Observation of structural universality in disordered systems using bulk diffusion measurement

TL;DR

This study experimentally demonstrates how bulk diffusion measurements can distinguish between different structural universality classes in disordered systems, linking microscopic disorder to macroscopic transport properties.

Contribution

The paper provides the first experimental verification of the relation between structural universality classes and diffusion dynamics in disordered one-dimensional systems.

Findings

Diffusion coefficients differ between hyperuniform and short-range disorder samples.

The relation between structural exponent and dynamical exponent is experimentally confirmed.

Transport properties are primarily determined by universality class rather than microscopic details.

Abstract

We report on an experimental observation of classical diffusion distinguishing between structural universality classes of disordered systems in one dimension. Samples of hyperuniform and short-range disorder were designed, characterized by the statistics of the placement of $\mu$m-thin parallel permeable barriers, and the time-dependent diffusion coefficient was measured by NMR methods over three orders of magnitude in time. The relation between the structural exponent, characterizing disorder universality class, and the dynamical exponent of the diffusion coefficient is experimentally verified. The experimentally established relation between structure and transport exemplifies the hierarchical nature of structural complexity --- dynamics are mainly determined by the universality class, whereas microscopic parameters affect the non-universal coefficients. These results open the way for non-invasive characterization of structural correlations in porous media, complex materials, and biological tissues via a bulk diffusion measurement.