Distance
d_X 6 · witness weight 6 (claimed exact)
witness operator (support, 6 qubits)
[3, 9, 14, 20, 26, 32]
d_Z 6 · witness weight 6 (claimed exact)
witness operator (support, 6 qubits)
[0, 7, 14, 21, 28, 35]
certificate exact, d = 6 · scipy/HiGHS MILP
X: min over 2 Z-logical cosets = 6, all proven; Z: min over 2 X-logical cosets = 6, all proven
Construction & provenance
authors Kitaev, A. Yu.
provenance literature baseline
construction Rotated toric code on an 6x6 torus, distance 6.
model classical construction (no AI model)
date 1997-07-09
notes Distance is exact by construction. 2D layout added 2026-07-23: the 6x6 torus folded into the plane (ring fold i -> 2i / 2(L-i)-1 per axis), making the wrap-around checks geometrically local; single layer, measured interaction radius 2*sqrt(2).
family topological (a tag, not a ranking)
locality 2D-local single (computed from the layout)
weight class weight ≤ 4 (computed)
Parity checks
X-checks 18 · Z-checks 18
H_X (18 checks, sparse supports)
[0, 5, 30, 35]
[1, 2, 31, 32]
[3, 4, 33, 34]
[0, 1, 6, 7]
[2, 3, 8, 9]
[4, 5, 10, 11]
[6, 11, 12, 17]
[7, 8, 13, 14]
[9, 10, 15, 16]
[12, 13, 18, 19]
[14, 15, 20, 21]
[16, 17, 22, 23]
[18, 23, 24, 29]
[19, 20, 25, 26]
[21, 22, 27, 28]
[24, 25, 30, 31]
[26, 27, 32, 33]
[28, 29, 34, 35]
H_Z (18 checks, sparse supports)
[0, 1, 30, 31]
[2, 3, 32, 33]
[4, 5, 34, 35]
[0, 5, 6, 11]
[1, 2, 7, 8]
[3, 4, 9, 10]
[6, 7, 12, 13]
[8, 9, 14, 15]
[10, 11, 16, 17]
[12, 17, 18, 23]
[13, 14, 19, 20]
[15, 16, 21, 22]
[18, 19, 24, 25]
[20, 21, 26, 27]
[22, 23, 28, 29]
[24, 29, 30, 35]
[25, 26, 31, 32]
[27, 28, 33, 34]