A quantum generalization of the thermal viscous friction law

On the basis of the equivalence of the energy balance deacription at micro- and macro-level we propose a quantum generalization of the viscous friction law for a macroscopic Langevin equation describing thermal fluctuations without the zero point contribution. This equation recovers the classical case in the limit h -> 0. In particular it satisfies the quantum regression theorem and resolves several anomalies appearing in the quantum extension of the fluctuation dissipation theorem.