Dissipative Dynamics of Two-Level Systems in Low Temperature Glasses

An approach based on a non-Markovian time-convolutionless polaron master equation is used to probe dynamics of a central chromophore embedded in a bath of two-level systems commonly found in low-temperature glasses. By treating the Hamiltonian in the polaron frame, we can account for initial nonequilibrium bath states as well as the spatially correlated environmental effect. Relevant realistic situations are explored by adopting parameters from previous experiments. It is found that the temperature of the boson bath has a substantial effect on the population relaxation and the decoherence process, and a higher temperature also results in a higher saturation value of the entanglement entropy, while the coupling between the chromophore and the TLS has an effect that goes counter to that of the temperature.