Erlangen 2001 – scientific programme

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HK: Physik der Hadronen und Kerne

HK 21: Theorie III

HK 21.1: Talk

Tuesday, March 20, 2001, 16:30–16:45, B

Thermodynamics of the chiral condensate — •Thomas M. Schwarz, Norbert Kaiser, and Wolfram Weise — Physik-Department, Technische Universität München.

We study the temperature and density dependence of the scalar quark condensate ⟨qq⟩ using effective field theory methods. Nucleons interact via perturbative chiral pion exchange and scalar and vector four-nucleon interactions. The latter are treated in mean field approximation giving rise to an effective nucleon mass M^∗ and an effective chemical potential µ^∗. Contributions from pion fluctuations are fully included in the self consistency equations for M^∗ and µ^∗. The strengths of the contact interactions are adjusted to the empirical nuclear matter saturation point. At a temperature of T≃ 20 MeV a liquid-gas phase transition is observed. The dependence of the equation of state P(T,µ,m_π) on the pion mass allows to calculate deviations from the linear decrease in density of the quark condensate. We find that those are small below normal nuclear matter density.
Supported in part by BMBF and GSI.