On a class of quantum channels, open random walks and recurrence
  We study a particular class of trace-preserving completely positive maps, called PQ-channels, for which classical and quantum evolutions are isolated in a certain sense. By combining open quantum random walks with a notion of recurrence, we are able to describe criteria for recurrence of the walk related to this class of channels. Positive recurrence for open walks is also discussed in this context. 
Carlos F. Lardizabal and Rafael R. Souza
math-ph math.MP math.PR