Signatures of nonlocal Cooper-pair transport and of a singlet-triplet transition in the critical current of a double-quantum-dot Josephson junction

Abstract

We study the critical Josephson current flowing through a double quantum dot weakly coupled to two superconducting leads. We use analytical as well as numerical methods to investigate this setup in the limit of small and large bandwidth leads in all possible charging states, where we account for on-site interactions exactly. Our results provide clear signatures of nonlocal spin-entangled pairs, which support interpretations of recent experiments [Deacon, R. S. et al., Nat. Commun. 6, 7446 (2015)]. In addition, we find that the ground state with one electron on each quantum dot can undergo a tunable singlet-triplet phase transition in the regime where the superconducting gap in the leads is not too large, which gives rise to an additional new signature of nonlocal Cooper pair transport.

13 pages, 9 figures

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Cited by in corpus (15)

• Tuning Topological Superconductivity in Phase-Controlled Josephson Junctions with Rashba and Dresselhaus Spin-Orbit Coupling
• Double quantum dot Cooper-pair splitter at finite couplings
• Coupled superconducting spin qubits with spin-orbit interaction
• From perfect to imperfect poor man's Majoranas in minimal Kitaev chains
• Josephson current via spin and orbital states of a tunable double quantum dot
• Superconductor-quantum dot hybrid coolers
• Supercurrent through an Andreev trimer
• Josephson junction π-0 transition induced by orbital hybridization in a double quantum dot
• BCS surrogate models for floating superconductor-semiconductor hybrids
• Spin-1 Haldane chains of superconductor-semiconductor hybrids
• Amplification of Cooper pair splitting current in a graphene based Cooper pair beam splitter geometry
• Aharonov-Bohm and Aharonov-Casher effects in double quantum dot Josephson junction
• Cooper pair splitting in ballistic ferromagnetic SQUIDs
• Renormalized and iterative formalism of the Andreev levels within large multi-parametric space
• Magnetic flux controlled current phase relationship in double Quantum Dot Josephson junction