论文标题
无序系统中的有限范围粘弹性延伸，包括惯性效应
Finite-range viscoelastic subdiffusion in disordered systems with inclusion of inertial effects
论文作者
论文摘要
这项工作证明了在随机环境中对于细胞生物系统的随机环境中粘弹性延伸的范式重要性。该模型显示了几个非凡的特征，这使其成为解释生物学细节的物理性质的吸引人范式。特别是，它结合了粘弹性与不同的非恋性特征。我们扩展了该模型，以使其适合于包括惯性效应的生物膜中脂质的细化。对于脂质，惯性效应发生在皮秒范围内，幂律腐烂的粘弹性存储器延伸到几个纳秒的范围内。因此，在没有障碍的情况下，扩散将在超出该记忆范围的时间尺度上变得正常。但是，在实验和某些分子动力模拟中，脂质延伸的时间范围远远超出了粘弹性记忆范围。我们研究了三个相关的淬灭高斯疾病的1D模型来解释难题：奇异的短距离（指数相关），光滑的短距离（高斯相关）和光滑的长距离（幂律相关）疾病。对于中等疾病的强度，瞬时粘弹性延伸变化会因环境的随机性而变化。它的特征在于，与最近的一些分子动力学模拟一致，它可能显示出非单调的行为。此外，在这种疾病主导的状态下，测试颗粒的空间分布被证明是一种非高斯，指数的功率分布，这也与分子 - 动力学的发现和实验息息相关。此外，这种细胞扩散是非迫切的，单个设备平均值显示出广泛的散射，这与实验性观察结果一致，该观察结果是活细胞中各种颗粒的细胞扩散。
This work justifies the paradigmatic importance of viscoelastic subdiffusion in random environments for cellular biological systems. This model displays several remarkable features, which makes it an attractive paradigm to explain the physical nature of biological subdiffusion. In particular, it combines viscoelasticity with distinct non-ergodic features. We extend this model to make it suitable for the subdiffusion of lipids in disordered biological membranes upon including the inertial effects. For lipids, the inertial effects occur in the range of picoseconds, and a power-law decaying viscoelastic memory extends over the range of several nanoseconds. Thus, in the absence of disorder, diffusion would become normal on a time scale beyond this memory range. However, both experimentally and in some molecular-dynamical simulations, the time range of lipid subdiffusion extends far beyond the viscoelastic memory range. We study three 1d models of correlated quenched Gaussian disorder to explain the puzzle: singular short-range (exponentially correlated), smooth short-range (Gaussian-correlated), and smooth long-range (power-law correlated) disorder. For a moderate disorder strength, transient viscoelastic subdiffusion changes into the subdiffusion caused by the randomness of the environment. It is characterized by a time-dependent power-law exponent of subdiffusion, which can show nonmonotonous behavior, in agreement with some recent molecular-dynamical simulations. Moreover, the spatial distribution of test particles in this disorder-dominated regime is shown to be a non-Gaussian, exponential power distribution, which also correlates well with molecular-dynamical findings and experiments. Furthermore, this subdiffusion is nonergodic with single-trajectory averages showing a broad scatter, in agreement with experimental observations for subdiffusion of various particles in living cells.
