ARBITRARILY SLOW RELAXATIONS IN A SPIN-BOSON MODEL UNDER THE NONINTERACTING-BLIP APPROXIMATION
A two-level system coupled to a thermal bath of bosons in the noninteracting-blip approximation, is studied in dependence on the low frequency behavior of the spectral density of the reservoir. The long time evolution of the polarization and the populations exhibits a discontinuity in correspondence of the power four of the super-ohmic regime. By approaching this boundary, the long time inverse power law relaxations become arbitrarily slow. The role of the temperature changes in the transition to powers larger than four, enhancing the amplitude of the long time polarization.
spin-boson noninteracting-blip