Vacuum Rabi oscillation of an atom without rotating-wave approximation

TL;DR

This paper investigates the exact vacuum Rabi oscillation of an atom coupled to a cavity field without using the rotating-wave approximation, revealing damping, frequency shifts, and decay modifications due to counter-rotating terms.

Contribution

It provides an exact analysis of vacuum Rabi oscillations beyond the Jaynes-Cummings model, highlighting the effects of counter-rotating wave interactions in various regimes.

Findings

Damping Rabi oscillation occurs even in strong coupling.

Counter-rotating interactions significantly alter oscillation frequency and decay rates.

Rabi oscillation can occur for initially unexcited atoms, contrary to J-C model predictions.

Abstract

We have investigated vacuum Rabi oscillation of an atom coupled with single-mode cavity field exactly, and compared the results with that of J-C model. The results show that, there is damping Rabi oscillation for an atom, even in strong coupling regime. For small detuning and weak coupling case, the probability for the atom in excited state oscillates against time with different frequency and amplitude from that of J-C model. It exhibits the counter-rotating wave interaction could significantly effect the dynamic behavior of the atom, even under the condition in which the RWA is considered to be justified. On the other hand, the results also reveal that the counter-rotating wave interaction could obviously modify the decay rate in strong coupling regime. And there is Rabi oscillation for initially unexcited atom, which is contrary to that of J-C model.