Pumping with symmetry

• Published in: Europhysics letters Vol. 146; no. 1; pp. 16004 - 16009
• Main Authors: Iglesias Martínez, J. A., Kadic, M., Laude, V., Prodan, E.
• Format: Journal Article
• Language: English
• Published: Les Ulis EDP Sciences, IOP Publishing and Società Italiana di Fisica 01.04.2024; IOP Publishing; European Physical Society / EDP Sciences / Società Italiana di Fisica / IOP Publishing
• Subjects: Acoustics; Adiabatic flow; Cavity resonators; Deformation; Engineering Sciences; Excitation spectra; Materials; Metamaterials; Micro and nanotechnologies; Microelectronics; Pumping; Symmetry; Topology
• ISSN: 0295-5075; 1286-4854
• DOI: 10.1209/0295-5075/ad3053

Abstract Re-configurable materials and meta-materials can jump between space symmetry classes during their deformations. Here, we introduce the concept of singular symmetry enhancement, which refers to an abrupt jump to a higher symmetry class accompanied by an un-avoidable reduction in the number of dispersion bands of the excitations of the material. Such phenomenon prompts closings of some of the spectral resonant gaps along singular manifolds in a parameter space. In this work, we demonstrate that these singular manifolds can carry topological charges. As a concrete example, we show that a deformation of an acoustic crystal that encircles a configuration of an array of cavity resonators results in an adiabatic cycle that carries a Chern number in the bulk and displays Thouless pumping at the edges. This points to a very general guiding principle for recognizing cyclic adiabatic processes with high potential for topological pumping in complex materials and meta-materials, which rests entirely on symmetry arguments.