摘要:
用n阶时间导数噪声作为内部热噪声驱动自由粒子运动时,若该噪声所对应的非各态历经强度b?=0,且系统初始处于热平衡,则此时系统的长时稳态速度可以作为非各态历经噪声使用。非各态历经噪声具有谱密度在零频处发散的特点,一维半无界耦合简谐振子链对与之相连的气体分子的作用具有非各态历经噪声的特点,是非各态历经噪声的实例。最后将非各态历经噪声作为外噪声驱动倾斜周期势中的粒子运动,系统出现扩散指数α>2的超弹道扩散现象。同时发现系统的速度分布将呈现出迁移态和锁定态两种不同状态,并且处于迁移态的粒子的速度分布为双峰。迁移态中双峰的出现是一种比较新奇的现象。
Abstract:
When using the noise of n-order time derivative as an internal thermal noise to drive a generalized Langevin equation, if the nonergodicty strength of the noise satisfies b = 0 and the system is in thermal equilibrium, then the stationary velocity variable of the system can be used as a non-ergodic noise. The spectra of the non-ergodic noise is infinite at zero frequency. The one-dimensional semi-unbounded coupled harmonic oscillator chains connected with the gas molecules act as the non-ergodic noise, which is an example of non-ergodic noise. Finally regarding the non-ergodic noise as an external noise to drive the particles in the titled periodic potential, it is found that there appears superballistic diffusion with the effective diffusion index exceeding a ballistic value of 2. It is also found that the velocity distribution of the system displays two motion states, the“locked state”and the“running state”. And in the“running state”there occurs a bimodal phenomenon, which is a relatively new phenomenon.
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