Chalmers University of Technology, Sweden
We study artificial atoms in the form of superconducting qubits and demonstrate how they interact with propagating photons and phonons at the quantum level. In the photon experiments, a superconducting qubit is coupled to a 1D transmission line and strong interaction between the artificial atom and photons is revealed in the reflection and transmission of the propagating microwaves. A number of different effects based on the scattering properties of the qubit is discussed, including an experiment where the ”atom" is placed in front of a mirror. We also present a new type of mechanical quantum device, where sound in the form of propagating surface acoustic wave (SAW) phonons couple to a superconducting qubit through the piezoelectric effect, thus realising atom-phonon interaction. New regimes that cannot be reached with real atoms can be studied with this type of device. In particular ”giant atoms” that are larger than the wavelength of the interacting field is discussed.