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arXiv · 2201.12297

Topology of multipartite non-Hermitian one-dimensional systems

Ritu Nehra·Dibyendu Roy
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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 M\"obius 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 the encircling of multiple EPs by complex-energy bands on parametric space and associated topology.

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Ritu Nehra, Dibyendu Roy. 2022-01-28. Topology of multipartite non-Hermitian one-dimensional systems. https://doi.org/10.1103/physrevb.105.195407

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