Cavity QED with surface acoustic waves and superconducting qubits
Surface acoustic waves (SAWs) are vibrations propagating along the surface of a substrate at a typical speed of 3000 m/s. Since it was discovered in the 1960s that electric signals can be converted to SAWs through piezoelectricity, SAWs have been an integral component of TVs, cell phones, etc. since their slow speed (compared to light) gives them a short wavelength (compared to light), which makes it possible to shrink filters, delay lines etc. substantially. Recently, SAWs have begun to be used in quantum-mechanics experiments. In experimental work at Chalmers University of Technology, where I provided theory support, it was shown in 2014 that SAWs can couple to a superconducting qubit. In the present work, we demonstrate, for the first time, coupling between a superconducting qubit and SAWs that have been confined to a cavity. This is thus the first cavity-quantum-electrodynamics (cavity-QED) experiment with SAWs taking the place of light, establishing the field of circuit quantum acoustodynamics. Because of the slow speed and short wavelength of the SAWs, new phenomena can be observed here. The figure above shows a measurement where the qubit is used to detect the SAWs bouncing back and forth in the cavity.
Circuit quantum acoustodynamics with surface acoustic waves
Riccardo Manenti, Anton Frisk Kockum, Andrew Patterson, Tanja Behrle, Joseph Rahamim, Giovanna Tancredi, Franco Nori, and Peter J. Leek
arXiv:1703.04495