Title:	Topology of multipartite non-Hermitian one-dimensional systems
Authors:	Nehra, Ritu Roy, Dibyendu
Keywords:	non-Hermitian physics topology composite loops Complex Zak phase Composite Zak phase topological invariant Penrose triagle
Issue Date:	4-May-2022
Publisher:	Americal Physical Society
Citation:	Physical Review B, 2022, 105, p195407
Abstract:	The multipartite non-Hermitian Su-Schrieffer-Heeger model is explored as a prototypical example of one-dimensional systems with several sublattice sites for unveiling intriguing insulating and metallic phases with no Hermitian counterparts. These phases are characterized by composite cyclic loops of multiple complex-energy bands encircling single or multiple exceptional points (EPs) on the parametric space of real and imaginary energy. We show the topology of these composite loops is similar to well-known topological objects like Möbius strips and Penrose triangles, and can be quantified by a nonadiabatic cyclic geometric phase which includes contributions only from the participating bands. We analytically derive a complete phase diagram with the phase boundaries of the model. We further examine the connection between encircling of multiple EPs by complex-energy bands on parametric space and associated topology.
Description:	Restricted Access. An open-access version is available at arXiv.org (one of the alternative locations)
URI:	http://hdl.handle.net/2289/7992
ISSN:	2469-9950 2469-9969 (Online)
Alternative Location:	https://arxiv.org/abs/2201.12297 https://doi.org/10.1103/PhysRevB.105.195407 https://ui.adsabs.harvard.edu/abs/2022PhRvB.105s5407N/abstract
Copyright:	2022 American Physical Socity
Appears in Collections:	Research Papers (TP)

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