论文标题
由剪切胶体悬浮液形成的超一样结构
Hyperuniform structures formed by shearing colloidal suspensions
论文作者
论文摘要
在定期剪切的悬浮液中，有一个动力学相变为特征，其特征是在吸收状态之间的临界应变振幅$γ_c$，其中粒子轨迹是可逆的，而在轨迹混乱且扩散的活性状态。已经提出了“碰撞”粒子表面之间排斥性的非流动力相互作用，作为这种破裂的时间逆转对称性的来源。一个称为随机组织的简单玩具模型定性地重现了此过渡的动力学特征。随机组织和其他吸收状态模型表现出过度均匀性，对通过结构因子$ s（q \ rightarrow 0）（q \ rightarrow 0）\ sim q^α$量化的长度尺度的密度波动的强烈抑制，并以$ $α> 0 $在临界处。在这里，我们通过实验表明，定期剪切的悬浮液中的颗粒组织成各向异性短距离顺序的结构，但是当振荡性剪切振幅接近$γ_C$时，各向同性，远距离超均匀顺序。
In periodically sheared suspensions there is a dynamical phase transition characterized by a critical strain amplitude $γ_c$ 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 $S(q \rightarrow 0) \sim q^α$ with $α> 0$, 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 $γ_c$.
