Three-dimensional non-equilibrium Potts systems with magnetic friction

We study the non-equilibrium steady states that emerge when two interacting three-dimensional Potts blocks slide on each other. As at equilibrium the Potts model exhibits different types of phase transitions for different numbers $q$ of spin states, we consider the following three cases: $q=2$ (i.e. the Ising case), $q=3$, and $q=9$, which at equilibrium yield respectively a second order phase transition, a weak first order transition and a strong first order transition. In our study we focus on the anisotropic character of the steady states that result from the relative motion and discuss the change in finite-size signatures when changing the number $q$ of spin states.