Exceptional points in SSH-like models with hopping amplitude gradient

Abstract

The Su-Schrieffer-Heeger (SSH) system is a popular model for exploring topological insulators and topological phases in one dimension. Recent interest in exceptional points has led to re-examination of non-Hermitian generalizations of many physical models, including the SSH model. In such non-Hermitian systems, singular points called exceptional points (EPs) appear that are of interest for applications in super-resolution sensing systems and topological lasers. Here, a non-Hermitian and non-PT-symmetric variation of the SSH model is introduced, in which the hopping amplitudes are non-reciprocal and vary monotonically along the chain. It is found that, while the existence of the EPs is due to the nonreciprocal couplings, the number, position, and order of the EPs can all be altered by the addition of the hopping amplitude gradient, adding a new tool for tailoring the spectrum of a non-Hermitian system.

References in corpus (12)

• The physics of exceptional points
• Quantum Walk in Position Space with Single Optically Trapped Atoms
• Topological phases in the non-Hermitian Su-Schrieffer-Heeger model
• Discrete single-photon quantum walks with tunable decoherence
• Non-Hermitian Ring Laser Gyroscopes with Enhanced Sagnac Sensitivity
• PT-Symmetry in Non-Hermitian Su-Schrieffer-Heeger model with complex boundary potentials
• Symmetry-protected zero-mode laser with a tunable spatial profile
• Design of resonant microcavities: application to optical gyroscopes
• Exceptional Points in three-dimensional Nanostructures
• Non-Hermitian gauged laser arrays with localized excitations: Anomalous threshold and generalized principle of selective pumping
• Non-Hermitian systems with a real spectrum and selective skin effect
• Enhanced Signal-to-Noise Performance of EP-based Electromechanical Accelerometers