{
 "schema_version": "0.1",
 "name": "[[26,8,4]] [[4,2,2]]-amplified [[6,4,2]]",
 "code_type": "CSS",
 "n": 26,
 "k": 8,
 "checks": {
  "X": [
   [
    0,
    4,
    8,
    12,
    16,
    20,
    25
   ],
   [
    1,
    5,
    9,
    13,
    17,
    21,
    25
   ],
   [
    2,
    6,
    10,
    14,
    18,
    22,
    25
   ],
   [
    3,
    7,
    11,
    15,
    19,
    23,
    25
   ],
   [
    0,
    1,
    2,
    3,
    24
   ],
   [
    4,
    5,
    6,
    7,
    24
   ],
   [
    8,
    9,
    10,
    11,
    24
   ],
   [
    12,
    13,
    14,
    15,
    24
   ],
   [
    16,
    17,
    18,
    19,
    24
   ],
   [
    20,
    21,
    22,
    23,
    24
   ]
  ],
  "Z": [
   [
    0,
    4,
    8,
    12,
    16,
    20,
    24
   ],
   [
    1,
    5,
    9,
    13,
    17,
    21,
    24
   ],
   [
    2,
    6,
    10,
    14,
    18,
    22,
    24
   ],
   [
    3,
    7,
    11,
    15,
    19,
    23,
    24
   ],
   [
    0,
    1,
    2,
    3,
    25
   ],
   [
    4,
    5,
    6,
    7,
    25
   ],
   [
    8,
    9,
    10,
    11,
    25
   ],
   [
    12,
    13,
    14,
    15,
    25
   ],
   [
    16,
    17,
    18,
    19,
    25
   ],
   [
    20,
    21,
    22,
    23,
    25
   ]
  ]
 },
 "distance": {
  "d": 4,
  "X": {
   "value": 4,
   "confidence": "upper_bound",
   "witness": [
    0,
    1,
    4,
    5
   ]
  },
  "Z": {
   "value": 4,
   "confidence": "upper_bound",
   "witness": [
    0,
    1,
    4,
    5
   ]
  }
 },
 "provenance": {
  "authors": [
   "@MathysRennela"
  ],
  "construction": "Distance-amplified code: one [[4,2,2]] tensor-product amplification step (central three-term truncation of the chain-complex tensor product, arXiv:2609.37231 Eq. 1/Eq. 12-15) applied to the board's [[6,4,2]] entry, using a sparse independent-row presentation of its checks: n' = 4n + m_X + m_Z = 26, k' = 2k = 8, check weight w' = w+1 = 7. X/Z witnesses are the base witnesses tensored with the weight-2 [[4,2,2]] logical on the central register (weights 4/4); a 100000-trial fast-backend search (seed 5000) found nothing lighter (min weight 4). Base provenance: error-detecting CSS code (H_X = H_Z = the all-ones row on 6 qubits; reproduced from the Error Correction Zoo entry stab_6_4_2, https://errorcorrectionzoo.org/c/stab_6_4_2)",
  "references": [
   "arXiv:2609.37231"
  ],
  "date": "2026-09-30",
  "notes": "Constructed and packaged with the Space Bunny Alpha 1.0 model.",
  "model": "Space Bunny Alpha 1.0"
 },
 "family": "distance-amplified"
}