QuTech and Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA, Delft, The Netherlands.
Department of Physics, University of California, Santa Barbara, CA, 93106, USA.
Nat Commun. 2019 Jan 16;10(1):245. doi: 10.1038/s41467-018-08161-2.
Quantum computation by non-Abelian Majorana zero modes (MZMs) offers an approach to achieve fault tolerance by encoding quantum information in the non-local charge parity states of semiconductor nanowire networks in the topological superconductor regime. Thus far, experimental studies of MZMs chiefly relied on single electron tunneling measurements, which lead to the decoherence of the quantum information stored in the MZM. As a next step towards topological quantum computation, charge parity conserving experiments based on the Josephson effect are required, which can also help exclude suggested non-topological origins of the zero bias conductance anomaly. Here we report the direct measurement of the Josephson radiation frequency in indium arsenide nanowires with epitaxial aluminium shells. We observe the 4π-periodic Josephson effect above a magnetic field of ≈200 mT, consistent with the estimated and measured topological phase transition of similar devices.
非阿贝尔马约拉纳零模（MZM）的量子计算为在拓扑超导体区域的半导体纳米线网络的非局域电荷宇称态中编码量子信息提供了一种容错方法。到目前为止，MZM 的实验研究主要依赖于单电子隧道测量，这会导致存储在 MZM 中的量子信息的退相干。作为迈向拓扑量子计算的下一步，需要基于约瑟夫森效应的电荷宇称守恒实验，这也有助于排除零偏置电导异常的非拓扑起源的建议。在这里，我们报告了在具有外延铝壳的砷化铟纳米线中直接测量约瑟夫森辐射频率。我们在磁场约 200 mT 以上观察到了 4π 周期性的约瑟夫森效应，与类似器件的估计和测量的拓扑相变一致。
