1,586 research outputs found
On the probability of finding marked connected components using quantum walks
Finding a marked vertex in a graph can be a complicated task when using
quantum walks. Recent results show that for two or more adjacent marked
vertices search by quantum walk with Grover's coin may have no speed-up over
classical exhaustive search. In this paper, we analyze the probability of
finding a marked vertex for a set of connected components of marked vertices.
We prove two upper bounds on the probability of finding a marked vertex and
sketch further research directions.Comment: 13 pages. To appear at Lobachevskii Journal of Mathematic
Exponential algorithmic speedup by quantum walk
We construct an oracular (i.e., black box) problem that can be solved
exponentially faster on a quantum computer than on a classical computer. The
quantum algorithm is based on a continuous time quantum walk, and thus employs
a different technique from previous quantum algorithms based on quantum Fourier
transforms. We show how to implement the quantum walk efficiently in our
oracular setting. We then show how this quantum walk can be used to solve our
problem by rapidly traversing a graph. Finally, we prove that no classical
algorithm can solve this problem with high probability in subexponential time.Comment: 24 pages, 7 figures; minor corrections and clarification
- …