Two-color QCD in a strong magnetic field: The role of the Polyakov loop

TL;DR

This paper investigates how an external magnetic field influences the phase transitions of two-color QCD using a Polyakov-loop extended NJL model, revealing magnetic field-dependent shifts in chiral and deconfinement transition temperatures.

Contribution

It provides the first detailed analysis of magnetic field effects on two-color QCD phase transitions within a Polyakov-loop extended NJL framework, highlighting the splitting and temperature shifts of these transitions.

Findings

Chiral condensate increases with magnetic field strength.

Deconfinement and chiral transitions coincide at low magnetic fields.

Transition temperatures shift differently under magnetic fields, with chiral transition rising by ~35 MeV at high fields.

Abstract

We study two-color QCD in an external magnetic backround at finite temperature using the Polyakov-loop extended two-flavor two-color NJL model. At T=0, the chiral condensate is calculated and it is found to increase as a function of the magnetic field $B$. In the chiral limit the deconfinement transition lies below the chiral transition for nonzero magnetic fields $B$. At the physical point, the two transitions seem to coincide for field strengths up to $|qB|\approx 5m_{\pi}^2$ whereafter they split. The splitting between the two increases as a function of $B$ in both the chiral limit and at the physical point. In the range from zero magnetic field and $|qB|=20 m_{\pi}^2$, the transition temperature for the chiral transition increases by approximately 35 MeV, while the transition temperature for deconfinement is essentially constant.