Stability of superconducting resonators: Motional narrowing and the role of Landau-Zener driving of two-level defects
Journal article, 2021

Frequency instability of superconducting resonators and qubits leads to dephasing and time-varying energy loss and hinders quantum processor tune-up. Its main source is dielectric noise originating in surface oxides. Thorough noise studies are needed to develop a comprehensive understanding and mitigation strategy of these fluctuations. We use a frequency-locked loop to track the resonant frequency jitter of three different resonator types—one niobium nitride superinductor, one aluminum coplanar waveguide, and one aluminum cavity—and we observe notably similar random telegraph signal fluctuations. At low microwave drive power, the resonators exhibit multiple, unstable frequency positions, which, for increasing power, coalesce into one frequency due to motional narrowing caused by sympathetic driving of two-level system defects by the resonator. In all three devices, we identify a dominant fluctuator whose switching amplitude (separation between states) saturates with increasing drive power, but whose characteristic switching rate follows the power law dependence of quasi-classical Landau-Zener transitions.

Coplanar waveguides

Aluminum

Energy dissipation

Microwave resonators

Niobium compounds

Natural frequencies

Author

David Niepce

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Technology

J. Burnett

National Physical Laboratory (NPL)

Marina Kudra

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Technology

Jared H. Cole

RMIT University

Jonas Bylander

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Technology

Science advances

2375-2548 (eISSN)

Vol. 7 39 eabh0462

Subject Categories

Other Physics Topics

Fluid Mechanics and Acoustics

Other Electrical Engineering, Electronic Engineering, Information Engineering

DOI

10.1126/sciadv.abh0462

More information

Latest update

10/13/2021