Mixing of quantum walk on circulant bunkbeds

  • Authors:
  • Peter Lo;Siddharth Rajaram;Diana Schepens;Daniel Sullivan;Christino Tamon;Jeffrey Ward

  • Affiliations:
  • Dept. Mathematics and Computer Science, St. Mary's College of Maryland, St. Mary's City, MD;Dept. Mathematics, Middlebury College, VT;Dept. Mathematics and Computer Science, Houghton College, Houghton, NY;Dept. Mathematics and Statistics, Swarthmore College, Swarthmore, PA;Dept. Computer Science and Center for Quantum Device Technology, Clarkson University, Potsdam, NY;Div. Mathematics and Computer Science, Clarkson University, Potsdam, NY

  • Venue:
  • Quantum Information & Computation
  • Year:
  • 2006

Quantified Score

Hi-index 0.00

Visualization

Abstract

This paper give new observations on the mixing dynamics of a continuous-time quantumwalk on circulants and their bunkbed extensions. These bunkbeds are defined throughtwo standard graph operators: the join G + H and the Cartesian product G × H ofgraphs G and H. Our results include the following: (i) The quantum walk is average uniform mixing oncirculants with bounded eigenvalue multiplicity. This extends a known fact about thecycles Cn. (ii) Explicit analysis of the probability distribution of the quantum walk onthe join of circulants. This explains why complete partite graphs are not averageuniform mixing, using the fact Kn = K1 + Kn-1 and Kn....,n = Kn + ... + Kn.(iii)The quantum walk on the Cartesian product of a m-vertex path Pm and a circulantG, namely, Pm × G, is average uniform mixing if G is. This highlights a differencebetween circulants and the hypercubes Qn = P2 × Qn-1.Our proofs employ purely elementary arguments based on the spectra of the graphs.