Quantum Information Theory and the Foundations of Quantum Mechanics

Quantum Information Theory and the Foundations of Quantum Mechanics is a conceptual analysis of one of the most prominent and exciting new areas of physics, providing the first full-length philosophical treatment of quantum information theory and the questions it raises for our understanding of the quantum world. Beginning from a careful, revisionary, analysis of the concepts of information in the everyday and classical information-theory settings, Christopher G. Timpson argues for an ontologically deflationary account of the nature of quantum information. Against what many have supposed, quantum information can be clearly defined (it is not a primitive or vague notion) but it is not part of the material contents of the world. Timpson's account sheds light on the nature of nonlocality and information flow in the presence of entanglement and, in particular, dissolves puzzles surrounding the remarkable process of quantum teleportation. In addition it permits a clear view of what the ontological and methodological lessons provided by quantum information theory are; lessons which bear on the gripping question of what role a concept like information has to play in fundamental physics. Topics discussed include the slogan 'Information is Physical', the prospects for an informational immaterialism (the view that information rather than matter might fundamentally constitute the world), and the status of the Church-Turing hypothesis in light of quantum computation. With a clear grasp of the concept of information in hand, Timpson turns his attention to the pressing question of whether advances in quantum information theory pave the way for the resolution of the traditional conceptual problems of quantum mechanics: the deep problems which loom over measurement, nonlocality and the general nature of quantum ontology. He marks out a number of common pitfalls to be avoided before analysing in detail some concrete proposals, including the radical quantum Bayesian programme of Caves, Fuchs, and Schack. One central moral which is drawn is that, for all the interest that the quantum information-inspired approaches hold, no cheap resolutions to the traditional problems of quantum mechanics are to be had.1. Introduction ; 2. What is Information? ; 3. Quantum Information Theory ; 4. Case Study: Teleportation ; 5. The Deutsch{Hayden Approach: Nonlocality, Entanglementm, and Information Flow ; 6. Quantum Computation and the Church-Turing Hypothesis ; 7. Information and the Foundations of Quantum Mechanics: Preliminaries ; 8. Some Information-Theoretic Approaches ; 9. Quantum Bayesianism 1: The Proposal ; 10. Quantum Bayesianism 2: Challenges ; 11. Conclusions ; A. A Review of the Quantum Formalism ; B. Generalised Uncertainty Measures: U+nk's Axioms