Non-Gaussian diffusion and energy balance of a Brownian particle in active baths

We present a minimal model to generalize the iconic feature of active matter that Brownian particles diffusing in a harmonic potential are kicked by external forces to engender mobility beyond that attributable to thermal energy. The wide time and length scales of usual active matter systems are mapped onto the generic concept of a single Brownian diffusion time (a particle diffusing in a harmonic potential) and kicks from external forces that arrive at random intervals with a defined, programmable, duration time for each kick. Our experiments using an optical trap agree in showing enhanced diffusion that is Gaussian only if the kick duration time is larger than the Poisson interval time. In addition, we conclude that maximum energy dissipation occurs at the time-scale of the geometric mean of the kick duration time and the particle thermal equilibration time. Usual active matter systems do not allow this independent variation of thermal motion, active motion, and the relative time scales of both. In this streamlined system they are varied independently, allowing one to rapidly prototype the limits of various stochastic thermodynamic models.