Porto, M. Max Planck Institute for the Physics of Complex Systems, Max Planck Society;
https://www.researchgate.net/profile/Michael_Urbakh/publication/11557664_Hopping_motion_of_interacting_particles_From_time-dependent_interaction_to_directed_transport/links/0fcfd5110fac8715f1000000.pdf (Publisher version)
Porto, M., Urbakh, M., & Klafter, J. (2002). Hopping motion of interacting particles: From time-dependent interaction to directed transport. Physical Review E, 65(1): 011108. doi:10.1103/PhysRevE.65.011108.