Temperature Resistant Optimal Ratchet Transport

Stable periodic structures containing optimal ratchet transport, recently found in the parameter space dissipation versus ratchet parameter [PRL 106, 234101 (2011)], are shown to be resistant to reasonable temperatures, reinforcing the expectation that they are essential to explain the optimal ratchet transport in nature. Critical temperatures for their destruction, valid from the overdamping to close to the conservative limits, are obtained numerically and shown to be connected to the current efficiency, given here analytically. Results are demonstrated for a discrete ratchet model and generalized to the Langevin equation with an additional external oscillating force.