{
  "model": "J1J2",
  "lattice": "square",
  "n_sites": 324,
  "boundary": "P",
  "params": {
    "J2": 0.45
  },
  "instance_id": "J1J2/square_324_P_0.45",
  "rows": [
    {
      "energy": -657.43488,
      "sigma": 0.01296,
      "energy_variance": null,
      "dof": 324,
      "einf": 0,
      "v_score": null,
      "method": "VMC, p = 0 Lanczos steps",
      "bound_type": "variational",
      "bound_type_reason": "variational ansatz at a stated size; energy is an upper bound (assigned during source reading)",
      "reference": "Hu, Becca, Parola & Sorella, Direct evidence for a gapless Z2 spin liquid by frustrating Neel antiferromagnetism, Phys. Rev. B 88, 060402 (2013), arXiv:1304.2630",
      "peer_reviewed": true,
      "source": "sweep-allresults-2026-09-15",
      "provenance": "primary",
      "verified": {
        "checked_on": "2026-09-15",
        "method": "source text of arXiv:1304.2630 read locally (arXiv HTML or pypdf layout text); value copied from the harvested cell and the text, no LLM transcription of numbers; parsed by column from the primary table",
        "reported_as": "-0.50728(1)",
        "note": "TABLE I of arXiv:1304.2630 (pypdf layout text, line 332), L = 18, S = 0, J2/J1 = 0.45 | E/J1 per site in S.S units on the L x L periodic torus; the S = 0 row is the ground state",
        "secondary_of": null
      }
    },
    {
      "energy": -659.32704,
      "sigma": 0.01296,
      "energy_variance": null,
      "dof": 324,
      "einf": 0,
      "v_score": null,
      "method": "VMC + 1 Lanczos step",
      "bound_type": "variational",
      "bound_type_reason": "variational ansatz at a stated size; energy is an upper bound (assigned during source reading)",
      "reference": "Hu, Becca, Parola & Sorella, Direct evidence for a gapless Z2 spin liquid by frustrating Neel antiferromagnetism, Phys. Rev. B 88, 060402 (2013), arXiv:1304.2630",
      "peer_reviewed": true,
      "source": "sweep-allresults-2026-09-15",
      "provenance": "primary",
      "verified": {
        "checked_on": "2026-09-15",
        "method": "source text of arXiv:1304.2630 read locally (arXiv HTML or pypdf layout text); value copied from the harvested cell and the text, no LLM transcription of numbers; parsed by column from the primary table",
        "reported_as": "-0.50874(1)",
        "note": "TABLE II of arXiv:1304.2630 (pypdf layout text, line 354), L = 18, S = 0, J2/J1 = 0.45 | E/J1 per site in S.S units on the L x L periodic torus; the S = 0 row is the ground state",
        "secondary_of": null
      }
    },
    {
      "energy": -660.1824,
      "sigma": 0.01296,
      "energy_variance": null,
      "dof": 324,
      "einf": 0,
      "v_score": null,
      "method": "VMC + Lanczos steps, extrapolated in the variance",
      "bound_type": "extrapolated",
      "bound_type_reason": "zero-variance or bond-dimension extrapolation; not an upper bound (assigned during source reading)",
      "reference": "Hu, Becca, Parola & Sorella, Direct evidence for a gapless Z2 spin liquid by frustrating Neel antiferromagnetism, Phys. Rev. B 88, 060402 (2013), arXiv:1304.2630",
      "peer_reviewed": true,
      "source": "sweep-allresults-2026-09-15",
      "provenance": "primary",
      "verified": {
        "checked_on": "2026-09-15",
        "method": "source text of arXiv:1304.2630 read locally (arXiv HTML or pypdf layout text); value copied from the harvested cell and the text, no LLM transcription of numbers; parsed by column from the primary table",
        "reported_as": "-0.50940(1)",
        "note": "TABLE IV of arXiv:1304.2630 (pypdf layout text, line 396), L = 18, S = 0, J2/J1 = 0.45 | E/J1 per site in S.S units on the L x L periodic torus; the S = 0 row is the ground state",
        "secondary_of": null
      }
    }
  ],
  "url": "https://qmbl.org/i/J1J2/square_324_P_0.45/",
  "per_site_divisor": 1296,
  "per_site_label": "E/N (S.S)",
  "record": {
    "energy": -659.32704,
    "sigma": 0.01296,
    "method": "VMC + 1 Lanczos step",
    "reference": "Hu, Becca, Parola & Sorella, Direct evidence for a gapless Z2 spin liquid by frustrating Neel antiferromagnetism, Phys. Rev. B 88, 060402 (2013), arXiv:1304.2630",
    "bound_type": "variational",
    "energy_per_site": -0.50874
  },
  "no_record_reason": null
}