SU(3) Polyakov linear-sigma model: Magnetic properties of QCD matter in thermal and dense medium

TL;DR

This paper uses the Polyakov linear-sigma model to study how strong magnetic fields affect the thermal and dense properties of QCD matter, revealing paramagnetic behavior at high temperatures and inverse magnetic catalysis.

Contribution

The study extends the PLSM to include magnetic field effects using Landau quantization, providing new insights into magnetic properties and phase transitions of QCD matter.

Findings

QCD matter exhibits paramagnetism at high temperatures.

Inverse magnetic catalysis observed with decreasing critical temperatures.

Magnetic field influences Landau level population and order parameters.

Abstract

The linear-sigma model, in which information about confining gluons is included through the Polyakov-loop potential (PLSM), is considered in order to perform a systematic study for various magnetic properties of QCD matter under extreme conditions of high temperatures and densities and finite magnetic field strengths. The introduction of magnetic field to the PLSM Lagrangian requires suitable utilization of Landau quantization, modification in the dispersion relations, and momentum-space dimension-reduction. We observed that increasing the magnetic field leads to filling-up lower Landau levels first and decreasing the number of occupied levels. We conclude that the population of Landau levels is most sensitive to the magnetic field and to the quark charges. The influences of finite magnetic field on the temperature dependence of chiral and deconfinement order-parameter(s) are studied. We present estimations for the magnetization, the magnetic susceptibility, the permeability and the catalysis properties of QCD matter as functions of temperature. The dependences of the resulting freezeout parameters, temperatures and baryon chemical potentials on the corresponding magnetic field strengths have been analyzed, as well. These calculations are compared with recent lattice QCD simulations, whenever available. We conclude that the QCD matter seems to have paramagnetic property at temperatures greater than the critical one. There is an evidence for weak diamagnetic property at low temperatures. Last but not least, we observe that the magnetic catalysis is inverse, namely the critical temperatures decrease with increasing the magnetic field.