  Dissipation and fluctuations of one-body observables in heavy-ion reactions
around the Coulomb barrier are investigated with a microscopic stochastic
mean-field approach. By projecting the stochastic mean-field dynamics on a
suitable collective path, transport coefficients associated with the relative
distance between colliding nuclei and a fragment mass are extracted. Although
microscopic mean-field approach is know to underestimate the variance of
fragment mass distribution, the description of the variance is much improved by
the stochastic mean-field method. While fluctuations are consistent with the
empirical (semiclassical) analysis of the experimental data, concerning mean
values of macroscopic variables the semiclassical description breaks down below
the Coulomb barrier.
