局限超扩散分数布朗运动的非能量性
Yingjie Liang1,2, Wei Wang2, Ralf Metzler2,3
1College of Mechanics and Materials, Hohai University, 211100 Nanjing, China.
Physical review. E
|December 20, 2023
概括
我们量化了受限分数布朗运动中的非能极性. 对于超扩散的情况 (赫斯特指数H>1/2),整体和时间平均平均平方位移的差异很大,显示了结果的广泛分布.
科学领域:
- 物理 物理学 物理
- 统计力学 统计力学
- 复杂的系统复杂的系统.
背景情况:
- 分数布朗运动 (fBm) 是异常扩散的一个基本模型.
- 非能量性描述的是时间平均值不同于集合平均值的系统,这对于理解复杂动态至关重要.
- 局限系统引入边界效应,可以改变扩散特性.
研究的目的:
- 为了确定盒子受限的分数布朗运动中的非ergodicity的程度.
- 分析亚和超扩散模式 (Hurst指数) 对非ergodicity的影响.
- 调查集体平均和时间平均的平均平方位移 (TAMSDs) 之间的关系.
主要方法:
- 随机模拟被用来在有限的边界内建模分数布朗运动.
- 分析方法用于支持和解释模拟结果.
- 计算和比较了集成平均和时间平均的平均平方位移.
主要成果:
- 盒子限制的fBm的非ergodicity被量化为亚和超扩散的赫斯特指数 (H).
- 对于H > 1/2的集合和时间平均平均平方位移之间观察到明显的不等价性.
- 当H接近1时,发现了个别TAMSDs的巨大传播,并确定了两个明显的短延迟时间TAMSD指数.
结论:
- 盒子限制显著影响了分数布朗运动的非ergodicity.
- 超扩散模式 (H > 1/2) 呈现出最强的非能量性,其特点是整体和时间平均值的分歧.
- 这些发现强调了在分析异常扩散动态时考虑系统封闭和扩散制度的重要性.
相关概念视频
First Law: Particles in One-dimensional Equilibrium
6.9K
Newton's first law of motion states that a body at rest remains at rest, or if in motion, remains in motion at constant velocity, unless acted on by a net external force. It also states that there must be a cause for any change in velocity (a change in either magnitude or direction) to occur. This cause is a net external force. For example, consider what happens to an object sliding along a rough horizontal surface. The object quickly grinds to a halt, due to the net force of friction. If...
6.9K
Behavior of Gas Molecules: Molecular Diffusion, Mean Free Path, and Effusion
29.0K
Although gaseous molecules travel at tremendous speeds (hundreds of meters per second), they collide with other gaseous molecules and travel in many different directions before reaching the desired target. At room temperature, a gaseous molecule will experience billions of collisions per second. The mean free path is the average distance a molecule travels between collisions. The mean free path increases with decreasing pressure; in general, the mean free path for a gaseous molecule will be...
29.0K
Diffusion
192.6K
Diffusion is the passive movement of substances down their concentration gradients—requiring no expenditure of cellular energy. Substances, such as molecules or ions, diffuse from an area of high concentration to an area of low concentration in the cytosol or across membranes. Eventually, the concentration will even out, with the substance moving randomly but causing no net change in concentration. Such a state is called dynamic equilibrium, which is essential for maintaining overall...
192.6K
Protein Diffusion in the Membrane
4.4K
Proteins show rotational as well as lateral diffusion across the membrane. The lateral diffusion of proteins was confirmed through the cell fusion experiment where mouse and human cells were fused, resulting in hybrid cells. When the human and mouse cells fused, the specific membrane proteins on human and mouse cells were marked with the red and green-fluorescent markers, respectively. Initially, the red and green fluorescence was located on the respective hemisphere of the cell. As time...
4.4K
The de Broglie Wavelength
25.9K
In the macroscopic world, objects that are large enough to be seen by the naked eye follow the rules of classical physics. A billiard ball moving on a table will behave like a particle; it will continue traveling in a straight line unless it collides with another ball, or it is acted on by some other force, such as friction. The ball has a well-defined position and velocity or well-defined momentum, p = mv, which is defined by mass m and velocity v at any given moment. This is the typical...
25.9K
Entropy
30.2K
Salt particles that have dissolved in water never spontaneously come back together in solution to reform solid particles. Moreover, a gas that has expanded in a vacuum remains dispersed and never spontaneously reassembles. The unidirectional nature of these phenomena is the result of a thermodynamic state function called entropy (S). Entropy is the measure of the extent to which the energy is dispersed throughout a system, or in other words, it is proportional to the degree of disorder of a...
30.2K


