Friction Causing Unpredictability

We study the effect of friction on the dynamics of a classical point particle in a onedimensional double-well potential. It is shown that finite uncertainty in the initial conditions of the particle may prevent us from reliably predicting the well in which the particle will come to rest. This difficulty – to make reliable long-term predictions – originates from the layered structure of phase-space regions sending the particle to the left and the right well, respectively. Similar structures are known to arise, for example, in models used to described the tossing of a coin where friction is, however, not the root cause of the phenomenon.