English

On the quantum symmetry of distance-transitive graphs

Combinatorics 2020-05-26 v1 Operator Algebras Quantum Algebra

Abstract

In this article, we study quantum automorphism groups of distance-transitive graphs. We show that the odd graphs, the Hamming graphs H(n,3)H(n,3), the Johnson graphs J(n,2)J(n,2) and the Kneser graphs K(n,2)K(n,2) do not have quantum symmetry. We also give a table with the quantum automorphism groups of all cubic distance-transitive graphs. Furthermore, with one graph missing, we can now decide whether or not a distance-regular graph of order 20\leq 20 has quantum symmetry. Moreover, we prove that the Hoffman-Singleton graph has no quantum symmetry. On a final note, we present an example of a pair of graphs with the same intersection array (the Shrikhande graph and the 4×44 \times 4 rook's graph), where one of them has quantum symmetry and the other one does not.

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Cite

@article{arxiv.1906.06537,
  title  = {On the quantum symmetry of distance-transitive graphs},
  author = {Simon Schmidt},
  journal= {arXiv preprint arXiv:1906.06537},
  year   = {2020}
}

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43 pages