Revealing the topology of quasicrystals with a diffraction experiment

TL;DR

This paper demonstrates a diffraction-based experimental method to directly observe and verify the topological invariants of quasicrystals, specifically Fibonacci chains, and assesses their stability under disorder.

Contribution

It introduces a novel interferometric diffraction technique to directly measure topological invariants in quasicrystals, advancing understanding of their topological properties.

Findings

All topological invariants of Fibonacci chains are directly observable in diffraction patterns.

Topological invariants remain stable despite structural disorder.

The method provides a new way to study topological properties in quasicrystals.

Abstract

Topological properties of crystals and quasicrystals is a subject of recent and growing interest. This Letter reports an experiment where, for certain quasicrystals, these properties can be directly retrieved from diffraction. We directly observe, using an interferometric approach, all the topological invariants of finite-length Fibonacci chains in their diffraction pattern. We also demonstrate quantitatively the stability of these topological invariants with respect to structural disorder.