Quantum Vacuum in Hot Nuclear Matter – A Nonperturbative Treatment

We derive the equation of state for hot nuclear matter using Walecka model in a nonperturbative formalism. We include here the vacuum polarisation effects arising from the nucleon and scalar mesons through a realignment of the vacuum. A ground state structure with baryon-antibaryon condensates yields the results obtained through the relativistic Hartree approximation (RHA) of summing baryonic tadpole diagrams. Generalization of such a state to include the quantum effects for the scalar meson fields through the σ-meson condensates amounts to summing over a class of multiloop diagrams. The techniques of thermofield dynamics (TFD) method are used for the finite temperature and finite density calculations. The in-medium nucleon and sigma meson masses are also calculated in a self consistent manner. We examine the liquid-gas phase transition at low temperatures (≈ 20 MeV), as well as apply email: [email protected] 1 the formalism to high temperatures to examine for a possible chiral symmetry restoration phase transition. PACS number: 21.65.+f,21.30.+y Typeset using REVTEX 2