2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/25103An ensemble of particles in thermal equilibrium at temperature $T$, modeled by Nosè-Hoover dynamics, moves on a triangular lattice of oriented semi-disk elastic scatterers. Despite the scatterer asymmetry a directed transport is clearly ruled out by the second law of thermodynamics. Introduction of a polarized zero mean monochromatic field creates a directed stationary flow with nontrivial dependence on temperature and field parameters. We give a theoretical estimate of directed current induced by a microwave field in an antidot superlattice in semiconductor heterostructures.4 pages, 5 figures (small changes added)Statistical MechanicsMesoscale and Nanoscale PhysicsSoft Condensed Mattertext