{
  "abstract": "Nonreciprocal supercurrents in interacting nanostructures can arise when the positive and negative critical currents probe inequivalent portions of a phase-dependent many-body spectrum. We study this mechanism in a parallel double-quantum-dot Josephson junction with strong intradot Coulomb repulsion, where local and non-local Cooper-pair transfer coexist. Using exact diagonalization of a zero-bandwidth Hamiltonian with explicit superconducting orbitals, we show that orbital flux and the gauge-invariant tunnel-sign parity control the interference between local Josephson processes and non-local exchange. For detuned dots, this produces flux-tunable singlet, triplet, and doublet ground-state spectral branches and two rectification regimes. Near the boundaries of the charge sector with singly occupied dots [(1,1) sector], doublet branches compete with singlet or triplet branches, yielding diode efficiencies approaching 40%. Within the triplet-dominated (1,1) sector, nearby singlet crossings asymmetrically reshape the ground-state envelope even when both critical-current extrema lie on the triplet-like branch, producing a broader response of order 10-15%. Finite temperature generally suppresses charge-crossover rectification, however, for intermediate temperatures we find an enhancement of both the normalized efficiency and the absolute critical-current asymmetry in the triplet regime. These results establish phase-dependent many-body branch competition as a gate-, flux-, and tunnel-parity-sensitive source of Josephson nonreciprocity.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.01830",
  "author_total": 3,
  "authors": [
    {
      "name": "Debika Debnath"
    },
    {
      "name": "Fernando Dominguez"
    },
    {
      "name": "Patrik Recher"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/7qdgjw8s1b40g.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.01830",
  "fulltext_url": null,
  "id": "7qdgjw8s1b40g",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.01830",
  "language": null,
  "licence": "LicenseRef-arXiv-nonexclusive-1.0",
  "licence_label": "arXiv licence",
  "licence_source": "article",
  "licence_url": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "cond-mat.mes-hall"
    ],
    [
      "openalex",
      "3107|Quantum and electron transport phenomena"
    ]
  ],
  "openalex": "W7216553502",
  "pdf_url": "https://arxiv.org/pdf/2610.01830",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-01",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/7qdgjw8s1b40g.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:26:03Z",
      "native_id": "2610.01830",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.01830"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:cond-mat.mes-hall",
      "subfield": "condensed-matter"
    }
  ],
  "title": "Flux- and tunnel-parity-controlled Josephson nonreciprocity from singlet-triplet competition in a parallel double quantum dot",
  "title_text": "Flux- and tunnel-parity-controlled Josephson nonreciprocity from singlet-triplet competition in a parallel double quantum dot",
  "type": "preprint",
  "updated_at": "2026-10-30T12:26:03Z",
  "url": "https://research.draconitic.com/paper/7qdgjw8s1b40g",
  "venue": "arXiv",
  "versions": []
}