The QCD critical end point driven by an external magnetic field in asymmetric quark matter

TL;DR

This paper investigates how isospin asymmetry and external magnetic fields influence the critical end point in the QCD phase diagram using a PNJL model, revealing shifts and the potential re-emergence of phase transitions.

Contribution

It demonstrates that isospin asymmetry shifts the CEP and can eliminate it, while strong magnetic fields can restore the first order phase transition in asymmetric quark matter.

Findings

Isospin asymmetry shifts the CEP to higher chemical potentials and lower temperatures.

Large isospin asymmetry can cause the CEP to disappear.

Strong magnetic fields can reintroduce a first order phase transition.

Abstract

The effect of the isospin/charge asymmetry and an external magnetic field in the location of the critical end point (CEP) in the QCD phase diagram is investigated. By using the 2+1 flavor Nambu--Jona-Lasinio model with Polyakov loop (PNJL), it is shown that the isospin asymmetry shifts the CEP to larger baryonic chemical potentials and smaller temperatures, and in the presence of a large enough isospin asymmetry the CEP disappears. Nevertheless, a sufficiently high external magnetic field can drive the system into a first order phase transition again.