The quantum Rabi model: solution and dynamics
  This article presents a review of recent developments on various aspects of the quantum Rabi model. Particular emphasis is given on the exact analytic solution obtained in terms of confluent Heun functions. The analytic solutions for various generalisations of the quantum Rabi model are also discussed. Results are also reviewed on the level statistics and the dynamics of the quantum Rabi model. The article concludes with an introductory overview of several experimental realisations of the quantum Rabi model. An outlook towards future developments is also given. 
Qiongtao Xie, Honghua Zhong, Murray T. Batchelor, Chaohong Lee
quant-ph physics.atom-ph