Sunday, December 18, 2022

Path Integrals and Entanglement with Kenneth Wharton

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Recorded: 2022/11/08 Released: 2022/12/18

Jim talks with Ken Wharton of San Jose State University about how to apply path integrals to situations to entangled particles. Being an equivalent way to compute amplitudes for different experiments, when applied to various experiments, Bell-type correlations, entanglement swapping, delayed choice experiments, and the triangle network, the mathematics gives the same correlations. But, the interpretation of a path integral - a Lorentz covariant description based on local paths - is very different than that of a traditional wave function - a non-local description of the effects of measurements. This leads to a tension in how to interpret entanglement in the first place.
------------------------------------------- Notes:

1. The article that we discussed in this program:
2. Related papers that I read or Ken referred to in the podcast: 3. Books referred to in the program:
  • Feynman, R. QED: The Strange Theory of Light and Matter. [Amazon] A great, non-technical introduction to quantum electrodynamics, and therefore path integrals. As an undergraduate I found it an inspiring text, and when I ran a book club at Xavier for the physics students, we always had a good time when it came around.
  • Griffiths, R., Consistent Quantum Theory. [Amazon]. I have to confess that, although I bought a copy of this book after Randy and I did the episode on Consistent Histories, I have yet to read it.
  • Mattuck, R., A Guide to Feynman Diagrams in the Many-Body Problem. [Amazon] This has the pinball-game description the sum-over-histories approach - before getting into the deepest, darkest forest of constructing Green's functions for probability amplitudes. Since it's a Dover book, the first couple of chapters alone are worth the price. Like I said, the transition from the pinball game to the quantum pinball game was a little too much for me as an undergraduate, but after the recording podcast I've been working through it, and it's really not so difficult -- as long as you're up on your basic non-relativistic quantum mechanics. The reason why the it was called "Feynman Diagrams for Idiots" by graduate students and, looking at the preface to the second addition, much worse by reviewers (especially Russian reviewers) is that it has lots of cartoons scattered throughout the book. These are actually jewels, and are a third reason to pick up this book, either at the physics library or the bookstore, not a reason to avoid it.
  • Aharanov, A. and D. Rohrlich, Quantum Paradoxes: Quantum Theory for the Perplexed. [Amazon] Randy and I started our first podcast with this book. Partially because of that, I've read it three times, cover-to-cover. The Perimeter Institute gave a conference on the topic in 2016, "Concepts and Paradoxes in a Quantum Universe," which you can view either all contributions or just Aharonov's. I have all the talks on mp3 to play in the car (back when PIRSA allowed you to download the mp3's directly - I'm not bitter about the change [Yes I am]).
4. Related Episodes of Physics Frontiers:
5. If you'd like to know more about Ken Wharton, I have some additional questions not about path integrals on YouTube. 5. Please visit and comment on our subreddit, YouTube Channel, or Twitter account. These are also places to look for announcements of new episodes and the like. And if you could help us keep this going by contributing to our Patreon, we'd be grateful.
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Sunday, November 20, 2022

Flavor Unification with Joe Davighi

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Recorded: 2022/08/23 Released: 2022/11/20

Jim talks with Joe Davighi about gauge flavor unification. Joe's work is on a set of gauge theories that unify the various generations of leptons at high energies. We discuss gauge symmetries, symmetry breaking, and so on, as well as some implications of his work including leptoquarks and proton stability.
------------------------------------------- Notes:

1. The article that we discussed in this program:
2. Related Episodes of Physics Frontiers:
3. The book I mention, Georgi's Lie Algebras in Particle Physics [Amazon]. 4. If you'd like to know more about Joe Davighi, I have some additional questions not about flavor unification on YouTube. 5. Please visit and comment on our subreddit, YouTube Channel, or Twitter account. These are also places to look for announcements of new episodes and the like. And if you could help us keep this going by contributing to our Patreon, we'd be grateful.
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Sunday, September 25, 2022

Quantum Resource Theories with Gilad Gour

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Recorded: 2022/08/04 Released: 2022/09/25

Jim talks to Gilad Gour about Qunatum Resource Theories and partially ordered dynamics.
------------------------------------------- Notes:

1. The article that we discussed in this program:
2. Related Episodes of Physics Frontiers:
3. If you'd like to know more about Gilad Gour, I have some additional questions not about quantum resource theories on YouTube. You can also visit his faculty bio at The University of Calgary. It says he's looking for graduate students. 4. Please visit and comment on our subreddit, YouTube Channel, or Twitter account. These are also places to look for announcements of new episodes and the like. And if you could help us keep this going by contributing to our Patreon, we'd be grateful.
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Sunday, August 14, 2022

Optical Gravity with Matthew R. Edwards

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Recorded: 2022/07/20 Released: 2022/08/14

Jim talks to Matthew R. Edwards about optical gravity. Matthew's theory of gravity is a Le Sage model, one that envisions space-time as a dispersive medium made of graviton filaments.
------------------------------------------- Notes:

1. The article that we discussed in this program:
2. Other articles mentioned in this program:
3. Related Episodes of Physics Frontiers:
4. Books mentioned on the program:
  • Pushing Gravity: New perspectives on Le Sage's theory of gravitation, Matthew R. Edwards (ed.), Amazon
  • The Expanding Earth: Some Consequences of Dirac's Gravitation Hypothesis, Pasqual Jordan. Amazon
5. If you'd like to know more about Matthew Edwards, I have some additional questions not about optical gravity on YouTube. I ask him about his background, how he decides to research something, and his experiences in publishing. 6. Please visit and comment on our subreddit, YouTube Channel, or Twitter account. These are also places to look for announcements of new episodes and the like. And if you could help us keep this going by contributing to our Patreon, we'd be grateful.
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Sunday, June 26, 2022

Limit of General Relativity with James Owen Weatherall

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Recorded: 2022/05/19 Released: 2022/06/26

Jim talks to James Owen Weatherall of the University of California, Irvine about the conditions in which general relativity is likely to break down and a new theory is likely to be required.
------------------------------------------- Notes:

1. The article that we discussed in this program:
  • Weatherall, J.O., "Where Does General Relativity Break Down?" (2022) [arXiv]
2. Other articles mentioned in this program:
3. Related Episodes of Physics Frontiers:
4. An excerpt from this interview in which I talk with Jim about how philosophers of physics interact with physicists is on YouTube. 5. Please visit and comment on our subreddit, YouTube Channel, or Twitter account. These are also places to look for announcements of new episodes and the like. And if you could help us keep this going by contributing to our Patreon, we'd be grateful.
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Sunday, May 22, 2022

Causality, Time and the Experiment Paradox

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Recorded: 2022/03/21 Released: 2022/05/22

Jim talks to Michal Eckstein of the Coperincus Center for Interdisciplinary Studies on how two different ways to order events, that of chronology (this comes before that) and causality (this makes that happen) come together to define time. We then go on to discuss the Experiment Paradox, which pulls together a number of measurement paradoxes in physics.
------------------------------------------- Notes:

1. Michal Eckstein's articles we discussed in this program:
2. Michal Eckstein's articles that we discussed in this program:
  • Ehlers, J., F.A.E. Pirani, A. Schild, “The Geometry of Free Fall and Light Propagation [2012 Republication].” General Relativity: Papers in Honour of J. L. Synge, 63. (1972).
  • Linnemann, N. and J. Read, "Constructive Axiomatics in Spacetime Physics Part I: Walkthrough to the Ehlers-Pirani-Schild Axiomatisation" (2021). [arXiv]
  • Minguzzi, E. and M. Sanchez, "The Causal Heirarchy of Space Times." Recent Developments in Pseudo-Riemannian Geometry, 299 (2008). [arXiv]
3. Related Episodes of Physics Frontiers:
4. Please visit and comment on our subreddit, YouTube Channel, or Twitter account. These are also places to look for announcements of new episodes and the like. And if you could help us keep this going by contributing to our Patreon, we'd be grateful.
← Previous ( Born's Rule ) ( GR's Breakdown ) Next →

Sunday, April 24, 2022

Born's Rule

← Previous ( Gleason's Theorem ) ( Causality and Time ) Next →



Recorded: 2022/01/18 Released: 2022/04/24

Jim discusses Gleason's Theorem with Blake C. Stacey of the University of Massachuesetts - Boston. Gleason's Theorem is a theorem in the foundations of quantum mechanics that, for a system meets some simple requirements, you can find a set of valid staes and a rule for calculating probailities, a la the Born Rule. This is the first part of the interview, the next will be on Blake's discussion of how people are trying to reformulate the Born Rule.
------------------------------------------- Notes:

1. Papers we both read for this program:
2. This series: