Physics Frontiers

Jim talks with Blake Stacey about Gleason's Theorem, a foundational topic in the foundations of quantum mechanics.  Gleason's theorem gives us a set of characteristic states for a measurement and the probability rule associated measuring them.  This is the first part of the interview.  The second part will discuss recent attempts to replace the Born Rule.Show Notes: http://frontiers.physicsfm.com/63

Jim and Randy talk about how special relativity might be amended to incorporate a minimum length scale.  Such scales are common in quantum gravity theories, and in the limit where both QM and GR are less important, QG should induce first order corrections to SR.  We then talk about how these corrections seem to lead to unreasonable paradoxes.Show Notes: http://frontiers.physicsfm.com/62

Jim and Randy talk about alternatives to black holes without event horizons or singularities.Show Notes: http://frontiers.physicsfm.com/61

Randy tells Jim about developments of metrics describing isolated spacetime bubbles that could, possibly, move faster than light.Show Notes: http://frontiers.physicsfm.com/60

Randy and Jim discuss the current tension between measurements of the Hubble constant by different methods, and some attempts to resolve the issue.Show Notes: http://frontiers.physicsfm.com/59

Jim and Randy talk about the Higgs portal to dark matter and the nightmare scenario for particle physicists: what if the LHC never saw any traces of supersymmetric particles?Show Notes: http://frontiers.physicsfm.com/58

Randy and Jim talk about two proposals to use gravitational wave interferometry to show that gravitons exist through noise measurements.Show Notes: http://frontiers.physicsfm.com/57

Jim and Randy discuss the measurements of the anomalous magnetic moment of the muon and some of the ways in which the discrepancy between theory and experiment could manifest themselves in new physics.Show Notes: http://frontiers.physicsfm.com/56

Jim and Randy discuss the rationales for multiverses based on quantum mechanics, string theory, and the anthropic principle.Show Notes: http://frontiers.physicsfm.com/55

Randy and Jim talk about the strange results of the ANITA experiment: tau neutrinos that seem to come up out of the Earth.Notes: http://frontiers.physicsfm.com/54

Randy tells Jim about ways in which electromagnetism reduces the gravitational attraction caused by a body.

Jim and Randy discuss the hypothesis of sterile neutrinos, neutrinos that are even more ghostly than neutrinos that are dark matter candidates.

Jim and Randy talk about gravitational waves.

Jim and Randy discuss a possible "fifth force," the hypothetical X17 particle that has been seen in several experiments. Erratum: The g-2 of the muon was shown to be off by 1 part in 500,000 in 2001 at Brookhaven. It may not be in there, I'm not sure how much of that I cut out.Show Notes: http://frontiers.physicsfm.com/50

Jim and Randy discuss the apparent creation of quanta seen by comparing the viewpoints of relatively accelerating observers -- the Unruh Effect. (There is a little noise that shows up on Randy's track half way through - I did my best)Show Notes: http://frontiers.physicsfm.com/49(links to papers, podcasts, and more!)

Randy introduces Jim to the Gertsenshtein effect, the conversion of gravitational waves to electromagnetic waves through resonances.Show Notes: http://frontiers.physicsfm.com/48

Randy introduces Jim to Sabine Hossenfelder's bimetric theory of gravity. In this gravitational theory, there are two types of matter whose only interaction is through gravitation. However, each one reacts to space-time differently, resulting in different metric tensors for each. In low-curvature situations, this creates a kind of anti-gravitation.Show Notes: http://frontiers.physicsfm.com/47

Randy and Jim discuss experiments that purport to show that there is no such thing as objective reality.Show Notes: http://frontiers.physicsfm.com/46

Jim and Randy discuss loop quantum gravity, and integration of quantum mechanics and gravity that quantizes space-time itself through the use of uncertain quanta of volumes and the random connections between them.

Jim and Randy discuss experiments that put a minimum superluminal speed of communication between parts of a wavefunction.Show Notes: http://frontiers.physicsfm.com/44