2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/23743Theory of quantum corrections to conductivity of granular metal films is developed for the realistic case of large randomly distributed tunnel conductances. Quantum fluctuations of intergrain voltages (at energies E much below bare charging energy scale E_C) suppress the mean conductance \bar{g}(E) much stronger than its standard deviation σ(E). At sufficiently low energies E_* any distribution becomes broad, with σ(E_*) ~ \bar{g}(E_*), leading to strong local fluctuations of the tunneling density of states. Percolative nature of metal-insulator transition is established by combination of analytic and numerical analysis of the matrix renormalization group equations.6 pages, 5 figures, REVTeX 4Mesoscale and Nanoscale PhysicsDisordered Systems and Neural Networkstext