  Quantum transport properties of electron systems driven by strong electric
fields are studied by mapping the Landau-Zener transition dynamics to a quantum
walk on a semi-infinite one-dimensional lattice with a reflecting boundary,
where the sites correspond to energy levels and the boundary the ground state.
Quantum interference induces a distribution localized around the ground state,
and when the electric field is strengthened, a delocalization transition occurs
describing breakdown of the original electron system.
