The Taming of the Superconducting Qubit: A Tale of Loss

Stuart J. Masson, Ana Asenjo-Garcı́a

Yasunobu Nakamura

A team of physicists claim to have entangled a tardigrade with a superconducting qubit.

Irfan A. Siddiqi

Haoxin Zhou, Kangdi Yu, Yashwanth Balaji +5 more

Dissipation remains a central obstacle to improving superconducting quantum circuits, yet the microscopic origins of loss in widely used materials platforms are not fully understood. Here, we report the observation of interface piezoelectricity-induced dissipation in superconducting qubits fabricated on high-resistivity silicon. Our devices use a transmon qubit with a shunt capacitor that simultaneously serves as an interdigital transducer embedded in a surface acoustic wave resonator. By tuning the qubit transition into resonance with discrete mechanical modes, we observe up to a factor-of-two reduction in qubit lifetime, consistent with energy exchange between the qubit and mechanical modes mediated by piezoelectric coupling at the aluminum-silicon interface. Our findings provide direct evidence for interface piezoelectricity as a distinct loss channel in superconducting qubits. Combined with multiphysics simulations, these findings suggest that interface piezoelectric loss can dominate over loss from two-level systems at sufficiently high frequencies.

Yasunobu Nakamura