3D Anderson localization of classical scalar waves.

Area of Science:

• Acoustic Metamaterials
• Wave Physics
• Condensed Matter Physics

Background:

• Anderson localization, predicted in 1958, describes the cessation of diffusive transport in disordered systems.
• Experimental observation of Anderson localization for classical waves (light, sound) in 3D disordered systems remains a significant challenge.
• Scalar wave Anderson localization has not been experimentally demonstrated in three dimensions.

Purpose of the Study:

• To experimentally demonstrate three-dimensional (3D) Anderson localization for scalar acoustic waves.
• To investigate the potential of locally resonant ultrasonic metafluids for achieving wave localization.
• To determine the mobility edges and construct the localization phase diagram for acoustic waves in a disordered metafluid.

Main Methods:

• Fabrication of a locally resonant ultrasonic metafluid composed of a suspension of soft metallic beads.
• Conducting time- and position-resolved ultrasonic experiments to probe wave propagation.
• Analyzing experimental data to identify transitions between diffusive and localized wave transport regimes.

Main Results:

• Clear experimental evidence of Anderson transitions between diffusion and localization was observed in the 3D metafluid.
• The study successfully determined the mobility edges, critical parameters for the onset of localization.
• A comprehensive localization phase diagram for scalar acoustic waves was accurately mapped.

Conclusions:

• Locally resonant ultrasonic metafluids offer a viable platform for observing 3D Anderson localization of scalar acoustic waves.
• The experimental findings validate theoretical predictions and open new avenues for controlling wave transport in disordered media.
• This work paves the way for future research into wave localization phenomena in classical systems.