Small differences between hydrogen's measured energy levels and earlier theoretical predictions helped drive the development of quantum electrodynamics. Krishna Choudhary and Lester Nare discuss the Lamb shift, Hans Bethe's calculation, and why very precise atomic measurements can expose missing pieces in a theory.
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The Lamb shift revealed a small separation between hydrogen energy levels.
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Bethe calculated a correction that helped explain the observation.
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Precision experiments gave physicists demanding tests of quantum electrodynamics.
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1:09:48the lamb shift. One of my favorites. This is huge. Um, Columbia University Willis Lamb, he uses all of the radar technology that has been developed over World War II to look at the quantum states of hydrogen. And he discovers an unexpected energy difference in two states of hydrogen that no one has accounted for. And as the great Freeman Dyson said, if you can't understand hydrogen, you can't understand anything. This was a huge deal because um it started the revolution of quantum field theory that we all know and love. >> We all know and love
1:10:28>> 1955 Nobel Prize in physics. >> Same in 1947 calculation >> of the lambshift. Another reference to Hans Beta here. >> Yes. So 1947 the earlier one was the lamb shift discovered at Columbia University. There was this thing called the shelter island conference. Okay. It was in a hotel in Long Island. A random hotel that you can still visit today and one of the destinations for our future field trips. >> Yes. >> This hotel was a legendary venue for one of the greatest scientific conferences in modern physics because Lamb described
1:11:09his lamb shift and all of the theorists were like, "Okay, so I guess we don't know anything." um Hans Beta on his train back from that conference, he's on a train back to Ithaca, New York to Cornell and he figures out how to calculate it. He calculates it and it is now known as one of the greatest calculations in 20th century physics because he basically starts this idea of renormalization and the idea of sort of taking into account relativistic effects of how the electron is moving around the proton in the hydrogen atom. One of the things that contributed to his 1967 Nobel Prize in
1:11:50physics, >> still in 1947, precision measurement of electron anomalous magnetic moment. >> That's right. So the electron it's spinning right? >> Yes. >> And because it's spinning and it has a charge, it's going to interact with the magnetic field that's created by the proton that's also spinning. Now according to Dac that factor of the relationship between the electron mag magnetic moment and the spin of the electron should be about two. It turns out this guy at Columbia University Polycarp Kush he measured it and it's not exactly two. It's a little bit above
1:12:31two. And that little bit above two along with the lamb shift that was also in 1947 also at Columbia University was this sort of wakeup call to all the theorists like guys we should have this down we really don't. >> You know what else happened in 1947? The Roswell UFO crash. Interesting how we have all these discoveries in the same year. Continuing with 1947 invention of