In the last decade, experiments in quantum optics have increasingly been realised with various artificial atoms such as superconducting qubits, quantum dots or NV-centers, rather than with natural atoms. Also, hybrid systems with natural or artificial atoms, coupled to superconducting microwave resonators or to mechanical resonators, have attracted much interest.
In this talk, I will introduce a new hybrid system, where a superconducting transmon qubit is coupled to propagating phonons in the form of surface acoustic waves (SAWs) . The slow propagation speed of the phonons, and their correspondingly short wavelength, opens up possibilities to investigate new regimes of quantum optics. In particular, I will discuss the concept of a ”giant artificial atom”, an artificial atom which couples to its surroundings at several points that can be spaced wavelengths apart .
Quantum optics, or rather quantum acoustics, with SAWs is a new field with exciting prospects. It appears that not only superconducting qubits, but also quantum dots, trapped ions, and NV-centers can be strongly coupled to SAWs, and that high-quality SAW resonators and waveguides can be built . Thus, many experiments could now be done with phonons instead of photons.