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Quantum Latin squares with all possible cardinalities

Quantum Physics 2025-07-09 v1

Abstract

A quantum Latin square of order nn (denoted as QLS(n)(n)) is an n×nn\times n array whose entries are unit column vectors from the nn-dimensional Hilbert space Hn\mathcal{H}_n, such that each row and column forms an orthonormal basis. Two unit vectors u,vHn|u\rangle, |v\rangle\in \mathcal{H}_n are regarded as identical if there exists a real number θ\theta such that u=eiθv|u\rangle=e^{i\theta}|v\rangle; otherwise, they are considered distinct. The cardinality cc of a QLS(n)(n) is the number of distinct vectors in the array. In this paper, we use sub-QLS(4)(4)s to prove that for any integer m2m\geq 2 and any integer c[4m,16m2]{4m+1}c\in [4m,16m^2]\setminus \{4m+1\}, there is a QLS(4m)(4m) with cardinality cc.

Cite

@article{arxiv.2507.05642,
  title  = {Quantum Latin squares with all possible cardinalities},
  author = {Ying Zhang and Xin Wang and Lijun Ji},
  journal= {arXiv preprint arXiv:2507.05642},
  year   = {2025}
}
R2 v1 2026-07-01T03:50:44.859Z