Generalized $\mathbb{Z}_p$ toric codes as qudit low-density parity-check codes
We study two-dimensional translation-invariant CSS stabilizer codes over prime-dimensional qudits on the square lattice under twisted boundary conditions, generalizing the Kitaev $\mathbb{Z}_p$ toric code by augmenting each stabilizer with two additi…
Authors: Zijian Liang, Yu-An Chen
Generalized Z p toric co des as qudit lo w-densit y parit y-c hec k co des Zijian Liang 1 and Y u-An Chen 1 , ∗ 1 International Center for Quantum Materials, Scho ol of Physics, Peking University, Beijing 100871, China (Dated: F ebruary 24, 2026) W e study tw o-dimensional translation-in v arian t CSS stabilizer co des o v er prime-dimensional qu- dits on the square lattice under t wisted boundary conditions, generalizing the Kitaev Z p toric co de b y augmenting each stabilizer with tw o additional qudits. Using the Laurent-polynomial formalism, w e adapt the Gr¨ obner basis to compute the logical dimension k efficien tly , without explicitly con- structing large parit y-chec k matrices. W e then perform a systematic searc h ov er v arious stabilizer realizations and lattice geometries for p ∈ { 3 , 5 , 7 , 11 } , iden tifying qudit low-densit y parity-c heck co des with the optimal finite-size p erformance. Representativ e examples include [[242 , 10 , 22]] 3 and [[120 , 6 , 20]] 11 , b oth achieving kd 2 /n = 20. Across the searched regime, the b est observed k d 2 at fixed n increases with p , with an empirical relation k d 2 = 0 . 0541 n 2 ln p + 3 . 84 n , compatible with a Bra vyi–Poulin–T erhal–t yp e tradeoff when the in teraction range gro ws with system size. In tro duction. — F ault-tolerant quantum computation requires activ e protection against noise, and quan- tum error-correcting codes are essen tial to ac hiev e this goal [ 1 – 5 ]. T op ological stabilizer codes, such as toric co des, are promising because they use lo cal parit y chec ks to ac hieve high thresholds on tw o-dimensional arc hitec- tures [ 6 – 18 ]. Recen t dev elopments on biv ariate bicy- cle (BB) codes sho w that t wo-dimensional translation- in v arian t CSS codes with weigh t-6 chec ks can outper- form the standard toric code on relativ ely small tori, with p erformance improv ed b y nearly an order of mag- nitude [ 19 – 32 ]. Most of the existing literature, ho wev er, fo cuses on qubit co des, ev en though several experimental platforms naturally realize higher-level systems suc h as qutrits or more general qudits [ 33 – 41 ]. This motiv ates the question of ho w to design and analyze efficient quan- tum low-densit y parit y-c hec k (LDPC) co des directly in the qudit setting [ 42 ]. A t an abstract level, tw o-dimensional translation- in v arian t Pauli stabilizer co des ov er prime-dimensional qudits that satisfy the top ological order (TO) condition are kno wn to b e locally equiv alent to stacks of Z p toric co des and trivial product states [ 43 – 51 ]. The language of topological order and top ological quan tum field the- ory (TQFT) [ 52 – 88 ], such as any on types, fusion and braiding, ground-state degeneracy , and Wilson-line op- erators, can therefore be imported directly in to the qudit stabilizer setting. F rom this p ersp ective, a Z p qudit sta- bilizer code can b e view ed as a discrete Z p top ological gauge theory equipp ed with a built-in notion of topolog- ical excitations and their syndromes. In parallel, an algebraic viewpoint base d on Laurent p olynomial rings provides a pow erful framew ork for an- alyzing translation-inv ariant stabilizer codes [ 31 , 46 , 47 , 89 ]. By represen ting P auli operators as mo dules o v er the p olynomial ring R = Z p [ x ± 1 , y ± 1 ], one enco des lo cal- it y and translation inv ariance in to polynomial data and extracts the asso ciated an yon conten t via ring-theoretic metho ds. Gr¨ obner-basis techniques then enable efficient ∗ E-mail: yuanchen@pku.edu.cn computation of the ground-state degeneracy and logi- cal op erators on twisted tori, without constructing large parit y-chec k matrices. In this work, we adapt this ma- c hinery to prime-dimensional qudits, focusing on gener- alized Z p toric co des in whic h the standard X -star and Z -plaquette stabilizers are augmented b y tw o additional qudits, yielding w eight-6 chec ks. W e then systematically searc h for lo w-ov erhead qudit LDPC co des at system sizes of a few h undred qudits. Summary of results. — W e study t wo-dimensional translation-in v arian t CSS co des ov er Z p qudits with p ∈ { 3 , 5 , 7 , 11 } , sp ecified b y a pair of Laurent p olynomials f ( x, y ) , g ( x, y ) ∈ R . This p olynomial data determines the stabilizers of generalized Z p toric co des on t wisted tori. W e systematically enumerate lo cal stabilizer real- izations together with twisted b oundary conditions, and compute the corresp onding code parameters [[ n, k, d ]] p , where n is the n umber of physical qudits, k is the n um- b er of logical qudits, and d is the code distance. F or p = 3 w e searc h system sizes up to n ≤ 250, while for p ∈ { 5 , 7 , 11 } w e search up to n ≤ 150. The resulting high-p erforming qudit LDPC co des and their [[ n, k , d ]] p parameters are summarized in T ables I – IV . W e explicitly present these [[ n, k , d ]] p co des via their stabilizers (Fig. 1(a) ) and the t wisted torus (Fig. 1(b) ). F or fixed parameters [[ n, k , d ]] p , there are t ypically man y c hoices of stabilizer polynomials and lattice v ectors; in the tables, we highlight realizations with the most lo cal stabilizers, whic h are most promising for implemen tation on qudit hardw are. Represen tative examples include [[52 , 8 , 7]] 3 , [[78 , 6 , 11]] 3 , [[156 , 10 , 15]] 3 , [[242 , 10 , 22]] 3 , [[30 , 4 , 7]] 5 , [[40 , 4 , 9]] 5 , [[78 , 10 , 9]] 5 , [[120 , 6 , 17]] 5 , [[28 , 4 , 7]] 7 , [[96 , 6 , 15]] 7 , [[98 , 10 , 12]] 7 , [[144 , 6 , 21]] 7 , [[40 , 4 , 10]] 11 , [[100 , 6 , 17]] 11 , [[120 , 6 , 20]] 11 , [[144 , 6 , 23]] 11 . In particular, the co des [[242 , 10 , 22]] 3 and [[120 , 6 , 20]] 11 b oth attain k d 2 /n = 20; their stabilizers and twisted tori are shown in Fig. 2 . Moreo ver, within the searc hed regime the b est observed kd 2 at fixed n increases with p , sho wn as Fig. 3 , and the fit in Fig. 4 yields the empirical relation k d 2 = 0 . 0541 n 2 ln p + 3 . 84 n . 2 (a) Generalized toric co des ov er Z p . (b) Twisted torus in three-dimensional space. FIG. 1. (a) The A v and B p stabilizers of the generalized Z p toric co des, parameterized by the Laurent p olynomials f ( x, y ) = 1 + r 1 x + r 2 x a y b and g ( x, y ) = 1 + r 3 y + r 4 x c y d in Eq. ( 5 ), with r 1 , r 2 , r 3 , r 4 ∈ Z p \ { 0 } and a, b, c, d ∈ Z . The green-shaded edges denote the unit cell at the origin used to generate the P auli mo dule o v er the Lauren t p olynomial ring [ 46 ]. F or the same pair ( f , g ), different c hoices of twisted b oundary conditions can realize distinct quantum LDPC codes. (b) Adapted from Ref. [ 90 ]. A twisted torus embedded in three-dimensional space. The twist is applied along the longitudinal cycle b y an angle that is a fraction of 2 π , as indicated by the red curve tracing a noncontractible cycle. The t wisted torus is specified b y t w o v ectors a 1 = (0 , α ) and a 2 = ( β , γ ), i.e., lattice sites are identified by v ∼ v + a 1 ∼ v + a 2 for all v . Review of ring-theoretical approac h for biv ariate bicycle co des. — In this section, w e review the algebraic framew ork for analyzing translation-inv ariant quan tum co des on lattices [ 47 ]. W e follo w the notation of Ref. [ 90 ] and extend its Gr¨ obner-basis analysis to Z p qudits. W e b egin by recalling the standard p × p (generalized) Pauli op erators for a Z p qudit: X = X j ∈ Z p | j + 1 ⟩⟨ j | , Z = X j ∈ Z p ω j | j ⟩⟨ j | . (1) where ω is defined as ω := exp 2 π i d . More explicitly , X = 0 0 · · · 0 1 1 0 · · · 0 0 0 1 · · · 0 0 . . . . . . . . . . . . . . . 0 0 · · · 1 0 , Z = 1 0 0 · · · 0 0 ω 0 · · · 0 0 0 ω 2 · · · 0 . . . . . . . . . . . . . . . 0 0 0 · · · ω d − 1 , (2) and X and Z satisfy the commutation relation Z X = ω X Z . (3) F or simplicit y , w e fo cus on the square lattice with one Z p qudit living at each edge. W e briefly review the p oly- nomial represen tation of Pauli op erators [ 46 ]. A unit cell con tains tw o vertices, e 1 and e 2 , whose P auli op erators are represented by four-dimensional vectors: X e 1 = 1 0 0 0 , Z e 1 = 0 0 1 0 , X e 2 = 0 1 0 0 , Z e 2 = 0 0 0 1 . (4) A translation b y ( n, m ) ∈ Z 2 is implemented by multi- plying the corresp onding v ector b y the monomial x n y m . More generally , an y Pauli operator (modulo an o v erall phase) is represented by a vector in R 4 , where R = Z p [ x ± 1 , y ± 1 ]. V ector addition corresponds to op erator m ultiplication, while m ultiplication b y elemen ts of R en- co des lattice translations and Z p exp onen ts. Thus, the P auli group mo dulo phase is naturally identified with an R -mo dule. A translation-inv ariant CSS code is sp ecified by a pair of Laurent p olynomials f , g ∈ R : A v = f ( x, y ) g ( x, y ) 0 0 , B p = 0 0 − g ( x, y ) f ( x, y ) , (5) where ( · ) denotes the antipo de map x n y m 7→ x − n y − m . The stabilizer group is generated by all lattice translates of A v and B p . As a simple example, the Kitaev toric co de [ 6 ] corresp onds to f ( x, y ) = 1 − x and g ( x, y ) = 1 − y . The top ological order condition is satisfied when f ( x, y ) and g ( x, y ) are coprime [ 31 ], which ensures that an y lo cal operator commuting with all stabilizers is it- self a stabilizer. Moreov er, the maximal num ber of logi- cal qudits on a torus equals the num ber of indep enden t an yon generators in the underlying topological order [ 92 – 94 ]. It can b e computed from the co dimension of the ideal generated b y f and g : k max = 2 dim Å Z p [ x ± 1 , y ± 1 ] ⟨ f , g ⟩ ã . (6) F or twisted boundary conditions sp ecified by a 1 = (0 , α ) and a 2 = ( β , γ ), the resulting co de has logical dimen- sion [ 90 ] k = 2 dim Å Z p [ x ± 1 , y ± 1 ] ⟨ f ( x, y ) , g ( x, y ) , y α − 1 , x β y γ − 1 ⟩ ã . (7) 3 [[ n, k, d ]] 3 f ( x, y ) g ( x, y ) a 1 a 2 kd 2 n [[16 , 4 , 4]] 3 1 + x + y 1 + y − x − 1 y (0 , 4) (2 , 1) 4 [[26 , 6 , 5]] 3 1 + x + x − 1 y 1 − y − x − 1 (0 , 13) (1 , 5) 5.77 [[42 , 4 , 8]] 3 1 + x + x − 2 y − 1 1 + y + x (0 , 3) (7 , 1) 6.10 [[48 , 4 , 9]] 3 1 − x + xy 2 1 − y + x 2 (0 , 8) (3 , 3) 6.75 [[52 , 8 , 7]] 3 1 + x + x − 1 y − 2 1 + y + xy − 1 (0 , 13) (2 , 5) 7.54 [[64 , 4 , 11]] 3 1 + x + x − 1 y − 2 1 + y − x − 1 y 2 (0 , 16) (2 , 7) 7.56 [[72 , 4 , 12]] 3 1 − x + y 2 1 − y + x 2 (0 , 12) (3 , 3) 8 [[78 , 6 , 11]] 3 1 + x + x − 1 y 2 1 − y + x − 2 y − 1 (0 , 13) (3 , 4) 9.31 [[104 , 6 , 14]] 3 1 − x + xy − 3 1 − y + x − 2 y 2 (0 , 26) (2 , − 9) 11.31 [[130 , 6 , 16]] 3 1 + x + x 2 y 3 1 + y − x − 2 y 2 (0 , 13) (5 , 3) 11.82 [[144 , 6 , 17]] 3 1 + x + x 2 y 2 1 + y + xy − 3 (0 , 36) (2 , 15) 12.04 [[156 , 10 , 15]] 3 1 + x + x − 1 y 2 1 + y + x − 3 y 2 (0 , 26) (3 , 4) 14.42 [[160 , 12 , 14]] 3 1 − x − x − 2 y 2 1 − y − x − 3 y − 2 (0 , 40) (2 , 7) 14.7 [[192 , 8 , 19]] 3 1 + x + x 2 y − 2 1 + y + x 3 y (0 , 16) (6 , 7) 15.04 [[208 , 8 , 20]] 3 1 − x + xy − 3 1 − y + x − 2 y 2 (0 , 26) (4 , 8) 15.38 [[224 , 6 , 24]] 3 1 + x + x 2 y 2 1 + y + xy − 3 (0 , 56) (2 , 15) 15.43 [[234 , 6 , 25]] 3 1 + x − x 2 y − 6 1 + y + x 2 y 3 (0 , 13) (9 , 2) 16.03 [[240 , 8 , 22]] 3 1 + x + xy − 5 1 + y + x 5 (0 , 60) (2 , 13) 16.13 [[242 , 10 , 22]] 3 1 − x + x 3 y − 3 1 − y + x − 4 (0 , 11) (11 , 4) 20 T ABLE I. Z 3 qutrit LDPC co des with n ≤ 250. The Lau- ren t p olynomials f ( x, y ) and g ( x, y ) sp ecify the translation- in v arian t stabilizers, while the vectors a 1 and a 2 define the t wisted b oundary conditions of the torus (see Fig. 1 ). W e list [[ n, k , d ]] 3 suc h that k d 2 /n for each entry in the table exceeds that of all instances with smaller n . W e empha- size that the code distances are obtained using the proba- bilistic algorithm of Ref. [ 91 ]; accordingly , the reported v al- ues of d are upper bounds on the exact distance. F or eac h co de, we sample 5 , 000–10 , 000 information sets and repeat the procedure 1 , 000 times to assess consistency , yielding up- p er b ounds that we b elieve are tigh t in practice. [[ n, k, d ]] 5 f ( x, y ) g ( x, y ) a 1 a 2 kd 2 n [[16 , 4 , 4]] 5 1 + x + 3 y 1 + 3 y + x − 1 y (0 , 4) (2 , 1) 4.00 [[20 , 4 , 5]] 5 1 + 2 x + 4 x − 1 y 1 + 3 y + 4 x (0 , 5) (2 , 1) 5.00 [[24 , 4 , 6]] 5 1 + 2 x + 2 xy 1 + 3 y + x − 1 y (0 , 4) (3 , 2) 6.00 [[30 , 4 , 7]] 5 1 + x + 3 x 2 y − 1 1 + 2 y + 2 x 2 y (0 , 15) (1 , 6) 6.53 [[40 , 4 , 9]] 5 1 + x + 3 x 2 y − 1 1 + 3 y + x 2 y (0 , 4) (5 , 1) 8.10 [[48 , 4 , 10]] 5 1 + x + 4 x − 1 y − 1 1 + y + 2 xy − 1 (0 , 6) (4 , 3) 8.33 [[56 , 4 , 11]] 5 1 + 2 x + 2 x − 2 1 + 2 y + 2 x − 1 y − 1 (0 , 4) (7 , 1) 8.64 [[62 , 6 , 10]] 5 1 + 2 x + 4 y 2 1 + 4 y + 3 x 2 y (0 , 31) (1 , 7) 9.68 [[78 , 10 , 9]] 5 1 + 2 x + 2 x 2 y 2 1 + 3 y + x − 3 (0 , 39) (1 , 5) 10.38 [[80 , 6 , 12]] 5 1 + x + 3 x − 2 1 + 3 y + xy − 2 (0 , 10) (4 , 4) 10.80 [[90 , 4 , 16]] 5 1 + x + x − 2 y 1 + y + x − 1 y 3 (0 , 9) (5 , 1) 11.38 [[96 , 6 , 14]] 5 1 + 2 x + 2 x 2 y 1 + 2 y + 3 x − 1 y 2 (0 , 16) (3 , 6) 12.25 [[114 , 4 , 19]] 5 1 + x + x − 1 y − 2 1 + y + 3 x 3 (0 , 19) (3 , 7) 12.67 [[120 , 6 , 17]] 5 1 + x + 3 y 3 1 + 2 y + 2 xy 3 (0 , 30) (2 , 13) 14.45 [[124 , 6 , 18]] 5 1 + x + 3 x 3 y − 2 1 + 3 y + 4 x 3 y (0 , 31) (2 , 12) 15.68 [[144 , 6 , 20]] 5 1 + x + 3 x − 2 y 1 + y + 3 x 2 y 3 (0 , 9) (8 , 1) 16.67 T ABLE I I. Z 5 qudit LDPC codes with n ≤ 150. Similar to T able I . The deriv ations of Eqs. ( 6 ) and ( 7 ) for Z p qudits fol- lo w directly from the corresp onding pro ofs for the Z 2 case established previously in Refs. [ 90 , 95 ]. The right- hand side of Eq. ( 7 ) can be ev aluated efficien tly using a Gr¨ obner basis computed via Buc hberger’s algorithm [ 96 ]. Searc h for biv ariate bicycle codes o v er Z p . — W e [[ n, k, d ]] 7 f ( x, y ) g ( x, y ) a 1 a 2 kd 2 n [[12 , 4 , 3]] 7 1 + 2 x + 5 y 1 + 2 y + 2 x − 1 (0 , 2) (3 , 0) 3.00 [[14 , 4 , 4]] 7 1 + 2 x + 4 xy 1 + 4 y + 2 xy (0 , 7) (1 , 3) 4.57 [[24 , 4 , 6]] 7 1 + 2 x + 5 y 1 + 2 y + 2 x − 1 (0 , 4) (3 , 2) 6.00 [[28 , 4 , 7]] 7 1 + 5 x + x − 1 y − 1 1 + 5 y + x (0 , 7) (2 , 3) 7.00 [[32 , 4 , 8]] 7 1 + x + 2 x 2 y 1 + 2 y + 3 x − 1 y 2 (0 , 4) (4 , 1) 8.00 [[48 , 4 , 10]] 7 1 + x + 5 x 2 y 1 + 3 y + 3 x − 1 y 2 (0 , 8) (3 , 3) 8.33 [[56 , 4 , 12]] 7 1 + x + 5 xy 1 + 2 y + 4 xy − 2 (0 , 7) (4 , 1) 10.29 [[64 , 4 , 13]] 7 1 + 2 x + 2 x − 1 y − 2 1 + 4 y + 5 xy − 1 (0 , 8) (4 , 1) 10.56 [[70 , 4 , 14]] 7 1 + x + 5 xy − 2 1 + 4 y + 2 x − 2 y − 1 (0 , 7) (5 , 1) 11.20 [[76 , 6 , 12]] 7 1 + x + x − 1 y 2 1 + 2 y + 4 x − 1 y − 1 (0 , 19) (2 , 7) 11.37 [[84 , 4 , 16]] 7 1 + x + x − 1 y − 2 1 + y + 3 x 2 y − 2 (0 , 14) (3 , 5) 12.19 [[96 , 6 , 15]] 7 1 + x + y 2 1 + 4 y + 5 x − 2 (0 , 16) (3 , 5) 14.06 [[98 , 10 , 12]] 7 1 + 2 x + 4 x − 1 y 2 1 + 4 y + 2 x − 2 y − 1 (0 , 7) (7 , 0) 14.69 [[126 , 6 , 18]] 7 1 + x + x 2 y 2 1 + 3 y + 3 x 3 (0 , 21) (3 , 15) 15.43 [[128 , 6 , 19]] 7 1 + x + 5 x 3 y − 2 1 + 2 y + 4 xy − 4 (0 , 16) (4 , 7) 16.92 [[144 , 6 , 21]] 7 1 + x + 3 x 2 y − 2 1 + y + 5 x − 1 y − 2 (0 , 12) (6 , 3) 18.38 T ABLE I I I. Z 7 qudit LDPC co des with n ≤ 150. Similar to T able I . [[ n, k, d ]] 11 f ( x, y ) g ( x, y ) a 1 a 2 kd 2 n [[16 , 4 , 4]] 11 1 + 7 x + 4 xy 1 + 10 y + 3 x − 1 y 2 (0 , 4) (2 , 1) 4.00 [[20 , 4 , 5]] 11 1 + x + 2 xy 1 + 7 y + 10 xy − 1 (0 , 5) (2 , 1) 5.00 [[22 , 4 , 6]] 11 1 + 5 x + 5 x − 1 1 + 8 y + 2 xy − 1 (0 , 11) (1 , 3) 6.55 [[32 , 4 , 8]] 11 1 + 3 x + 10 y 3 1 + 10 y + 3 x − 1 y 2 (0 , 8) (2 , 1) 8.00 [[40 , 4 , 10]] 11 1 + x + 10 x − 1 y − 1 1 + 7 y + 10 xy − 1 (0 , 10) (2 , 4) 10.00 [[48 , 4 , 11]] 11 1 + 3 x + x − 1 y 1 + 6 y + x − 1 y − 1 (0 , 6) (4 , 1) 10.08 [[60 , 4 , 13]] 11 1 + x + 9 x 2 y 2 1 + 5 y + 5 xy − 1 (0 , 5) (6 , 2) 11.27 [[66 , 4 , 14]] 11 1 + 5 x + 5 y 2 1 + 8 y + 2 x 2 (0 , 11) (3 , 6) 11.88 [[72 , 4 , 15]] 11 1 + 2 x + 9 x − 1 y − 2 1 + 5 y + 2 x − 2 y 2 (0 , 12) (3 , 5) 12.50 [[80 , 6 , 14]] 11 1 + x + 2 x − 2 y − 1 1 + 8 y + 7 xy − 2 (0 , 10) (4 , 4) 14.70 [[96 , 6 , 16]] 11 1 + 2 x + 8 xy − 3 1 + 3 y + 7 x − 2 y 2 (0 , 16) (3 , 3) 16.00 [[100 , 6 , 17]] 11 1 + x + x − 2 y − 1 1 + 5 y + 10 x 2 y − 1 (0 , 10) (5 , 5) 17.34 [[120 , 6 , 20]] 11 1 + x + 2 x − 2 y 3 1 + y + 4 x − 1 y − 4 (0 , 10) (6 , 2) 20.00 [[144 , 6 , 23]] 11 1 + 2 x + 8 x − 2 y 2 1 + 2 y + 8 x − 2 y − 3 (0 , 8) (9 , 1) 22.04 T ABLE IV. Z 11 qudit LDPC co des with n ≤ 150. Similar to T able I . in tro duce the gener alize d toric c o de ov er Z p , a particular sub class of biv ariate bicycle (BB) co des, defined b y f ( x, y ) = 1 + r 1 x + r 2 x a y b , g ( x, y ) = 1 + r 3 y + r 4 x c y d , (8) with r i ∈ Z p \ { 0 } and a, b, c, d ∈ Z , as illustrated in Fig. 1(a) . W e systematically searc h for high-performing w eigh t-6 BB codes of the form ( 8 ) o v er Z p qudits with t wisted- p eriodic boundary conditions. F or each even n , we enu- merate all factorizations n = 2 αβ and define a twisted torus by the basis vectors a 1 = (0 , α ) and a 2 = ( β , γ ) with 0 ≤ γ < β . W e then enumerate all p olynomials of the form ( 8 ) whose exp onent pairs ( a, b ) and ( c, d ) lie within the fundamen tal parallelogram spanned by a 1 and a 2 . F or eac h candidate, we compute the corresponding logical dimension k using Eq. ( 7 ). The computational cost of ev aluating k in Eq. ( 7 ) is essen tially indep en- den t of system size: the b oundary relations y α − 1 and x β y γ − 1 are reduced modulo the ideal ⟨ f , g ⟩ , and only the 4 A B C D E F G H I J K A B C D E F G H I J K 1 2 3 4 5 6 7 8 9 10 11 1 2 3 4 5 6 7 8 9 10 11 (a) [[242 , 10 , 22]] 3 code. A B C D E F A B C D E F 1 2 3 4 5 6 7 8 9 10 1 2 3 4 5 6 7 8 9 10 (b) [[120 , 6 , 20]] 11 code. FIG. 2. Representativ e stabilizer realizations on t wisted tori. (a) X - and Z -stabilizers of the [[242 , 10 , 22]] 3 co de with f = 1 − x + x 3 y − 3 and g = 1 − y + x − 4 , defined with t wisted b oundary v ectors a 1 = (0 , 11) and a 2 = (11 , 4). (b) X - and Z -stabilizers of the [[120 , 6 , 20]] 11 co de with f = 1 + x + 2 x − 2 y 3 and g = 1 + y + 4 x − 1 y − 4 , defined with a 1 = (0 , 10) and a 2 = (6 , 2). All other stabilizers are obtained by translations. In eac h panel, v ertices with the same letter (top/bottom) or the same num b er (left/right) are identified, yielding a twisted torus. resulting remainders en ter the Gr¨ obner-basis dimension calculation. F or instances with k > 0, w e then compute the code distance d using the probabilistic algorithm [ 91 ], thereb y obtaining the full [[ n, k , d ]] p parameters. The results for qudit LDPC co des o v er Z p with p = 3 , 5 , 7 , 11 are summarized in T ables I – IV , cov ering p = 3 with n ≤ 250 and p = 5 , 7 , 11 with n ≤ 150. When m ul- tiple co des achiev e the same optimal kd 2 /n , w e select the one with the most local stabilizers as the representativ e example. By comparing the Z 2 results [ 90 ] summarized in Ap- p endix A with our data for Z 3 , Z 5 , Z 7 , and Z 11 , w e obtain the plot in Fig. 3(a) . The vertical axis shows the figure of merit k d 2 /n , while the horizon tal axis shows the minimum num b er of ph ysical qudits n required to ac hieve a given v alue of kd 2 /n . F or each fixed p , the dependence of k d 2 /n on n is ap- pro ximately linear o v er the fitted range, with coefficient of determination R 2 ≈ 0 . 95–0 . 98. Moreo v er, at fixed n we observe that the b est ac hiev able k d 2 /n increases with the qudit dimension p . F or example, at comparable p erformance, the [[120 , 6 , 20]] 11 co de ( k d 2 /n = 20) uses n = 120 qudits, whereas the best Z 2 instance in our com- parison, [[360 , 12 , 24]] 2 ( k d 2 /n = 19 . 2), requires n = 360 qubits. Finally , the linear fits in Fig. 3(a) suggest that the fitted slope of k d 2 /n versus n grows approximately as ln p , as summarized in Fig. 3(b) . Relation to the Bra vyi–P oulin–T erhal T radeoff. — Motiv ated by the trend in k d 2 /n across different primes p in Fig. 3 , w e replot the same data in Fig. 4 as k d 2 /n v ersus (ln p ) n and p erform a linear least-squares fit, ob- taining k d 2 = 0 . 0541 n 2 ln p + 3 . 84 n, (9) for the explored primes p ∈ { 2 , 3 , 5 , 7 , 11 } . At first glance, the quadratic dep endence on n ma y seem to con- tradict the Bra vyi–Poulin–T erhal (BPT) b ound [ 97 , 98 ], whic h states that for geometrically lo cal stabilizer co des in tw o dimensions k d 2 = O ( n ) , (10) where the implicit constan t depends on the in teraction range r and the on-site Hilbert-space dimension. T o make this dependence explicit, w e follo w the BPT argumen t. The lattice is partitioned in to an array of R × R blo c ks suc h that eac h block is correctable, and the blo ck corners are co vered by a region C . By the cleaning lemma, one may c ho ose R = Ω( d/r ). The pro of in Ref. [ 98 ] then implies k ≤ S ( C ) ≤ | C | = O Å nr 2 R 2 ã = O Å nr 4 d 2 ã , (11) where S ( C ) denotes the entanglemen t entrop y of region C . Here, we use the fact that each corner region has linear size O ( r ) (and hence area O ( r 2 )), and that the n umber of blo c ks is n/R 2 . It follows that k d 2 = O ( nr 4 ) . (12) Sup erlinear b eha vior in n is therefore compatible with BPT whenever the in teraction range r increases with system size. In our generalized toric constructions, the geometric diameter of the weigh t-6 stabilizers can gro w with n , dep ending on the chosen exponents in f ( x, y ) and g ( x, y ). This relaxes the BPT constraint and is con- sisten t with the empirical relation ( 9 ). Discussion and future directions. — W e hav e de- v elop ed a top ological-order p erspective on translation- in v arian t Z p stabilizer co des on twisted tori. In this 5 0 50 100 150 200 250 300 350 n 2.5 5.0 7.5 10.0 12.5 15.0 17.5 20.0 k d 2 / n Z 2 q u b i t c o d e s k d 2 / n = 0 . 0 4 0 5 n + 3 . 8 5 , R 2 = 0 . 9 7 6 Z 3 q u t r i t c o d e s k d 2 / n = 0 . 0 5 5 7 n + 4 . 3 0 , R 2 = 0 . 9 4 7 Z 5 q u d i t c o d e s k d 2 / n = 0 . 0 9 0 6 n + 3 . 5 7 , R 2 = 0 . 9 7 6 Z 7 q u d i t c o d e s k d 2 / n = 0 . 1 0 4 7 n + 3 . 5 5 , R 2 = 0 . 9 7 0 Z 1 1 q u d i t c o d e s k d 2 / n = 0 . 1 4 2 4 n + 2 . 8 7 , R 2 = 0 . 9 7 9 (a) k d 2 /n vs. n for the [[ n, k , d ]] p codes in T ables I – V . l n ( 2 ) l n ( 3 ) l n ( 5 ) l n ( 7 ) l n ( 1 1 ) l n ( p ) 0.04 0.06 0.08 0.10 0.12 0.14 Slope y = 0 . 0 5 9 5 4 l n ( p ) - 0 . 0 0 5 4 3 , R 2 = 0 . 9 8 4 9 5 p = 2 p = 3 p = 5 p = 7 p = 1 1 (b) Fitted slop es from panel (a) vs. ln( p ). FIG. 3. Finite-size p erformance across qudit dimensions. (a) [[ n, k , d ]] p LDPC co des from T ables I – V : the metric k d 2 /n is plotted versus block length n for p ∈ { 2 , 3 , 5 , 7 , 11 } , together with linear fits for each p . (b) Slopes extracted from the fits in panel (a), plotted against ln( p ), with error bars given b y the standard errors from the linear fits in panel (a). Linear regression indicates an approximately linear dep endence on ln( p ). 0 50 100 150 200 250 300 350 x = ( l n p ) n 2.5 5.0 7.5 10.0 12.5 15.0 17.5 20.0 22.5 y = k d 2 / n p=2 p=3 p=5 p=7 p=11 y = 0 . 0 5 4 1 x + 3 . 8 4 2 9 , R 2 = 0 . 9 6 0 0 4 FIG. 4. Finite-size performance metric k d 2 /n for all code instances listed in T ables I – V , plotted against (ln p ) n for the explored primes p ∈ 2 , 3 , 5 , 7 , 11. The solid line is the least- squares linear fit k d 2 /n = 0 . 0541 (ln p ) n + 3 . 84 with R 2 = 0 . 96. framew ork, the logical dimension k is determined by the an yon algebra and computed as the dimension of the quotien t ring R /I , where I = ⟨ f ( x, y ) , g ( x, y ) ⟩ is the stabilizer ideal. This ring-theoretic approac h naturally incorp orates t wisted b oundary conditions and, together with Gr¨ obner-basis techniques, enables efficient c harac- terization and systematic searches for new qudit LDPC co des. The high-p erforming instances summarized in T a- bles I – IV pro vide a foundation for further theoretical and hardw are-oriented in vestigations. F uture w ork ma y extend the searc h to larger system sizes, where further impro v ements could emerge. Be- cause the en umeration procedure is fully parallelizable, it can b e scaled to n ≤ 500 or b ey ond using clusters or sup ercomputers, approaching the scale of current exp er- imen tal platforms [ 99 – 104 ]. The primary computational b ottlenec k is distance estimation: for n of a few h undred and d > 25, existing probabilistic distance algorithms t ypically yield only upp er bounds and may become un- reliable. It will also be imp ortan t to v erify whether the empirical relation ( 9 ) persists at larger n and p , and to establish a theoretical understanding of the observ ed n 2 ln p scaling. F urthermore, allo wing higher-w eight stabilizers is an- other natural direction, as suc h constructions ha v e led to impro ved [[ n, k , d ]] parameters in other quan tum LDPC co de families [ 22 , 31 , 105 – 116 ]. Finally , it will be imp ortant to assess the p erformance of these codes under circuit-lev el noise models [ 19 ]. In particular, syndrome-extraction circuits m ust b e opti- mized for low depth, as the circuit-level distance is t ypically smaller than the co de distance. Numerical sim ulations to estimate pseudo-thresholds, along with the developmen t of efficien t logical-gate implemen tations and hardware realizations, will b e essen tial steps tow ard practical deploymen t. Ac kno wledgement. — This work is s upported by the National Natural Science F oundation of China (Grant No. 12474491) and the F undamental Research F unds for the Central Universities, P eking Univ ersit y . 6 [1] P eter W. Shor, “Scheme for reducing decoherence in quan tum computer memory ,” Phys. Rev. A 52 , R2493– R2496 (1995) . [2] A. M. Steane, “Error correcting co des in quan tum the- ory ,” Ph ys. Rev. Lett. 77 , 793–797 (1996) . [3] Eman uel Knill and Raymond Laflamme, “Theory of quan tum error-correcting co des,” Phys. Rev. A 55 , 900–911 (1997) . [4] Daniel Gottesman, “Stabilizer co des and quan tum error correction,” (1997), arXiv:quan t-ph/9705052 [quan t- ph] . [5] A.Y u. Kitaev, “F ault-tolerant quantum computation b y an yons,” Annals of Ph ysics 303 , 2–30 (2003) . [6] Sergey B Bravyi and A Y u Kitaev, “Quantum co des on a lattice with b oundary ,” arXiv preprint quant- ph/9811052 (1998). [7] Eric Dennis, Alexei Kitaev, Andrew Landahl, and John Preskill, “T op ological quan tum memory ,” Journal of Mathematical Physics 43 , 4452–4505 (2002) . [8] G. Semeghini, H. Levine, A. Keesling, S. Ebadi, T. T. W ang, D. Bluvstein, R. V erresen, H. Pichler, M. Kali- no wski, R. Sama jdar, A. Omran, S. Sachdev, A. Vish- w anath, M. Greiner, V. V uleti ´ c, and M. D. Lukin, “Probing top ological spin liquids on a programmable quan tum simulator,” Science 374 , 1242–1247 (2021) . [9] Ruben V erresen, Mikhail D. Lukin, and Ashvin Vish- w anath, “Prediction of toric co de top ological order from rydb erg blo c k ade,” Phys. Rev. X 11 , 031005 (2021) . [10] Nik olas P . Breuckmann and Jens Niklas Eberhardt, “Quan tum lo w-density parity-c hec k codes,” PRX Quan tum 2 , 040101 (2021) . [11] Dolev Bluvstein, Harry Levine, Giulia Semeghini, T out T. W ang, Sep ehr Ebadi, Marcin Kalinowski, Alexander Keesling, Nishad Mask ara, Hannes Pic h- ler, Markus Greiner, Vladan V uleti´ c, and Mikhail D. Lukin, “A quantum pro cessor based on coherent trans- p ort of entangled atom arra ys,” Nature 604 , 451–456 (2022) . [12] Google Quan tum AI and Collaborators, “Suppressing quan tum errors b y scaling a surface co de logical qubit,” Nature 614 , 676–681 (2023) . [13] Google Quantum AI and Collaborators, “Non-ab elian braiding of graph vertices in a sup erconducting pro ces- sor,” Nature 618 , 264–269 (2023) . [14] Google Quantum AI and Collab orators, “Quantum er- ror correction b elo w the surface code threshold,” Na- ture (2024), 10.1038/s41586-024-08449-y . [15] Zijian Liang, Jens Niklas Eberhardt, and Y u-An Chen, “Planar quantum low-densit y parity-c hec k codes with op en b oundaries,” PRX Quantum 6 , 040330 (2025) . [16] Mohsin Iqbal, Nathanan T antiv asadak arn, Thomas M. Gatterman, Justin A. Gerb er, Kevin Gilmore, Dan Gresh, Aaron Hankin, Nathan Hewitt, Chandler V. Horst, Mitc hell Mathen y , T anner Mengle, Brian Ney en- h uis, Ashvin Vish wanath, Michael F oss-F eig, Rub en V erresen, and Henrik Dreyer, “T op ological order from measuremen ts and feed-forward on a trapp ed ion quan tum computer,” Comm unications Physics 7 , 205 (2024) . [17] Mohsin Iqbal, Nathanan T antiv asadak arn, Rub en V er- resen, Sara L. Campb ell, Joan M. Dreiling, Caroline Figgatt, John P . Gaebler, Jacob Johansen, Michael Mills, Stev en A. Moses, Juan M. Pino, Anthon y Rans- ford, Mary Row e, P eter Siegfried, Russell P . Stutz, Mic hael F oss-F eig, Ashvin Vish w anath, and Henrik Drey er, “Non-abelian topological order and any ons on a trapp ed-ion pro cessor,” Nature 626 , 505–511 (2024) . [18] Iris Cong, Nishad Mask ara, Minh C. T ran, Hannes Pic hler, Giulia Semeghini, Susanne F. Y elin, So onw on Choi, and Mikhail D. Lukin, “Enhancing detection of topological order by local error correction,” Nature Comm unications 15 , 1527 (2024) . [19] Sergey Bravyi, Andrew W. Cross, Ja y M. Gambetta, Dmitri Maslov, P atric k Rall, and Theo dore J. Y oder, “High-threshold and low-o v erhead fault-tolerant quan- tum memory ,” Nature 627 , 778–782 (2024) . [20] Ming W ang and F rank Mueller, “Coprime biv ariate bicycle co des and their prop erties,” arXiv preprin t arXiv:2408.10001 (2024). [21] Ming W ang and F rank Mueller, “Rate adjustable bi- v ariate bicycle co des for quan tum error correction,” in 2024 IEEE International Confer enc e on Quantum Computing and Engine ering (QCE) , V ol. 02 (2024) pp. 412–413. [22] Ry an Tiew and Nik olas P Breuc kmann, “Low-o v erhead en tangling gates from generalised dehn t wists,” arXiv preprin t arXiv:2411.03302 (2024). [23] Stasiu W olanski and Ben Barb er, “Am biguit y cluster- ing: an accurate and efficien t deco der for qldp c co des,” arXiv preprint arXiv:2406.14527 (2024). [24] Anqi Gong, Sebastian Cammerer, and Joseph M Renes, “T ow ard low-latency iterativ e deco ding of qldp c codes under circuit-lev el noise,” arXiv preprin t arXiv:2403.18901 (2024). [25] Arshpreet Singh Maan and Alexandru Paler, “Machine learning message-passing for the scalable decoding of qldp c co des,” arXiv preprint arXiv:2408.07038 (2024). [26] Alexander Cowtan, “Ssip: automated surgery with quan tum ldp c co des,” arXiv preprint (2024). [27] Mac k enzie H Shaw and Barbara M T erhal, “Low- ering connectivit y requirements for biv ariate bicy- cle co des using morphing circuits,” arXiv preprint arXiv:2407.16336 (2024). [28] Andrew Cross, Zhiyang He, Patric k Rall, and Theo dore Y oder, “Linear-size ancilla systems for log- ical measurements in qldp c codes,” arXiv preprin t arXiv:2407.18393 (2024). [29] Luk as V oss, Sim Jian Xian, T obias Haug, and Kishor Bharti, “Multiv ariate bicycle co des,” arXiv preprint arXiv:2406.19151 (2024). [30] Noah Berthusen, Dhruv Devulapalli, Eddie Schoute, Andrew M. Childs, Michael J. Gullans, Alexey V. Gor- shk ov, and Daniel Gottesman, “T ow ard a 2d lo cal implemen tation of quan tum low-densit y parity-c hec k co des,” PRX Quantum 6 , 010306 (2025) . [31] Jens Niklas Eberhardt and Vincen t Steffan, “Logical op erators and fold-transv ersal gates of biv ariate bicycle co des,” arXiv preprint arXiv:2407.03973 (2024). [32] Hsiang-Ku Lin, Xingrui Liu, Pak Kau Lim, and Leonid P Pryadk o, “Single-shot and tw o-shot decod- ing with generalized bicycle co des,” arXiv preprin t arXiv:2502.19406 (2025). 7 [33] Noah Goss, Alexis Morv an, Brian Marinelli, Bradley K. Mitc hell, Long B. Nguyen, Ra vi K. Naik, Larry Chen, Christian J ¨ unger, John Mark Kreikebaum, Da vid I. Santiago, Jo el J. W allman, and Irfan Sid- diqi, “High-fidelity qutrit entangling gates for supercon- ducting circuits,” Nature Comm unications 13 (2022), 10.1038/s41467-022-34851-z . [34] Mohsin Iqbal, Anasuya Ly ons, Chiu F an Bow en Lo, Nathanan T an tiv asadak arn, Joan Dreiling, Cameron F oltz, Thomas M. Gatterman, Dan Gresh, Nathan He- witt, Craig A. Holliman, Jacob Johansen, Brian Ney en- h uis, Y ohei Matsuok a, Michael Mills, Steven A. Moses, P eter Siegfried, Ashvin Vishw anath, Rub en V erresen, and Henrik Drey er, “Qutrit toric co de and parafermions in trapped ions,” Nature Communications 16 (2025), 10.1038/s41467-025-61391-z . [35] M. S. Blok, V. V. Ramasesh, T. Sch uster, K. O’Brien, J. M. Kreikebaum, D. Dahlen, A. Morv an, B. Y oshida, N. Y. Y ao, and I. Siddiqi, “Quantum information scram bling on a superconducting qutrit pro cessor,” Ph ys. Rev. X 11 , 021010 (2021) . [36] A. Morv an, V. V. Ramasesh, M. S. Blok, J. M. Kreike- baum, K. O’Brien, L. Chen, B. K. Mitc hell, R. K. Naik, D. I. Santiago, and I. Siddiqi, “Qutrit randomized b enc hmarking,” Phys. Rev. Lett. 126 , 210504 (2021) . [37] Kai Luo, W enhui Huang, Ziyu T ao, Lib o Zhang, Y ux- uan Zhou, Ji Ch u, W uxin Liu, Biying W ang, Jiangyu Cui, Song Liu, F ei Y an, Man-Hong Y ung, Y uanzhen Chen, T ongxing Y an, and Dap eng Y u, “Experimental realization of tw o qutrits gate with tunable coupling in sup erconducting circuits,” Ph ysical Review Letters 130 (2023), 10.1103/physrevlett.130.030603 . [38] Alba Cervera-Lierta, Mario Krenn, Al´ an Aspuru- Guzik, and Alexey Galda, “Exp erimen tal high- dimensional greenberger-horne-zeilinger en tanglement with superconducting transmon qutrits,” Phys. Rev. Appl. 17 , 024062 (2022) . [39] Xiao-Min Hu, Cen-Xiao Huang, Nicola d’Alessandro, Gabriele Cobucci, Chao Zhang, Y u Guo, Y un-F eng Huang, Chuan-F eng Li, Guang-Can Guo, Xiao qin Gao, Marcus Huber, Armin T av akoli, and Bi-Heng Liu, “Observ ation of gen uine high-dimensional multi-partite non-lo calit y in entangled photon states,” Nature Com- m unications 16 (2025), 10.1038/s41467-025-59717-y . [40] Xiao-Min Hu, W en-Bo Xing, Chao Zhang, Bi-Heng Liu, Matej Piv olusk a, Marcus Huber, Y un-F eng Huang, Ch uan-F eng Li, and Guang-Can Guo, “Exp erimen- tal creation of multi-photon high-dimensional la y ered quan tum states,” np j Quantum Information 6 (2020), 10.1038/s41534-020-00318-6 . [41] P ei Liu, Ruixia W ang, Jing-Ning Zhang, Yingshan Zhang, Xiao xia Cai, Huik ai Xu, Zhiyuan Li, Jiaxiu Han, Xuegang Li, Guangming Xue, W eiy ang Liu, Li Y ou, Yirong Jin, and Haifeng Y u, “Performing SU( d ) opera- tions and rudimen tary algorithms in a sup erconducting transmon qudit for d = 3 and d = 4,” Ph ys. Rev. X 13 , 021028 (2023) . [42] Daniel J. Sp encer, Andrew T anggara, T obias Haug, Derek Khu, and Kishor Bharti, “Qudit low-densit y parit y-chec k co des,” (2025), arXiv:2510.06495 [quan t- ph] . [43] Sergey Bravyi, Matthew B. Hastings, and Spyri- don Michalakis, “T op ological quan tum order: Stabil- it y under local perturbations,” Journal of Mathemati- cal Physics 51 , 093512 (2010) . [44] Sergey Bra vyi and Matthew B Hastings, “A short pro of of stabilit y of top ological order under lo cal perturba- tions,” Communications in mathematical ph ysics 307 , 609–627 (2011) . [45] H ´ ector Bom b ´ ın, “Structure of 2d top ological stabilizer co des,” Comm unications in Mathematical Ph ysics 327 , 387–432 (2014) . [46] Jeongw an Haah, “Comm uting pauli hamiltonians as maps betw een free modules,” Communications in Mathematical Physics 324 , 351–399 (2013) . [47] Jeongw an Haah, “Algebraic methods for quantum co des on lattices,” Revista colombiana de matematicas 50 , 299–349 (2016) . [48] Jeongw an Haah, “Classification of translation in v arian t top ological P auli stabilizer co des for prime dimensional qudits on t wo-dimensional lattices,” Journal of Mathe- matical Physics 62 , 012201 (2021) . [49] Y u-An Chen and Yijia Xu, “Equiv alence b et ween fermion-to-qubit mappings in t wo spatial dimensions,” PRX Quantum 4 , 010326 (2023) . [50] Blazej Ruba and Bow en Y ang, “Homological inv ariants of pauli stabilizer codes,” Comm unications in Mathe- matical Physics 405 , 126 (2024) . [51] B la ˙ zej Ruba and Bow en Y ang, “Witt groups and bulk- b oundary correspondence for stabilizer states,” (2025), arXiv:2509.10418 [math-ph] . [52] Robbert Dijkgraaf and Edward Witten, “T op ological gauge theories and group cohomology ,” Comm unica- tions in Mathematical Physics 129 , 393–429 (1990) . [53] Xiao-Gang W en, “T op ological order and edge structure of ν =1/2 quantum hall state,” Ph ys. Rev. Lett. 70 , 355–358 (1993) . [54] Alexei Kitaev, “Any ons in an exactly solved model and b ey ond,” Annals of Ph ysics 321 , 2–111 (2006) , january Sp ecial Issue. [55] H. Bom bin and M. A. Martin-Delgado, “T op ological quan tum distillation,” Phys. Rev. Lett. 97 , 180501 (2006) . [56] Mic hael Levin and Xiao-Gang W en, “Detecting top o- logical order in a ground state wa v e function,” Ph ys. Rev. Lett. 96 , 110405 (2006) . [57] Xie Chen, Zheng-Cheng Gu, and Xiao-Gang W en, “Complete classification of one-dimensional gapped quan tum phases in in teracting spin systems,” Phys. Rev. B 84 , 235128 (2011) . [58] Mic hael Levin and Zheng-Cheng Gu, “Braiding statistics approach to symmetry-protected topological phases,” Phys. Rev. B 86 , 115109 (2012) . [59] Xie Chen, Zheng-Cheng Gu, Zheng-Xin Liu, and Xiao- Gang W en, “Symmetry-protected top ological orders in in teracting bosonic systems,” Science 338 , 1604–1606 (2012) . [60] Hong-Chen Jiang, Zhenghan W ang, and Leon Ba- len ts, “Identifying top ological order by entanglemen t en tropy ,” Nature Physics 8 , 902–905 (2012) . [61] L. Cincio and G. Vidal, “Characterizing top ological or- der by studying the ground states on an infinite cylin- der,” Phys. Rev. Lett. 110 , 067208 (2013) . [62] Zheng-Cheng Gu and Michael Levin, “Effect of in- teractions on t w o-dimensional fermionic symmetry- protected topological phases with Z 2 symmetry ,” Phys. Rev. B 89 , 201113 (2014) . [63] Zheng-Cheng Gu, Zhenghan W ang, and Xiao-Gang W en, “Lattice model for fermionic toric code,” Phys. Rev. B 90 , 085140 (2014) . 8 [64] Chao-Ming Jian and Xiao-Liang Qi, “La y er construc- tion of 3d topological states and string braiding statis- tics,” Phys. Rev. X 4 , 041043 (2014) . [65] H. Bombin, “Gauge color co des: Optimal transv ersal gates and gauge fixing in topological stabilizer co des,” (2015), arXiv:1311.0879 [quant-ph] . [66] Beni Y oshida, “T op ological phases with generalized global symmetries,” Phys. Rev. B 93 , 155131 (2016) . [67] An ton Kapustin and Ry an Thorngren, “Higher symme- try and gapp ed phases of gauge theories,” in A lgebr a, Ge ometry, and Physics in the 21st Century: Kontsevich F estschrift , edited b y Denis Auroux, Ludmil Katzarko v, T ony P antev, Y an Soibelman, and Y uri Tschink el (Springer In ternational Publishing, Cham, 2017) pp. 177–202. [68] Y u-An Chen, Anton Kapustin, and Djordje Radicevic, “Exact b osonization in tw o spatial dimensions and a new class of lattice gauge theories,” Annals of Ph ysics 393 , 234–253 (2018) . [69] Tian Lan, Liang Kong, and Xiao-Gang W en, “Classifi- cation of (3 + 1)D b osonic top ological orders: The case when pointlik e excitations are all bosons,” Phys. Rev. X 8 , 021074 (2018) . [70] Meng Cheng, Nathanan T antiv asadak arn, and Chen- jie W ang, “Lo op braiding statistics and interacting fermionic symmetry-protected topological phases in three dimensions,” Phys. Rev. X 8 , 011054 (2018) . [71] A tMa P . O. Chan, Peng Y e, and Shinsei Ryu, “Braid- ing with b orromean rings in (3 + 1)-dimensional space- time,” Phys. Rev. Lett. 121 , 061601 (2018) . [72] Bo Han, Hua jia W ang, and Peng Y e, “Generalized w en- zee terms,” Phys. Rev. B 99 , 205120 (2019) . [73] Qing-Rui W ang, Y ang Qi, and Zheng-Cheng Gu, “Anomalous symmetry protected top ological states in in teracting fermion systems,” Ph ys. Rev. Lett. 123 , 207003 (2019) . [74] Y u-An Chen and Anton Kapustin, “Bosonization in three spatial dimensions and a 2-form gauge theory ,” Ph ys. Rev. B 100 , 245127 (2019) . [75] Tian Lan and Xiao-Gang W en, “Classification of 3 + 1D b osonic top ological orders (ii): The case when some p oin tlik e excitations are fermions,” Ph ys. Rev. X 9 , 021005 (2019) . [76] Y u-An Chen, “Exact b osonization in arbitrary dimen- sions,” Phys. Rev. Res. 2 , 033527 (2020) . [77] Y u-An Chen, T yler D. Ellison, and Nathanan T antiv asadak arn, “Disen tangling supercohomology symmetry-protected top ological phases in three spatial dimensions,” Phys. Rev. Res. 3 , 013056 (2021) . [78] Maissam Bark eshli, Y u-An Chen, Po-Shen Hsin, and Naren Manjunath, “Classification of (2 + 1)d in vertible fermionic top ological phases with symmetry ,” Phys. Rev. B 105 , 235143 (2022) . [79] Theo Johnson-F reyd, “On the classification of top olog- ical orders,” Communications in Mathematical Physics 393 , 989–1033 (2022) . [80] T yler D. Ellison, Y u-An Chen, Arpit Dua, Wilbur Shirley , Nathanan T an tiv asadak arn, and Dominic J. Williamson, “P auli stabilizer models of twisted quan- tum doubles,” PRX Quantum 3 , 010353 (2022) . [81] Y u-An Chen and Sri T ata, “Higher cup pro ducts on h yp ercubic lattices: Application to lattice models of top ological phases,” Journal of Mathematical Physics 64 , 091902 (2023) . [82] Y u-An Chen and P o-Shen Hsin, “Exactly solv able lat- tice Hamiltonians and gravitational anomalies,” Sci- P ost Phys. 14 , 089 (2023) . [83] Maissam Bark eshli, Y u-An Chen, Sheng-Jie Huang, Ry ohei Kobay ashi, Nathanan T an tiv asadak arn, and Guan yu Zhu, “Codimension-2 defects and higher sym- metries in (3+1)D top ological phases,” SciPost Phys. 14 , 065 (2023) . [84] Ry ohei Koba y ashi and Guan yu Zh u, “Cross-cap defects and fault-tolerant logical gates in the surface co de and the honeycom b floquet code,” PRX Quantum 5 , 020360 (2024) . [85] Maissam Bark eshli, Y u-An Chen, Po-Shen Hsin, and Ry ohei Kobay ashi, “Higher-group symmetry in finite gauge theory and stabilizer codes,” SciP ost Ph ys. 16 , 089 (2024) . [86] Maissam Barkeshli, Po-Shen Hsin, and Ry- ohei Koba yashi, “Higher-group symmetry of (3+1)D fermionic Z 2 gauge theory: Logical CCZ, CS, and T gates from higher symmetry ,” SciP ost Ph ys. 16 , 122 (2024) . [87] Zijian Liang, Bow en Y ang, Joseph T. Iosue, and Y u-An Chen, “Op erator algebra and algorithmic construction of b oundaries and defects in (2+1)d topological pauli stabilizer co des,” (2025), arXiv:2410.11942 [quant-ph] . [88] Ry ohei Kobay ashi, Y uyang Li, Hanyu Xue, Po-Shen Hsin, and Y u-An Chen, “Generalized statistics on lat- tices,” Phys. Rev. X 16 , 011010 (2026) . [89] Zijian Liang, Yijia Xu, Joseph T. Iosue, and Y u- An Chen, “Extracting top ological orders of generalized pauli stabilizer codes in tw o dimensions,” PRX Quan- tum 5 , 030328 (2024) . [90] Zijian Liang, Ke Liu, Hao Song, and Y u-An Chen, “Generalized toric codes on t wisted tori for quan tum error correction,” PRX Quantum 6 , 020357 (2025) . [91] Leonid P . Pryadk o, V adim A. Shabashov, and V a- lerii K. Kozin, “Qdistrnd: A gap pac k age for computing the distance of quantum error-correcting co des,” Jour- nal of Op en Source Softw are 7 , 4120 (2022) . [92] Edw ard Witten, “Quantum field theory and the jones polynomial,” Communications in Mathematical Ph ysics 121 , 351–399 (1989) . [93] Xiao-Gang W en, “T op ological orders and edge excitations in fractional quantum hall states,” Adv ances in Physics 44 , 405–473 (1995) , h ttps://doi.org/10.1080/00018739500101566 . [94] Haruki W atanab e, Meng Cheng, and Y ohei F uji, “Ground state degeneracy on torus in a family of zn toric co de,” Journal of Mathematical Ph ysics 64 (2023), 10.1063/5.0134010 . [95] Key ang Chen, Y uanting Liu, Yiming Zhang, Zijian Liang, Y u-An Chen, Ke Liu, and Hao Song, “An yon theory and top ological frustration of high-efficiency quan tum low-densit y parit y-chec k codes,” Phys. Rev. Lett. 135 , 076603 (2025) . [96] Bruno Buch berger, “Bruno buch berger’s phd thesis 1965: An algorithm for finding the basis elemen ts of the residue class ring of a zero dimensional p olynomial ideal,” Journal of Symbolic Computation 41 , 475–511 (2006) . [97] Sergey Bra vyi and Barbara T erhal, “A no-go theorem for a t wo-dimensional self-correcting quantum memory based on stabilizer co des,” New Journal of Physics 11 , 043029 (2009) . [98] Sergey Bravyi, David P oulin, and Barbara T erhal, “T radeoffs for reliable quan tum information storage in 9 2d systems,” Phys. Rev. Lett. 104 , 050503 (2010) . [99] Google Quantum AI and Collab orators, “Quan tum supremacy using a programmable superconducting pro- cessor,” Nature 574 , 505–510 (2019) . [100] Han-Sen Zhong, Hui W ang, Y u-Hao Deng, Ming-Cheng Chen, Li-Chao Peng, Yi-Han Luo, Jian Qin, Dian W u, Xing Ding, Yi Hu, P eng Hu, Xiao-Y an Y ang, W ei- Jun Zhang, Hao Li, Y uxuan Li, Xiao Jiang, Lin Gan, Guangw en Y ang, Lixing Y ou, Zhen W ang, Li Li, Nai- Le Liu, Chao-Y ang Lu, and Jian-W ei Pan, “Quantum computational adv an tage using photons,” Science 370 , 1460–1463 (2020) . [101] Sepehr Ebadi, T out T. W ang, Harry Levine, Alexander Keesling, Giulia Semeghini, Ahmed Omran, Dolev Blu- vstein, Rhine Sama jdar, Hannes Pichler, W en W ei Ho, So on w on Choi, Subir Sachdev, Markus Greiner, Vladan V uleti´ c, and Mikhail D. Lukin, “Quantum phases of matter on a 256-atom programmable quantum simula- tor,” Nature 595 , 227–232 (2021) . [102] Lars S. Madsen, F abian Lauden bach, Mohsen F ala- marzi. Ask arani, F abien Rortais, T revor Vincen t, Jacob F. F. Bulmer, Filippo M. Miatto, Leonhard Neuhaus, Luk as G. Helt, Matthew J. Collins, Adriana E. Lita, Thomas Gerrits, Sae W oo Nam, V arun D. V aidy a, Mat- teo Menotti, Ish Dhand, Zachary V ernon, Nicol´ as Que- sada, and Jonathan La voie, “Quantum computational adv an tage with a programmable photonic processor,” Nature 606 , 75–81 (2022) . [103] Sergey Bra vyi, Oliver Dial, Jay M. Gambetta, Dar ´ ıo Gil, and Zaira Nazario, “The future of quantum com- puting with sup erconducting qubits,” Journal of Ap- plied Physics 132 , 160902 (2022) . [104] T om Manovitz, Sophie H. Li, Sepehr Ebadi, Rhine Sama jdar, Alexandra A. Geim, Simon J. Evered, Dolev Bluvstein, Hengyun Zhou, Nazli Ugur Koyluoglu, Jo- hannes F eldmeier, P a vel E. Dolgirev, Nishad Mask ara, Marcin Kalino wski, Subir Sachdev, David A. Huse, Markus Greiner, Vladan V uleti´ c, and Mikhail D. Lukin, “Quantum coarsening and collective dynam- ics on a programmable sim ulator,” Nature 638 , 86–92 (2025) . [105] Alexey A. Ko v alev and Leonid P . Pry adk o, “Quantum kronec ker sum-product low-densit y parity-c hec k co des with finite rate,” Phys. Rev. A 88 , 012311 (2013) . [106] Nik olas P . Breuc kmann and Jens N. Eb erhardt, “Bal- anced pro duct quantum co des,” IEEE T ransactions on Information Theory 67 , 6653–6674 (2021) . [107] P a vel P an teleev and Gleb Kalachev, “Degenerate quan- tum ldpc co des with goo d finite length performance,” Quan tum 5 , 585 (2021) . [108] Ting-Ch un Lin and Min-Hsiu Hsieh, “c3-locally testable codes from lossless expanders,” in 2022 IEEE International Symp osium on Information The ory (ISIT) (2022) pp. 1175–1180. [109] An thon y Leverrier and Gilles Zemor, “ Quantum T an- ner co des ,” in 2022 IEEE 63r d Annual Symp osium on F oundations of Computer Scienc e (F OCS) (IEEE Com- puter So ciety , Los Alamitos, CA, USA, 2022) pp. 872– 883. [110] P a vel Pan teleev and Gleb Kalachev, “Asymptoti- cally go o d quantum and lo cally testable classical ldp c codes,” in Pr o c ee dings of the 54th Annual ACM SIGACT Symp osium on The ory of Computing , STOC 2022 (Asso ciation for Computing Mac hinery , New Y ork, NY, USA, 2022) p. 375–388. [111] Irit Dinur, Min-Hsiu Hsieh, Ting-Chun Lin, and Thomas Vidick, “Go o d quantum ldp c co des with lin- ear time decoders,” in Pr o c e e dings of the 55th Annual ACM Symp osium on The ory of Computing , STOC 2023 (Asso ciation for Computing Mac hinery , New Y ork, NY, USA, 2023) p. 905–918. [112] Ren yu W ang, Hsiang-Ku Lin, and Leonid P Pryadk o, “Ab elian and non-abelian quan tum tw o-block co des,” in 2023 12th International Symp osium on T opics in Co ding (ISTC) (IEEE, 2023) pp. 1–5. [113] Hsiang-Ku Lin and Leonid P . Pry adk o, “Quantum t wo- blo c k group algebra co des,” Ph ys. Rev. A 109 , 022407 (2024) . [114] Adam Wills, Ting-Ch un Lin, and Min-Hsiu Hsieh, “Lo- cal testability of distance-balanced quantum co des,” np j Quantum Information 10 , 120 (2024) . [115] Adam Wills, Ting-Chun Lin, and Min-Hsiu Hsieh, “T radeoff constructions for quantum lo cally testable co des,” IEEE T ransactions on Information Theory 71 , 426–458 (2025) . [116] Zijian Liang and Y u-An Chen, “Self-dual biv ariate bi- cycle co des with transversal clifford gates,” (2026), arXiv:2510.05211 [quant-ph] . 10 App endix A: Z 2 biv ariate bicycle co des This app endix collects representativ e instances of Z 2 biv ariate bicycle (BB) codes, compiled from Ref. [ 90 ]. W e adopt the polynomial description used there: each co de instance is sp ecified by a pair of Laurent p olynomials f ( x, y ) and g ( x, y ) with Z 2 co efficien ts, together with a c hoice of b oundary iden tifications that render the translation lattice finite. The latter are enco ded by tw o twisted boundary v ectors a 1 , a 2 ∈ Z 2 . F or eac h choice of ( f , g ; a 1 , a 2 ), one obtains a qubit LDPC stabilizer co de with parameters [[ n, k, d ]] 2 , where k is the num ber of logical qubits and d is the code distance of the underlying stabilizer code. Since our goal here is to pro vide concrete test cases spanning a range of performance, we select examples with progressiv ely larger v alues of the figure of merit k d 2 /n . This quan tit y is a conv enien t summary statistic that com bines rate and distance for finite-size comparisons; it do es not b y itself determine p erformance under a sp ecific deco der or circuit-level noise mo del, but it is useful for organizing represen tativ e instances. T able V lists the resulting co de parameters, the defining polynomials f ( x, y ) and g ( x, y ), the boundary vectors a 1 , a 2 , and the corresp onding k d 2 /n v alues. These instances serve as representativ e b enchmarks in the main text for comparing finite-size behavior across differen t co de constructions. [[ n, k , d ]] f ( x, y ) g ( x, y ) a 1 a 2 kd 2 n [[18 , 4 , 4]] 1 + x + xy 1 + y + xy (0 , 3) (3 , 0) 3.56 [[30 , 4 , 6]] 1 + x + x 2 1 + y + x 2 (0 , 3) (5 , 1) 4.8 [[42 , 6 , 6]] 1 + x + xy 1 + y + xy − 1 (0 , 7) (3 , 2) 5.14 [[48 , 4 , 8]] 1 + x + x 2 1 + y + x 2 (0 , 3) (8 , 1) 5.33 [[56 , 6 , 8]] 1 + x + y − 2 1 + y + x − 2 (0 , 7) (4 , 3) 6.86 [[72 , 8 , 8]] 1 + x + x − 1 y 3 1 + y + x 3 y − 1 (0 , 12) (3 , 3) 7.11 [[84 , 6 , 10]] 1 + x + x − 2 1 + y + x − 2 y 2 (0 , 14) (3 , − 6) 7.14 [[90 , 8 , 10]] 1 + x + x − 1 y − 3 1 + y + x 3 y − 1 (0 , 15) (3 , − 6) 8.89 [[120 , 8 , 12]] 1 + x + x − 2 y 1 + y + xy 2 (0 , 10) (6 , 4) 9.6 [[144 , 12 , 12]] 1 + x + x − 1 y − 3 1 + y + x 3 y − 1 (0 , 12) (6 , 0) 12 [[210 , 10 , 16]] 1 + x + x − 3 y 2 1 + y + x − 3 y − 1 (0 , 21) (5 , 10) 12.19 [[248 , 10 , 18]] 1 + x + x − 2 y 1 + y + x − 3 y − 2 (0 , 62) (2 , 25) 13.06 [[254 , 14 , 16]] 1 + x + x − 1 y − 3 1 + y + y − 6 (0 , 127) (1 , 25) 14.11 [[310 , 10 , 22]] 1 + x + x 3 y 2 1 + y + x − 4 y 4 (0 , 31) (5 , 11) 15.61 [[360 , 12 , 24]] 1 + x + x − 1 y 3 1 + y + x 3 y − 1 (0 , 30) (6 , 6) 19.2 T ABLE V. Z 2 qubit LDPC co des compiled from Ref. [ 90 ]. The table rep orts the co de parameters [[ n, k , d ]], the corresp onding p olynomials f ( x, y ) and g ( x, y ), the twisted b oundary vectors a 1 , a 2 , and the metric k d 2 /n .
Original Paper
Loading high-quality paper...
Comments & Academic Discussion
Loading comments...
Leave a Comment