Phase space dynamics of overdamped quantum systems
Physikalisches Institut, Albert-Ludwigs-Universität
Freiburg Hermann-Herder-Straße 3, D-79104 Freiburg, Germany
Accepted: 15 November 2002
The phase space dynamics of dissipative quantum systems in strongly condensed phase is considered. Based on the exact path integral approach, it is shown that the Wigner transform of the reduced density matrix obeys a time evolution equation of Fokker-Planck type valid from high down to very low temperatures. The effect of quantum fluctuations is discussed and the accuracy of these findings is tested against exact data for a harmonic system.
PACS: 05.40.-a – Fluctuation phenomena, random processes, noise, and Brownian motion / 03.65.Yz – Decoherence; open systems; quantum statistical methods / 05.60.-k – Transport processes
© EDP Sciences, 2003