Non-Markovian behavior for spontaneous decay of a V-type three-level atom with quantum interference

The non-Markovian behavior of a V-type three-level atom coupled to a zero-temperature bosonic Lorentzian reservoir is investigated. The two decay channels from two upper states to the ground one are connected due to the spontaneously generated interference. When the two upper states are degenerate, the two channels can be decoupled, and an analytical lower bound of the non-Markovian behavior can be obtained by the optimal choice of a pair of initial states. The non-Markovian behavior can be enhanced by the interference.