CHAPTER 6 - Physical Realization of Quantum Information Processing Systems

Abstract

Any physical implementation of a quantum information processing system must be based on a system insulated from unwanted interactions with the environment, must be controlled through some required interactions implementing logical quantum gates, and must be measured. This chapter provides an analysis of the requirements for a physical implementation of a quantum information processing systems. Quantum computing and communication devices must satisfy a set of generic requirements; these requirements guide the implementation efforts for quantum information processing systems. DiVincenzo formulated several criteria for realization of quantum computers, these criteria were reformulated and generalized for systems with low level of decoherence. From the multitude of proposals for the physical implementation of quantum information processing devices, only a subset is selected. The concepts of cold ion traps, liquid nuclear magnetic resonance, quantum dots and the quantum Hall effect are discussed. The basic problems facing a physical implementation of a quantum computer are related to finding a system that is sufficiently insulated from unwanted interactions with the environment but, at the same time, can be controlled through some required interactions implementing logical quantum gates, and can be measured.