{
 "schema_version": "0.2",
 "name": "[[23,3,3]] multi-band dense-packed code",
 "code_type": "CSS",
 "n": 23,
 "k": 3,
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 "distance": {
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   "confidence": "upper_bound",
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  "Z": {
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   "confidence": "upper_bound",
   "witness": [
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 "provenance": {
  "authors": [
   "@mathysrennela"
  ],
  "construction": "multi-band dense-packed surface code, rows=2 m=2 pitch=2 (raised-pitch generalization of arXiv:2511.06758)",
  "references": [],
  "date": "2026-09-01",
  "notes": "",
  "model": "GLM 5.3 Flash",
  "origin": "submission"
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 "circuit": {
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    "confidence": "upper_bound",
    "witness": [
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   "Z": {
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    "confidence": "upper_bound",
    "witness": [
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  "rounds": 3,
  "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 8 of a seeded alternating-path coloring). Screened by RIS on ker(H_dem) and an observable-constrained seeded BP+OSD search; witnesses validated in GF(2).",
  "contributed_by": {
   "by": [
    "@vprusso"
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   "date": "2026-09-16",
   "method": "generic CSS memory schedule: one ancilla per check, CX layers from a seeded bipartite edge coloring; screened by RIS on ker(H_dem) and an observable-constrained seeded BP+OSD search"
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    "shots": 21000,
    "failures": 167,
    "seed": 7,
    "decoder": "bposd-cs-10",
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   "Z": {
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    "shots": 20000,
    "failures": 192,
    "seed": 7,
    "decoder": "bposd-cs-10",
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    "ci95": [
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}