Superconducting resonators with voltage-controlled frequency and nonlinearity

TL;DR

This paper demonstrates a voltage-tunable superconducting resonator using a gated InAs-Al Josephson junction, achieving over 2 GHz frequency tuning and mode hybridization, advancing quantum circuit control.

Contribution

It introduces a wide-range, gate-controlled superconducting resonator with non-dissipative non-linearity, enabling dynamic frequency tuning and mode hybridization in quantum circuits.

Findings

Resonant frequency tuned over 2 GHz via gate voltage.

Achieved 44% inductive participation of the junction.

Observed strong hybridization with 51 MHz coupling.

Abstract

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 wide-range gate-tunable superconducting element. We show that the resonant frequency is controlled via a gate-tunable Josephson inductance and that the non-linearity of the voltage-controlled InAs-Al junction is non-dissipative as is the case with conventional Al-AlO$_{x}$ 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.