Title
Quantum walks can find a marked element on any graph
Abstract
We solve an open problem by constructing quantum walks that not only detect but also find marked vertices in a graph. In the case when the marked set consists of a single vertex, the number of steps of the quantum walk is quadratically smaller than the classical hitting time of any reversible random walk on the graph. In the case of multiple marked elements, the number of steps is given in terms of a related quantity which we call extended hitting time. Our approach is new, simpler and more general than previous ones. We introduce a notion of interpolation between the random walk and the absorbing walk , whose marked states are absorbing. Then our quantum walk is simply the quantum analogue of this interpolation. Contrary to previous approaches, our results remain valid when the random walk is not state-transitive. We also provide algorithms in the cases when only approximations or bounds on parameters (the probability of picking a marked vertex from the stationary distribution) and are known.
Year
DOI
Venue
2016
10.1007/s00453-015-9979-8
Algorithmica
Keywords
Field
DocType
Quantum algorithms,Quantum walks,Markov chains,Interpolated quantum walks
Discrete mathematics,Quantum,Combinatorics,Open problem,Vertex (geometry),Random walk,Quantum walk,Quantum algorithm,Stationary distribution,Hitting time,Mathematics
Journal
Volume
Issue
ISSN
74
2
Algorithmica 74(2), pp. 851-907 (2016)
Citations 
PageRank 
References 
13
0.89
14
Authors
4
Name
Order
Citations
PageRank
Hari Krovi1578.29
Frédéric Magniez257044.33
Maris Ozols3497.80
Jeremie Roland4462.91