Quantum Transport Enhancement by Time-Reversal Symmetry Breaking
  Quantum mechanics still provides new unexpected effects when considering the transport of energy and information. Models of continuous time quantum walks, which implicitly use time-reversal symmetric Hamiltonians, have been intensely used to investigate the effectiveness of transport. Here we show how breaking time-reversal symmetry of the unitary dynamics in this model can enable directional control, enhancement, and suppression of quantum transport. Examples ranging from exciton transport to complex networks are presented. This opens new prospects for more efficient methods to transport energy and information. 
Zoltan Zimboras, Mauro Faccin, Zoltan Kadar, James Whitfield, Ben   Lanyon and Jacob Biamonte
quant-ph cond-mat.stat-mech