Bell’s Universe: A Personal Recollection

Abstract

My collaboration and friendship with John Bell is recollected. I will explain his outstanding contributions in particle physics, in accelerator physics, and his joint work with Mary Bell. Mary's work in accelerator physics is also summarized. I recall our quantum debates, mention some personal reminiscences, and give my personal view on Bell's fundamental work on quantum theory, in particular, on the concept of contextuality and nonlocality of quantum physics. Finally, I describe the huge influence Bell had on my own work, in particular on entanglement and Bell inequalities in particle physics and their experimental verification, and on mathematical physics, where some geometric aspects of the quantum states are illustrated.

Real or not real that is the question...

“…This position led him to one of the most profound discoveries in physics, to Bell's Theorem, but also to further deep insights in quantum field theory, like the "Anomalies" [18], for an overview of this field, see my book [124]. More about the work of John Bell can be found in my reminiscences [125,126].…”

"Philosophysics" at the University of Vienna: The (pre-)history of foundations of quantum physics in the Viennese cultural context

“…In April 1978, Bertlmann moved to the Theory Division of CERN in Geneva, where he soon made the acquaintance of Bell [112]. They started a close friendship and a prolific collaboration on topics of particle physics, notably on quarkonium, i.e., bound states of quark-antiquark pairs (their first joint paper is [116], see Ref.…”

“…They started a close friendship and a prolific collaboration on topics of particle physics, notably on quarkonium, i.e., bound states of quark-antiquark pairs (their first joint paper is [116], see Ref. [112] for a bibliography). Bell was a recognized authority in the field of theoretical particle physics and accelerator physics -he was called "the Oracle of CERN" [110]-but he never discussed his paramount results on FQM (Bell's inequalities had been published as early as 1964!…”

“…This I understood later on, John was reluctant to push somebody into a field that was quite unpopular at that time." [112] The first direct contact between Bell and the University of Vienna occurred in May 1980, when he was invited by Walter Thirring as "Schrödinger Guest Professor" for about ten days. On that occasion, Bell gave three lectures: it must have been quite surprising for Thirring to figure out that only the first one was about particle physics, "On the role of duality for bound states in QCD" (on May 19), whereas the other two focused on his (at that time) virtually unknown work on FQM, "Assuming the Schrödinger equation is exact" (on may 21), and "On locality in quantum mechanics" (on May 22).…”

“…On that day, in fact, Bertlmann was at the Institute of Physics in Vienna, which he had returned to in July, when his colleague Gerhard Ecker ran to him with a paper in his hands, shouting: "Reinhold look-now you're famous!" [112]. This was a pre-print authored by Bell, transmitted from CERN, whose title was "Bertlmann's socks and the nature of reality" [118].…”