Spectral and asymptotic properties of Grover walks on crystal lattices

Yusuke Higuchi, Norio Konno, Iwao Sato, Etsuo Segawa

Research output: Contribution to journalArticlepeer-review

30 Citations (Scopus)

Abstract

We propose a twisted Szegedy walk for estimating the limit behavior of a discrete-time quantum walk on a crystal lattice, an infinite abelian covering graph, whose notion was introduced by [14]. First, we show that the spectrum of the twisted Szegedy walk on the quotient graph can be expressed by mapping the spectrum of a twisted random walk onto the unit circle. Secondly, we show that the spatial Fourier transform of the twisted Szegedy walk on a finite graph with appropriate parameters becomes the Grover walk on its infinite abelian covering graph. Finally, as an application, we show that if the Betti number of the quotient graph is strictly greater than one, then localization is ensured with some appropriated initial state. We also compute the limit density function for the Grover walk on Zd with flip flop shift, which implies the coexistence of linear spreading and localization. We partially obtain the abstractive shape of the limit density function: the support is within the d-dimensional sphere of radius 1/d, and 2d singular points reside on the sphere's surface.

Original languageEnglish
Pages (from-to)4197-4235
Number of pages39
JournalJournal of Functional Analysis
Volume267
Issue number11
DOIs
Publication statusPublished - 2014 Dec 1

Keywords

  • Crystal lattice
  • Quantum walks
  • Spectral mapping theorem
  • Weak limit theorem

ASJC Scopus subject areas

  • Analysis

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