Location : Institut de Science et d’Ingénierie Supramoléculaires (ISIS), Strasbourg

Date : Tuesday 8th April 2025, Starting at 16:00

Scenes from the Quantum Century: From Curious Hippies to Novel Tests of Bell’s Inequality, by David Kaiser (MIT)

The hundredth anniversary of quantum mechanics in 2025 offers opportunities to consider the history of quantum theory and ask how some of our core ideas were introduced, debated, tested, and ultimately accepted. One of the most central conceptual ingredients of quantum theory is entanglement, nowadays so important to the burgeoning field of quantum information science and technology. Yet the history of quantum entanglement—and of physicists’ efforts to understand whether entanglement is a robust feature of the world rather than merely an intriguing hypothesis—has been far from straightforward. In this talk I will describe how a colorful group of physicists during the 1970s wrestled with entanglement and with John Bell’s now-famous inequality, exploring the subtle interplay between quantum nonlocality and relativity amid the California counterculture scene. More recently, retracing the history of efforts to conduct experimental tests of Bell’s inequality helped to catalyze novel tests, which have aimed to close a series of loopholes, including my group’s recent « Cosmic Bell » experiments. These experiments provided compelling evidence for quantum entanglement while constraining certain classes of alternative models—which exploit a particularly subtle loophole—more thoroughly than ever before.

David Kaiser is Germeshausen Professor of the History of Science and Professor of Physics at the Massachusetts Institute of Technology. He is the author of several award-winning books on the history of modern physics, including How the Hippies Saved Physics: Science, Counterculture, and the Quantum Revival (2011), which received the Davis Prize from the History of Science Society and was named « Book of the Year » by Physics World magazine. His latest book, Quantum Legacies: Dispatches from an Uncertain World (2020), was named a Choice Outstanding Academic Title and was honored as among the best books of the year by Physics Today and Physics World magazines. Kaiser directs a research group on early-universe cosmology in MIT’s Center for Theoretical Physics, and has also designed and helped to conduct novel experimental tests of quantum theory. A Fellow of the American Physical Society, Kaiser has received MIT’s highest awards for excellence in teaching. His work has been featured in Science, Nature, the New York Times, and the New Yorker magazine. His group’s efforts to conduct a « Cosmic Bell » test of quantum entanglement, together with Nobel laureate Anton Zeilinger, were featured in the documentary film, Einstein’s Quantum Riddle.