Grover search with lackadaisical quantum walks

Research output: Contribution to journalArticle

21 Citations (Scopus)

Abstract

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 Grover's 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.

Original languageEnglish (US)
Article number435304
JournalJournal of Physics A: Mathematical and Theoretical
Volume48
Issue number43
DOIs
StatePublished - Oct 7 2015
Externally publishedYes

Fingerprint

Quantum Walk
apexes
Discrete-time
Vertex of a graph
Flip
acceleration (physics)
random walk
Complete Graph
Continuous Time
Random walk
analogs
Analogue
Decrease
Generalise

All Science Journal Classification (ASJC) codes

  • Statistical and Nonlinear Physics
  • Statistics and Probability
  • Modeling and Simulation
  • Mathematical Physics
  • Physics and Astronomy(all)

Cite this

Grover search with lackadaisical quantum walks. / Wong, Thomas.

In: Journal of Physics A: Mathematical and Theoretical, Vol. 48, No. 43, 435304, 07.10.2015.

Research output: Contribution to journalArticle

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