Drift of particles caused by fluctuations of their sizes

Externally stimulated fluctuations of the size of a particle in an asymmetric environment result in its directional motion. This is demonstrated by considering the particle drift in a periodic symmetric channel, which arises due to fluctuations of the particle size. The emergence of the drift is caused by the time variation of the particle entropy, whereas fluctuations of the diffusion coefficient accompanying fluctuations of the size enhance the drift. The effect of the geometry of the channel and the amplitude and frequency of fluctuations on the drift velocity is studied by the Brownian dynamics method. A coarse-grained analytical description of the process is proposed whose predictions are in satisfactory agreement with the results of simulation.