No abstract

No abstract

No abstract

A Dyson boson realization for two-particle operators at finite temperature is derived using the thermal-field dynamic formalism. The nature of spurious state appearance in the ideal-boson states is investigated. It is further observed that the matrix element of the pairing interaction between the ideal-boson basis is identical to the corresponding fermion matrix element.

The conventional RPA is extended to take into account the effect of the Pauli principle and the ground-state correlations based on the thermo field dynamics formalism. The calculations have been performed for the dipole state in the scheme of 58 nucleons within the degenerate schematic model. A comparison of these results with the calculations carried out within the framework of the standard thermo field dynamics of the RPA is made.