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Who was John Bell?
The short answer (tap to open)
John Stewart Bell (1928 to 1990) was a physicist from Belfast who spent his career designing particle accelerators and doing particle theory at CERN. In his spare time he worked on the foundations of quantum theory, and in 1964 proved the theorem that lets experiments test entanglement. Experiments testing it won the 2022 Nobel.
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How did a side project win others a Nobel?
Card 1 · Belfast, 1928
Bell grows up in a working-class family. Money is short, and he leaves school at 16 to work as a lab assistant at Queen's University Belfast, where the staff spot his talent and he enrols as a student.
Card 2 · Bothered
As a student he's uneasy with how quantum theory is taught: the line between the quantum system and the measuring device seems vague. He's told not to worry about it.
Card 3 · The day job
He works on accelerator design in Britain, then from 1960 at CERN in Geneva, alongside his wife Mary Bell, also an accelerator physicist. Foundations are, as he puts it, his hobby.
Card 4 · 1964
On a year away in the US he writes a short paper on Einstein, Podolsky and Rosen's argument. He proves that no theory of pre-written local instructions can match quantum predictions at every angle. It appears in a little-read new journal.
Card 5 · The slow fuse
For years few notice. Then John Clauser reads it and, in 1972, runs the first test. In 1975 Alain Aspect visits Bell, who asks whether he has a permanent job before risking his career on it. Aspect's tests follow in 1982.
Card 6 · The pilot wave
Bell champions the de Broglie-Bohm pilot-wave picture (chapter 6), not because he believes it is final, but because it proves a clear, realistic quantum theory is possible.
Card 7 · 1990 and 2022
Bell dies suddenly in 1990, aged 62, reportedly the year someone nominated him for a Nobel Prize. In 2022 the prize goes to Aspect, Clauser and Zeilinger, for experiments built on his theorem.
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A side project changed physics.
Bell turned a philosophical argument into a test, and the experiments that followed won a Nobel.
Next in the path · Chapter 6
What do the interpretations say, and how does popular culture show them?
Next in the path