The effective action approach applied to nuclear chiral sigma model
The nuclear chiral sigma model of nuclear matter is considered by means of the Cornwall-Jackiw-Tomboulis (CJT) effective action. The method provides a very general framework for investigating many important problems: chiral symmetry in nuclear medium, energy density of nuclear ground state, nuclear Schwinger-Dyson (SD) equations, etc. It is shown that the SD equations for sigma-omega mixing are actually not present in this formalism. For numerical computation purposes the Hartree-Fock (HF) approximation for ground-state energy density is also presented.