe for magnetic field effects and provides a detailed phase diagram showing the splitting of crossovers under strong magnetic fields.

Findings

Dressed Polyakov loop captures both deconfinement and chiral crossovers.

Magnetic field causes a slight split (~10%) between the two crossovers.

Results align qualitatively with other models and recent lattice data.

Abstract

We evaluate the dressed Polyakov loop for hot quark matter in strong magnetic field. To compute the finite temperature effective potential, we use the Polyakov extended Nambu-Jona Lasinio model with eight-quark interactions taken into account. The bare quark mass is adjusted in order to reproduce the physical value of the vacuum pion mass. Our results show that the dressed Polyakov loop is very sensitive to the strenght of the magnetic field, and it is capable to capture both the deconfinement crossover and the chiral crossover. Besides, we compute self-consistently the phase diagram of the model. We find a tiny split of the two aforementioned crossovers as the strength of the magnetic field is increased. Concretely, for the largest value of magnetic field investigated here, $eB=19 m_\pi^2$, the split is of the order of $10\%$. A qualitative comparison with other effective models and recent Lattice results is also performed.