Topological protection in non-Hermitian Haldane honeycomb lattices

Abstract

Topological phenomena in non-Hermitian systems have 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 are sustained. Here we present a study of the emergence of topological edge states in two-dimensional Haldane lattices exhibiting balanced gain and loss. In line with recent studies on other Chern insulator models, we show that edge states can be observed in the so-called broken PT-symmetric phase, that is, when the spectrum of the gain-loss-balanced system's Hamiltonian is not entirely real. More importantly, we find that such topologically protected edge states emerge irrespective of the lattice boundaries, namely, zigzag, bearded, or armchair.

Reconfigurable network for quantum transport simulations

“…This is precisely the result of the topological edge protection [38,39]. It is important to remark that, as in other topological-insulator examples, this energy-localization effect becomes stronger as the system's size is increased [53,54].…”

Linear response theory of open systems with exceptional points

“…These include electronic, acoustic, mechanical, and thermal systems. In addition, our framework provides a powerful tool for understanding the complex interplay between non-Hermiticity and other physical effects such as topological invariants 12 , 28 , 55 , 65 , 111 , 112 , optomechanical coupling 14 , 54 , 113 – 115 as well as quantum statistics 10 , 24 , 72 , 103 , 116 , 117 , to just mention a few examples. This in turn may enable the engineering of more elaborate schemes for controlling energy and information flow in complex non-Hermitian systems.…”

Noise-Assisted Discord-Like Correlations in Light-Harvesting Photosynthetic Complexes

“…Transport phenomena in nanostructured materials [1][2][3][4] and biomolecules [5][6][7][8][9] have been the main subject of interest in several investigations in the last two decades. Of particular importance is the study of energy transport and energy conversion, in photosynthetic complexes, from a quantum mechanical perspective [10,11].…”