报告题目：Generalized Beth--Uhlenbeck approach to correlations in quark matter
报 告 人：David Blaschke，University of Wroclaw, Poland
报告摘要：The thermodynamic potential of a bosonized (P)NJL model for quark matter in the gaussian approximation for the meson and diquark fields is given in the Beth-Uhlenbeck form. This allows a detailed discussion of bound state dissociation in hot, dense matter (Mott effect) in terms of the in-medium scattering phase shift of two-particle correlations. It is shown for the case without meson-diquark mixing that the phase shift can be separated into a continuum and a resonance part. In the latter, the Mott transition manifests itself by a change of the phase shift at threshold by $\pi$ in accordance with Levinson's theorem, when a bound state transforms to a resonance in the scattering continuum. The consequences for the contribution of pionic correlations to the pressure are discussed by evaluating the Beth-Uhlenbeck equation of state in different approximations. A similar discussion is performed for the scalar diquark channel in the normal phase. Further developments and applications of the developed approach are outlined.