Journal of Chemical Physics, Vol.104, No.4, 1506-1518, 1996
On the Relaxation of a 2-Level System - Beyond the Weak-Coupling Approximation
The model of two nondegenerate quantum levels coupled linearly and off-diagonally to a bath of quantum mechanical harmonic; oscillators studied previously by Laird, Budimir, and Skinner is re-examined. Interpretations are made for both the fourth order population relaxation and dephasing processes. Some of the methods used are applied to the standard spin-boson problem. The question of experimental detection of predicted phenomena is discussed. An approximate method, based on a canonical transformation of the original Hamiltonian is proposed to study the problem.
Keywords:CONDENSED MEDIA;ENERGY-TRANSFER;2-STATE SYSTEM;BATH;T2;TEMPERATURE;DYNAMICS;DISSIPATION;OSCILLATOR;MOLECULES