Optimal entanglement witness for Cooper pair splitters

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A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
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Date
2021-12-15
Department
Department of Applied Physics
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Language
en
Pages
10
1-10
Series
Physical Review B, Volume 104, issue 24
Abstract
The generation of spin-entangled electrons is an important prerequisite for future solid-state quantum technologies. Cooper pairs in a superconductor can be split into separate electrons in a spin-singlet state, however, detecting their entanglement remains an open experimental challenge. Proposals to detect the entanglement by violating a Bell inequality typically require a large number of current cross-correlation measurements, and not all entangled states can be detected in this way. Here, we instead formulate an entanglement witness that can detect the spin-entanglement using only three cross-correlation measurements of the currents in the outputs of a Cooper pair splitter. We identify the optimal measurement settings for witnessing the entanglement, and we illustrate the use of our entanglement witness with a realistic model of a Cooper pair splitter for which we evaluate the cross-correlations of the output currents. Specifically, we find that the entanglement of the spins can be detected even with a moderate level of decoherence. Our work thereby paves the way for an experimental detection of the entanglement produced by Cooper pair splitters.
Description
Funding Information: The work was supported by Academy of Finland through the Finnish Centre of Excellence in Quantum Technology (Projects No. 312057 and No. 312299) and Grants No. 308515 and No. 331737. Publisher Copyright: ©2021 American Physical Society
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DOI
10.1103/PhysRevB.104.245425
Citation
Tam, M, Flindt, C & Brange, F 2021, ' Optimal entanglement witness for Cooper pair splitters ', Physical Review B, vol. 104, no. 24, 245425, pp. 1-10 . https://doi.org/10.1103/PhysRevB.104.245425
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https://urn.fi/URN:NBN:fi:aalto-202201121180
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[article-cris] Perustieteiden korkeakoulu / SCI