Minimal motor for powering particle motion from spin imbalance
  We introduce a minimalistic quantum motor for coupled energy and particle transport. The system is composed of two spins, each coupled to a different bath and to a particle which can move on a ring consisting of three sites. We show that the energy flowing from the baths to the system can be partially converted to perform work against an external driving, even in the presence of moderate dissipation. We also analytically demonstrate the necessity of coupling between the spins. We suggest an experimental realization of our model using trapped ions or quantum dots. 
Ulf Bissbort, Colin Teo, Chu Guo, Giulio Casati, Giuliano Benenti,   Dario Poletti
cond-mat.stat-mech cond-mat.quant-gas quant-ph