%0 Journal Article %T Harmonic measures versus quasiconformal measures for hyperbolic groups %+ Laboratoire d'Analyse, Topologie, Probabilités (LATP) %+ European Institute for Statistics, Probability, Stochastic Operations Research and its Applications (EURANDOM) %+ Picard %A Blachère, Sébastien %A Haïssinsky, Peter %A Mathieu, Pierre %Z Besides minor modifications, we provide a new proof that the harmonic measure of a finitely supported random walk on a Fuchsian group with cusps is singular. 52 pp. %< avec comité de lecture %@ 0012-9593 %J Annales Scientifiques de l'École Normale Supérieure %I Société mathématique de France %V 44 %N no. 4 %P 683 -- 721 %8 2011 %D 2011 %Z 0806.3915 %K Hyperbolic groups %K random walks on groups %K harmonic measures %K quasiconformal measures %K dimension of a measure %K Martin boundary %K Brownian motion %K Green metric %Z 20F67, 60B15 (11K55, 20F69, 28A75, 60J50, 60J65) %Z Mathematics [math]/Probability [math.PR] %Z Mathematics [math]/Metric Geometry [math.MG] %Z Mathematics [math]/Group Theory [math.GR]Journal articles %X We establish a dimension formula for the harmonic measure of a finitely supported and symmetric random walk on a hyperbolic group. We also characterize random walks for which this dimension is maximal. Our approach is based on the Green metric, a metric which provides a geometric point of view on random walks and, in particular, which allows us to interpret harmonic measures as \qc measures on the boundary of the group. %G English %2 https://hal.science/hal-00290127v2/document %2 https://hal.science/hal-00290127v2/file/qcharm2.pdf %L hal-00290127 %U https://hal.science/hal-00290127 %~ LATP %~ CNRS %~ UNIV-AMU %~ INSMI %~ I2M