Quantum computation with ballistic electrons

We describe a solid state implementation of a quantum computer using ballis tic single electrons as flying qubits in 1D nanowires. We show how to imple ment all the steps required for universal quantum computation: preparation of the initial state, measurement of the final state and a universal set of quantum gates. An important advantage of this model is the fact that we do not need ultrafast optoelectronics for gate operations. We use cold progra mming (or pre-programming), i.e. the gates are set before launching the ele ctrons; all programming can be done using static electric fields only.