论文标题
剪切眼镜中雪崩的统一视图
Unified View of Avalanche Criticality in Sheared Glasses
论文作者
论文摘要
剪切眼镜中的塑料事件被认为是所谓的雪崩的一个例子，其尺寸符合雪崩关键指数$τ$的幂律概率分布。尽管平均场理论预测了该指数的通用值，但$τ_ {\ rm Mf} = 1.5 $，但数值模拟报告了不同的值，取决于文献。此外，在弹性制度中，已经注意到，关键指数可能与稳定状态不同，甚至批判性本身也是一个辩论问题。由于这些令人困惑的变化结果是在不同的设置下报告的，因此我们对剪切眼镜中的雪崩关键性的了解受到了极大的限制。为了获得统一的理解，在这项工作中，我们对Athermal Athermal-Ater-Aquasistatic Shear下的Lennard-Jones眼镜中的雪崩进行了全面的数值研究。特别是，通过排除已渗入常规测量方案的歧义和任意性，我们实现了高精度的测量，并证明了稳态的指数$τ$遵循$τ_{\ rm Mf} = 1.5 $的平均景观预测。我们的结果还表明，有两个质量上不同的雪崩事件。这种二进制性导致雪崩大小分布的非宇宙行为，并且很可能是迄今为止报道的$τ$变化值的原因。为了研究临界和普遍性对应用剪切的依赖性，我们进一步研究了弹性制度中雪崩的统计数据，以及不同样本中第一个雪崩事件的合奏，这些雪崩事件提供了有关未扰动系统的信息。我们表明，尽管不受干扰的系统确实是非批判性的，但随着剪切的应用，批判性逐渐发展。此外，一旦系统变得至关重要，关键指数会遵守均值范围预测$τ_ {\ rm mf} $。
Plastic events in sheared glasses are considered an example of so-called avalanches, whose sizes obey a power-law probability distribution with the avalanche critical exponent $τ$. Although mean-field theory predicts a universal value of this exponent, $τ_{\rm MF}=1.5$, numerical simulations have reported different values depending on the literature. Moreover, in the elastic regime, it has been noted that the critical exponent can be different from that in the steady state, and even criticality itself is a matter of debate. Because these confusingly varying results were reported under different setups, our knowledge of avalanche criticality in sheared glasses is greatly limited. To gain a unified understanding, in this work, we conduct a comprehensive numerical investigation of avalanches in Lennard-Jones glasses under athermal quasistatic shear. In particular, by excluding the ambiguity and arbitrariness that has crept into the conventional measurement schemes, we achieve high-precision measurement and demonstrate that the exponent $τ$ in the steady state follows the mean-field prediction of $τ_{\rm MF}=1.5$. Our results also suggest that there are two qualitatively different avalanche events. This binariness leads to the non-universal behavior of the avalanche size distribution and is likely to be the cause of the varying values of $τ$ reported thus far. To investigate the dependence of criticality and universality on applied shear, we further study the statistics of avalanches in the elastic regime and the ensemble of the first avalanche event in different samples, which provide information about the unperturbed system. We show that while the unperturbed system is indeed off-critical, criticality gradually develops as shear is applied. Moreover, the critical exponent obeys the mean-field prediction $τ_{\rm MF}$ universally, once the system becomes critical.
