Voltage-tunable superconducting quantum circuits with InAs two-dimensional electron gases
Cooper pair transport in Josephson elements provides the key nonlinearity to construct quantum devices with superconducting circuits. While state of the art superconducting qubits are almost exclusively based on Al/AlOx/Al tunnel junctions, an alternative approach using hybrid superconductor-semiconductor Josephson junctions (JJs) can enable a superconducting qubit architecture with full electric field control. In this talk, I will present progress on using superconductor-semiconductor JJs as the key element in voltage-tunable qubits and couplers where our team has demonstrated a gate voltage tunable frequency (several GHz), impedance, and nonlinearity, as well as coherent control of the qubit state. Crucial to its application in qubit technologies, I will present a comprehensive analysis of the losses in the semiconductor and superconductor materials. Finally, I will present a new qubit architecture, named gatemonium, which may provide a path forward not only for improved coherence times in superconducting circuits based on S-Sm hybrid materials, but also provide a path forward for Josephson junction arrays with enhanced plasma frequencies.