Thomas G. Wong
University of Latvia
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Publication
Featured researches published by Thomas G. Wong.
Journal of Physics A | 2015
Thomas G. Wong
The lazy random walk, where the walker has some probability of staying put, is a useful tool in classical algorithms. We propose a quantum analogue, the lackadaisical quantum walk, where each vertex is given l self-loops, and we investigate its effects on Grovers algorithm when formulated as search for a marked vertex on the complete graph of N vertices. For the discrete-time quantum walk using the phase flip coin, adding a self-loop to each vertex boosts the success probability from 1/2 to 1. Additional self-loops, however, decrease the success probability. Using instead the Shenvi, Kempe, and Whaley (2003) coin, adding self-loops simply slows down the search. These coins also differ in that the first is faster than classical when l scales less than N, while the second requires that l scale less than N 2. Finally, continuous-time quantum walks differ from both of these discrete-time examples—the self-loops make no difference at all. These behaviors generalize to multiple marked vertices.
Quantum Information Processing | 2015
Thomas G. Wong
We introduce a simple diagrammatic approach for estimating how a randomly walking quantum particle searches on a graph in continuous time, which involves sketching small weighted graphs with self-loops and considering degenerate perturbation theory’s effects on them. Using this method, we give the first example of degenerate perturbation theory solving search on a graph whose evolution occurs in a subspace whose dimension grows with
Quantum Information Processing | 2016
Thomas G. Wong
Journal of Physics A | 2016
Thomas G. Wong
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Quantum Information Processing | 2016
Thomas G. Wong; Luís Tarrataca; Nikolay Nahimov
Physical Review A | 2016
Thomas G. Wong; Pascal Philipp
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Journal of Physics A | 2016
Thomas G. Wong
In the typical spatial search problems solved by continuous-time quantum walk, changing the location of the marked vertices does not alter the search problem. In this paper, we consider search when this is no longer true. In particular, we analytically solve search on the “simplex of
Journal of Physics A | 2016
Krišjānis Prūsis; Jevgēnijs Vihrovs; Thomas G. Wong
Journal of Physics A | 2015
Thomas G. Wong
K_M
Quantum Information Processing | 2016
Thomas G. Wong