Understanding nuclear shape phase transitions at the nucleon level with a boson mapping approach

Implementing a shell model Hamiltonian with monopole-pair, quadrupole-pair and quadrupole-quadrupole interactions between nucleons, we study the shape phases of nuclei and their transitions, with the Dyson boson mapping approach. The investigation concentrates on the influence of each interaction on the nuclear shape phases. A correspondence between the strength of each of the interactions and the nuclear shape phases is obtained. The investigation also indicates that increasing the quadrupole-pair interaction strength can induce the vibrational to the axially prolate rotational shape phase transition and enhancing the quadrupole-quadrupole interaction can drive the phase transition from the axially oblate rotational to the axially prolate rotational, with the γ-soft rotational being the critical point.