Correlation between two distant quasiparticles in separate superconducting islands mediated by a single spin.
Correlation between two distant quasiparticles in separate superconducting islands mediated by a single spin.
复制标题
由单个自旋介导的单独超导岛中两个遥远的准粒子之间的相关性。
DOI：
10.1038/s41467-024-47694-7
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发表时间：
2024
影响因子：
16.6
通讯作者：
Nygård,Jesper
中科院分区：
文献类型：
--
作者：
EstradaSaldaña,JuanCarlos;Vekris,Alexandros;Pavešič,Luka;Žitko,Rok;Grove-Rasmussen,Kasper;Nygård,Jesper
远距离粒子之间的受控耦合是实现量子信息技术的关键要求。一个很有前途的平台是耦合到超导岛上的半导体量子点的混合系统，其中点的可调性与超导岛的宏观相干性相结合来产生具有非局域关联的态，例如在库珀对分离器中。混合量子点中的电子通常不受长距离自旋排列的影响，因为它们往往会被束缚的超导准粒子屏蔽成局域单重态。然而，来自不同超导体的两个准粒子可以通过屏蔽量子点进入双重状态，导致超导岛之间的铁磁关联。我们提出了稳定的过屏蔽态的实验证据，这意味着在微米距离上存在关联的准粒子。我们提出了一种由量子点和超导岛交替组成的链作为可控大规模自旋耦合的新平台。
Controlled coupling between distant particles is a key requirement for the implementation of quantum information technologies. A promising platform are hybrid systems of semiconducting quantum dots coupled to superconducting islands, where the tunability of the dots is combined with the macroscopic coherence of the islands to produce states with non-local correlations, e.g. in Cooper pair splitters. Electrons in hybrid quantum dots are typically not amenable to long-distance spin alignment as they tend to be screened into a localized singlet state by bound superconducting quasiparticles. However, two quasiparticles coming from different superconductors can overscreen the quantum dot into a doublet state, leading to ferromagnetic correlations between the superconducting islands. We present experimental evidence of a stabilized overscreened state, implying correlated quasiparticles over a micrometer distance. We propose alternating chains of quantum dots and superconducting islands as a novel platform for controllable large-scale spin coupling.