2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/187336The Lindblad master equation for an open quantum system with a Hamiltonian containing an arbitrary potential is written as an equation for the Wigner distribution function in the phase space representation. The time derivative of this function is given by a sum of three parts: the classical one, the quantum corrections and the contribution due to the opening of the system. In the particular case of a harmonic oscillator, quantum corrections do not exist.19 pages, Latex, accepted for publication in Int. J. Mod. Phys. BQuantum Physicstext