Control and readout of a superconducting artificial atom

Cavity quantum electrodynamics (CQED) features all unique characteristics of quantum mechanics, studying the strong interaction of single photons and atoms. The implementation of artificial superconducting atoms in high quality transmission line cavities realizes such a CQED setup in a solid state environment. This opens the field of quantum optics to embedded devices. Furthermore, the relatively simple fabrication of these devices makes them a promising candidate for the realization of a quantum information processor. In this architecture, macroscopic quantum circuits act as effective two- and three-level systems (qubits and qutrits) by employing the large non-linearity of a Josephson junction. They strongly couple to single photons in a one-dimensional superconducting cavity which inhibits radiative decay for the contained fragile states and at the same time acts as a readout device.