近日，美国微软Azure量子公司Chetan Nayak团队研究了砷化铟-铝混合器件中的干涉单次宇称测量。相关论文于2025年2月19日发表在《自然》杂志上。

非阿贝尔任意子的融合是仅测量拓扑量子计算中的一个基本操作。在一维拓扑超导体（1DTS）中，融合相当于确定马约拉纳零模（MZMs）的共享费米子宇称。

研究组介绍了一种与未来融合规则测试兼容的设备架构。使用栅极定义的超导纳米线对砷化铟-铝异质结构中的费米子宇称进行了单次干涉测量。干涉仪通过将邻近的纳米线隧道耦合到量子点而形成。纳米线导致这些量子点的量子电容的状态依赖性偏移高达1 fF。量子电容测量结果显示，在最佳通量值下，磁通周期为h/2e的双模态信号的信噪比（SNR）在3.6微秒内为1。

从量子电容测量的时间轨迹中，研究组提取了在约2T的面内磁场下两个相关态长于1ms的停留时间。根据拓扑平凡和非平凡的起源来区分该测量结果的解释。大电容偏移和长相干时间使得宇称校验测量的分配误差概率为1%。

附：英文原文

Title: Interferometric single-shot parity measurement in InAs–Al hybrid devices

Author: Aghaee, Morteza, Alcaraz Ramirez, Alejandro, Alam, Zulfi, Ali, Rizwan, Andrzejczuk, Mariusz, Antipov, Andrey, Astafev, Mikhail, Barzegar, Amin, Bauer, Bela, Becker, Jonathan, Bhaskar, Umesh Kumar, Bocharov, Alex, Boddapati, Srini, Bohn, David, Bommer, Jouri, Bourdet, Leo, Bousquet, Arnaud, Boutin, Samuel, Casparis, Lucas, Chapman, Benjamin J., Chatoor, Sohail, Christensen, Anna Wulff, Chua, Cassandra, Codd, Patrick, Cole, William, Cooper, Paul, Corsetti, Fabiano, Cui, Ajuan, Dalpasso, Paolo, Dehollain, Juan Pablo, de Lange, Gijs, de Moor, Michiel, Ekefjrd, Andreas, El Dandachi, Tareq, Estrada Saldaa, Juan Carlos, Fallahi, Saeed, Galletti, Luca, Gardner, Geoff, Govender, Deshan, Griggio, Flavio, Grigoryan, Ruben, Grijalva, Sebastian, Gronin, Sergei, Gukelberger, Jan, Hamdast, Marzie, Hamze, Firas, Hansen, Esben Bork, Heedt, Sebastian, Heidarnia, Zahra, Herranz Zamorano, Jess, Ho, Samantha, Holgaard, Laurens, Hornibrook, John, Indrapiromkul, Jinnapat, Ingerslev, Henrik, Ivancevic, Lovro, Jensen, Thomas, Jhoja, Jaspreet, Jones, Jeffrey, Kalashnikov, Konstantin V., Kallaher, Ray, Kalra, Rachpon, Karimi, Farhad, Karzig, Torsten, King, Evelyn, Kloster, Maren Elisabeth, Knapp, Christina, Kocon, Dariusz, Koski, Jonne V., Kostamo, Pasi, Kumar, Mahesh, Laeven, Tom, Larsen, Thorvald, Lee, Jason, Lee, Kyunghoon

Issue&Volume: 2025-02-19

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 parity6,7,8,9,10,11 in indium arsenide–aluminium heterostructures with a gate-defined superconducting nanowire12,13,14. 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 1fF. Our quantum-capacitance measurements show flux h/2e-periodic bimodality with a signal-to-noise ratio (SNR) of 1 in 3.6μs 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 1ms at in-plane magnetic fields of approximately 2T. 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%.

DOI: 10.1038/s41586-024-08445-2

Source: https://www.nature.com/articles/s41586-024-08445-2