Decoherence time in self-induced decoherence

A general method for obtaining the decoherence time in self- induced decoherence is presented. In particular, it is shown that such a time can be computed from the poles of the resolvent or of the initial conditions in the complex extension of the Hamiltonian's spectrum. Several decoherence times are estimated: 10-(13) - 10(-15) s for microscopic systems, and 10(-37) - 10(-39) s for macroscopic bodies. For the particular case of a thermal bath, the order of magnitude of our results agrees with that obtained by the einselection (environment- induced decoherence) approach.