Discrete Breathers in One-Dimensional Diatomic Granular Crystals

TL;DR

This paper reports the experimental observation and numerical analysis of discrete breathers in a one-dimensional diatomic granular crystal, demonstrating their formation through modulational instability and matching experimental data with theoretical predictions.

Contribution

It provides the first experimental evidence of discrete breathers in diatomic granular crystals and combines theoretical, numerical, and experimental approaches to study their properties.

Findings

Discrete breathers observed experimentally in granular crystals.

Breather formation linked to modulational instability of the optical band.

Quantitative agreement between experimental measurements and numerical simulations.

Abstract

We report the experimental observation of discrete breathers in a one-dimensional diatomic granular crystal composed of compressed elastic beads that interact via Hertzian contact. We first characterize their effective linear spectrum both theoretically and experimentally. We then illustrate theoretically and numerically the modulational instability of the lower edge of the optical band. This leads to the dynamical formation of long-lived breather structures, whose families of solutions we compute throughout the linear spectral gap. Finally, we observe experimentally such localized breathing modes with quantitative characteristics that agree with our numerical results.