We publish a paper to J. Phys. Chem. Lett. that generalizes the theory for the electronic decoherence timescale. The theory offers a rigorous understanding of early time electronic decoherence and revealed that electronic transitions among diabatic states can play an important role in the decoherence dynamics.
I highly recommend the book “Nonequilibrium Many-Body Theory of Quantum Systems” by G. Stefanucci and R. van Leeuwen for those who want to learn many-body perturbation theory, especially in the context of quantum transport.
Ignacio Franco and I derive a general but simple formula for decoherence times. As it demonstrates, the initial purity decay is Gaussian and the associated timescale is determined only by the fluctuations of system and bath operators that enter into the interaction Hamiltonian. Using this formula, we also showed that mixed quantum-classical methods like Ehrenfest dynamics can capture decoherence correctly provided the initial conditions are sampled from a Wigner distribution.