John Stewart Bell FRS (28 June 1928 – 1 October 1990) was a Northern Irish physicist, and the originator of Bell's theorem, a significant theorem in quantum physics regarding hidden variable theories.

John Bell was born in Belfast, Northern Ireland. When he was 11 years old, he decided to be a scientist, and at 16 graduated from Belfast Technical High School. Bell then attended the Queen's University of Belfast, and obtained a bachelor's degree in experimental physics in 1948, and one in mathematical physics a year later. He went on to complete a Ph.D. in physics at the University of Birmingham in 1956, specialising in nuclear physics and quantum field theory. In 1954, he married Mary Ross, also a physicist, whom he had met while working on accelerator physics at Malvern, UK.

Bell's career began with the UK Atomic Energy Research Establishment, near Harwell, Oxfordshire, known as AERE or Harwell Laboratory. After several years he moved to work for the European Council for Nuclear Research (CERN, Conseil Européen pour la Recherche Nucléaire), in Geneva, Switzerland. Here he worked almost exclusively on theoretical particle physics and on accelerator design, but found time to pursue a major avocation, investigating the foundations of quantum theory. He was elected a Foreign Honorary Member of the American Academy of Arts and Sciences in 1987. Also of significance during his career, Bell, together with John Bradbury Sykes, M. J. Kearsley, and W. H. Reid, translated several of the famous ten volume Course of Theoretical Physics of Lev Landau and Evgeny Lifshitz, making these works available to a vast English speaking audience in impeccable translation, all of which remain in print.

In 1964, after a year's leave from CERN that he spent at Stanford University, the University of Wisconsin–Madison and Brandeis University, he wrote a paper entitled "On the Einstein-Podolsky-Rosen Paradox". In this work, he showed that carrying forward EPR's analysis permits one to derive the famous Bell's theorem. The resultant inequality, derived from certain assumptions, is violated by quantum theory.

There is some disagreement regarding what Bell's inequality—in conjunction with the EPR analysis—can be said to imply. Bell held that not only local hidden variables, but any and all local theoretical explanations must conflict with the predictions of quantum theory: "It is known that with Bohm's example of EPR correlations, involving particles with spin, there is an irreducible nonlocality." According to an alternative interpretation, not all local theories in general, but only local hidden variables theories (or "local realist" theories) have shown to be incompatible with the predictions of quantum theory.

Bell died unexpectedly of a cerebral hemorrhage in Geneva in 1990. Unbeknownst to Bell, that year he had been nominated for a Nobel prize (which is never awarded posthumously). His contribution to the issues raised by EPR was significant. Some regard him as having demonstrated the failure of local realism (local hidden variables). Bell's own interpretation is that locality itself met its demise.

In 2008, the John Stewart Bell Prize was created by the Centre for Quantum Information and Quantum Control at the University of Toronto. The prize is awarded every other year for significant contributions first published during the six preceding years. The award recognizes major advances relating to the foundations of quantum mechanics and to the applications of these principles. In 2009, the first award was presented by Alain Aspect to Nicolas Gisin for his theoretical and experimental work on foundations and applications of quantum physics — notably quantum nonlocality, quantum cryptography, and quantum teleportation.

More: http://en.wikipedia.org/wiki/Bell'...

http://www-history.mcs.st-andrews.ac....

http://cqiqc.physics.utoronto.ca/bell...