Random walks on the braid group B3 and magnetic translations in hyperbolic geometry

We study random walks on the three-strand braid group B-3, and in particular compute the drift, or average topological complexity of a random braid, as well as the probability of trivial entanglement. These results involve the study of magnetic random walks on hyperbolic graphs (hyperbolic Harper-Hofstadter problem), what enables to build a faithful representation of B-3 as generalized magnetic translation operators for the problem of a quantum particle on the hyperbolic plane. (C) 2002 Elsevier Science B.V. All rights reserved.