Thermodynamic Emergence of a Brownian Motor
  Human-created engines and evolutionarily optimized molecular motors exhibit sophisticated design in order to harvest chemical or thermal energy for generating unidirectional motion. The complexity of these motors makes their random emergence unlikely. Molecules capable of locomotion, however, seem to be essential to the creation of the first self-replicator and initiation of Darwinian evolution, posing a question of the physical mechanism that can facilitate emergence of directed motion in an isotropic environment. Here we show a universal thermodynamic mechanism for spontaneous emergence of motor abilities in a mechanical system. A non-equilibrium system with multiple degrees of freedom develops symmetry breaking that favors rectification of environmental thermal fluctuations. The corresponding velocities and its fluctuations are calculated. Homochirality of living matter is explained as chirality breaking resulting from the emergence of a motor. Universality of the results provides a general extension of the Onsager relations to the non-linear regime. 
Alexander Feigel and Asaf Rozen
cond-mat.stat-mech