Sunday, October 26, 2025
Do Aliens Speak Physics with Daniel Whiteson
I will be unable to provide more detailed links for a few days:
Whiteson, Daniel, Do Aliens Speak Phyiscs?. Norton (2025).[Amazon]
Daniel and Kelly's Extraordinary Unvierse
I was having some problems with Audacity, and I don't think they showed up here, but if you're listening and you hear me cussing out the computer, please let me know with a time stamp.
Tuesday, September 30, 2025
Quantum Random Access Memory with Koustubh Phalak
| ← Previous ( Emergent Histories ) | |
Recorded: 2025/01/08 Released: 2025/09/30
Jim talks with Koustubh Phalak about quantum random access memory (QRAM), a proposed technology that would allow the storage of quantum states in qunatum computation. Koustubh discusses quantum computing, the need for QRAM, proposed implementations of QRAM, and some of the difficulties in its implementation. ------------------------------------------- Notes: 1. The articles that we discussed for this program:
- Phalak, K., A. Chatterjee, S. Ghosh, "Quantum Random Access Memory for Dummies." Sensors 23(17), 7462 (2023) [arXiv]
2. Related Episodes of Physics Frontiers:
- Physics Frontiers 78: Quantum Machine Learning with Bruna Shinohara
- Physics Frontiers 73: Quantum Money with Jiahui Liu
| ← Previous ( Quantum Machine Learning ) | |
Sunday, February 9, 2025
Pixelated Space Time with Philip Tee
| ← Previous ( Emergent Histories ) | |
Recorded: 2024/12/19 Released: 2025/02/09
Jim talks with Philip Tee about the effects of having a pixelated space time. Phil uses doubly special relativity and quantum feild theory to explore models for spacetimes that are fundmentally discrete. Here he looks for tangible results in light bending and the Casimir effect.
------------------------------------------- Notes:
1. The articles that we discussed for this program:
- Davies, P.C.W. and P. Tee, "The Quantum Vacuum of Spacetime with a Fundamental Length." Phys. Rev. D 110 025009 (2024) [arXiv]
- Tee, P. and N. Jafari, "Fundamental length scale and the bending of light in a gravitational field." Eur. Phys. J. C 82, 571 (2022) [ arXiv ]
- Physics Frontiers 72: Born's Rule and Qunatum Gravity with Antony Valentini
- Physics Frontiers 62: Deformed Special Relativity
- Physics Frontiers 45: Loop Qunatum Gravity
- Physics Frontiers 28: Quantum Vacuum the Casimir Effect
- Physics Frontiers 8: Vacuum Fluctuations and the Casimir Effect
- Rovellio, C. and F. Vidotto, Covariant Loop Quantum Gravity, [Amazon] Cambridge (2022). This is the book I was referring to in the podcast.
- Gradshteyn, I.S. and I.M. Ryzhik Tables of Integrals, Series, and Products.[Amazon] I bought my copy used thirty-five years ago. I constantly used it, but now I almost always use Wolfram Alpha.
| ← Previous ( Quantum Machine Learning ) | |
Sunday, December 29, 2024
Emergent Decoherent Histories with Philipp Strasberg
| ← Previous ( Quantum Machine Learning ) | |
Recorded: 2024/03/19 Released: 2024/12/29
Jim talks with Philipp Strasberg
------------------------------------------- Notes:
1. The articles that we discussed for this program:
- Strasberg, P., T.E. Reinhard and J. Schindler, "First Principles Numerical Demonstration of Emergent Decoherent Histories." Phys. Rev. X 14 231402 (2024) [arXiv]
- Strasberg, P. and J. Schindler, "Shearing Off the Tree: Emerging Branch Structure and Born's Rule in an Equilibrated Multiverse." (2024) [ arXiv ]
- Everett III, H., The Many Worlds Interpretation of Quantum Mechanics. Princeton University (1956) [ Free ]
- Physics Frontiers 75: Which Theories Have a Measurement Problem? with Nick Ormrod and Vilasini Venkatesh
- Physics Frontiers 70: Path Integrals and Entanglement with Kenneth Wharton
- Physics Frontiers 30: Consistent Histories Interpretation of Quantum Mechanics
5. Books mentioned in this podcast:
- Bell, J., The Speakable and Unspeakable in Quantum Mechanics.
- Subsbury, Quantum Mechanics and the Particles of Nature.
| ← Previous ( Quantum Machine Learning ) | |
Tuesday, September 3, 2024
Primordial Black Holes with Elba Alonso-Monsalve and David Kaiser
| ← Previous ( Quantum Machine Learning ) | |
Recorded: 2024/07/03 Released: 2024/09/03
Jim talks with Elba Alonso-Monsalve and David Kaiser about the prospects of a class of primordial black holes as a candidate for dark matter. These tiny black holes form just after the inflationary epoch when it is possible for them to form from inhomogeneities wihtout a prior history as a star. Black holes forming during this time time-frame would not have to be color neutral as baryons and mesons are.
------------------------------------------- Notes:
1. The articles that we discussed for this program:
- Alonso-Monsalve, E. and D.I. Kaiser, "Primordial Black Holes with QCD Color Charge." Phys. Rev. Lett. 132 231402 (2024) [arXiv]
- Alonso-Monsalve, E. and D.I. Kaiser, "Debye Screening of Non-Abelian Plasmas in Curved Spacetimes." Phys. Rev. D 108 125010 (2023) [ arXiv ]
- De Swart, J., "How Dark Matter Came To Matter." Nature Astronomy 1 0059 (2017) . [ Free
- One of Dave's books I particularly liked: Drawing Theories Apart
- Dave's OCW lectures on YouTube - Einstein, Oppenheimer, Feynman: Physics of the 20th Century.
- Physics Frontiers 71: Inflation and the Primordial Graviton Background with Sunny Vagnozzi
- Physics Frontiers 69: The Flavor Puzzle with Joe Davighi
- Physics Frontiers 57: Quantum Effects and Gravitational Waves
- Physics Frontiers 51: Gravitational Wave Astronomy
- Physics Frontiers 31: The Parameterized Post-Newtonian Framework
- Physics Frontiers 10: Requirements for Gravitational Theories
| ← Previous ( Quantum Machine Learning ) | |
Friday, May 31, 2024
Quantum Machine Learning with Bruna Shinohara
| ← Previous ( Maxwellian Ratchets ) | |
Recorded: 2024/02/16 Released: 2024/05/31
Jim talks with Bruna Shinohara about quantum machine learning.
------------------------------------------- Notes:
1. The article that we discussed in this program:
- Biamonte, J. P. Wittek, N. Pancotti, P. Rebentrost, N. Wiebe, S. Lloyd, "Quantum Machine Learning." Nature 549 195 (2017) [arXiv]
- Wang, Y., "When Quantum Computing Meets Data Science." [ Free ]
- Schuld, M. and N. Killoran, "Is Quantum Advantange the Right Goal for Quantum Machine Learning?." PRX 3 030101 (2022) [ arXiv ]
- Aaronson, Scott, "Read the Fine Print." Nature Physics 11 211 (2015). [ Free
- I'll ask Bruna to send me a link to the large QML article she talked about in the podcast.
- Physics Frontiers 73: Quantum Money with Jiahui Liu
- Physics Frontiers 64: Born's Rule with Blake Stacey
| ← Previous ( Maxwellian Ratchets ) | |
Sunday, March 31, 2024
Maxwellian Ratchets with Alex Jurgens
| ← Previous ( Undecidability & TOES ) | |
Recorded: 2023/12/18 Released: 2024/03/31
Jim talks with Alex Jurgens of INRIA about Maxwellian Ratchets. These are abstract machines that react to outside stimuli, These are highly specified theoretical realizations of Maxwell's Demon, who flaunts the second law of thermodynamics. Jurgens discusses these in terms of entropy, information processessing, and the second law.
------------------------------------------- Notes:
1. The article that we discussed in this program:
- Kiefer, Claus, "Functional Thermodynamics of Mawellian Ratchets: Constructing and Deconstructing Patterns, Randomizing and Derandomizing Behaviors." Phys. Rev. Research 2 033334 (2020) [arXiv]
- Physics Frontiers 74: Maxwellian Ratchets with David Wolpert
- Physics Frontiers 68: Qunatum Resource Theories with Gilad Gour
- The Road to Maxwell's Demon, Meir Hemmo and Orly R. Shenker. Claus' book on quantum gravity. 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 ( Undecidability & TOES ) | |
Sunday, January 28, 2024
Undecidability and Theories of Everything with Claus Kiefer
| ← Previous ( Measurement Problem ) | |
Recorded: 2023/08/07 Released: 2024/01/28
Jim talks with Claus Kiefer about his recent essay on the relationship between the Gödel's incompleteness theoerems and the possibility of developing a theory of everything. Incompleteness was originally developed to show that every axiomatic system that is sufficiently robust admits well-formed statements that have a liar's paradox-like structure - if you assume the statement is true, you can prove it's false, and vice-versa. This statement is then said to be undecidable. Undecidability also famously comes up in the halting problem of computer science and the continuum hypothesis. Professor Kiefer speculates here that theories of everything are similarly undecidable.
------------------------------------------- Notes:
1. The article that we discussed in this program:
- Kiefer, Claus, "Gödel's undecidability theorems and the search for a theory of everything" (2023) [arXiv]
- Cubitt, T.,D. Perez-Garcia and H.M. Wolf, "Undecidability of the Spectral Gap." Nature 528 207 (2015) [arXiv]
- Goedel,, K., "On Formally Undecidable Propositions of Principia Mathematica and Related Systems." Monatshefte für Mathematik und Physik 38 173 (1931) [Free]
- The Undecidable [Amazon], M. Davis, ed. Reprints Goedel's paper and other work from the 1930's. Dover book.
- Physics Frontiers 69: The Flavor Puzzle with Joe Davighi
- Physics Frontiers 62: Deformed Special Relativity
- Physics Frontiers 45: Loop Quantum Gravity
- Physics Frontiers 35: The String THeory Landscape.
- Quantum Gravity, 3rd. Ed., Claus Kiefer. Claus' book on quantum gravity.
- The Physical Basis of the Direction of Time, H. Dieter Zeh. Excellent book going over how the arrow of time might be directed via different aspects of physics. Video Review
- The Undecidable [Amazon], M. Davis, ed. Reprints Goedel's paper and other work from the 1930's. Dover book.
- The Character of Physical Law, Richard Feynman
- Road to Reality, Roger Penrose
- Non Standard Analysis, Abraham Robinson or Applied Non-Standard Analysis, Martin Davis. Two books on non-standard analysis. Despite The Undecidable and Applied Non-Standard Analysis being about 6" from each other on my bookshelves for at least a decade, I didn't make the connection that the editor of the first was also the author of the second until this moment.
- Goedel, Escher, Bach, D. Hofstadter.
| ← Previous ( Measurement Problem ) | |
Sunday, August 20, 2023
The Measurement Problem with Nick Ormrod and V. Vilasini
| ← Previous ( Stochastic Thermodynamics ) | |
Recorded: 2023/07/17 Released: 2023/08/20
Jim talks with Nick Ormrod and V. Vilasini about their use of categorical probability theory to study the measurement problem of quantum mechanics. They use the CPT to analyze a no-go theorem to see where there are weaknesses in the underlying structure of quantum mechanics without referring to particular mathematical formualtions of the subject, allowing them to show that the measurement problem comes from difficulties in our understanding of the evolution of quantum states or the way we interpret measurements.
------------------------------------------- Notes:
1. The article that we discussed in this program:
- Ormrod, N., V. Vilasini, and J. Barrett, "Which Theories Have a Measurement Problem?" (2023) [arXiv]
- N. Ormrod and J. Barrett, "A No-Go Theorem for Absolute Observed Events Without Inequalities or Modal Logic." [arXiv]
- V. Vilasini and M. P. Woods, "A General Framework for Consistent Logical Reasoning in Wigner's Friend Scenarios: Subjective Perspectives of Agents Within a Single Quantum Circuit." [arXiv]
- Maudlin, T., "Three Measurement Problems." Topoi 14 7 (1995).
- Physics Frontiers 46: Wigner's Friend
- Physics Frontiers 44: Spooky Action at a Distance
- Physics Frontiers 30: The Consistent Histories Interpretation of Quantum Mechanics
- Physics Frontiers 2: The de Broglie-Bohm Interpretation of Quantum Mechanics
| ← Previous ( Stochastic Thermodynamics ) | |
Sunday, July 9, 2023
Stochastic Thermodynamics with David Wolpert
| ← Previous ( Quantum Money ) | |
Recorded: 2023/05/10 Released: 2023/07/09
Jim talks with David Wolpert about the stochastic thermodynamics of compuation. The discussion focuses on recent developments in the relationship between non-equilibrium processes and information processing, having deep implications on how we view the world and how we apply statistical physics to biological, computational, and other systems.
------------------------------------------- Notes:
1. The articles that we discussed in this program:
- Tasmin, F., N. Fuentes, and D. Wolpert, "The Fundamental Thermodynamic Costs of Communications." (2023) [arXiv]
- Wolpert, D., "Minimal Entropy Production of Interacting Systems." New Journal of Physics 22 113013 (2020) [arXiv]
- Wolpert, D., "The Stochastic Thermodynamcis of Computation." J. Phys. A: Math. Theor. 52 193001 (2019). [arXiv] (Review Article)
- Landauer, R., "Irreversibility and the Heat Generation in the Computing Process" (IEEE Reprint). IBM J. Res. Dev. 5 283 (1961).[Free] [see 4]
- Bennett, C.H., "Logical Reversibility of Computation." IBM J. Res. Dev. 17 525 (1973). [Free] [see 4]
- Sagawa, T., "Thermodynamic and Logical Reversibilities Revisited." J. Stat. Mech. 2014 P03025 (2014).[arXiv]
- Parrondo, J.M.R/, J. M. Horowitz, and T. Sagawa, "Thermodynamics of Information." Nature Physics 11, 131 (2015). 3. Related Episodes of Physics Frontiers:
- Physics Frontiers 68: Quantum Resource Theories
- Physics Frontiers 16: Stochastic Resonance Energy Harvesting
| ← Previous ( Quantum Money ) | |
Sunday, June 18, 2023
Quantum Money with Jiahui Liu
| ← Previous ( Born Rule and Gravity ) | |
Recorded: 2023/03/28 Released: 2023/06/18
Jim talks with Jiahui Liu about quantum money. Quantum Money is a key milestone in quantum crytography -- not for the breaking of codes (e.g., Shor's algothrithm), but instead for using quantum computing to improve cryptography beyond what is possible in classical cryptography. The difficulty is, however, a fully satisfactory way to implement quantum money is not currently known. Jiahui discusses both how to show that a possible implementation doesn't work, and how she developed another scheme to implemet quantum money. She also discusses the history of quantum money and some of the things quantum crytographers can do once they have a reliable quantum money scheme.
------------------------------------------- Notes:
1. The articles that we discussed in this program:
- Liu, J., H. Montogomery, and M. Zhandry, "Another Round of Breaking and Making Quantum Money: How to Not Build It from Lattices, and More." in Advances in Cryptography - EUROCRYPT2023 Lecture Notes in Computer Science 14004 611 (2023) [arXiv]
3. 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 Rule and Gravity ) | |
Sunday, April 23, 2023
The Born Rule and Gravity with Antony Valentini
| ← Previous ( Graviton Background ) | |
Recorded: 2023/03/03 Released: 2023/04/23
Jim talks with Antony Valentini about the status of the Born Rule in quantum gravity. In particular, it doesn't work. Since the wavefunction cannot be normalized in quantum gravity, there is no way to interpret Ψ as the knowledge of the observer about the quantum system. Instead, some realist interpretation of the wavefunction is required. In this regard, Jim and Anotony also discuss the de Broglie-Bohm interpretation in light of quantum gravity.
------------------------------------------- Notes:
1. The articles that we discussed in this program:
- Valentini, A., "Beyond the Born Rule in Qunatum Gravity." Found. Phys. 53, 6 (2023) [arXiv]
- Valentini, A., "Beyond the Quantum." Physics World 22, 32 (2009) [arXiv]
- Valentini, A., "Quantum Gravity and Quantum Probability." (2021) [arXiv]
- Kiefer, C. and T. Singh, "Quantum Gravitational Ccorrections to the Functional Schrödinger Equation." Phys. Rev. D 44 1067 (1991).
- Kiefer, C. and P. Peter, "Time in Quantum Cosmology." Universe 8 36 (2022). [arXiv].
- Bohm, D. "A Suggested Interpretation of Quantum Theory in Terms of 'Hidden' Variables I." Phys. Rev. 85, 166 (1952).
- Bohm, D. "A Suggested Interpretation of Quantum Theory in Terms of 'Hidden' Variables II." Phys. Rev. 85, 180 (1952).
- Holland, P. R., The Quantum Theory of Motion: an Account of the de Broglie-Bohm Causal Interpretation of Quantum Mechanics. Cambridge, 1993. [Amazon]
- Anderson, E., The Problem of Time: Quantum Mechanics Versus General Relativity. Springer, 2017. [Amazon]
- Valentini, A., "The Born Rule Unstable in Quantum Gravity." Perimeter Institute, February 15th, 2018.>
- Valentini, A., "Quantum Gravity and Quantum Probability." Quantum Limits of Knowledge Conference, 2021.
- Physics Frontiers 71: The Primordial Graviton Background
- Physics Frontiers 64: Teh Born Rule
- Physics Frontiers 51: Gravitational Wave Astronomy
- Physics Frontiers 2: The de Broglie-Bohm Interpretation of Quantum Mechanics
| ← Previous ( Graviton Background ) | |
Sunday, February 19, 2023
The Primordial Graviton Background with Sunny Vagnozzi
| ← Previous ( Path Integrals ) | |
Recorded: 2022/12/01 Released: 2023/2/19
Jim talks with Sunny Vagnozzi of the University of Trento about a way to disprove inflationary theories of cosmology. All of them. If we were able to see a Primordial Graviton Background, which is the graviational equivalent to the cosmic microwave background, then we would know that there was no inflation. The event that would create the graviton background would have to occur before cosmic inflation started, and inflation would smooth it out. And the background would disappear.
------------------------------------------- Notes:
1. The article that we discussed in this program:
- Vagnozzi, S. and A. Loeb, "The Challenge of Ruling Out Inflation via the Primordial Graviton Background." ApJL 939, L22 (2022) [arXiv]
- Physics Frontiers 59: The Hubble Crisis
- Physics Frontiers 57: Quantum Effects in Gravitational Waves
- Physics Frontiers 51: Gravitational Wave Astronomy
- Physics Frontiers 48: The Gertsenstein Effect
| ← Previous ( Path Integrals ) | |
Sunday, December 18, 2022
Path Integrals and Entanglement with Kenneth Wharton
| ← Previous ( Flavor Puzzle ) | |
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:
- Wharton, K. and R. Liu, "Entanglement and Path Integrals." Foundations of Physics 53, 23 (2023) [arXiv]
- Tyagi, N. nad K. Wharton, "Spacetime Path Integrals for Entangled Staes." Foundations of Physics 52 9 (2022) [arXiv]
- Wharton, K., "Towards and Realistic Parsing of the Feynman Path Integral." Quanta 5, 1 (2016). [arXiv]
- Price, H. and K. Wharton, "Entanglement Swapping and Action at a Distance." Foundations of Physics, 51 105 (2021) [arXiv]
- Sorkin, R., "Quantum Mechanics as Quantum Measure Theory." Mod. Phys. Lett. 9 3119 (1994) [arXiv].
- 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]).
- Physics Frontiers 65: Time and Causality.
- Physics Frontiers 46: Wigner's Friend
- Physics Frontiers 44: Spooky Action at a Distance
- Physics Frontiers 33: Retrocausality
- Physics Frontiers 30: The Consistent Histories Interpretation of Quantum Mechanics
- Physics Frontiers 13: Exotic Photon Trajectories in Quantum Mechanics
| ← Previous ( Flavor Puzzle ) | |
Sunday, November 20, 2022
Flavor Unification with Joe Davighi
| ← Previous ( Resource Theories ) | |
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:
- Davighi, J., "Gauge Flavor Unification fron the Flavour Puzzle to Stable Protons." [arXiv]
- Davighi, J. and J. Tooby-Smith, "Electroweak Flavour Unification." JHEP 2022 193 (2022) [arXiv]
- Dahivghi, J., A. Greljo, and A.E. Thomsen, "Leptoquarks with Exactly Stable Protons." Phys. Lett. B 833, 137310 (2022). [arXiv]
- Physics Frontiers 58: The Higgs Portal.
- Physics Frontiers 52: Sterile Neutrinos
- Physics Frontiers 50: Sterile Neutrinos
- Physics Frontiers 35: The String Theory Landscape Theorem
| ← Previous ( Resource Theories ) | |
Sunday, September 25, 2022
Quantum Resource Theories with Gilad Gour
| ← Previous ( Optical Gravity ) | |
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:
- Gour, G. "On the Role of Quantum Coherence in Thermodynamics" (2022) [arXiv]
- Chitambar, E., and G. Gour, "Quantum Resource Theories." Rev. Mod. Phys. 91, 025001 (2019). [arXiv]
- Physics Frontiers 62: Deformed Special Relativity.
- Physics Frontiers 57: Quantum Effects in Gravity Waves
- Physics Frontiers 53: The Positive Energy Theorem
| ← Previous ( Optical Gravity ) | |
Sunday, August 14, 2022
Optical Gravity with Matthew R. Edwards
| ← Previous ( Limits of GR ) | |
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:
- Edwards, Matthew R., "Optical Gravity in a Graviton Spacetime" Optik 260, 169059 (2022) [arXiv]
- Mansuripur, M., "Radiation Pressure and the Linear Momentum of the Electromagnetic Field." Opt. Express 12, 5375 (2004) [arXiv]
- Mansuripur, M., ", Resolution of the Abraham–Minkowski controversy." Opt. Comm. 283, 1997 (2010) [arXiv]
- Mansuripur, M., ", Resolution of the Abraham–Minkowski controversy." Opt. Comm. 283, 1997 (2010) [arXiv]
- Physics Frontiers 62: Deformed Special Relativity.
- Physics Frontiers 57: Quantum Effects in Gravity Waves
- Physics Frontiers 53: The Positive Energy Theorem
- 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
| ← Previous ( Limits of GR ) | |
Sunday, June 26, 2022
Limit of General Relativity with James Owen Weatherall
| ← Previous ( Causality and Time ) | |
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]
- Defermos, M. and Luk, J., “The Interior of Dynamical Black Holes I: The C0 Stability of the Kerr Cauchy Horizon.” Pure Appl. Analysis 1, 263 (2019). [arXiv]
- Physics Frontiers 62: Deformed Special Relativity.
- Physics Frontiers 57: Quantum Effects in Gravity Waves
- Physics Frontiers 53: The Positive Energy Theorem
- Physics Frontiers 45: Loop Quantum Gravity
- Physics Frontiers 38: Why Is Space-Time Four Dimensional?
- Physics Frontiers 27: The Gravitational Equivalence Principles
- Physics Frontiers 17: The Physics of Time Travel
| ← Previous ( Causality and Time ) | |
Sunday, May 22, 2022
Causality, Time and the Experiment Paradox
| ← Previous ( Born's Rule ) | |
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:
- Eckstein, M. and M. Heller, "Causality and Time Order -- Relativistic and Probabilistic Aspects." (2022) [arXiv]
- Eckstein, M. and P. Horodecki, “The Experiment Paradox in Physics.” Foundations of Science 27, 1 (2020). [arXiv]
- Eckstein, M., P. Horodecki, R. Horodecki, and T. Miller, "Operational Causality in Spacetime" Phys. Rev. A 101 042128 (2020). [arXiv]
- 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]
- Physics Frontiers 62: Deformed Special Relativity.
- Physics Frontiers 46: Wigner's Friend
- Physics Frontiers 45: Loop Quantum Gravity
- Physics Frontiers 44: Spooky Action at a Distance
- Physics Frontiers 38: Why Is Space-Time Four Dimensional?
- Physics Frontiers 33: Retrocausality
- Physics Frontiers 30: The Consistent Hisotories Interpretation of Quantum Mechanics
- Physics Frontiers 27: The Gravitational Equivalence Principles
- Physics Frontiers 17: The Physics of Time Travel
- Physics Frontiers 12: A Gravitational Arrow of Time
- Physics Frontiers 9: f(R) Theories of Gravity
| ← Previous ( Born's Rule ) | Sunday, April 24, 2022Born's Rule
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:
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