Observation of the topological soliton state in the Su-Schrieffer-Heeger model

TL;DR

This paper reports the experimental quantum simulation of the SSH model using ultracold atoms, demonstrating the observation of topological soliton states through various dynamical and preparation techniques.

Contribution

It provides the first experimental realization and observation of topological soliton states in a tunable quantum simulation of the SSH model.

Findings

Observation of localized topological soliton states

Demonstration of quench dynamics and phase-sensitive injection

Adiabatic preparation of topological states

Abstract

The Su-Schrieffer-Heeger (SSH) model, which captures the most striking transport properties of the conductive organic polymer $trans$-polyacetylene, provides perhaps the most basic model system supporting topological excitations. The alternating bond pattern of polyacetylene chains is captured by the bipartite sublattice structure of the SSH model, emblematic of one-dimensional chiral symmetric topological insulators. This structure supports two distinct nontrivial topological phases, which, when interfaced with one another or with a topologically trivial phase, give rise to topologically-protected, dispersionless boundary states. Using $^{87}$Rb atoms in a momentum-space lattice, we realize fully-tunable condensed matter Hamiltonians, allowing us to probe the dynamics and equilibrium properties of the SSH model. We report on the experimental quantum simulation of this model and observation of the localized topological soliton state through quench dynamics, phase-sensitive injection, and adiabatic preparation.