issues raised by quantum theory, a topic not very popular during his student days at Queen's University, Belfast. Apparently, John Bell, who had been interested in the Bohr-Einstein dialogue, always took the position of Albert Einstein on philosophical issues. He also felt that a completion of quantum mechanics using so-called "hidden variables" would be highly desired, as it would help to regain a realistic and objective picture of the world. That way, Bell hoped one would be able to arrive at a physics where "measurement" would not play such a central role as in the Copenhagen interpretation of quantum mechanics. Then, a most interesting sequence of events set in. In 1952, David Bohm had achieved something which had earlier been proclaimed impossible. It had been proved by John von Neumann that no hidden variable theory could agree with quantum mechanics. Bohm actually formulated such a theory, where each particle at any time has both a well-defined position and a well defined momentum. The conflict raised between von Neumann and Bohm was elegantly resolved by Bell, who showed that von Neumann's proof contained a physically unjustifiable assumption. So while John Bell had flung open the door widely for hidden variable theories, he immediately dealt them a major blow. In 1964, in his celebrated paper "On the Einstein-Podolsky-Rosen Paradox", he showed that any hidden variable theory, which obeys Einstein's requirement of locality, i. e.

Contributions written by world leading experts On the fundamentals of quantum information Hot physics for the 21st century Includes supplementary material: sn.pub/extras

Autorentext
Anton Zeilinger, Professor am Institut für Experimentalphysik der Universität Wien zählt zu den international bedeutendsten Quantenphysikern der Gegenwart. Er lehrte und forschte u.a. an den Universitäten von Innsbruck und München, am MIT (USA) sowie am Collège de France und ist Gastforscher weiterer bedeutender Forschungseinrichtungen wie z.B. am Los Alamos National Laboratory oder am Merton College in Oxford. Für seine überragenden Leistungen wurde er vielfach ausgezeichnet, darunter mit dem 'Alexander-von-Humboldt-Forschungspreis' und dem 'Orden pour le mérite', der begehrtesten deutschen Auszeichnung für Wissenschaft und Künste. Der Nobelpreis-Anwärter hat drei Kinder, spielt Cello und Bass und lebt in Wien.

Klappentext
This outstanding collection of essays in commemoration of John S. Bell is the result of the "Quantum (Un)speakables" conference organised by the University of Vienna. The title was taken from a famous note written by John Bell during the "Schrödinger Symposium" of 1987. The book leads the reader from the foundations of quantum mechanics to quantum entanglement, quantum cryptography, and quantum information, and is written for all those who need more insight into this new area of physics.

Inhalt
John S. Bell - The Man.- Tests of Bell's Inequalities.- Quantum Information.- Quantum Ideas.- Quantum Specials.- Particles and Fields.