Harmonic velocity noise: New features of noise-driven system in long times

摘要

We propose a harmonic velocity noise, i.e, time derivative of the harmonic noise, which has a broadband-passing feature and a vanishing Markovian friction. If this noise is regarded as a thermal one, which will lead to nonvanishing mean velocity and ballistic diffusion of a free particle in long time limit. The effective temperature of the system coupled to such a structured heat bath represented by harmonic velocity noise is introduced, and it is shown that the fluctuation-dissipation theorem still holds when the particle at the initial time is in thermal equilibrium. When applied to a titled periodic potential, we find that the Brownian particle does not have a stationary state in the phase space, however, a constant acceleration is obtained.