Distinct Lifetimes for X and Z Loop Measurements in a Majorana Tetron Device

2025/07/11 by Morteza Aghaee, Zulfi Alam, Aghaee, Morteza +329 · 1 voice · 5 citations
#cond-mat.mes-hall #quant-ph

paper · pdf · doi:10.48550/arxiv.2507.08795

Abstract

We present a hardware realization and measurements of a tetron qubit device in a superconductor-semiconductor heterostructure. The device architecture contains two parallel superconducting nanowires, which support four Majorana zero modes (MZMs) when tuned into the topological phase, and a trivial superconducting backbone. Two distinct readout interferometers are formed by connecting the superconducting structure to a series of quantum dots. We perform single-shot interferometric measurements of the fermion parity for the two loops, designed to implement Pauli-X and Z measurements of the tetron. Performing repeated single-shot measurements yields two widely separated time scales τ_X = 14.5± 0.3 μs and τ_Z = 12.4± 0.4 ms for parity switches observed in the X and Z measurement loops, which we attribute to intra-wire parity switches and external quasiparticle poisoning, respectively. We estimate assignment errors of err^X_a=16% and err^Z_a=0.5% for X and Z measurement-based operations, respectively.

Cited by

• Universal Gates from Braiding and Fusing Anyons on Quantum Hardware
• Unreasonable effectiveness of unsupervised learning in identifying Majorana topology
• Quantum Frustration as a Protection Mechanism in Non-Topological Majorana Qubits
• Hybrid superinductance with Al/InAs
• Pareto-optimality of Majoranas in hybrid platforms

Discussions

• The data in the March meeting talk were incredibly unconvincing In a subsequent preprint, again based on a single region in a single device, Microsoft claimed X-measurements. However, the preprint foc [bsky, 4 points, 1 comments]

Related

• 20 Second Parity Lifetime in an InAs--Pb Tetron Device
• Interferometric Single-Shot Parity Measurement in an InAs-Al Hybrid Device
• Interferometric single-shot parity measurement in InAs–Al hybrid devices
• Leakage at zero temperature from changes in chemical potential in Majorana qubits
• Single-shot parity readout of a minimal Kitaev chain