Self-consistent quantal treatment of decay rates within the perturbed static path approximation.

The framework of the perturbed static path approximation is used to calculate the partition function of a finite Fermi system from a Hamiltonian with a separable two body interaction. Therein, the collective degree of freedom is introduced in self-consistent fashion through a Hubbard-Stratonovich transformation. In this way, all transport coefficients that dominate the decay of a metastable system are defined and calculated microscopically. Otherwise the same formalism is applied as in the Caldeira-Leggett model to deduce the decay rate from the free energy above the so called crossover temperature T(0).