Quantal Brownian Motion - Dephasing and Dissipation

Abstract

We analyze quantal Brownian motion in $d$ dimensions using the unified model for diffusion localization and dissipation, and Feynman-Vernon formalism. At high temperatures the propagator possess a Markovian property and we can write down an equivalent Master equation. Unlike the case of the Zwanzig-Caldeira-Leggett model, genuine quantum mechanical effects manifest themselves due to the disordered nature of the environment. Using Wigner picture of the dynamics we distinguish between two different mechanisms for destruction of coherence. The analysis of dephasing is extended to the low temperature regime by using a semiclassical strategy. Various results are derived for ballistic, chaotic, diffusive, both ergodic and non-ergodic motion. We also analyze loss of coherence at the limit of zero temperature and clarify the limitations of the semiclassical approach. The condition for having coherent effect due to scattering by low-frequency fluctuations is also pointed out. It is interesting that the dephasing rate can be either larger or smaller than the dissipation rate, depending on the physical circumstances.

LaTex, 23 pages, 4 figures, published vesion

References in corpus (3)

• Intrinsic Decoherence in Mesoscopic Systems
• Quantum Dissipation versus Classical Dissipation for Generalized Brownian Motion
• Dynamics of a Simple Quantum System in a Complex Environment

Cited by in corpus (8)

• Chaos and energy spreading for time-Dependent Hamiltonians, and the various Regimes in the theory of Quantum Dissipation
• Quantum dissipation due to the interaction with chaotic degrees-of-freedom and the correspondence principle
• Dephasing at Low Temperatures
• Dephasing due to the interaction with chaotic degrees of freedom
• Decoherence of a particle in a ring
• Dephasing of a particle in a dissipative environment
• Renormalization of the dephasing by zero point fluctuations
• The dephasing rate formula in the many body context