QCD phase transition with nonextensive NJL model in the strong magnetic field

In this work we make use of the Nambu–Jona-Lasinio model to investigate thermodynamic properties of magnetized three-flavor quark matter. The nonequilibrium Tsallis distribution is characterized by a dimensionless nonextensive parameter <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mi>q</a:mi></a:math>. We find that the system always undergoes a crossover transition for all given <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mi>q</c:mi></c:math> values and the pseudocritical temperature decreases with the increasing nonextensive parameter. We show the variation of the pressure and its anisotropy in parallel and perpendicular directions. However, the diamagnetic nature appears within a certain temperature range at zero chemical potential. Moreover, strong magnetic fields can affect the property of a nonextensive system by changing the magnetization significantly. At high temperatures, the paramagnetic nature always occurs no matter how strong the magnetic field is. Finally, we study the effects of nonextensive parameter <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"><e:mi>q</e:mi></e:math> on the trace anomaly and the speed of sound of the system. Published by the American Physical Society 2024