Tuesday, March 20, 2012
12:30pm (JFB Library)
Title: Rabi-Vibronic Resonance with a Large Number of Vibrational Quanta
A Resonantly driven two-level system undergoes oscillations of the level populations with Rabi frequency, ΩR. According to the conventional description, coupling to environment leads to the damping of the Rabi oscillations. This description, however, assumes that the environment has a continuous spectrum of frequencies. In the present talk the opposite situation is considered. It is assumed that the environment consists of one discrete mode with frequency, ω0. We demonstrate that near the resonant condition, ΩR=ω0, the motion of the oscillator and two-level system acquire a collective character. The width Δ0 of this Rabi-vibronic resonance depends on the coupling strength, λ, in a singular way, as Δ0 =λ4/3 ω0. Moreover, within the domain, ΩR-ω0 ~ Δ0, the actual frequency of the collective oscillations exhibits a bistable behavior as a function of ΩR. The theory developed relies strongly on the fact that, within the resonant domain, the oscillator is highly excited and can be, thus, treated classically.