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Quantum walks in synthetic gauge fields with three-dimensional integrated photonics

Kerans, O. ; Novo, L.N. ; Sciarrino, F. ; Omar, Y.

Physical Review A - Atomic, Molecular, and Optical Physics Vol. 95, Nº 1, pp. 013830 - --, January, 2017.

ISSN (print): 1050-2947
ISSN (online): 1094-1622

Journal Impact Factor: 2,808 (in 2014)

Digital Object Identifier: 10.1103/PhysRevA.95.013830

Abstract
There is great interest in designing photonic devices capable of disorder-resistant transport and information processing. In this work we propose to exploit three-dimensional integrated photonic circuits in order to realize two-dimensional discrete-time quantum walks in a background synthetic gauge field. The gauge fields are generated by introducing the appropriate phase shifts between waveguides. Polarization-independent phase shifts lead to an Abelian or magnetic field, a case we describe in detail. We find that, in the disordered case, the magnetic field enhances transport due to the presence of topologically protected chiral edge states that do not localize. Polarization-dependent phase shifts lead to effective non-Abelian gauge fields, which could be adopted to realize Rashba-like quantum walks with spin-orbit coupling. Our work introduces a flexible platform for the experimental study of multiparticle quantum walks in the presence of synthetic gauge fields, which paves the way towards topologically robust transport of many-body states of photons.