2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/170837We analyze the operation of a molecular machine driven by the non-adiabatic variation of external parameters. We derive a formula for the integrated flow from one configuration to another, obtain a "no-pumping theorem" for cyclic processes with thermally activated transitions, and show that in the adiabatic limit the pumped current is given by a geometric expression.5 pages, 2 figures, very minor changesStatistical Mechanicstext