CQED

Abstract

In this chapter we will discuss two different physical systems in which a single mode of the electromagnetic field in a cavity interacts with a two-level dipole emitter. In the first example, the system is comprised of a single two-level atom inside an optical cavity. The study of this system is often known as cavity quantum electrodynamics (cavity QED) as it may be described using the techniques of the previous chapter. The second example is comprised of a superconducting Cooper pair box inside a co-planar microwave resonator. The description of this system is given in terms of the quantisation of an equivalent electronic circuit and thus goes by the name of circuit quantum electrodynamics (circuit QED). In both cases we are typically interested in the strong coupling regime in which the single photon Rabi frequency g (the coupling constant in the Jaynes–Cummings model) is lager than both the spontaneous decay rate, γ, of the two-level emitter and the rate, κ , at which photons are lost from the cavity.