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arXiv · 2002.04499

Hyperuniform structures formed by shearing colloidal suspensions

Sam Wilken·Rodrigo E. Guerra·David J. Pine·Paul M. Chaikin
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Abstract

In periodically sheared suspensions there is a dynamical phase transition characterized by a critical strain amplitude $\gamma_c$ between an absorbing state where particle trajectories are reversible and an active state where trajectories are chaotic and diffusive. Repulsive non-hydrodynamic interactions between "colliding" particles' surfaces have been proposed as a source of this broken time reversal symmetry. A simple toy model called Random Organization qualitatively reproduces the dynamical features of this transition. Random Organization and other absorbing state models exhibit hyperuniformity, a strong suppression of density fluctuations on long length-scales quantified by a structure factor $S(q \rightarrow 0) \sim q^\alpha$ with $\alpha > 0$, at criticality. Here we show experimentally that the particles in periodically sheared suspensions organize into structures with anisotropic short-range order but isotropic, long-range hyperuniform order when oscillatory shear amplitudes approach $\gamma_c$.

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Sam Wilken, Rodrigo E. Guerra, David J. Pine, Paul M. Chaikin. 2020-02-11. Hyperuniform structures formed by shearing colloidal suspensions. https://doi.org/10.1103/physrevlett.125.148001

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