Random-matrix model for quantum Brownian motion

We use a random band-matrix model for the system-bath interaction to derive a Markovian master equation for the time evolution of one-dimensional quan tum systems weakly coupled to a heat bath. We study in detail the damped ha rmonic oscillator and discuss the fluctuation-dissipation relation. In the large-bandwidth, high-temperature limit, our master equation coincides with the equations derived by Agarwal and Caldeira-Leggett. This shows that the Markovian master equations for quantum Brownian motion are independent of model assumptions used in their derivation and, thus, universal. (C) 2001 E lsevier Science B.V. All rights reserved.