Quantum random walks with decoherent coins
Journal Article
·
· Physical Review. A
- Institute for Advanced Study, Einstein Drive, Princeton, New Jersey 08540 (United States)
- Department of Combinatorics and Optimization, University of Waterloo, Waterloo, Ontario, N2L 3G1 (Canada)
The quantum random walk has been much studied recently, largely due to its highly nonclassical behavior. In this paper, we study one possible route to classical behavior for the discrete quantum walk on the line: the presence of decoherence in the quantum ''coin'' which drives the walk. We find exact analytical expressions for the time dependence of the first two moments of position, and show that in the long-time limit the variance grows linearly with time, unlike the unitary walk. We compare this to the results of direct numerical simulation, and see how the form of the position distribution changes from the unitary to the usual classical result as we increase the strength of the decoherence.
- OSTI ID:
- 20633819
- Journal Information:
- Physical Review. A, Vol. 67, Issue 3; Other Information: DOI: 10.1103/PhysRevA.67.032304; (c) 2003 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1050-2947
- Country of Publication:
- United States
- Language:
- English
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