No abstract

By now active Brownian motion is a well-established model to describe the motion of mesoscopic self-propelled particles in a Newtonian fluid. Here we use an extended model for swimming in a viscoelastic medium including memory effects of the solvent via a friction kernel for both translational and orientational degrees of freedom. We present an analytic framework for this extended model and evaluate it in particular for a Maxwell fluid characterized by a kernel which decays exponentially in time. We obtain analytical results for the mean displacement, the mean-square displacements and the orientational correlation function. We identify a memory induced delay between the effective self-propulsion force and the particle orientation which we quantify in terms of a special dynamical correlation function. In principle our predictions can be verified for an active colloidal particle in various viscoelastic environments such as a polymer solution.