We give a brief introduction to quantum computation and we discuss a possible solid state implementation. We show how to prepare and measure qubit states and how to implement single and 2-qubit gates with ballistic electrons.
We present a study of ballistic electron waveguides as used to construct simple quantum computational networks.We begin with an introduction to ballistic electron waveguides, some basic theory of quantum computers, and the possible role of electron waveguides in quantum computation.Following that, our study of various waveguide networks and the physics of the specific components of those networks.We continue with a discussion of shot noise in network elements and its possible role in helping to build good computational gates.Finally we conclude with a summary of research and possible future projects.
We propose a new solid state implementation of a quantum computer (quputer) using ballistic single electrons as flying qubits in 1D nanowires. We use a single electron pump (SEP) to prepare the initial state and a single electron transistor (SET) to measure the final state. Single qubit gates are implemented using quantum dots as phase shifters and electron waveguide couplers as beam splitters. A Coulomb coupler acts as a 2-qubit gate, using a mutual phase modulation effect. Since the electron phase coherence length in GaAs/AlGaAs heterostructures is of the order of 30μm, several gates (tens) can be implemented before the system decoheres.
We describe a solid state implementation of a quantum computer using ballistic single electrons as flying qubits in 1D nanowires. We show how to implement 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 programming (or pre-programming), i.e. the gates are set before launching the electrons; all programming can be done using static electric fields only.