Quantum walks with a one-dimensional coin
Mar 24, 2016Citations per year
Abstract: (arXiv)
Quantum walks (QWs) describe particles evolving coherently on a lattice. The internal degree of freedom corresponds to a Hilbert space, called coin system. We consider QWs on Cayley graphs of some group . In the literature, investigations concerning infinite have been focused on graphs corresponding to with coin system of dimension 2, whereas for one-dimensional coin (so called scalar QWs) only the case of finite has been studied. Here we prove that the evolution of a scalar QW with infinite Abelian is trivial, providing a thorough classification of this kind of walks. Then we consider the infinite dihedral group , that is the unique non-Abelian group containing a subgroup with two cosets. We characterize the class of QWs on the Cayley graphs of and, via a coarse-graining technique, we show that it coincides with the class of spinorial walks on which satisfies parity symmetry. This class of QWs includes the Weyl and the Dirac QWs. Remarkably, there exist also spinorial walks that are not coarse-graining of a scalar QW, such as the Hadamard walk.Note:
- 8 pages, 4 figures
- 03.67.Ac
- 02.20.-a
References(32)
Figures(6)
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