Quantum Profiles (1991)Edit
John Stewart Bell: Quantum EngineerEdit
- Although it is always somewhat dangerous to look for the cause of a complex sociological phenomenon in a single event, nonetheless, I believe that a cause can be made for the proposition that the present widespread interest in the quantum theory can be traced to a single paper with the nontransparent title “On the Einstein-Podolsky-Rosen Paradox,” which was written in 1964 by the then thirty-four-year-old Irish physicist John Bell. It was published in the obscure journal Physics, which expired after a few issues. Bell’s paper was, as it happens, published in its first issue. Bell, who has worked since 1960 at CERN, the gigantic elementary-particle physics laboratory near Geneva, has been known to claim that his paper involves only the use of “high school mathematics”; however, its six pages are dense with an extremely abstract set of arguments, which even professionals in the field must work hard at to understand. In fact, for several years after its publication, few if any professional physicists bothered to try.
- The signs on Bell’s door read “J.Bell” and “M.Bell.” I knocked and was invited in by Bell. He looked about the same as he had the last time I saw him, a couple of years ago. He has long, neatly combed red hair and a pointed beard, which give him a somewhat Shavian figura. On one wall of the office is a photograph of Bell with something that looks like a halo behind his head, and his expression in the photograph is mischievous. Theoretical physicists’ offices run the gamut from chaotic clutter to obsessive neatness; the Bells’ is somewhere in between. Bell invited me to sit down after warning me that the “visitor’s chair” tilted backward at unexpected angles. When I had mastered it, and had a chance to look around, the first thing that struck me was the absence of Mary. “Mary,” said Bell, with a note of some disbelief in his voice, “has retired.” This, it turned out, had occurred not long before my visit. “She will not look at any mathematics now. I hope she comes back,” he went on almost plaintively; “I need her. We are doing several problems together.” In recent years, the Bells have been studying new quantum mechanical effects that will become relevant for the generation of particle accelerators that will perhaps succeed the LEP. Bell began his career as a professional physicist by designing accelerators, and Mary has spent her entire career in accelerator design. A couple of years ago Bell, like the rest of the members of CERN theory division, was asked to list his physics speciality. Among the more “conventional” entries in the division such as “super strings,” “weak interactions,” “cosmology,” and the like, Bell’s read “quantum engineering.”
- I once asked Bell whether during the years he was studying the quantum theory it ever occurred to him that the theory might simply be wrong. He thought a moment and answered, “I hesitated to think it might be wrong, but I knew that it was rotten.” Bell pronounced the word “rotten” with a good deal of relish and then added, “That is to say, one has to find some decent way of expressing whatever truth there is in it.” The attitude that even if there is not something actually wrong with the theory, there is something deeply unsettling—“rotten”—about it, was common to most of the creators of the quantum theory. Niels Bohr was reported to have remarked, “Well, I think that if a man says it is completely clear to him these days, then he has not really understood the subject.” He later added, “If you do not getschwindlig [dizzy] sometimes when you think about these things then you have not really understood it.” My teacher Philipp Frank used to tell about the time he visited Einstein in Prague in 1911. Einstein had an office at the university that over looked a park. People were milling around in the park, some engaged in vehement gesture-filled discussions. When Professor Frank asked Einstein what was going on, Einstein replied that it was the grounds of a lunatic asylum, adding, “Those are the madmen who do not occupy themselves with the quantum theory.”