Piezoelectric loss in superconducting quantum circuits: Part II*

Recent demonstrations of strong coupling between a superconducting qubit and an acoustic wave resonator [1,2] implies the adoption of sound as a versatile quantum resource. The qubits used in these experiments exhibited reduced coherence times as compared with the state of the art in circuit-QED. While many factors contribute to determining a qubit's coherence, unintentional electromechanical coupling between the circuit and piezoelectric material may be appreciable. In this talk, we will present a technique for measuring the microwave loss due to the presence of known piezoelectric materials. Since electromechanical coupling has an expected frequency dependence, we use the overtones of a stripline resonator to measure the intrinsic loss resulting from piezoelectric materials placed in the field of the resonator. The frequency dependence of this effect may enable us to distinguish it from microwave dielectric loss.
[1] Y. Chu, et al. (2018) arXiv:1804.07426
[2] K. Satzinger, et al. (2018) arXiv:1804.07308