Issue
EPL
Volume 86, Number 6, June 2009
Article Number 60009
Number of page(s) 6
Section General
DOI http://dx.doi.org/10.1209/0295-5075/86/60009
Published online 10 July 2009
EPL, 86 (2009) 60009
DOI: 10.1209/0295-5075/86/60009

Non-Markovian dynamical effects and time evolution of the entanglement entropy of a dissipative two-state system

Zhiguo Lü and Hang Zheng

Department of Physics, Shanghai Jiao Tong University - Shanghai 200240, China

zglv@sjtu.edu.cn

received 19 April 2009; accepted in final form 9 June 2009; published June 2009
published online 10 July 2009

Abstract
We investigate the dynamical information exchange between a two-state system and its environment which is measured by the von Neumann entropy. It is found that in the underdamping regime, the entropy dynamics exhibits an extremely non-Markovian oscillation-hump feature, in which oscillations manifest quantum coherence and a hump of envelop demonstrates temporal memory of bath. It indicates that the process of entropy exchange is bidirectional. When the coupling strength increases up to a certain threshold, the hump along with ripple disappears, which is indicative of the coherent-incoherent dynamical crossover. The long-time limit of entropy evolution reaches the ground-state value which agrees with that of the numerical renormalization group.

PACS
03.65.Yz - Decoherence; open systems; quantum statistical methods.
05.30.-d - Quantum statistical mechanics.
89.70.Cf - Entropy and other measures of information .

© EPLA 2009