Superconducting Resonators with Voltage-Controlled Frequency and Nonlinearity

Voltage-tunable superconductor-semiconductor devices offer a unique platform to realize dynamic tunability in superconducting quantum circuits. By galvanically connecting a gated InAs-Al Josephson junction to a coplanar waveguide resonator, we demonstrate the use of a superconducting element with wideband gate tunability. We show that the resonant frequency is controlled via a gate-tunable Josephson inductance and that the nonlinearity of the InAs-Al junction is nondissipative as is the case with conventional AlOx-Al junctions. As the gate voltage is decreased, the inductive participation of the junction increases up to 44%, resulting in the resonant frequency being tuned by over 2 GHz. Utilizing the wide tunability of the device, we demonstrate that two resonant modes can be adjusted such that they strongly hybridize, exhibiting an avoided-level crossing with a coupling strength of 51 MHz. Implementing such voltage-tunable resonators is the first step toward realizing wafer-scale continuous voltage control in superconducting circuits for qubit-qubit coupling, quantum limited amplifiers, and quantum memory platforms.

Automated summary

Voltage-tunable superconductor-semiconductor devices with wideband gate tunability have been demonstrated by connecting a gated InAs-Al Josephson junction to a coplanar waveguide resonator. The resonant frequency is controlled via a gate-tunable Josephson inductance and the nonlinearity of the InAs-Al junction is nondissipative. The device exhibits a high tunability, with a resonant frequency tuning range of over 2 GHz, and can strongly hybridize two resonant modes with a coupling strength of 51 MHz.