The Physical Implementation of Quantum Computation

Abstract

After a brief introduction to the principles and promise of quantum information processing, the requirements for the physical implementation of quantum computation are discussed. These five requirements, plus two relating to the communication of quantum information, are extensively explored and related to the many schemes in atomic physics, quantum optics, nuclear and electron magnetic resonance spectroscopy, superconducting electronics, and quantum-dot physics, for achieving quantum computing. * Prepared for Fortschritte der Physik special issue, Experimental Proposals for Quantum Computation, eds. H.-K. Lo and S. Braunstein.

A quantum probability splitter and its application to qubit preparation

“…Figure 5 shows the result of all these simplifications. 3 The simplified circuit has much less gates and it is functionally equivalent to the original of Fig. 4.…”

“…2 and 3) as a guide, with the ancilla qubit set to |0 , the first cNOT-NOT sequence checks if |s and |q are equal. If this happens |q is set to |1 at point P 2 and the controlled-Hadamard (cH) changes the ancilla qubit to |+ at point P 3 . Otherwise, the ancilla qubit remains |0 .…”

“…The first and crucial [3] implementation stage in every quantum algorithm is to properly prepare the qubits of the quantum register. Although most current quantum algorithms (e.g.…”

Quantum Computing with Spins in Solids

“…|0 . These qubits must be sufficiently isolated from the surrounding environment to reduce decoherence, there must be some way to perform fast single-and two-qubit operations in a time scale much less than the qubit decoherence time, and it must be possible to read out the final state of the qubits after any quantum computation (DiVincenzo 2000). In the following sections, we address these issues and others…”

Josephson charge qubits: a brief review

“…The Josephson charge qubit circuits satisfy basically all the criteria for the implementation of quantum computation put forward by DiVincenzo [24]. They offer single qubits, i.e., structures that can be approximated as quantum two-level systems.…”