Physics Nobel recognizes Berkeley experiment on ‘spooky action at a distance’

October 4, 2022

In 1971, graduate student Stuart Freedman and postdoctoral fellow John Clauser took over a room in the sub-basement of Birge Hall at the University of California, Berkeley, and built an experiment that would put to the test one of the most enduring weirdnesses of quantum mechanics, what Einstein called “spooky action at a distance.”

That experiment was the first to show that quantum mechanics really is weird. Two particles, once linked quantum mechanically, or entangled, can be separated by large distances — even the diameter of the universe — and still “know” what happens to one another.

The research was Freedman’s Ph.D. dissertation in 1972, but he subsequently moved onto a broad range of subfields of physics, all related to quantum mechanics, and died tragically in 2012. Clauser continued to refine the experiment to provide more convincing proof that nature violates what’s called Bell’s inequality and prove that the quantum mechanical description of entangled particles is right.

That initial experiment at UC Berkeley and the research it spawned were honored today with a Nobel Prize in Physics to Clauser and two others who followed in his and Freedman’s footsteps: Alain Aspect of the Université Paris-Saclay and École Polytechnique in Palaiseau, France, and Anton Zeilinger of the University of Vienna, Austria. Nobel Prizes are not awarded posthumously, though the Nobel Academy acknowledged Freedman’s role in the research.

Berkeley News