穷人的马约拉纳四极子
The poor man's Majorana tetron
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中文总结 AI 辅助
该研究提出了一种由四个量子点和超导岛构成的穷人马约拉纳四极子，通过调控参数可实现拓扑Kondo效应，为观察马约拉纳模式的非局域性提供新途径。
中文摘要 AI 辅助
马约拉纳四极子是一种典型的拓扑量子比特，源于一个 hosting 四个马约拉纳模式的超导岛的基态简并性。这种简并性表现为一种有效的非局域自旋自由度，其最典型的特征是拓扑Kondo效应。具有不同费米奇点 parity 的态简并也刻画了最近出现的最小Kitaev链，这些链已成为实现和研究未保护的马约拉纳模式的平台，称为穷人马约拉纳模式。在这里，我们介绍了由四个量子点通过浮动超导岛耦合构成的“穷人马约拉纳四极子”。其充电能量导致点之间非平凡的关联，尽管不像标准四极子，它并不直接由马约拉纳模式的费米奇点 parity 决定。穷人四极子显示了具有奇数费米奇点 parity 的两倍简并基态的参数区域，当与外部导体耦合时，会形成有效的安德森杂质模型。我们展示该系统可以在适当调节实验参数下进入具有拓扑Kondo效应的区域。因此，穷人四极子是一种有望观察马约拉纳模式的非局域性和其相关分数电导的设备。
英文摘要
The Majorana tetron is a prototypical topological qubit stemming from the ground state degeneracy of a superconducting island hosting four Majorana modes. This degeneracy manifests as an effective non-local spin degree of freedom, whose most paradigmatic signature is the topological Kondo effect. Degeneracies of states with different fermionic parities characterize also minimal Kitaev chains which have lately emerged as a platform to realize and study unprotected versions of Majorana modes, dubbed poor man's Majorana modes. Here, we introduce the ``poor man's Majorana tetron'', comprising four quantum dots coupled via a floating superconducting island. Its charging energy yields non-trivial correlations among the dots, although, unlike a standard tetron, it is not directly determined by the fermionic parity of the Majorana modes. The poor man's tetron displays parameter regions with a two-fold degenerate ground state with odd fermionic parity, that gives rise to an effective Anderson impurity model when coupled to external leads. We show that this system can approach a regime featuring the topological Kondo effect under a suitable tuning of experimental parameters. Therefore, the poor man's tetron is a promising device to observe the non-locality of Majorana modes and their related fractional conductance.
