Friday, August 10, 2018

CPT Symmetry and Gravitation

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Recorded: 3/28/2018 Released: 8/10/2018

Jim and Randy discuss what happens when CPT symmetry is applied to gravitation. CPT symmetry -- what happens to a theory when you reverse the sign of the charge, the handedness of a particle, and the direction of time evolution all at the same time -- is a basic tenet of the standard model. Massimo Villata has applied this symmetry to gravitation and has derived consequences for the way in which antimatter particles interact with gravity and various cosmological conclusions that follow from that.

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Notes:

1. The papers we read for this program:
2. I found these papers in the footnotes to Alberto Vecchiato's Variational Approach to Gravity Field Theories.

3. Please visit and comment on our subreddit, and if you can help us keep this going by contributing to our Patreon, we'd be grateful.

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Retrocausality

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Recorded: 3/3/2018 Released: 7/25/2018

Randy talks to Jim about retrocausality in quantum physics -- how does the future affect the past? In particular, they talk about the ideas of Huw Price and Ken Wharton on using temporal boundary conditions to constrain the wave function through its initial and final boundary conditions, effectively creating quantum harmonics in the time domain. They also discuss what this means in terms of the de Broglie-Bohm hypothesis, the multiple worlds interpretation, and Yakir Aharonov's interpretation in Quantum Paradoxes.

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Notes:

1. The papers we read for this program:
2. Books discussed in the program:


3. Huw Price also wrote a book about the philosophy of time called Time's Arrow and Archimedes' Point that, according to the plane ticket I was using as a bookmark, I last read in 2003.

4. Please visit and comment on our subreddit, and if you can help us keep this going by contributing to our Patreon, we'd be grateful.

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Thursday, August 2, 2018

Physics Frontiers: Most Popular Episodes

Most popular episodes, by downloads/month after 4 months.

2017 The Physics of Time Travel
Vacuum Fluctuations and the Casimir Effect
f(R) theories of gravity

Physics Frontiers Index