Emergent localized states at the interface of a twofold $\mathcal{P}\mathcal{T}$-symmetric lattice

Abstract

We consider the role of non-triviality resulting from a non-Hermitian Hamiltonian that conserves twofold PT-symmetry assembled by interconnections between a PT-symmetric lattice and its time reversal partner. Twofold PT-symmetry in the lattice produces additional surface exceptional points that play the role of new critical points, along with the bulk exceptional point. We show that there are two distinct regimes possessing symmetry-protected localized states, of which localization lengths are robust against external gain and loss. The states are demonstrated by numerical calculation of a quasi-1D ladder lattice and a 2D bilayered square lattice.

arXiv comment10 pages, 7 figures

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Cited by in corpus (4)

• Symmetry breaking and spectral structure of the interacting Hatano-Nelson model
• From scale-free to Anderson localization: a size-dependent transition
• Topological split-ring resonator based metamaterials with $\mathcal{P}\mathcal{T}$ symmetry relying on gain and loss
• Non-orientability induced PT phase transition in Moebius ladder lattices