淬火结构玻璃的弛豫：在拐点‘减速带’上的硬化笼状势下降
Relaxation of quenched structural glasses: descent in a stiffening caging potential over inflection-point 'speed bumps'
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中文总结 AI 辅助
研究淬火玻璃能量弛豫，通过模拟典型结构玻璃形成体中的梯度下降，发现幂律行为源于简单笼效应，该机制可分析得出幂律衰减，还建立了梯度下降动力学的完整物理图像，且不存在特征温度分隔不同动力学区域。
中文摘要 AI 辅助
淬火玻璃中缓慢的能量弛豫是一种普遍存在但却了解甚少的现象。尽管进行了广泛研究，但观测到的幂律衰减的微观起源仍存在争议，提出的机制包括鞍点减速、边缘稳定性、局域激发的粗化和声子动力学等。通过模拟典型结构玻璃形成体中的梯度下降，我们发现这些情况都无法解释我们的数据。相反，幂律行为源于一种非常简单的笼效应：每个粒子都经历一个由多体限制产生的有效硬化势，该势在特征笼尺寸处发散。这种机制通过分析得出观测到的幂律衰减，并由具有固定邻居的最小单粒子笼模型定量重现，表明集体弛豫模式并非必不可少。当系统在能量景观上滚动通过拐点时，动力学被波动打断，这些拐点起到‘减速带’的作用，但不影响整体幂律行为。与平均场自旋玻璃理论不同，我们没有发现将不同动力学区域分开的特征温度；只要系统足够接近固有结构，在给定玻璃盆地内的状态跟随在所有初始温度下普遍发生。我们的结果建立了典型结构玻璃中梯度下降动力学的完整物理图像。
英文摘要
The slow energy relaxation in quenched glasses is a ubiquitous yet poorly understood phenomenon. Despite extensive study, the microscopic origin of the observed power-law decay remains debated, with proposed mechanisms ranging from saddle-point slowdown and marginal stability to coarsening of localized excitations and phonon dynamics. Here, by simulating gradient descent in archetypal structural glass formers, we show that none of these scenarios can account for our data. Instead, the power-law behavior emerges from a remarkably simple caging effect: each particle experiences an effective stiffening potential that arises from many-body confinement and diverges at a characteristic cage size. This mechanism analytically yields the observed power-law decay and is quantitatively reproduced by a minimal single-particle cage model with fixed neighbours, demonstrating that collective relaxation modes are not essential. The dynamics is punctuated by fluctuations as the system rolls through inflection points on the energy landscape, which act as `speed bumps' but do not affect the overall power-law behaviour. In contrast to mean-field spin glass theory, we find no characteristic temperature that separates distinct dynamical regimes; state following within a given glass basin occurs universally for all initial temperatures whenever the system is sufficiently close to the inherent structure. Our results establish a complete physical picture of gradient descent dynamics in typical structural glasses.
