We study the thermomagnetic properties of the strong coupling constant $G$ and quark mass $M$ entering the Nambu–Jona-Lasinio model. For this purpose, we compute the quark condensate and compare it to lattice QCD (LQCD) results to extract the behavior of $G$ and $M$ as functions of the magnetic field strength and temperature. We also study the correlation length between test quarks with the same electric and color charges from the probability amplitude to bring a given quark into the plasma, once a previous one with the same quantum numbers is placed at a given distance apart. The behaviour of these quantities changes dramatically as a function of the magnetic field strength at temperatures above and below the critical temperature for the chiral transition. The turn over of these quantities as functions of temperature and field strength provides clues for a better understanding of the inverse magnetic catalysis phenomenon.

Pertubative and nonperturbative QCD