Ground state and thermal dynamics of strong interaction

Abstract

We analyze both the groundstate of strong interaction and its behavior at finite temperature and density within an effective low-energy description of strong interaction. This is done in terms of quarks which interact by a local chiral four-fermion NJL-interaction at a scale of order 1 GeV. To address the non-perturbative dynamics, we derive renormalization group flow equations in next to leading order in the derivative expansion that go beyond the leading renormalizable couplings and include the entire bosonic field dependence. We examine these flow equations both in there general form that includes corrections in 1/N_c and in large N_c approximation in order to make contact to previous work on the NJL-model. As an application of the model in the vacuum sector, we compute the spectrum of the Dirac operator. The flow equations are generalized to finite temperatures and densities via the Matsubara formalism. Within this scheme, we analyze the chiral phase diagram and the equation of state of quark matter and compare our results to recent lattice simulations. In addition we study the scale dependence inherent in the RG method in the different context of scale dependent quark masses derived from lattice results on current-current correlators.