Parity switching in a full-shell superconductor-semiconductor nanowire qubit

TL;DR

This paper measures charge-parity switching times in a superconductor-semiconductor nanowire qubit, revealing long parity lifetimes at zero magnetic field and their dependence on temperature and magnetic field, which impacts qubit coherence.

Contribution

It provides the first direct measurement of charge-parity switching times in full-shell nanowire qubits and models their dependence on temperature and magnetic field.

Findings

Parity switching time T_P is about 100 ms at zero magnetic field.

T_P decreases exponentially with increasing temperature or magnetic field.

Long T_P at zero field is promising for qubit development.

Abstract

The rate of charge-parity switching in a full-shell superconductor-semiconductor nanowire qubit is measured by directly monitoring the dispersive shift of a readout resonator. At zero magnetic field, the measured switching time scale $T_P$ is on the order of 100 ms. Two-tone spectroscopy data post-selected on charge-parity is demonstrated. With increasing temperature or magnetic field, TP is at first constant, then exponentially suppressed, consistent with a model that includes both non-equilibrium and thermally activated quasiparticles. As TP is suppressed, qubit lifetime T1 also decreases. The long $T_P\sim 0.1$ s at zero field is promising for future development of qubits based on hybrid nanowires.