Dynamical density functional theory for driven interacting particles in a ratchet potential

Held by Dr. Andrew Archer (Loughborough University, UK)

Abstract:
I will discuss the use of dynamical density functional theory (DDFT) to describe the transport of (Brownian) colloidal particles along a narrow channel, when they are driven along by a DC or low frequency AC external driving potential. In addition, the walls of the channel interact with the particles via a ratchet-like periodic potential. We consider particles which interact with each other via a pair potential having a hard-core repulsion plus an attractive tail. In the case of DC drive, we find that as the attraction strength between the colloids is increased beyond a critical value, the stationary density distribution of the particles loses its stability leading to depinning and a time-dependent density profile. Attraction induced symmetry breaking gives rise to the coexistence of stable stationary density profiles with different spatial periods and time-periodic density profiles, each characterized by different values for the particle current.