Characterizing losses in InAs two-dimensional electron gas-based gatemon qubits

TL;DR

This paper characterizes InAs 2D electron gas-based gatemon qubits, demonstrating their coherence properties, loss mechanisms, and potential for improved superconducting qubit architectures with all-electric control.

Contribution

It provides the first detailed characterization of InAs 2DEG gatemon qubits, including their coherence times, loss mechanisms, and resonator quality factors, highlighting pathways for enhancement.

Findings

Qubit undergoes vacuum Rabi splitting with readout cavity

Measured qubit relaxation time T1 is 100 ns over 1.5 GHz tunable band

Identified loss mechanisms affecting qubit and resonator performance

Abstract

The tunnelling of cooper pairs across a Josephson junction (JJ) allow for the nonlinear inductance necessary to construct superconducting qubits, amplifiers, and various other quantum circuits. An alternative approach using hybrid superconductor-semiconductor JJs can enable superconducting qubit architectures with all electric control. Here we present continuous-wave and time-domain characterization of gatemon qubits and coplanar waveguide resonators based on an InAs two-dimensional electron gas. We show that the qubit undergoes a vacuum Rabi splitting with a readout cavity and we drive coherent Rabi oscillations between the qubit ground and first excited states. We measure qubit relaxation times to be $T_1 =$ 100 ns over a 1.5 GHz tunable band. We detail the loss mechanisms present in these materials through a systematic study of the quality factors of coplanar waveguide resonators. While various loss mechanisms are present in III-V gatemon circuits we detail future directions in enhancing the relaxation times of qubit devices on this platform.