Nonlinear Topological Edge States in a non-Hermitian Array of Optical Waveguides Embedded in an Atomic Gas

Abstract

We propose a scheme comprising an array of anisotropic optical waveguides, embedded in a gas of cold atoms, which can be tuned from a Hermitian to an odd-PT -- symmetric configuration through the manipulation of control and assistant laser fields. We show that the system can be controlled by tuning intra -- and inter-cell coupling coefficients, enabling the creation of topologically distinct phases and linear topological edge states. The waveguide array, characterized by a quadrimer primitive cell, allows for implementing transitions between Hermitian and odd-PT -symmetric configurations, broken and unbroken PT -symmetric phases, topologically trivial and nontrivial phases, as well as transitions between linear and nonlinear regimes. The introduced scheme generalizes the Rice-Mele Hamiltonian for a nonlinear non-Hermitian quadrimer array featuring odd-PT symmetry and makes accessible unique phenomena and functionalities that emerge from the interplay of non-Hermiticity, topology, and nonlinearity. We also show that in the presence of nonlinearity the system sustains nonlinear topological edge states bifurcating from the linear topological edge states and the modes without linear limit. Each nonlinear mode represents a doublet of odd-PT -conjugate states. In the broken PT phase, the nonlinear edge states may be effectively stabilized when an additional absorption is introduced into the system.

7 pages, 3 figures

References in corpus (7)

• Topological Photonics
• Making Sense of Non-Hermitian Hamiltonians
• Analogs of quantum Hall effect edge states in photonic crystals
• Low-Light-Level Optical Interactions with Rubidium Vapor in a Photonic Bandgap Fiber
• Symmetry breaking of solitons in one-dimensional parity-time-symmetric optical potentials
• Discrete solitons in PT-symmetric lattices
• Surface modes and breathers in finite arrays of nonlinear waveguides

Cited by in corpus (7)

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• Observation of nonlinearity-controlled switching of topological edge states
• Floquet edge solitons in modulated trimer waveguide arrays
• Topological gap solitons in Rabi Su-Schrieffer-Heeger lattices
• Topological solitons in coupled Su-Schrieffer-Heeger waveguide arrays
• Topological edge solitons in \{chi}(2) waveguide arrays
• Antichiral and trap-skin dynamics in a nonreciprocal bosonic two-leg ladder with artificial magnetic flux