Parity lifetime of bound states in a proximitized semiconductor nanowire

TL;DR

This paper investigates quasiparticle excitations in a semiconductor-superconductor nanowire system, revealing a parity lifetime exceeding 10 milliseconds, which is crucial for quantum computing applications.

Contribution

It introduces a new proximitized semiconductor nanowire system and measures quasiparticle dynamics and parity lifetime in this novel setup.

Findings

Identified Andreev-like bound states via bias spectroscopy.

Determined characteristic temperatures and magnetic fields for quasiparticle excitations.

Measured a parity lifetime exceeding 10 milliseconds.

Abstract

Quasiparticle excitations can compromise the performance of superconducting devices, causing high frequency dissipation, decoherence in Josephson qubits, and braiding errors in proposed Majorana-based topological quantum computers. Quasiparticle dynamics have been studied in detail in metallic superconductors but remain relatively unexplored in semiconductor-superconductor structures, which are now being intensely pursued in the context of topological superconductivity. To this end, we introduce a new physical system comprised of a gate-confined semiconductor nanowire with an epitaxially grown superconductor layer, yielding an isolated, proximitized nanowire segment. We identify Andreev-like bound states in the semiconductor via bias spectroscopy, determine the characteristic temperatures and magnetic fields for quasiparticle excitations, and extract a parity lifetime (poisoning time) of the bound state in the semiconductor exceeding 10 ms.