Description
Qubit stabilizer code for which the binary space \(S_X\) of \(X\) components of stabilizers is \(k\)-orthogonal in the symplectic representation. In other words, the overlap of any \(j\) vectors in \(S_X\) is even for every \(1\leq j\leq k\) [3; Def. 4]. This definition applies to general qubit stabilizer codes and does not require a CSS presentation. The notion extends to modular qudits [1].
Equivalently, a generator matrix for \(S_X\) is \(k\)-orthogonal if \begin{align} |x^1|&\equiv 0 \mod 2 \tag*{(1)}\\ |x^1\cdot x^2|&\equiv 0 \mod 2 \tag*{(2)}\\ |x^1\cdot x^2\cdot x^3|&\equiv 0 \mod 2 \tag*{(3)}\\ &\vdots \tag*{(4)}\\ |x^1\cdot x^2\cdot x^3\cdot\ldots\cdot x^k|&\equiv 0 \mod 2 \tag*{(5)}\end{align} for all vectors \(x^j\) in its row space, where the generalized dot-product notation means a sum of products of the respective coordinates of all vectors.
Transversal and Permutation-Based Gates
For every fixed \(h\geq 3\), there exist explicit asymptotically good binary CSS codes whose \(X\)-type stabilizer space is \(2^{h-1}\)-orthogonal. For these codes, strongly transversal \(R_h\) gates implement logical \(R_h\) on every encoded qubit with no subsequent correction [4; Cor. 6.7].Gates
For every fixed \(h\geq 3\), there exist explicit asymptotically good binary CSS codes whose \(X\)-type stabilizer space is \(h\)-orthogonal. Strongly transversal \(R_h=\operatorname{diag}(1,e^{2\pi i/2^h})\) gates, followed by a diagonal correction from the \((h-1)\)st level of the Clifford hierarchy, implement logical \(R_h\) on every encoded qubit [4; Cor. 5.6].Cousins
- Modular-qudit lattice color code— The notion of \(k\)-orthogonality can be extended to modular-qudit codes and is known as \(k^{\star}\)-orthogonality [1; Def. 2]. Modular-qudit lattice color codes defined on lattices in \(D\) spatial dimension whose \(X\)-type stabilizers are placed on cells of dimension \(\nu \leq D\) are \(k^{\star}\)-orthogonal for all \(k \leq \nu\) [1; Lemma 5].
- Reed-Muller (RM) code— A unital \(k\)-orthogonal space is a \(k\)-orthogonal binary space containing the all-ones vector. For dimension \(m+1\), its generator matrix has columns \((1,y)\) for \(y\) in a subset \(Y\subseteq\mathbb{F}_2^m\), and the overlap of any \(j\leq k\) rows, repetitions allowed, is the sum over \(Y\) of a monomial of degree at most \(j\). The indicator function of \(Y\) is therefore orthogonal to \(RM(k,m)\), i.e., it is a codeword of \(RM(m-k-1,m)\). For \(k=3\), unital triorthogonal spaces correspond one-to-one to affine-equivalence classes of \(RM(m-4,m)\) codewords whose weight equals the length of the space and that are not divisible by a nonconstant affine function [5][6; Supp. Sec. III]. The correspondence yielded a classification of unital triorthogonal spaces through length 38 via the Kasami-Tokura classification of low-weight RM codewords [5]. It was extended through length 54 by a directional-derivative recursion that reconstructs a codeword from its derivative along a direction with the fewest pairs of support points [6; Supp. Sec. III].
- \([[2^r-1,1,3]]\) simplex code— \([[2^r-1,1,3]]\) simplex codes are \((r-1)\)-orthogonal [3; Lemma 2].
Primary Hierarchy
References
- [1]
- F. H. E. Watson, E. T. Campbell, H. Anwar, and D. E. Browne, “Qudit color codes and gauge color codes in all spatial dimensions”, Physical Review A 92, (2015) arXiv:1503.08800 DOI
- [2]
- C. Vuillot and N. P. Breuckmann, “Quantum Pin Codes”, IEEE Transactions on Information Theory 68, 5955 (2022) arXiv:1906.11394 DOI
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- S. Koutsioumpas, D. Banfield, and A. Kay, “The Smallest Code with Transversal T”, (2022) arXiv:2210.14066
- [4]
- R. San-José, “Asymptotically good binary triorthogonal codes and higher-level transversal gates”, (2026) arXiv:2609.08203
- [5]
- S. Nezami and J. Haah, “Classification of small triorthogonal codes”, Physical Review A 106, (2022) arXiv:2107.09684 DOI
- [6]
- A. Wills, S. P. Jain, and S. Singh, “Classification of Generalised Triorthogonal Codes through Length 54”, (2026) arXiv:2609.30860
- [7]
- S. Bravyi and J. Haah, “Magic-state distillation with low overhead”, Physical Review A 86, (2012) arXiv:1209.2426 DOI
- [8]
- J. Haah and M. B. Hastings, “Codes and Protocols for DistillingT, controlled-S, and Toffoli Gates”, Quantum 2, 71 (2018) arXiv:1709.02832 DOI
Page edit log
- Rodrigo San-José (2026-10-05) — most recent
- Victor V. Albert (2026-10-12)
- Victor V. Albert (2026-09-06)
- Victor V. Albert (2026-06-08)
- Victor V. Albert (2024-03-01)
Cite as:
“\(k\)-orthogonal code”, The Error Correction Zoo (V. V. Albert & P. Faist, eds.), 2026. https://errorcorrectionzoo.org/c/quantum_k-orthogonal, arXiv:2606.11484