トポロジカル量子プロセッサの開発（Topological quantum processor marks breakthrough in computing）

2025-02-20 カリフォルニア大学サンタバーバラ校 (UCSB)

＜関連情報＞

• https://news.ucsb.edu/2025/021760/topological-quantum-processor-marks-breakthrough-computing
• https://www.nature.com/articles/s41586-024-08445-2

InAs-Alハイブリッドデバイスにおける干渉計シングルショットパリティ測定 Interferometric single-shot parity measurement in InAs–Al hybrid devices

Microsoft Azure Quantum,Morteza Aghaee,Alejandro Alcaraz Ramirez,Zulfi Alam,Rizwan Ali,Mariusz Andrzejczuk,Andrey Antipov,Mikhail Astafev,Amin Barzegar,Bela Bauer,Jonathan Becker,Umesh Kumar Bhaskar,Alex Bocharov,Srini Boddapati,David Bohn,Jouri Bommer,Leo Bourdet,Arnaud Bousquet,Samuel Boutin,Lucas Casparis,Benjamin J. Chapman,Sohail Chatoor,Anna Wulff Christensen,Cassandra Chua,… Justin Zilke
Nature  Published:19 February 2025
DOI:https://doi.org/10.1038/s41586-024-08445-2

Abstract

The fusion of non-Abelian anyons is a fundamental operation in measurement-only topological quantum computation¹. In one-dimensional topological superconductors (1DTSs)^2,3,4, fusion amounts to a determination of the shared fermion parity of Majorana zero modes (MZMs). Here we introduce a device architecture⁵ that is compatible with future tests of fusion rules. We implement a single-shot interferometric measurement of fermion parity^{6,7,8,9,10,11} in indium arsenide–aluminium heterostructures with a gate-defined superconducting nanowire^12,13,14. The interferometer is formed by tunnel-coupling the proximitized nanowire to quantum dots. The nanowire causes a state-dependent shift of the quantum capacitance of these quantum dots of up to 1 fF. Our quantum-capacitance measurements show flux h/2e-periodic bimodality with a signal-to-noise ratio (SNR) of 1 in 3.6 μs at optimal flux values. From the time traces of the quantum-capacitance measurements, we extract a dwell time in the two associated states that is longer than 1 ms at in-plane magnetic fields of approximately 2 T. We discuss the interpretation of our measurements in terms of both topologically trivial and non-trivial origins. The large capacitance shift and long poisoning time enable a parity measurement with an assignment error probability of 1%.