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 "provenance": {
  "authors": [
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  "construction": "Dense-packed surface code (arXiv:2511.06758): five rotated surface-code patches fused via code deformation into one weight-4 patch, reconstructed from the authors' stim simulation (github.com/kohei-fujiu/Dense_Pakcing). Data qubits at odd,odd sites of the five_dense_num lattice; each stabilizer on the four diagonal neighbors of its ancilla.",
  "origin": "submission",
  "date": "2026-08-13",
  "novelty": "known_parameters",
  "notes": "Reconstruction of the dense-packed surface code of arXiv:2511.06758 (Fujiu et al.), from the authors' released stim simulation (github.com/kohei-fujiu/Dense_Pakcing). The [[n,k,d]] parameter set is the paper's construction; this entry adds an honest single-layer layout and verifier-checked witnesses. Not a new code family.",
  "references": [
   "arXiv:2511.06758"
  ]
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  "rounds": 5,
  "stim_version": "1.16.0",
  "notes": "Generic sequential two-block extraction: one ancilla per check, X checks then Z checks each round with joint reset/measure layers; CX layers are a proper edge coloring of each Tanner graph (4 X + 4 Z CX layers per round, schedule seed 0; hook-aware orders: every CNOT order suffix needs >= d-1 further data errors to complete a logical, layered by min-conflicts search). Screened by RIS on ker(H_dem) and an observable-constrained seeded BP+OSD search; witnesses validated in GF(2).",
  "contributed_by": {
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   "date": "2026-09-16",
   "method": "generic CSS memory schedule: one ancilla per check, CX layers from a bipartite edge coloring, CNOT orders filtered by a hook-error criterion; screened by RIS on ker(H_dem) and an observable-constrained seeded BP+OSD search"
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}