Isothermal ratchets: Numerical study of the efficiency of the energy transduction

The energetics of isothermal ratchets, that are driven by an external force and operate in contact with a single heat bath, is studied by Langevin equation simulations. The system is analyzed in terms of the mass, friction and amplitude of the external forcing. We found a regime where the efficiency is optimized at finite temperatures, proving that thermal fluctuations facilitate the efficiency of the energy conversion. The condition of optimal efficiency is found, relating mass, temperature and friction to the properties of the ratchet potential. [Copyright &y& Elsevier]