English

How symmetric is too symmetric for large quantum speedups?

Quantum Physics 2020-01-28 v1 Computational Complexity

Abstract

Suppose a Boolean function ff is symmetric under a group action GG acting on the nn bits of the input. For which GG does this mean ff does not have an exponential quantum speedup? Is there a characterization of how rich GG must be before the function ff cannot have enough structure for quantum algorithms to exploit? In this work, we make several steps towards understanding the group actions GG which are "quantum intolerant" in this way. We show that sufficiently transitive group actions do not allow a quantum speedup, and that a "well-shuffling" property of group actions -- which happens to be preserved by several natural transformations -- implies a lack of super-polynomial speedups for functions symmetric under the group action. Our techniques are motivated by a recent paper by Chailloux (2018), which deals with the case where G=SnG=S_n. Our main application is for graph symmetries: we show that any Boolean function ff defined on the adjacency matrix of a graph (and symmetric under relabeling the vertices of the graph) has a power 66 relationship between its randomized and quantum query complexities, even if ff is a partial function. In particular, this means no graph property testing problems can have super-polynomial quantum speedups, settling an open problem of Ambainis, Childs, and Liu (2011).

Cite

@article{arxiv.2001.09642,
  title  = {How symmetric is too symmetric for large quantum speedups?},
  author = {Shalev Ben-David and Supartha Podder},
  journal= {arXiv preprint arXiv:2001.09642},
  year   = {2020}
}

Comments

18 pages

R2 v1 2026-06-23T13:21:20.007Z