In 1959 physicists Yakir Aharonov and David Bohm startled their colleagues by predicting a new type of quantum nonlocality, distinct from the phenomenon that had spooked Einstein. They showed that an electric or magnetic field can have an effect on a particle at a distance: even when the field exerts no force on that particle, it can shift the wave interference pattern that the particle generates. (For a good explanation, see this diagram in Nature.) The Aharonov-Bohm effect proved influential in the development of quantum field theory. In this video interview, which I conducted last month at the Emergent Quantum Mechanics conference, Aharonov describes the effect and some of its implications.



An Israeli-born physicist who was a professor at Tel Aviv University (among other institutions) and is now at the Institute of Quantum Studies at Chapman University in Orange, Calif., Aharonov remains one of the most consistently innovative thinkers in quantum physics. He also came up with the concept of weak measurement, whereby you can glean information about quantum systems without disturbing them (which had been thought impossible); the proposition that the present is as influenced as much by the future as by the past; and a real-life version of the Cheshire cat from Alice in Wonderland. He’s the kind of person who really does believe in six impossible things before breakfast. “A typical day starts with Yakir pulling out a numbered list of discoveries he made while he was sleeping,” says Jeff Tollaksen, director of the institute at Chapman. And many prove to be not so impossible.