Ground State of a Spin-Boson System. II-- Wave/unction and Variational Study--

We first present a clarifying explanation of the wavefunction of the au~hor's dynamic compensa· tion theory of a spin-boson system. The ground state energy is examined ty the variational method to justify the diagonal approximation introduced in the first part of the present series of works. We present a unified description of the ground state and the resulting phase diagram of the tunneling~ localization transition with varying the strength of spin-boson interaction