Collective quantum phase slips in multiple nanowire junctions

TL;DR

This paper proposes a novel design of a phase-slip flux qubit using multiple nanowire junctions with tunable symmetry, demonstrating enhanced collective quantum phase slips and potential for quantum computing applications.

Contribution

It introduces a new multi-junction phase-slip flux qubit design with tunable symmetry, showing how asymmetry improves device performance and coupling capabilities.

Findings

Asymmetry enhances collective quantum phase slips.

Tunable gates allow control over device performance.

Coupling two devices via mutual inductance is feasible.

Abstract

Realization of robust coherent quantum phase slips represents a significant experimental challenge. Here we propose a new design consisting of multiple nanowire junctions to realize a phase-slip flux qubit. It admits good tunability provided by gate voltages applied on superconducting islands separating nanowire junctions. In addition, the gates and junctions can be identical or distinct to each other leading to symmetric and asymmetric setups. We find that the asymmetry can improve the performance of the proposed device, compared with the symmetric case. In particular, it can enhance the effective rate of collective quantum phase slips. Furthermore, we demonstrate how to couple two such devices via a mutual inductance. This is potentially useful for quantum gate operations. Our investigation on how symmetry in multiple nanowire junctions affects the device performance should be useful for the application of phase-slip flux qubits in quantum information processing and quantum metrology.