Hannover 2020 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 13: Posters: Quantum Optics and Photonics I
Q 13.54: Poster
Monday, March 9, 2020, 16:30–18:30, Empore Lichthof
Topological Protection in non-Hermitian Haldane Honeycomb Lattices — Pablo Reséndiz-Vázquez1, •Konrad Tschernig2,3, Armando Perez-Leija2,3, Kurt Busch2,3, and Roberto de J. León-Montiel1 — 1Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Apartado Postal 70-543, 04510 Cd. Mx., México — 2Max-Born-Institut, Max-Born-Straße 2A, 12489 Berlin, Germany — 3Humboldt-Universität zu Berlin, Institut für Physik, AG Theoretische Optik & Photonik, D-12489 Berlin, Germany
Topological phenomena in non-Hermitian systems has recently become a subject of great interest in the photonics and condensed-matter communities. In particular, the possibility of observing topologically-protected edge states in non-Hermitian lattices has sparked an intensive search for systems where this kind of states is sustained. Here, we present the first study on the emergence of topological edge states in a two-dimensional Haldane lattice endowed with balanced gain and loss. We show that edge states can be observed in the trivial PT-symmetric phase, that is, when the gain and loss are absent, as well as in the broken PT-symmetric phase, that is, when the spectrum of the system’s Hamiltonian is not entirely real. Remarkably, we find that this behavior is universal in the sense that any geometry of the lattice edge, namely zigzag, bearded or armchair supports edge states. These results demonstrate that two-dimensional topologically-protected edge states may exist even in the absence of PT symmetry.