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[[246,4,22]] d ≤
n
246
k
4
d
22
kd²/n
7.87
w
6

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Distance

d_X 22 · witness weight 22 (claimed upper_bound)
witness operator (support, 22 qubits)
[12, 16, 18, 50, 63, 77, 80, 82, 84, 93, 97, 125, 133, 138, 140, 142, 160, 176, 197, 201, 217, 234]
d_Z 22 · witness weight 22 (claimed upper_bound)
witness operator (support, 22 qubits)
[2, 5, 8, 12, 17, 33, 54, 59, 64, 71, 89, 90, 99, 104, 107, 147, 178, 180, 182, 203, 205, 244]
certificate none yet · distance stands as a self-certified upper bound (d ≤)

Construction & provenance

authors Zijian Liang and Ke Liu and Hao Song and Yu-An Chen
provenance literature baseline
construction Twisted-torus bivariate-bicycle code from Generalized toric codes on twisted tori for quantum error correction (PRX Quantum 6, 020357, 2025). Stabilizers f(x,y)=1+x+x3y, g(x,y)=1+y+x2y-2 on the abelian quotient group Z2/L with twist basis a_1=[0, 123], a_2=[1, 22] (n=2|det[a_1,a_2]|=2*123). Reconstructed from the published polynomials and twist; CSS form H_X=[f|g], H_Z=[gbar|fbar].
model classical construction (no AI model)
date 2025
notes Reconstructed baseline from Liang, Liu, Song, Chen, Generalized toric codes on twisted tori for quantum error correction (PRX Quantum 6, 020357, 2025), arXiv:2503.03827. The [[n,k,d]] parameter set and stabilizer polynomials are published in that paper; this entry reproduces them. Distance is an upper bound per the paper (probabilistic for d>20); the witness is the surrogate logical of that weight. Seeded to fill a board coverage gap at this block size, not a discovery.
family bivariate bicycle (a tag, not a ranking)
locality unrestricted (computed from the layout)
weight class weight ≤ 6 (computed)

How this code was found

no research note was staged with this submission — notes are requested for new submissions (notes/README.md)

Parity checks

X-checks 123 · Z-checks 123
H_X (123 checks, sparse supports)
[0, 1, 11, 123, 125, 232] [1, 3, 16, 124, 127, 238] [2, 4, 17, 125, 128, 239] [3, 6, 22, 126, 130, 242] [4, 7, 23, 127, 131, 243] [5, 8, 24, 126, 128, 132] [6, 10, 29, 129, 134, 199] [7, 11, 30, 130, 135, 245] [8, 12, 31, 129, 131, 136] [9, 13, 32, 130, 132, 137] [10, 15, 37, 133, 139, 209] [11, 16, 38, 134, 140, 210] [12, 17, 39, 133, 135, 141] [13, 18, 40, 134, 136, 142] [14, 19, 41, 135, 137, 143] [15, 21, 46, 138, 145, 219] [16, 22, 47, 139, 146, 220] [17, 23, 48, 138, 140, 147] [18, 24, 49, 139, 141, 148] [19, 25, 50, 140, 142, 149] [20, 26, 51, 141, 143, 150] [21, 28, 56, 144, 152, 228] [22, 29, 57, 145, 153, 229] [23, 30, 58, 144, 146, 154] [24, 31, 59, 145, 147, 155] [25, 32, 60, 146, 148, 156] [26, 33, 61, 147, 149, 157] [27, 34, 62, 148, 150, 158] [28, 36, 66, 151, 160, 235] [29, 37, 67, 152, 161, 236] [30, 38, 68, 151, 153, 162] [31, 39, 69, 152, 154, 163] [32, 40, 70, 153, 155, 164] [33, 41, 71, 154, 156, 165] [34, 42, 72, 155, 157, 166] [35, 43, 73, 156, 158, 167] [20, 36, 45, 159, 169, 240] [37, 46, 77, 160, 170, 241] [38, 47, 78, 159, 161, 171] [39, 48, 79, 160, 162, 172] [40, 49, 80, 161, 163, 173] [41, 50, 81, 162, 164, 174] [42, 51, 82, 163, 165, 175] [43, 52, 83, 164, 166, 176] [44, 53, 84, 165, 167, 177] [26, 45, 55, 128, 168, 179] [27, 46, 56, 169, 180, 244] [47, 57, 88, 168, 170, 181] [48, 58, 89, 169, 171, 182] [49, 59, 90, 170, 172, 183] [50, 60, 91, 171, 173, 184] [51, 61, 92, 172, 174, 185] [52, 62, 93, 173, 175, 186] [53, 63, 94, 174, 176, 187] [54, 64, 95, 175, 177, 188] [14, 33, 55, 131, 178, 189] [34, 56, 66, 132, 179, 190] [35, 57, 67, 178, 180, 191] [58, 68, 98, 179, 181, 192] [59, 69, 99, 180, 182, 193] [60, 70, 100, 181, 183, 194] [61, 71, 101, 182, 184, 195] [62, 72, 102, 183, 185, 196] [63, 73, 103, 184, 186, 197] [64, 74, 104, 185, 187, 198] [65, 75, 105, 186, 188, 199] [20, 42, 66, 136, 189, 200] [43, 67, 77, 137, 190, 201] [44, 68, 78, 189, 191, 202] [69, 79, 107, 190, 192, 203] [70, 80, 108, 191, 193, 204] [71, 81, 109, 192, 194, 205] [72, 82, 110, 193, 195, 206] [0, 73, 83, 194, 196, 207] [74, 84, 111, 195, 197, 208] [75, 85, 112, 196, 198, 209] [76, 86, 113, 197, 199, 210] [27, 52, 77, 142, 200, 211] [53, 78, 88, 143, 201, 212] [54, 79, 89, 200, 202, 213] [80, 90, 114, 201, 203, 214] [81, 91, 115, 202, 204, 215] [82, 92, 116, 203, 205, 216] [1, 83, 93, 204, 206, 217] [2, 84, 94, 205, 207, 218] [85, 95, 117, 206, 208, 219] [86, 96, 118, 207, 209, 220] [36, 87, 97, 138, 208, 210] [35, 63, 88, 149, 211, 221] [64, 89, 98, 150, 212, 222] [65, 90, 99, 211, 213, 223] [91, 100, 119, 212, 214, 224] [92, 101, 120, 213, 215, 225] [3, 93, 102, 214, 216, 226] [4, 94, 103, 215, 217, 227] [5, 95, 104, 216, 218, 228] [96, 105, 121, 217, 219, 229] [45, 97, 106, 144, 218, 220] [44, 74, 98, 157, 221, 230] [75, 99, 107, 158, 222, 231] [76, 100, 108, 221, 223, 232] [101, 109, 122, 222, 224, 233] [6, 102, 110, 123, 223, 225] [0, 7, 103, 224, 226, 234] [8, 104, 111, 225, 227, 235] [9, 105, 112, 226, 228, 236] [55, 106, 113, 151, 227, 229] [54, 85, 107, 166, 230, 237] [86, 108, 114, 167, 231, 238] [87, 109, 115, 230, 232, 239] [10, 110, 116, 124, 231, 233] [2, 12, 111, 233, 234, 240] [13, 112, 117, 123, 235, 241] [14, 113, 118, 159, 234, 236] [65, 96, 114, 176, 237, 242] [97, 115, 119, 177, 238, 243] [15, 116, 120, 126, 237, 239] [5, 18, 117, 124, 240, 244] [19, 118, 121, 125, 168, 241] [76, 106, 119, 187, 242, 245] [21, 120, 122, 129, 188, 243] [9, 25, 121, 127, 178, 244] [28, 87, 122, 133, 198, 245]
H_Z (123 checks, sparse supports)
[0, 102, 112, 123, 196, 226] [1, 110, 117, 123, 124, 206] [0, 2, 118, 125, 207, 234] [3, 5, 116, 124, 126, 216] [1, 4, 121, 125, 127, 217] [2, 5, 45, 128, 218, 240] [6, 8, 120, 126, 129, 225] [3, 7, 9, 127, 130, 226] [4, 8, 55, 128, 131, 227] [5, 9, 56, 132, 228, 244] [10, 12, 122, 129, 133, 233] [6, 11, 13, 123, 130, 134] [7, 12, 14, 131, 135, 234] [8, 13, 66, 132, 136, 235] [9, 14, 67, 137, 178, 236] [15, 17, 87, 133, 138, 239] [10, 16, 18, 124, 134, 139] [11, 17, 19, 125, 135, 140] [12, 18, 20, 136, 141, 240] [13, 19, 77, 137, 142, 241] [14, 20, 78, 143, 159, 189] [21, 23, 97, 138, 144, 243] [15, 22, 24, 126, 139, 145] [16, 23, 25, 127, 140, 146] [17, 24, 26, 128, 141, 147] [18, 25, 27, 142, 148, 244] [19, 26, 88, 143, 149, 168] [20, 27, 89, 150, 169, 200] [28, 30, 106, 144, 151, 245] [21, 29, 31, 129, 145, 152] [22, 30, 32, 130, 146, 153] [23, 31, 33, 131, 147, 154] [24, 32, 34, 132, 148, 155] [25, 33, 35, 149, 156, 178] [26, 34, 98, 150, 157, 179] [27, 35, 99, 158, 180, 211] [36, 38, 113, 151, 159, 210] [28, 37, 39, 133, 152, 160] [29, 38, 40, 134, 153, 161] [30, 39, 41, 135, 154, 162] [31, 40, 42, 136, 155, 163] [32, 41, 43, 137, 156, 164] [33, 42, 44, 157, 165, 189] [34, 43, 107, 158, 166, 190] [35, 44, 108, 167, 191, 221] [45, 47, 118, 159, 168, 220] [36, 46, 48, 138, 160, 169] [37, 47, 49, 139, 161, 170] [38, 48, 50, 140, 162, 171] [39, 49, 51, 141, 163, 172] [40, 50, 52, 142, 164, 173] [41, 51, 53, 143, 165, 174] [42, 52, 54, 166, 175, 200] [43, 53, 114, 167, 176, 201] [44, 54, 115, 177, 202, 230] [55, 57, 121, 168, 178, 229] [45, 56, 58, 144, 169, 179] [46, 57, 59, 145, 170, 180] [47, 58, 60, 146, 171, 181] [48, 59, 61, 147, 172, 182] [49, 60, 62, 148, 173, 183] [50, 61, 63, 149, 174, 184] [51, 62, 64, 150, 175, 185] [52, 63, 65, 176, 186, 211] [53, 64, 119, 177, 187, 212] [54, 65, 120, 188, 213, 237] [55, 66, 68, 151, 179, 189] [56, 67, 69, 152, 180, 190] [57, 68, 70, 153, 181, 191] [58, 69, 71, 154, 182, 192] [59, 70, 72, 155, 183, 193] [60, 71, 73, 156, 184, 194] [61, 72, 74, 157, 185, 195] [62, 73, 75, 158, 186, 196] [63, 74, 76, 187, 197, 221] [64, 75, 122, 188, 198, 222] [6, 65, 76, 199, 223, 242] [66, 77, 79, 160, 190, 200] [67, 78, 80, 161, 191, 201] [68, 79, 81, 162, 192, 202] [69, 80, 82, 163, 193, 203] [70, 81, 83, 164, 194, 204] [71, 82, 84, 165, 195, 205] [72, 83, 85, 166, 196, 206] [73, 84, 86, 167, 197, 207] [74, 85, 87, 198, 208, 230] [10, 75, 86, 199, 209, 231] [11, 76, 87, 210, 232, 245] [77, 88, 90, 170, 201, 211] [78, 89, 91, 171, 202, 212] [79, 90, 92, 172, 203, 213] [80, 91, 93, 173, 204, 214] [81, 92, 94, 174, 205, 215] [82, 93, 95, 175, 206, 216] [83, 94, 96, 176, 207, 217] [84, 95, 97, 177, 208, 218] [15, 85, 96, 209, 219, 237] [16, 86, 97, 210, 220, 238] [88, 98, 100, 181, 212, 221] [89, 99, 101, 182, 213, 222] [90, 100, 102, 183, 214, 223] [91, 101, 103, 184, 215, 224] [92, 102, 104, 185, 216, 225] [93, 103, 105, 186, 217, 226] [94, 104, 106, 187, 218, 227] [21, 95, 105, 188, 219, 228] [22, 96, 106, 220, 229, 242] [98, 107, 109, 192, 222, 230] [99, 108, 110, 193, 223, 231] [0, 100, 109, 194, 224, 232] [101, 110, 111, 195, 225, 233] [103, 111, 113, 197, 227, 234] [28, 104, 112, 198, 228, 235] [29, 105, 113, 199, 229, 236] [107, 114, 116, 203, 231, 237] [1, 108, 115, 204, 232, 238] [2, 109, 116, 205, 233, 239] [36, 111, 117, 208, 235, 240] [37, 112, 118, 209, 236, 241] [3, 114, 119, 214, 238, 242] [4, 115, 120, 215, 239, 243] [46, 117, 121, 219, 241, 244] [7, 119, 122, 224, 243, 245]