Quantum probability and applications III, Proc. Conf., Oberwolfach/FRG 1987, Lect. Notes Math. 1303, 103-106 (1988).
[For the entire collection see Zbl 0627.00022.]
Consider the quantum Langevin equation for the position operator x(t) of a Brownian particle in an extended potential V(x)
where the coupling to the heat bath is characterized by a friction or radiation- reaction force (with memory function (t)) and by a random Gaussian operator force F(t) with (symmetric) correlation
The term in square brackets completely characterizes the Langevin equation.
The paper shows that this model can be derived on the basis of the independent-oscillator model of the heat bath, where the Brownian particle is coupled with springs to a large number of surrounding bath particles.