VARIATIONAL STUDY FOR A COUPLED SYSTEM OF A QUANTUM TUNNELING STATE WITH PHONONS
量子隧道态-声子耦合系统的变分法研究

The ground state energy of a coupled system of a quantum tunneling state with phonons is investegated by a variational approach. We find that the ground state of the system may be described by two variation states-displaced state and displaced-squeezed state, and the transition of the stable ground state from displaced state to displaced-squeezed state will occur as coupling strength increases. The phase diagram of the transition is also given.