The ratchet effect in an aging glass

We study the dynamics of an asymmetric intruder in a glass-former model. At equilibrium, the intruder diffuses with average zero velocity. After an abrupt quench to T deeply under the mode-coupling temperature, a net average drift is observed, steady on a logarithmic time scale. The phenomenon is well reproduced in an asymmetric version of the Sinai model. The sub-velocity of the intruder grows with Teff/T, where Teff is defined by the response-correlation ratio, corresponding to a general behavior of thermal ratchets when in contact with two thermal reservoirs.