SummaryThe history of quantum physics has been deeply conditioned by the change in scientific practice as a social activity during the past fifty years. As a result the theory has not been allowed full maturing; both its formal and empirical advances have not resulted in a comparable conceptual progress. The recasting of quantum theory thus appears as an epistemological necessity. One of the main aspects of this process is to clear quantum theory from its persisting classical connections in order to (...) endow it with an autonomous and intrinsic status. Problems related to the foundations, description, interpretation and approximations of quantum theory are considered in turn, and various recent works are reviewed which contribute to the proposed endeavour.RésuméL'histoire de la théorie quantique a été fortement conditionnée par les changements intervenus au cours des cinquante dernières années dans la pratique scientifique en tant qu'activité sociale. La théorie en conséquence n'a pu atteindre sa pleine maturité et ses développements à la fois formels et empiriques n'ont pas conduit à des progrès conceptuels comparables. La refonte de la théorie quantique apparaît ainsi comme une nécessitéépistémologique. L'un des principaux aspects de ce processus consiste à débarrasser la théorie quantique de ses persistantes attaches classiques, de façon à lui conférer un statut autonome et intrinsèque. On considère ici tour à tour les problèmes de fondements, de terminologie, d'interprétation et de limites, de la théorie quantique, tout en passant en revue divers travaux récents contribuant à l'entreprise proposée.ZusammenfassungDie Geschichte der Quantenphysik ist in entscheidender Weise durch die Veränderungen, die in den letzten fünfzig Jahren in der wissenschaftlichen Praxis als einer sozialen Tätigkeit eingetreten sind, bestimmt worden. Die Theorie hat deshalb ihre volle Reife nicht erlangen können; ihre zugleich formalen und empirischen Entfaltungen haben nicht zu einem entsprechenden begrifflichen Fortschritt geführt. Eine Umgestaltung der Quantentheorie muss daher als ein erkenntnistheoretisches Desiderat betrachtet werden. Einer der wichtigsten Aspekte eines derartigen Unterfangens wird darin bestehen, die Theorie von ihren hartnäckigen Bindungen an klassische Begriffe zu befreien, um ihr einen eigenständigen und autonomen Status zu verleihen. Es werden die Probleme der Begründung, der Terminologie, der Interpretation und der Grenzen der Quantentheorie diskutiert, indem auch verschiedene kürzlich erschienene Arbeiten, die sich auf das vorgeschlagene Unternehmen beziehen, berücksichtigt werden. (shrink)

First-ever comprehensive introduction to the major new subject of quantum computing and quantum information.

Mathematical Foundations of Quantum Theory is a collection of papers presented at the 1977 conference on the Mathematical Foundations of Quantum Theory, held in New Orleans. The contributors present their topics from a wide variety of backgrounds and specialization, but all shared a common interest in answering quantum issues. Organized into 20 chapters, this book's opening chapters establish a sound mathematical basis for quantum theory and a mode of observation in the double slit experiment. This book then describes the Lorentz (...) particle system and other mathematical structures with which fun ... (shrink)

A coherent account of the connections and contrasts between the principles of complementarity and uncertainty is developed starting from a survey of the various formalizations of these principles. The conceptual analysis is illustrated by means of a set of experimental schemes based on Mach-Zehnder interferometry. In particular, path detection via entanglement with a probe system and (quantitative) quantum erasure are exhibited to constitute instances of joint unsharp measurements of complementary pairs of physical quantities, path and interference observables. The analysis uses (...) the representation of observables as positive-operator-valued measures (POVMs). The reconciliation of complementary experimental options in the sense of simultaneous unsharp preparations and measurements is expressed in terms of uncertainty relations of different kinds. The feature of complementarity, manifest in the present examples in the mutual exclusivity of path detection and interference observation, is recovered as a limit case from the appropriate uncertainty relation. It is noted that the complementarity and uncertainty principles are neither completely logically independent nor logical consequences of one another. Since entanglement is an instance of the uncertainty of quantum properties (of compound systems), it is moot to play out uncertainty and entanglement against each other as possible mechanisms enforcing complementarity. (shrink)