Quantum Rabi model for N-state atoms

TL;DR

This paper introduces an extended N-state Rabi Hamiltonian with parity symmetry, providing analytical solutions and insights into complex atom-cavity systems, including ground state parity changes and applications to molecular energy transfer.

Contribution

It develops a tractable N-state Rabi model with symmetry extension, offering analytical solutions and physical insights into multi-level atom-cavity interactions.

Findings

Ground state parity change at strong coupling in four-state systems

Group-theoretical analysis elucidates system dynamics

Modified rotating wave approximation yields accurate energies

Abstract

A tractable N-state Rabi Hamiltonian is introduced by extending the parity symmetry of the two-state model. The single-mode case provides a few-parameter description of a novel class of periodic systems, predicting that the ground state of certain four-state atom-cavity systems will undergo parity change at strong coupling. A group-theoretical treatment provides physical insight into dynamics and a modified rotating wave approximation obtains accurate analytical energies. The dissipative case can be applied to study excitation energy transfer in molecular rings or chains.