A SEMICLASSICAL APPROACH TO DISSIPATION IN QUANTUM-MECHANICS

Employing the path integral formalism, we study a quantum (test) syste m coupled to an environment consisting of infinitely many harmonic osc illators. A simple semiclassical approximation, in which only real cla ssical trajectories are required, is used to derive the propagator of the reduced density matrix for Ohmic dissipation and high temperatures . The inclusion of a summation over trajectories with the correct Masl ov phases in the final expression for the propagator permits investiga tion of nonharmonic test systems. In a numerical example for a Morse o scillator interacting with a high temperature heat bath, the semiclass ical result, obtained by the method described here, correctly displays the suppression of quantum behavior as observed in the exact calculat ion. (C) 1995 American Institute of Physics.