论文标题
合奏波动对于宏观变量方差很重要
Ensemble fluctuations matter for variances of macroscopic variables
论文作者
论文摘要
我们用一般术语描述了关于复杂液体和无定形固体压力波动的最新工作，$ v（Δt）$和标准偏差$ΔV（ΔV（ΔT）$的差异$ v [\ mathbf {x} $ time $ \ ntime $ \ naterbf {x} $ fir的时间$ \ x（x）假设一个固定的高斯和颈动过程，$ΔV$由自相关函数的功能性$ΔV_G[h] $给出。如果$ΔV（ΔT）$显示出大大，并且类似于$ v（ΔT）$，则如果$ΔT$对应于快速放松过程。尽管$ΔV=Δv_g[h] $一般不适合非共性系统，但与许多微晶体的常见系统的偏差仅是有限尺寸的校正。在简单的粗粒模型系统中说明了各种问题，以进行剪切压力波动。
Extending recent work on stress fluctuations in complex fluids and amorphous solids we describe in general terms the ensemble average $v(Δt)$ and the standard deviation $δv(Δt)$ of the variance $v[\mathbf{x}]$ of time series $\mathbf{x}$ of a stochastic process $x(t)$ measured over a finite sampling time $Δt$. Assuming a stationary, Gaussian and ergodic process, $δv$ is given by a functional $δv_G[h]$ of the autocorrelation function $h(t)$. $δv(Δt)$ is shown to become large and similar to $v(Δt)$ if $Δt$ corresponds to a fast relaxation process. Albeit $δv = δv_G[h]$ does not hold in general for non-ergodic systems, the deviations for common systems with many microstates are merely finite-size corrections. Various issues are illustrated for shear-stress fluctuations in simple coarse-grained model systems.
