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Fri, 14 Jul 2006 10:15:51 +0200Fri, 14 Jul 2006 10:15:51 +0200Structure of the vacuum in nuclear matter: a nonperturbative approach
http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/2383
We compute the vacuum polarization correction to the binding energy of nuclear matter in the Walecka model using a nonperturbative approach. We first study such a contribution as arising from a ground-state structure with baryon-antibaryon condensates. This yields the same results as obtained through the relativistic Hartree approximation of summing tadpole diagrams for the baryon propagator. Such a vacuum is then generalized to include quantum effects from meson fields through scalar-meson condensates which amounts to summing over a class of multiloop diagrams. The method is applied to study properties of nuclear matter and leads to a softer equation of state giving a lower value of the incompressibility than would be reached without quantum effects. The density-dependent effective sigma mass is also calculated including such vacuum polarization effects.Amruta Mishra; P. K. Panda; Stefan Schramm; Joachim Reinhardt; Walter Greinerarticlehttp://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/2383Fri, 14 Jul 2006 10:15:51 +0200Hot nuclear matter in the quark meson coupling model
http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/2381
We study here hot nuclear matter in the quark meson coupling model which incorporates explicitly quark degrees of freedom, with quarks coupled to scalar and vector mesons. The equation of state of nuclear matter including the composite nature of the nucleons is calculated at finite temperatures. The calculations are done taking into account the medium-dependent bag constant. Nucleon properties at finite temperatures as calculated here are found to be appreciably different from the value at T=0.P. K. Panda; Amruta Mishra; Judah M. Eisenberg; Walter Greinerarticlehttp://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/2381Fri, 14 Jul 2006 10:14:40 +0200