Properties of Nuclear Matter in A Nonlinear Realized Approach of the SU(2) Chiral Symmetry Spontaneous Breaking

A nonlinear realization of SU(2) chiral symmetry spontaneous breaking approach is developed in the composite operator formalism. The properties of nuclear matter, the pion and the quark condensates in nuclear matter are evaluated. The calculated results show that the saturation properties of nuclear matter can be reproduced well with the approach. Meanwhile, the expectation value of ~pi 2 becomes nonzero in the nuclear matter with minimal density ρN 0.235fm−3, and the quark condensate decreases monotonously with the increasing of the nuclear matter density. As the pion condensate appears, the decreasing rate of the quark condensate is enhanced. PACS numbers: 11.30.Rd, 11.30.Qc, 12.39.Fe,21.65.+f 1 It is known that Quantum chromodynamics (QCD) has a non-trivial vacuum with non-perturbative condensates of quarks and gluons. In the low energy region, QCD has two very important properties: chiral symmetry spontaneous breaking and conne-ment. It is believed that the two properties are closely related to the vacuum character