Eur. Phys. J. D 55, 181-187 (2009)
https://doi.org/10.1140/epjd/e2009-00230-6

Non-Markovian weak coupling limit of quantum Brownian motion

Department of Physics and Astronomy, University of Turku, 20014 Turku, Finland

Corresponding author: ^a sabrina.maniscalco@utu.fi

Received: 8 June 2009
Published online: 7 August 2009

Abstract

We derive and solve analytically the non-Markovian master equation for harmonic quantum Brownian motion proving that, for weak system-reservoir couplings and high temperatures, it can be recast in the form of the master equation for a harmonic oscillator interacting with a squeezed thermal bath. This equivalence guarantees preservation of positivity of the density operator during the time evolution and allows one to establish a connection between the dynamics of Schrödinger cat states in squeezed environments and environment-induced decoherence in quantum Brownian motion.