  We exploit the concept of Landau-Zener transitions at avoided energy
crossings as a quantum-control tool. In an avoided crossing the two quantum
states interchange their characteristics as an external parameter is varied.
Depending on the rate of change of the parameter it is possible to control the
final state. We use this simple idea to travel along the energy spectrum of a
realistic system: two interacting electrons confined in a quasi-one-dimensional
semiconductor system.
