Application of the Dyson-type non-unitary representation of the self-consistent collective-coordinate method to simple models (II). O(4) Model

The Dyson-type non-unitary representation of the self-consistent collective-coordinate (SCC) method is applied to a solvable O(4) model which is one of the simplest examples of superconducting cases. The particle-number non-conservation problem in the quasiparticle formalism is approximately solved within the framework of the SCC method by taking into account the coupling effect of the pairing-rotational mode. The numerical calculations show that the present Dyson-type SCC method gives as good results as the original unitary version.