English

Triplets of Mutually Unbiased Bases

Combinatorics 2025-07-22 v2

Abstract

We initiate a systematic study of triplets of mutually unbiased bases (MUBs). We show that in Cd\mathbb{C}^d each MUB-triplet is characterized by a d×d×dd\times d\times d object that we call a Hadamard cube. We describe the basic properties of Hadamard cubes, and show how an MUB-triplet can be reconstructed from such a cube, up to unitary equivalence. We also present an algebraic identity which is conjectured to hold for all MUB-triplets in dimension 6. If true, it would imply the long-standing conjecture of Zauner that the maximum number of MUBs in dimension 6 is three.

Keywords

Cite

@article{arxiv.2503.14752,
  title  = {Triplets of Mutually Unbiased Bases},
  author = {Máte Matolcsi and Ákos K. Matszangosz and Dániel Varga and Mihály Weiner},
  journal= {arXiv preprint arXiv:2503.14752},
  year   = {2025}
}
R2 v1 2026-06-28T22:26:01.068Z