近日，荷兰代尔夫特理工大学Kouwenhoven, Leo P.团队报道了最小基塔耶夫链的单次奇偶校验读出。相关论文于2026年2月11日发表在《自然》杂志上。

保护量子比特免受噪声干扰对于构建可靠的量子计算机至关重要。拓扑量子比特通过使用马约拉纳零模对的非局域编码量子信息为实现这一目标提供了一条途径。这些模式形成一个共享的费米子态，其占据数（偶数或奇数）定义了编码量子比特的费米子奇偶性。值得注意的是，这种奇偶性只能通过将两个马约拉纳模相互耦合的测量来读出。实现这种量子比特的一个有前景的平台是基塔耶夫链，通过使用超导体耦合量子点来实现。即使是最小的双位点链也承载着一对马约拉纳模，通常被称为“穷人的马约拉纳”，它们在空间上是分离的，但与更长的链相比，提供的保护有限。

研究组介绍了一种通过量子电容读取其奇偶性的测量技术。该方法将两个马约拉纳模耦合起来，并实时分辨其奇偶性，表现为持续时间超过一毫秒的随机电报切换。同时的电荷传感证实了两个奇偶性状态是电中性的，并且对于不耦合模式的探测器而言仍无法区分。这些结果确立了马约拉纳量子比特时域控制的关键读出步骤，解决了长期以来的一个实验难题。

附：英文原文

Title: Single-shot parity readout of a minimal Kitaev chain

Author: van Loo, Nick, Zatelli, Francesco, Steffensen, Gorm O., Roovers, Bart, Wang, Guanzhong, Van Caekenberghe, Thomas, Bordin, Alberto, van Driel, David, Zhang, Yining, Huisman, Wietze D., Badawy, Ghada, Bakkers, Erik P. A. M., Mazur, Grzegorz P., Aguado, Ramn, Kouwenhoven, Leo P.

Issue&Volume: 2026-02-11

Abstract: Protecting qubits from noise is essential for building reliable quantum computers. Topological qubits offer a route to this goal by encoding quantum information non-locally, using pairs of Majorana zero modes. These modes form a shared fermionic state whose occupation—either even or odd—defines the fermionic parity that encodes the qubit1. Notably, this parity can only be accessed by a measurement that couples two Majoranas to each other. A promising platform for realizing such qubits is the Kitaev chain1, implemented in quantum dots coupled using superconductors2. Even the minimal two-site chain hosts a pair of Majorana modes, often called ‘poor man’s Majoranas’, which are spatially separated but offer limited protection compared with longer chains3,4,5. Here we introduce a measurement technique that reads out their parity through quantum capacitance. Our method couples two Majoranas and resolves their parity in real time, visible as random telegraph switching with lifetimes exceeding a millisecond. Simultaneous charge sensing confirms that the two parity states are charge neutral and remain indistinguishable to a probe that does not couple the modes. These results establish the essential readout step for time-domain control of Majorana qubits, resolving a long-standing experimental challenge.

DOI: 10.1038/s41586-025-09927-7

Source: https://www.nature.com/articles/s41586-025-09927-7