How symmetric is too symmetric for large quantum speedups?
Abstract
Suppose a Boolean function is symmetric under a group action acting on the bits of the input. For which does this mean does not have an exponential quantum speedup? Is there a characterization of how rich must be before the function cannot have enough structure for quantum algorithms to exploit? In this work, we make several steps towards understanding the group actions 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 . Our main application is for graph symmetries: we show that any Boolean function defined on the adjacency matrix of a graph (and symmetric under relabeling the vertices of the graph) has a power relationship between its randomized and quantum query complexities, even if 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