The Octonions

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Recorded: 10/20/2018 Released: 12/23/2018

Randy tells Jim about the octonions, a cousin to the complex numbers in eight dimensions that Cohl Furey has made some headlines with by categorizing elementary particles with them. By looking at, basically, stable sets in the octonions, she has found representations that act like the elementary particles, and found ways to characterize some of their parameters, e.g., the charge, with them.
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Notes:

1. The papers we read for this program:

• Furey, C., "Unified Theory of Ideals" Phys Rev D 86, 025024 (2012). [Free]
• Furey, C, "Three Generations, Two Unbroken Gauge Symmetries, and One Eight-Dimensional Algebra" Phys Lett B 785, 84 (2018). [Free] [Supplement]

2. Related Papers:

• Furey, C., "Standard Model Physics from an Algebra" PhD. Thesis.
• Baez, J., "The Octonions." Bull. Amer. Math. Soc. 39 145 (2002).
• The Quanta magazine article that got Randy interested.

3. Related Episodes of Physics Frontiers:

• Physics Frontiers 35: The String Theory Landscape
• Physics Frontiers 30: The Consistent Histories Interpretation of Quantum Mechanics

4. Books mentioned in this podcast:

• Crowe, Michael, A History of Vector Analysis. A little bit dry, but a third of the book is about Hamilton and the quaternions.
• Whitehead, A.N., Process and Reality. If you think you're smart, try this.
• Fano and Fano, Physics of Atoms and Molecules. Lots of perturbations. That's what I remember.

5. John Baez' webpage for all things octonion.

6. Cohl Furey's video series on the octonions and the standard model.

6. 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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Negative Effective Mass

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Recorded: 9/29/2018 Released: 12/9/2018

Randy introduces Jim to gravitational effects on quasiparticles in materials. The inertial quality of the mass of a quasiparticle gets modified by the lattice, giving rise to an effective mass in the material. But how does the effective mass behave when confronted with a gravitational field?
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Notes:

1. The papers we read for this program:

• Raum, K., M. Weber, R. Gahler, and A. Zeilinger, "Gravity and inertia in neutron crystal optics and VCN interferometry" J Phys Soc Jpn 65, 227 (1996). [Free]
• Wimmer, M., A. Regensburger, C. Bersch, M.-A. Miri, S. Batz, G. Onishchukov, D.N. Christodoulides, and U. Peschel, "Optical Diametric Drive Acceleration through Action-Reaction Symmetry Breaking" Nature Physics 9, 780 (2013). [Free] [Supplement]

2. Related Papers:

• Coletta, R., A.W. Overhauser, and S.A. Werner, "..." Phys Rev Lett 34 1472 (1975).
• Raum, K., M.Koellner, A. Zeilinger, M. Arif, and R. Gahler, "Effective Mass Enhanced Deflection of Neutrons in Noninertial Frames" Phys Rev Lett 74, 2859 (1995). [Free]
• Bondi, H. "Negative Mass in General Relativity," Rev Mod Phys 29 423 (1957)
• Foreward, R.L., "Negative Matter Propulsion", J Prop Power 6 28 (1990) .
• I'm saving this for later.

2. Related Episodes of Physics Frontiers:

We referenced a lot of old episodes in this one:

• Physics Frontiers 31: The Parameterized Post-Newtonian Framework
• Physics Frontiers 29: Gravitational Alternatives to Dark Energy
• Physics Frontiers 25: Gravitational Field Propulsion
• Physics Frontiers 23: Dark Energy
• Physics Frontiers 22: Weyl and Quasiparticles
• Physics Frontiers 13: Exotic Photon Trajectories in Quantum Mechanics
• Physics Frontiers 6: General Relativity for the Experimentalist

Don't bother looking for our discussion of Manu Paranjape's essays on the "possibility of generating an negative effective mass in space-time" in the episode entitled "The Positive Energy Theorem." We're working on getting those up, but there's a content issue that we may not be able to resolve.

3. Books mentioned in this podcast:

• I mentioned that some of this is textbook stuff, when Jim Napolitano finished J.J. Sakurai's Modern Quantum Mechanics, he included he discusses Colletta, Overhauser and Werner's gravity induced phase changes that can be measured through interferometry. Somewhere Napolitano writes that he includes these interesting tidbits because he is an experimentalist and thinks it's helpful for understanding. I just know they're fun. Be advised that, although it's not as heavy going as Cohen-Tannoudji (which, thanks only to the psychic trauma induced by graduate school, I somehow spelled right), is a graduate level quantum mechanics textbook. Just a very well written one.

4. You can watch Martin Tejmar's talk at the 2016 breakthrough propulsion workshop put on by the Space Studies Institute

5. Martin Tejmar's group at TU-Dresden, and his publications page.

6. 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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