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arXiv · 2305.13174

Observation of Quantum metric and non-Hermitian Berry curvature in a plasmonic lattice

Javier Cuerda·Jani M. Taskinen·Nicki Källman·Leo Grabitz·Päivi Törmä
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Abstract

We experimentally observe the quantum geometric tensor, namely the quantum metric and the Berry curvature, for a square lattice of radiatively coupled plasmonic nanoparticles. We observe a non-zero Berry curvature and show that it arises solely from non-Hermitian effects. The quantum metric is found to originate from a pseudospin-orbit coupling. The long-range nature of the radiative interaction renders the behavior distinct from tight-binding systems: Berry curvature and quantum metric are centered around high-symmetry lines of the Brillouin zone instead of high-symmetry points. Our results inspire new pathways in the design of topological systems by tailoring losses or gain.

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Javier Cuerda, Jani M. Taskinen, Nicki Källman, Leo Grabitz, Päivi Törmä. 2023-05-22. Observation of Quantum metric and non-Hermitian Berry curvature in a plasmonic lattice. https://doi.org/10.1103/physrevresearch.6.l022020

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