Nonlinear construction of topological SSH models

TL;DR

This paper introduces a nonlinear scheme for constructing topological SSH models using a 1-D chain of bosonic modes with anharmonicities, revealing topological properties and bistability through spectroscopic analysis.

Contribution

It presents a novel nonlinear approach to realize topological SSH models via anharmonic bosonic chains, extending the understanding of topological phases in nonlinear systems.

Findings

Topological zero-energy modes emerge in the nonlinear bosonic chain.

Spectroscopic analysis reveals bistability at higher pump rates.

The linearized system matches the traditional SSH model topology.

Abstract

The Su-Schrieffer-Heeger (SSH) model describes a paradigmatic one-dimensional (1-D) system that exhibits a non-trivial band topology. In this paper, we foreground a new scheme involving a 1-D chain of $2N+1$ Bosonic modes with nearest-neighbor interactions, in which, the topology of the system is regulated by the selective excitation of intrinsic anharmonicities. In the dispersive regime, where the characteristic detunings are considerably larger than the coupling strengths, the linearized system is topologically identical to an SSH model. This is marked by the emergence of zero-energy eigenmodes of the system, and we specifically illustrate its rich topology in a chain of size $N=6$. We consider an experimentally realizable lattice involving optical cavities which are coupled to collective systems characterized by Bosonic modes. By investigating the transmission due to a weak probe field, we provide a spectroscopic analysis of the system, demonstrating, for instance, the emergence of bistability at higher pumping rates.