Does the Berry phase in a quantum optical system originate from the rotating wave approximation

TL;DR

This paper investigates the origin of the Berry phase in quantum optical systems, demonstrating that it exists regardless of the rotating wave approximation, contrary to recent claims that it only arises due to RWA.

Contribution

The study provides a consistent analysis showing the Berry phase exists in the Rabi model both with and without RWA, extending the understanding to three-level atoms.

Findings

Berry phase exists in the Rabi model regardless of RWA

Berry phase is present in three-level atom systems in quantized fields

The existence of Berry phase is not solely due to the rotating wave approximation

Abstract

The Berry phase (BP) in a quantized light field demonstrated more than a decade ago (Phys. Rev. Lett. 89, 220404) has attracted considerable attentions, since it plays an important role in the cavity quantum electrodynamics. However, it is argued in a recent paper ( Phys. Rev. Lett. 108, 033601) that such a BP is just due to the rotating wave approximation (RWA) and the relevant BP should vanish beyond this approximation. Based on a consistent analysis we conclude in this letter that the BP in a generic Rabi model actually exists, no matter whether the RWA is applied. The existence of BP is also generalized to a three-level atom in the quantized cavity field.