Circuit quantum electrodynamics focuses on the interaction of small superconducting circuits, tailored to behave as two-level quantum systems, with a single mode of the electromagnetic field sustained by a superconducting resonator. It is thus concerned with the investigation of phenomena that arise from the coupling between the simplest non-trivial quantum system — a spin-1/2 or qubit — and a harmonic oscillator. As such, circuit quantum electrodynamics belongs to the more general field of cavity quantum electrodynamics, which deals with natural or artificial spins in the optical, microwave or radio-frequency domains interacting with all kind of resonators. Here we survey the lineage of the concepts and experiments that led first to the development of cavity and then circuit quantum electrodynamics. We discuss similarities and differences between these two fields and compare their present achievements.

电路量子电动力学着重于小型超导电路的相互作用，该电路适合作为两级量子系统运行，并具有由超导谐振器维持的单模电磁场。因此，它涉及对由最简单的非平凡量子系统（自旋1/2或量子位）与谐波振荡器之间的耦合引起的现象的研究。因此，电路量子电动力学属于腔量子电动力学的更一般领域，其涉及与各种谐振器相互作用的光学，微波或射频域中的自然或人工自旋。在这里，我们调查了概念和实验的沿袭，这些概念和实验首先导致了腔的发展，然后导致了电路量子电动力学。