Related Experiment Video
Updated: Mar 19, 2026

An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids
Published on: December 4, 2017
Scattering of waves by impurities in precompressed granular chains
Alejandro J Martínez1, Hiromi Yasuda2, Eunho Kim2,3
1Oxford Centre for Industrial and Applied Mathematics, Mathematical Institute, University of Oxford, Oxford OX2 6GG, UK.
We discovered a quantum physics-like resonance in granular chains, enabling full wave transmission through impurities. This Ramsauer-Townsend (RT) resonance can be tuned and even create reflectionless modes in disordered chains.
Area of Science:
- Physics
- Materials Science
- Acoustics
Background:
- Granular chains exhibit unique wave propagation properties.
- Impurities can disrupt or modify wave transmission.
- Precompression significantly alters the behavior of granular materials.
Purpose of the Study:
- To investigate wave scattering by impurities in precompressed granular chains.
- To derive analytical expressions for wave reflection and transmission.
- To explore the phenomenon of resonance in such systems.
Main Methods:
- Linear scattering theory for plane waves.
- Derivation of closed-form expressions for scattering coefficients.
- Numerical simulations and experimental validation.
- Analysis of single and double impurity configurations.
Main Results:
- Identified frequency-dependent wave attenuation and transmission in single-impurity chains.
- Discovered a Ramsauer-Townsend (RT) resonance in double-impurity chains enabling full transmission.
- Demonstrated tunability of the RT resonance frequency within the host chain's passband.
- Observed near-complete transmission at RT resonance frequencies experimentally.
- Showcased RT resonance's potential for creating reflectionless modes.
Conclusions:
- Strongly precompressed granular chains exhibit tunable wave scattering properties.
- The Ramsauer-Townsend resonance offers a mechanism for complete wave transmission through impurities.
- This phenomenon has implications for designing advanced acoustic or mechanical filters and metamaterials.
More Related Videos
Related Concept Videos
The de Broglie Wavelength
Propagation of Waves
Consider a scenario where a wave propagates from a string of low linear mass density to a string of high linear mass density. In such a case, the reflected wave is out of phase with respect to the incident wave, however the...
Interference and Diffraction
X-ray Crystallography
Diffraction
Diffraction is the change in the direction of travel experienced by an electromagnetic wave when it encounters a physical barrier whose dimensions are comparable to those of the wavelength of the light. X-rays are electromagnetic radiation with wavelengths about as long as the distance between neighboring...
Imperfections in Crystal Structure: Point, Line and Plane Defects
Colloids

