English

Quantum query complexity of graph connectivity

Quantum Physics 2007-05-23 v3

Abstract

Harry Buhrman et al gave an Omega(sqrt n) lower bound for monotone graph properties in the adjacency matrix query model. Their proof is based on the polynomial method. However for some properties stronger lower bounds exist. We give an Omega(n^{3/2}) bound for Graph Connectivity using Andris Ambainis' method, and an O(n^{3/2} log n) upper bound based on Grover's search algorithm. In addition we study the adjacency list query model, where we have almost matching lower and upper bounds for Strong Connectivity of directed graphs.

Keywords

Cite

@article{arxiv.quant-ph/0303169,
  title  = {Quantum query complexity of graph connectivity},
  author = {Christoph Durr and Mehdi Mhalla and Yaohui Lei},
  journal= {arXiv preprint arXiv:quant-ph/0303169},
  year   = {2007}
}