Early History of Bell’s Theorem

Abstract

Bell’s Theorem is one of the most profound results in physics of the twentieth century. Not only does it have a significant impact on natural philosophy and on the true meaning of quantum mechanics, it also has stimulated important and practical new research in quantum optics. In 1972 at the CQ03 Rochester conference, in response to a number of disturbing issues and challenges then raised by Ed Jaynes concerning the foundations of quantum electrodynamics, I introduced the quantum optics community to Bell’s Theorem and a few of the associated mysteries manifest in quantum entanglement. Given the widespread belief that the foundations of quantum mechanics were then well understood, needless to say, my 1972 talks were then met with considerable skepticism. Eventually, however, the importance of Bell’s Theorem gained full acceptance, so that now it is discussed in many recent quantum mechanics and quantum optics textbooks. Similarly, my first experimental test (with Stuart Freedman in 1972) of the Bell-Clauser-Horne-Shimony-Holt prediction has since then been repeated and confirmed literally dozens of times, and that prediction now provides a standard quantitative measure of entanglement. Moreover, the fundamental ideas underlying Bell’s Theorem have been found to be sufficiently useful and important, that it is doubtful that the parallel conference ICQI-2001 would have occurred without them. This article recounts the important historical events behind the development of Bell’s Theorem.

Formerly at Department of Physics, univ. of California — Berkeley (retired).