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B. Vacchini and K. Hornberger
Relaxation dynamics of a quantum Brownian particle in an ideal gas
Eur. Phys. J. Special Topics 151, 59-72 (2007)


We show how the quantum analog of the Fokker-Planck equation for describing Brownian motion can be obtained as the diffusive limit of the quantum linear Boltzmann equation. The latter describes the quantum dynamics of a tracer particle in a dilute, ideal gas by means of a translation-covariant master equation. We discuss the type of approximations required to obtain the generalized form of the Caldeira-Leggett master equation, along with their physical justification. Microscopic expressions for the diffusion and relaxation coefficients are obtained by analyzing the limiting form of the equation in both the Schrödinger and the Heisenberg picture.

(14 pages)    [journal, pdf, arXiv:0706.4433]           (c) Springer-Verlag 2007