We show here that rotations of round particles in amorphous disk packing reveal various nontrivial microscopic features when the packing is close to rigidification. We analyze experimental measurements on disk packing subjected to simple shear deformation with various inter-particle friction coefficients and across a range of volume fractions where the system is known to stiffen. The analysis of measurements indicates that shear induces diffusive microrotation, that can be both enhanced and suppressed depending upon the volume fraction as well as the inter-particle friction. Rotations also display persistent anticorrelated motion. Spatial correlations in microrotation are observed to be directly correlated with system pressure. These observations point towards the broader mechanical relevance of collective dynamics in the rotational degree of freedom of particles.

中文翻译：

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剪切作用下摩擦非晶盘填料的旋转扩散和旋转相关性

我们在这里表明，当填料接近刚性时，无定形盘填料中圆形颗粒的旋转揭示了各种重要的微观特征。我们分析了在具有各种颗粒间摩擦系数的简单剪切变形下的圆盘填料的实验测量结果，并在已知系统变硬的体积分数范围内进行了分析。测量分析表明剪切会引起扩散微旋转，这可以根据体积分数和颗粒间摩擦来增强和抑制。旋转还显示持久的反相关运动。观察到微旋转的空间相关性与系统压力直接相关。