Abstract

The power of thermodynamics comes at the expense of certain assumptions and idealizations. An important premise is the concept of ​​a thermal bath which is coupled to the system under study. Typically, such baths are idealized as an infinite reservoir of heat that remain in equilibrium regardless of whether the system is in equilibrium or not. This, however, is only valid when the relaxation time of the bath is much faster than typical time scales of the system. Otherwise, a driven system will excite the bath out of equilibrium and in turn interact with nonequilibrium fluctuations. Experiments with externally driven or self-propelled colloidal particles suspended in viscoelastic baths, whose relaxation times are on the orders of seconds, have revealed astonishing and – compared to viscous fluids – qualitatively novel behaviors which are attributed to the nonequilibrium properties of the bath. In my talk, I will discuss recent experimental findings including particle oscillations within moving optical traps, a fastened hopping dynamics across potential barriers, the strongly enhanced rotational diffusion of self-propelled particles, but also the occurrence of memory-induced Magnus forces.