Quantum Smoluchowski equation: Escape from a metastable state
  We develop a quantum Smoluchowski equation in terms of a true probability distribution function to describe quantum Brownian motion in configuration space in large friction limit at arbitrary temperature and derive the rate of barrier crossing and tunneling within an unified scheme. The present treatment is independent of path integral formalism and is based on canonical quantization procedure. 
Dhruba Banerjee, Bidhan Chandra Bag, Suman Kumar Banik and Deb Shankar   Ray