  Friction is central to the motion of active (self-propelled) objects, such as
bacteria, animals or robots. While in a viscous fluid friction is typically
described by Stokes' law, objects in contact with other solid bodies are often
governed by more complex empirical friction laws. We study active dry particles
subject to dry Coulomb friction force numerically and analytically. The
interplay of friction and activity forces induces a rich behavior resulting in
three distinct dynamical regimes. While for low activity levels, active
Brownian motion is recovered, for large activity we observe a dynamical Stop &
Go regime continuously switching from diffusion and accelerated motion. For
further activity values, we observe a super-mobile dynamical regime
characterized by a fully accelerated motion which is described by an anomalous
scaling of the diffusion coefficient with the activity. These findings cannot
be observed with Stokes viscous forces typical of active swimmers but are
central in dry active objects.
