论文标题
颗粒材料中边缘临界的实验观察结果
Experimental observations of marginal criticality in granular materials
论文作者
论文摘要
两种截然不同的理论预测了干扰的边际关键。完整的副本对称性破坏（FULLRSB）理论[1-4]预测了无限二维硬球玻璃中弱接触力和小粒子间间隙的幂律分布，分别有两个非平凡的指数$θ_f= 0.42311 ... $和$γ= 0.41269 ... $。虽然边缘机械稳定性（MMS）分析[5-8]预测，在外部应力下，硬摩擦球的等静力随机堆积略有稳定，并为弱力和颗粒间间隙分布的指数提供了不平等关系。在这里，我们在各向同性堵塞的双分散光弹性磁盘中精确地接触力和颗粒位置，并找到弱力和小粒子间间隙的透明幂律分布，两个指数$θ_f= 0.44（2）$和$γ= 0.43（3）（3）$与FullRSB Inevelion达成了极好的一致性。由于被堵塞的堆积受到区域保存的循环纯剪切的接近屈服点，这两个指数与各向同性情况的变化很大变化，但它们仍然满足MMS参数提供的扩展关系。我们的结果为无限维理论的鲁棒性和现实世界中无定形材料的MMS分析提供了强烈的实验证据。
Two drastically different theories predict the marginal criticality of jamming. The full replica symmetry breaking (fullRSB) theory [1-4] predicts the power-law distributions of weak contact forces and small inter-particle gaps in infinite-dimensional hard-sphere glass, with two nontrivial exponents $θ_f=0.42311...$ and $γ=0.41269...$, respectively. While the marginal mechanical stability (MMS) analysis [5-8] predicts that the isostatic random packings of hard frictionless spheres under external stress are marginally stable and provides inequality relationships for the exponents of the weak-force and inter-particle-gap distributions. Here we measure precisely contact forces and particle positions in isotropic jammed bidisperse photoelastic disks and find the clear power-law distributions of weak forces and small inter-particle gaps, with both exponents $θ_f=0.44(2)$ and $γ= 0.43(3) $ in an excellent agreement with the fullRSB theory. As the jammed packing subject to area-conserved cyclic pure shear approaches the yielding point, the two exponents change substantially from those of the isotropic case but they still satisfy the scaling relationship provided by the MMS argument. Our results provide strong experimental evidences for the robustness of the infinite-dimensional theory and the MMS analysis in real-world amorphous materials.
