Resonant quantum kicked rotor with two internal levels
  We develop a system consisting of a quantum kicked rotor with an additional degree of freedom. This models a single two-level atom with internal ground and excited states, and it is characterized by its quantum resonances with ballistic spreading and by the entanglement between the internal and momentum degrees of freedom. These behaviors establish an equivalence between our model and the usual quantum walk on the line. 
Guzm\'an Hern\'andez and Alejandro Romanelli
quant-ph