Einstein Was Wrong: John Clauser on Bell's Theorem and the Nature of Reality
The 1972 experiment that proved quantum entanglement exists and disproved Einstein's view of local realism.
We'd like to share with you some lessons from our conversation with John Clauser, winner of the 2022 Nobel Prize in Physics for his groundbreaking experiments testing Bell's Theorem.
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I. The Physics Community Thought Testing Bell's Theorem Was Pointless
In 1969, when Clauser proposed testing Bell's Theorem experimentally, the physics community thought it was a waste of time. Even Richard Feynman dismissed the idea:
"Everybody knew what the results would be. Totally silly to even do the experiment... You're just wasting time and money," Feynman said before throwing Clauser out of his office.
II. The Birth of Bell's Theorem
John Bell made a startling discovery in 1964: If you try to describe two separated entangled particles in normal physical space (as Einstein wanted), you cannot reproduce the predictions of quantum mechanics.
This set up a clear experimental test between Einstein's view of local realism and the quantum mechanical description.
III. How to Win a Nobel Prize with No Money
In 1972, Clauser and Stuart Freedman performed the first experiment testing Bell's Theorem at UC Berkeley. The results definitively showed that Einstein was wrong - quantum mechanics was right.
Clauser's experiments in the early 1970s faced enormous technical hurdles:
Detection rates of only about 1 photon per second
Required hundreds of hours of data collection
Everything had to be built from scratch with minimal funding
Data recorded on paper tape and punch cards
Very inspiring!
IV. Wave-Particle Duality Confirmed
In 1974, Clauser performed another crucial experiment proving that light exhibits both wave and particle properties - the first experimental proof of wave-particle duality for optical photons.
This resolved a decades-old debate about the nature of light that went back to Einstein and Schrödinger.
V. The Physics Lab as Church
"The physics laboratory is really a church," Clauser reflects. "You walk in and ask God a question. If you ask carefully, you will get the correct answer. If someone else walks into their physics laboratory and asks exactly the same question, they will get exactly the same answer."
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