活性增强二维颗粒玻璃中的异质动力学
Activity enhances heterogenous dynamics in 2D granular glasses
- University of Massachusetts Amherst（马萨诸塞大学阿默斯特分校）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本文研究二维颗粒玻璃中活性对动力学的影响，发现活性系统在相同弛豫时间下表现出更强的动力学异质性，尽管活性方向与位移不对齐。
AI中文摘要：
我们研究了自推进在二维摩擦圆盘双分散混合物接近玻璃态过程中的影响，该混合物被限制在水平面内，并通过垂直振动流化。圆盘被设计为要么是被动的，即在平面内表现出各向同性运动，要么是活性的，具有优选的极性迁移率。当将大的活性圆盘和小的被动圆盘的混合物与大的和小的被动圆盘的混合物进行比较时，在相同的面积分数下，活性系统表现出更快的动力学。为了探究活性是否仅仅加速了运动，我们选择了具有相同弛豫时间的活性和被动混合物，并比较了它们的动力学。许多指标表明，活性玻璃中的动力学异质性要大得多，具有更长程的空间速度相关性、更大的位移时间变化以及更高的四点相关器振幅。在这个非常拥挤的体系中，尽管频繁碰撞，圆盘的活性方向仍然保持持久性。然而，圆盘的活性方向在空间上仍然不相关，此外，颗粒位移与活性方向不对齐，因此提出了一个谜题，即活性如何导致如此强烈的异质性。
英文摘要：
We study the effect of self-propulsion in the approach to the glassy regime of 2D bidisperse mixtures of frictional discs, confined to a horizontal plane, and fluidized by vertical vibrations. The discs are designed either to be passive, that is, exhibiting isotropic motion in the plane, or active, with a preferred polar mobility. When dynamics in mixtures of large active and small passive discs are compared to mixtures of large and small passive discs, the active system shows faster dynamics at equal area fractions. To explore whether activity merely speeds up motion, we select active and passive mixtures with the same relaxation time and compare their dynamics. Many indicators show that dynamical heterogeneity is much greater in the active glass with longer-ranged spatial velocity correlations, larger temporal variations in displacement, and higher amplitude of the four-point correlator. In this very crowded regime, despite frequent collisions, the activity directions of the discs remain persistent. However, the activity direction of the discs remains spatially uncorrelated, and furthermore, the particle displacements are not aligned with the activity direction, thus presenting a puzzle as to how activity leads to such strong heterogeneity.
