Albert Einstein once dubbed quantum entanglement “spooky action at a distance,” and the concept remains one of the starkest examples of how quantum theory differs from our usual intuitions about space, time, and matter. Physicists have tested quantum entanglement in laboratories for more than forty years, and have always found results consistent with quantum theory; today entanglement is at the heart of next-generation devices like quantum encryption and quantum computing. Yet every experimental test to date has been subject to one or more “loopholes,” which could possibly account for the results even in the absence of genuine quantum entanglement. This talk describes some of the latest experimental tests of quantum entanglement, including a new series of experiments that uses some of the oldest light in the universe to address the last major loophole and pave the way for a genuinely loophole-free test of quantum entanglement.
David Kaiser is Germeshausen Professor of the History of Science and Professor of Physics at MIT. His books include Drawing Theories Apart: The Dispersion of Feynman Diagrams in Postwar Physics (2005), which received the Pfizer Prize from the History of Science Society for best book in the field; and How the Hippies Saved Physics: Science, Counterculture, and the Quantum Revival (2011), which was named “Book of the Year” by Physics World magazine and received the Davis Prize from the History of Science Society for best book aimed at a general audience. He co-directs a research group with Alan Guth in MIT’s Center for Theoretical Physics, focusing on early-universe cosmology, and, with Anton Zeilinger, he also leads an international collaboration to conduct new experimental tests of quantum theory. Kaiser is a Fellow of the American Physical Society and 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, as well as on NOVA television programs, National Public Radio, and the BBC.