From coherent motion to localization: dynamics of the spin-boson model at zero temperature

Abstract

The dynamics of the spin-boson model at zero temperature is investigated using the multilayer multiconfiguration time-dependent Hartree (ML-MCTDH) method. This method allows a numerically exact description of the dynamics of the spin-boson model in a broad range of coupling strengths. The results show the transition of the dynamics from weakly damped coherent motion to incoherent decay and finally to localization upon increase of the system–bath coupling strength. A detailed analysis of the incoherent decay for stronger coupling reveals that multiple timescales are involved in the dynamics. Furthermore, the applicability of the scaling limit for large characteristic frequencies of the bath as well as the validity of the non-interacting blip approximation are studied in some detail.