Light–matter interaction Hamiltonians in cavity quantum electrodynamics
Michael A. D. Taylor, Arkajit Mandal, Pengfei Huo
Abstract
When matter is strongly coupled to an optical cavity, new hybrid light–matter states are formed, the so-called polariton states. These polaritons can qualitatively change the physical properties of the matter coupled to the cavity by completely altering its energy eigenspectrum. Fueled by experimental innovations in recent years, much progress has been made in simulating the intrinsic quantum behavior of these hybrid states. At the heart of each simulation is the choice of Hamiltonian to represent the total light–matter hybrid system. Even at this fundamental level, there has been significant progress in developing new gauges and representations for this Hamiltonian, whether exact or under approximations. As such, this review aims to discuss several different forms of Hamiltonians for the researcher trying to enter this field by clearly and concisely deriving each different representation from the fundamental Minimal Coupling Hamiltonian. In addition, this review provides commentary on the optimal usage and extent of approximations for each individual representation to assist the reader in choosing the appropriate Hamiltonian for their work.