Dephasing of interference in Landau-Zener transitions

We study the effect of dephasing on the Landau-Zener transition. Our approach is based on the interpretation of the transition as an interference process. We derive a phase-uncertainty factor for a general coupling to an environment, and demonstrate the enhancement of the asymptotic transition probability due to this phase uncertainty. We discuss the dependence of this enhancement on the properties of a specific environment at hand, the form of the coupling term, and the coupling strength. Given a certain type of coupling to the environment, we find the characteristic dephasing time (τ_φ) corresponding to the crossover from weak to strong dephasing. We argue that this crossover τ_φ can be regarded as a probe of the relevant time scale of phase oscillations, which are suppressed by the specific dephasing mechanism.