Ultralong-distance quantum correlations in three-terminal Josephson junctions

Abstract

The production of entangled pairs of electrons in ferromagnet-superconductor-ferromagnet or normal metal-superconductor-normal metal three-terminal structures has aroused considerable interest in the last twenty years. In these studies, the distance between the contacts is limited by the zero-energy superconducting coherence length. Here, we demonstrate nonlocality and quantum correlations in voltage-biased three-terminal Josephson junctions over the ultralong distance that exceeds the superconducting coherence length by orders of magnitude. The effect relies on} the interplay between the time-periodic Floquet-Josephson dynamics, Cooper pair splitting and long-range coupling similar to the two-terminal Tomasch effect. We find cross-over between the ``Floquet-Andreev quartets'' (if the spatial separation is smaller than the superconducting coherence length), and the ``ultralong-distance Floquet-Tomasch clusters of Cooper pairs'' if the separation exceeds the superconducting coherence length, possibly reaching the same $\simeq 30\mu$m as in the Tomasch experiments. The effect can be detected with DC-transport and zero-frequency quantum current-noise cross-correlation experiments, and it can be used for fundamental studies of superconducting quasiparticle quantum coherence in the circuits of quantum engineering.

Revised version: 21 pages, 11 figures, changes following suggestions of the Referees, discussion of AC-density of state oscillations added

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Cited by in corpus (10)

• Quantum circuits with multiterminal Josephson-Andreev junctions
• A quantum interferometer for quartets in superconducting three-terminal Josephson junctions
• Driven Andreev molecule
• Proposal for detecting the $\pi -$shifted Cooper quartet supercurrent
• Quartet Tomography in Multiterminal Josephson Junctions
• Magnetointerferometry of multiterminal Josephson junctions
• Long-range coupling between superconducting dots induced by periodic driving
• Nonlocal Josephson diode effect in minimal Kitaev chains
• Ballistic Andreev interferometers
• Revisiting the adiabatic limit in ballistic multiterminal Josephson junctions