Granular materials are an important physical realization of active matter. Invibration-fluidized granular matter, both diffusion and self-propulsion derivefrom the same collisional forcing, unlike many other active systems where thereis a clean separation between the origin of single-particle mobility and thecoupling to noise. Here we present experimental studies of single-particlemotion in a vibrated granular monolayer, along with theoretical analysis thatcompares grain motion at short and long time scales to the assumptions andpredictions, respectively, of the active Brownian particle (ABP) model. Theresults demonstrate that despite the unique relation between noise andpropulsion, granular media do show the generic features predicted by the ABPmodel and indicate that this is a valid framework to predict collectivephenomena. Additionally, our scheme of analysis for validating the inputs andoutputs of the model can be applied to other granular and non-granular systems.
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