Dynamical Behavior of the Dissipative Two-State System
Abstract
We investigate the dynamical correlation function of a quantum-mechanical two-state system which is coupled to a bosonic heat bath, utilizing the equivalence between the spin-boson Hamiltonian and the 1/r^2 Ising model. The imaginary-time correlation function is calculated by Monte-Carlo simulations on the Ising system and then continued to real time by a Pade approximation. In the unbiased system, the transition from oscillatory to strongly damped behavior is found to occur at a coupling strength close to alpha = 1/2. The biased system favors coherent relaxation and displays a significantly larger crossover value alpha_c. We introduce the quasiparticle picture to describe the relevant behavior at intermediate time scales. Within this approximation, we map out phase diagrams for the unbiased and biased systems.
Cite
@article{arxiv.cond-mat/9712080,
title = {Dynamical Behavior of the Dissipative Two-State System},
author = {Klaus Voelker},
journal= {arXiv preprint arXiv:cond-mat/9712080},
year = {2009}
}
Comments
RevTeX, 11 pages, 13 figures included