English

The quantum query complexity of certification

Quantum Physics 2018-12-20 v2 Computational Complexity

Abstract

We study the quantum query complexity of finding a certificate for a d-regular, k-level balanced NAND formula. Up to logarithmic factors, we show that the query complexity is Theta(d^{(k+1)/2}) for 0-certificates, and Theta(d^{k/2}) for 1-certificates. In particular, this shows that the zero-error quantum query complexity of evaluating such formulas is O(d^{(k+1)/2}) (again neglecting a logarithmic factor). Our lower bound relies on the fact that the quantum adversary method obeys a direct sum theorem.

Cite

@article{arxiv.0903.1291,
  title  = {The quantum query complexity of certification},
  author = {Andris Ambainis and Andrew M. Childs and François Le Gall and Seiichiro Tani},
  journal= {arXiv preprint arXiv:0903.1291},
  year   = {2018}
}

Comments

8 pages; Updated to reflect changes in final journal version and to point out that the main result only applies for k>1

R2 v1 2026-06-21T12:19:17.990Z