Quantum Computation and Quantum Information Theory: 12-23 July 1999 Villa Gualino, Torino, Italy

Description

Quantum information theory has revolutionised our view on the true nature of information and has led to such intriguing topics as teleportation and quantum computation. The field -- by its very nature strongly interdisciplinary, with deep roots in the foundations both of quantum mechanics and of information theory and computer science -- has become a major subject for scientists working in fields as diverse as quantum optics, superconductivity or information theory, all the way to computer engineers.The aim of this book is to provide guidance and introduce the broad literature in all the various aspects of quantum information theory. The topics covered range from the fundamental aspects of the theory, like quantum algorithms and quantum complexity, to the technological aspects of the design of quantum-information-processing devices. Each section of the book consists of a selection of key papers (with particular attention to their tutorial value), chosen and introduced by leading scientists in the specific area. An entirely new introduction to quantum complexity has been specially written for the book. Preface......Page 6 Contents......Page 8 Introductory Concepts......Page 14 1. Introductory Concepts......Page 16 1.1 Multiparticle Interferometry and the Superposition Principle......Page 17 1.2 Quantum Entanglement: A Fundamental Concept Finding its Applications......Page 25 1.3 Experiment and the Foundations of Quantum Physics......Page 32 Quantum Entanglement Manipulation......Page 42 2. Quantum Entanglement Manipulation......Page 44 2.1 Teleporting an Unknown Quantum State via Dual Classic and Einstein-Podolsky-Rosen Channels......Page 48 2.2 Experimental Quantum Teleportation......Page 53 2.3 Teleportation of Continuous Quantum Variables......Page 58 2.4 Going Beyond Bell's Theorem......Page 62 2.5 What is Wrong with These Elements of Reality......Page 66 2.6 Observation of Three-Photon Greenberger-Horne-Zeilinger Entanglement......Page 68 Quantum Algorithms......Page 74 3. Quantum Algorithms......Page 76 3.1 An Overview of Quantum Computing......Page 79 3.2 On Quantum Algorithms......Page 99 Quantum Complexity......Page 114 4. An Introduction to Quantum Complexity Theory......Page 116 Quantum Error Correction......Page 142 5. Quantum Error Correction......Page 144 5.1 Scheme for Reducing Decoherence in Quantum Computer Memory......Page 147 5.2 Error Correcting Codes in Quantum Theory......Page 151 5.3 Class of Quantum Error-Correcting Codes Saturating the Quantum Hamming Bound......Page 156 5.4 Fault-Tolerant Error Correction with Efficient Quantum Codes......Page 163 Quantum Channels......Page 168 6. Quantum Channels......Page 170 6.1 General Scheme of Measurement Processes......Page 174 6.2 Completely Positive Linear Maps on Complex Matrices......Page 187 6.3 Sending Entanglement Through Noisy Quantum Channels......Page 193 6.4 Noncommuting Mixed States Cannot Be Broadcast......Page 208 6.5 Sending Classical Information via Noisy Quantum Channels......Page 212 6.6 Nonorthogonal Quantum States Maximize Classical Information Capacity......Page 220 Entanglement Purification and Long-Distance Quantum Communication......Page 224 7. Long-Distance Quantum Communication......Page 226 7.1 Quantum Repeaters: The Role of Imperfect Local Operations in Quantum Communication......Page 230 7.2 Purification of Noisy Entanglement and Faithful Teleportation via Noisy Channels......Page 234 7.3 Quantum Privacy Amplification and the Security of Quantum Cryptography over Noisy Channels......Page 238 7.4 Photonic Channels for Quantum Communication......Page 242 Quantum Key Distribution......Page 246 8. Quantum Key Distribution......Page 248 8.1 Quantum Cryptography......Page 253 8.2 Practical Aspects of Quantum Cryptographic Key Distribution......Page 258 8.3 Quantum Key Distribution: From Principles to Practicalities......Page 272 Cavity Quantum Electrodynamics......Page 288 9. Cavity Quantum Electrodynamics......Page 290 9.1 Cavity Quantum Electrodynamics......Page 295 9.2 Measurement of Conditional Phase Shifts for Quantum Logic......Page 303 9.3 Real-Time Cavity QED with Single Atoms......Page 307 9.4 Quantum Memory with a Single Photon in a Cavity......Page 311 9.5 Observing the Progressive Decoherence of the "Meter" in a Quantum Measurement......Page 315 9.6 Inversion of Quantum Jumps in Quantum Optical Systems under Continuous Observation......Page 319 Quantum Computation with Ion Traps......Page 324 10. Quantum Computation with Ion Traps......Page 326 10.1 Electromagnetic Traps for Charged and Neutral Particles......Page 333 10.2 Quantum Computations with Cold Trapped Ions......Page 343 10.3 New Ion Trap for Frequency Standard Applications......Page 347 10.4 Ion Strings for Quantum Gates......Page 352 10.5 Quantum Dynamics of Cold Trapped Ions with Application to Quantum Computation......Page 358 10.6 Demonstration of a Fundamental Quantum Logic Gate......Page 368 10.7 Deterministic Entanglement of Two Trapped Ions......Page 372 Josephson Junctions and Quantum Computation......Page 376 11. Josephson Junctions and Quantum Computation......Page 378 11.1 Mesoscopic Effects in Superconductivity......Page 381 11.2 Quantum Manipulations of Small Josephson Junctions......Page 404 11.3 Josephson-Junction Qubits with Controlled Couplings......Page 408 Quantum Computing in Optical Lattices......Page 412 12. Quantum Information in Optical Lattices......Page 414 12.1 Quantum Computing with Neutral Atoms......Page 417 Quantum Computation and Quantum Communication with Electrons......Page 438 13. Quantum Computation and Quantum Communication with Electrons......Page 440 13.1 Quantum Computation with Quantum Dots......Page 446 13.2 Coupled Quantum Dots as Quantum Gates......Page 453 13.3 Quantum Computers and Quantum Coherence......Page 462 NMR Quantum Computing......Page 476 14. Quantum Computing with NMR......Page 478 14.1 Nuclear Magnetic Resonance Spectroscopy: An Experimentally Accessible Paradigm for Quantum Computing......Page 484 14.2 Implementation of a Quantum Algorithm on a Nuclear Magnetic Resonance Quantum Computer......Page 489 14.3 Experimental Implementation of Fast Quantum Searching......Page 495 14.4 An Implementation of the Deutsch-Jozsa Algorithm on a Three-Qubit NMR Quantum Computer......Page 499 Selected Bibliography......Page 506