Experimental confirmation of hyperuniformity of torque fluctuations in frictional matter
Abstract
Abstract A recent purely theoretical prediction stated that in frictional granular packings, mechanical balance and material isotropy constrain the stress auto-correlation matrix to be fully determined by two spatially isotropic functions: the pressure and torque auto-correlations. Moreover, and unexpectedly, the torque fluctuations were predicted to be hyperuniform, a condition for the stress auto-correlation to decay as the elastic Green's function. In this letter we present first experimental evidence for the hyperuniformity of the stress fluctuations. We propose that quite generally the variance of torque fluctuations in a d -dimensional ball of radius R will increase exactly like , satisfying the definition of hyperuniformity.
Fields of Study & Subjects
Granular flow and fluidized beds
Brake Systems and Friction Analysis
Material Dynamics and Properties
Publication details
- Journal / source
- Europhysics Letters (EPL)
- Publisher
- IOP Publishing
- Volume
- 153
- Issue
- 3
- Pages
- 37001–37001
- Publication date
- 1 February 2026