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Article
Winding around non-Hermitian singularities
Nature Communications
  • Qi Zhong, Michigan Technological University
  • Mercedeh Khajavikhan, University of Central Florida
  • Demetrios Christodoulides, University of Central Florida
  • Ramy El-Ganainy, Michigan Technological University
Document Type
Article
Publication Date
11-15-2018
Disciplines
Abstract

Non-Hermitian singularities are ubiquitous in non-conservative open systems. Owing to their peculiar topology, they can remotely induce observable effects when encircled by closed trajectories in the parameter space. To date, a general formalism for describing this process beyond simple cases is still lacking. Here we develop a general approach for treating this problem by utilizing the power of permutation operators and representation theory. This in turn allows us to reveal a surprising result that has so far escaped attention: loops that enclose the same singularities in the parameter space starting from the same point and traveling in the same direction, do not necessarily share the same end outcome. Interestingly, we find that this equivalence can be formally established only by invoking the topological notion of homotopy. Our findings are general with far reaching implications in various fields ranging from photonics and atomic physics to microwaves and acoustics.

Publisher's Statement

© The Author(s) 2018. Article deposited here in compliance with publisher policy. Publisher's version of record: https://doi.org/10.1038/s41467-018-07105-0

Creative Commons License
Creative Commons Attribution 4.0 International
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Publisher's PDF
Citation Information
Qi Zhong, Mercedeh Khajavikhan, Demetrios Christodoulides and Ramy El-Ganainy. "Winding around non-Hermitian singularities" Nature Communications Vol. 9 (2018)
Available at: http://works.bepress.com/ramy_el-ganainy/36/