Quantum equilibrium factor in the decay of a metastable state at low temperature

Abstract

The Kramers factor is the key nonequilibrium contribution to the decay rate of a metastable state of a system in contact with a thermal bath. In the 1980s Wolynes introduced a quantum equilibrium correction to the overall rate. This is responsible for tunnelling and quantum enhancement of rate at low temperature. Based on a quantum formulation of a system-reservoir model and a Wigner canonical thermal distribution function for the harmonic oscillator bath we suggest a generalization of the quantum equilibrium factor and a consequent rate expression which are valid in the deep tunnelling region. © 2006 IOP Publishing Ltd. and SISSA.