Topologically Protected Spatially Localized Modes: An Easy Experimental Realization of the Su--Schrieffer--Heeger Model

TL;DR

This paper demonstrates an accessible electrical circuit implementation of the Su--Schrieffer--Heeger model, illustrating topologically protected edge modes through theoretical analysis and experimental validation, thus making complex topological concepts more tangible.

Contribution

It introduces a simple electrical circuit setup that emulates the SSH model, providing an experimental platform to study topological edge modes.

Findings

Experimental results confirm the presence of topologically protected modes.

Good agreement between theoretical predictions and experimental data.

Abstract

In this paper, we review the basic concepts of topologically protected edge modes using the Su Schrieffer Heeger (SSH) model, originally introduced to describe electrical conductivity in doped polyacetylene polymer chains. We then propose an electrical circuit that emulates this model, provide its mathematical description, and present its experimental realization. The experimental setup is described in detail, with explanations designed to be broadly accessible without much prior familiarity with lattice theory, thus offering an introduction to this active area of research. Both theoretical predictions and experimental results confirm the presence of these modes, showing very good overall agreement. Using this concrete experimental system as a motivating example, we highlight the key aspects of topological protection.