Dissipative Quantum Dynamics with a Lindblad Functional

A Lindblad operator is proposed to describe quantum dynamics of an open system with linear dissipation. Its functional form is determined based on the microscopic Caldeira-Leggett model. It yields a new master equation which preserves positive density evolution on short times and approaches equilibrium at high and low temperatures. The new master equation is applied as an example to study the femtosecond dynamics of vibrational relaxation and desorption at a metal surface.