Eigenvalue Measurement of Topologically Protected Edge states in Split-Step Quantum Walks

authored by: Thomas Nitsche, Tobias Geib, Christoph Stahl, Lennart Lorz, Christopher Cedzich, Sonja Barkhofen, Reinhard F. Werner, Christine Silberhorn
Abstract: We study topological phenomena of quantum walks by implementing a novel protocol that extends the range of accessible properties to the eigenvalues of the walk operator. To this end, we experimentally realise for the first time a split-step quantum walk with decoupling, which allows for investigating the effect of a bulk-boundary while realising only a single bulk configuration. The experimental platform is implemented with the well-established time-multiplexing architecture based on fibre-loops and coherent input states. The symmetry protected edge states are approximated with high similarities and we read-out the phase relative to a reference for all modes. In this way we observe eigenvalues which are distinguished by the presence or absence of sign flips between steps. Furthermore, the results show that investigating a bulk-boundary with a single bulk is experimentally feasible when decoupling the walk beforehand.
Organisation(s): Institute of Theoretical Physics
CRC 1227 Designed Quantum States of Matter (DQ-mat)
External Organisation(s): Paderborn University
University of Cologne
Type: Article
Journal: New Journal of Physics
Volume: 21
ISSN: 1367-2630
Publication date: 04.2019
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Physics and Astronomy(all)
Electronic version(s): https://doi.org/10.48550/arXiv.1811.09520 (Access: Open)
https://doi.org/10.1088/1367-2630/ab12fa (Access: Open)
https://doi.org/10.15488/10404 (Access: Open)

BibTeX

@article{5b9fb19836a54da0a95795161d7bcce4,
title = "Eigenvalue Measurement of Topologically Protected Edge states in Split-Step Quantum Walks",
abstract = "We study topological phenomena of quantum walks by implementing a novel protocol that extends the range of accessible properties to the eigenvalues of the walk operator. To this end, we experimentally realise for the first time a split-step quantum walk with decoupling, which allows for investigating the effect of a bulk-boundary while realising only a single bulk configuration. The experimental platform is implemented with the well-established time-multiplexing architecture based on fibre-loops and coherent input states. The symmetry protected edge states are approximated with high similarities and we read-out the phase relative to a reference for all modes. In this way we observe eigenvalues which are distinguished by the presence or absence of sign flips between steps. Furthermore, the results show that investigating a bulk-boundary with a single bulk is experimentally feasible when decoupling the walk beforehand.",
keywords = "bulk-boundary correspondence, decoupling, quantum walks, split-step, symmetry protected edge states, topological phenomena",
author = "Thomas Nitsche and Tobias Geib and Christoph Stahl and Lennart Lorz and Christopher Cedzich and Sonja Barkhofen and Werner, {Reinhard F.} and Christine Silberhorn",
year = "2019",
month = apr,
doi = "10.48550/arXiv.1811.09520",
language = "English",
volume = "21",
journal = "New Journal of Physics",
issn = "1367-2630",
publisher = "IOP Publishing Ltd.",
number = "4",
}