Researchers Unveil Mechanism Behind Exotic Hyperuniform Matter's Emerging Properties

Hyperuniformity refers to a condition in heterogeneous media where large-scale fluctuations in density are greatly suppressed.

Scientists from the S. N. Bose National Centre for Basic Sciences (SNBNCBS) have made significant strides in understanding the exotic disordered state of matter known as hyperuniformity. This state, observed in a wide range of systems, from quasicrystals to biological emulsions, displays unusual properties where density fluctuations at long wavelengths approach zero, defying typical behaviours of disordered materials.

Hyperuniformity refers to a condition in heterogeneous media where large-scale fluctuations in density are greatly suppressed. This rare property has been observed in systems like colloids, quasicrystals, and even the large-scale structure of the universe. Unlike in traditional states of matter, mass fluctuations decrease as the system size grows, a feature that sharply contrasts with typical behaviour seen in critical states, such as water-vapour systems.

Researchers explored how these suppressed fluctuations arise, particularly focusing on systems where time-reversal symmetry is broken. In simpler terms, time-reversal symmetry allows one to theoretically "rewind" the dynamics of a system, like watching a video in reverse. However, breaking this symmetry — by introducing an external force or additional conservation laws — leads to the emergence of hyperuniformity.

The team, led by SNBNCBS researchers, demonstrated that in hyperuniform systems, spontaneous density perturbations diffuse like heat energy, but such fluctuations are unlikely to arise due to constrained particle mobility. This unique interplay between diffusion and constraint underpins the state’s defining property: suppressed fluctuations in mass and density.

The team’s findings, published in the journal Physical Review E, provide new insights into the dynamic organization of particles in hyperuniform matter. By studying driven diffusive systems—simple models of interacting particles—the researchers were able to quantify how hyperuniformity emerges in such states, offering a fresh perspective on its theoretical origins.

One of the study's key contributions is its explanation of how hyperuniform systems differ from typical critical states, like the critical point of liquids. At this critical point, mass fluctuations diverge, creating light-scattering phenomena known as critical opalescence. In hyperuniform states, however, mass fluctuations remain minimal, which is strikingly different from what is observed at criticality in other systems.

This new understanding of hyperuniformity holds promise for various technological and biological applications. Hyperuniform materials possess unique optical properties that make them ideal for designing photonic band-gap materials, which can be used in energy-efficient photonic devices for optical data transmission. Additionally, the mechanisms underlying hyperuniformity could be harnessed to control physiological functions in cells, opening avenues for applications in biotechnology.

This research enhances our theoretical grasp of hyperuniformity, potentially unlocking new strategies for creating materials with customized properties for use in optical communications, biological systems, and other advanced technologies.