Quark matter description in a Tsallis entropy approach

A non-additive entropy is used to describe quark matter. We consider a non-extensive thermodynamic system in the framework of the MIT bag model of hadrons, in order to consider the correlation between quarks and gluons due to strong interactions. The non-additive entropy of the system describes quarks and gluons as two probabilistically independent subsystems. We analyze the phase diagram in terms of the correlation parameter q that enters the sum of entropies in the Tsallis prescription. For the case of non-zero chemical potentials it can be shown that the systems with q <= q(max) may be associated with the weakly coupled systems while those with q > q(max) are more correlated. Furthermore, we find that the critical temperature for the hadron increases as the correlation between quarks and gluons increases, according to the expectations.