Sunday, December 9, 2018

Negative Effective Mass

<-- Previous (Space-Time Dimensions) (Octonions) Next -->


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?
-------------------------------------------

Notes:

1. The papers we read for this program:

2. Related Papers:

2. Related Episodes of Physics Frontiers:

We referenced a lot of old episodes in this one:

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 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.

<-- Previous (Space-Time Dimensions) (Octonions) Next -->

Sunday, November 25, 2018

The Dimensionality of Space Time

<-- Previous (Einstein-Cartan Theory) (Negative Effective Mass) Next -->


Recorded: 9/8/2018 Released: 11/25/2018

Jim and Randy discuss why space-time is four dimensional. Much of what they discuss is anthropic in nature: what sort of universe can we exist in? But they also discuss the stability of orbits, the predictability of nature, and so on, all of which constrain the universe to have three (3) macroscopic dimensions of space and one of time (or one of space and three of time, but that's not us).
-------------------------------------------

Notes:

1. The papers we read for this program:

2. Other papers mentioned in this program:

3. Related Episodes of Physics Frontiers:

4. Books mentioned in the podcast:
  • Tegmark talked about results discussed in Gravitation by Misner, Thorne and Wheeler. This is a standard text in the field, which I'm sad to say I never picked up. Although I did order a copy last week, and its on its way to my office right now.
  • After recording the podcast, I decided I needed to look a little deeper at partial differential equations. I failed because I started reading Partial Differential Equations for Scientists and Engineers by Farlow. The presentation is very practical, not theoretical, so it doesn't address the problems in this podcast directly. However, the methods used in the text seem to directly contradict the general discussion in Tegmark (since every problem is both an initial value problem and a boundary value problem, simultaneously). I haven't worked my way through it, so maybe I'll change my mind, but not at present. I have fallen in love with the presentation. I think that if you'd like to learn to solve PDEs and have a sufficient background, this is the book for you (because this book makes me feel smart).

5. 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.

<-- Previous (Einstein-Cartan Theory) (Negative Effective Mass) Next -->

Monday, October 29, 2018

The Einstein-Cartan Torsion Field Theory

<-- Previous (Metamaterial Stress Tensor) (Space-Time Dimension) Next -->


Recorded: 6/10/2018 Released: 10/29/2018

Randy explains some recent developments in the Einstein-Cartan torsion field to Jim. This theory introduces at least one tensor field representing the intrinsic angular momentum at a space-time point, and was originally intended to remove singularities from general relativity.
-------------------------------------------

Notes:

1. The papers we read for this program:

2. My review of Will's book. This paper serves as something of an update of it. A true update is scheduled to come in December 2018.

3. Related Episodes of Physics Frontiers:

4. Contact Randy at randy@physicsfm.com to take him up on his offer. Actually, I don't know if those e-mail redirects really work. I set them up some time ago, but I've never seen anything come in from them.

5. 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.

<-- Previous (Metamaterial Stress Tensor) (Space-Time Dimension) Next -->

Sunday, October 14, 2018

Metamaterial Stress Tensor

<-- Previous (String Theory Landscape) (Einstein-Cartan Theory) Next -->


Recorded: 5/26/2018 Released: 10/14/2018

Randy tells Jim about advances in the stress-momentum tensor of electrodynamics. This tensor can be integrated over the boundary of an object to describe the force on it from the magnetic field. It is closely related to the momentum carried in the electromagnetic field, and its proper formulation in materials has been the subject of debate for over a hundred years.
-------------------------------------------

Notes:

1. The papers we read for this program:

2. Our Patreon backers can see the Table of Stress Tensors I made for the podcast.

3. Other papers mentioned:

I found these papers useful for this program:

4. Books mentioned in this podcast:

  • J.D. Jackson's Classical Electromagnetism, discusses the Maxwell stress tensor twice: in a discussion about of conservation laws in macroscopic media (pp 239-40) and then in a discussion about forces in special relativity (pp 602-607). Page numbers from my copy of the 2nd edition.
  • Landau & Lifshitz' Electrodynamics of Continuous Media goes into more depth on how the stress tensor is derived. Beyond being one of my favorite books in grad school, the entire series is classic.
  • M. Schwartz' Principles of Electrodynamics (available from Dover, probably because of Schwartz' Nobel Prize, not because its great exposition (which it has)) uses the electromagnetic stress tensor repeatedly in different contexts and problems that gives you a good idea of what it actually means.
  • U. Leonhardt and T. Philbin's Geometry and Light: The Science of Invisbility is an excellent technical book of the use of the mathematics of general relativity in optics. This includes the optical analogue of black holes and the photonic Aharonov-Bohm effect.
5. Related Shows:


8. Randy mentions Harry Reid's Advanced Aerospace Threat Identification Program (AATIP) program, a government UFO program funded from 2007 to 2014. It was run by Luis Elizondo, who Randy mentions in the podcast. Randy says he was directed to this topic by a discussion that Joe Rogan had with Thomas DeLonge who funds AATIP's private successor, To the Stars Academy. Although they focused on things that were out in left field (Harry Reid says he met his wife on a UFO, but no one believed him), you can see from this list that they funded some good research as well (such as Ulf Leonhardt's (see above) and Maxim Tsoi's in spintronics). I didn't count, but it looked to be about a sixth solid research, a sixth reasonable research, as sixth fringy stuff, and a half to EarthTech International.

7. 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.

<-- Previous (String Theory Landscape) (Einstein-Cartan Theory) Next -->

Friday, September 21, 2018

The String Theory Landscape

<-- Previous (CPT Symmertry and Gravitation) (Metamaterial Stress Tensor) Next -->


Recorded: 5/12/2018 Released: 9/21/2018

Jim and Randy explore the landscape of string theory, an idea put forward by Leonard Susskind about how to interpret the cornucopia of universes possible in string theory.

-------------------------------------------

Notes:

1. The papers we read for this program:
  • Susskind, L., "The Anthropic Landscape of String Theory" in Carr, Bernard (ed.), Universe or Multiverse? (Cambridge, 2009), 247-266. [arXiv]
  • Susskind, L., "Supersymmetry Breaking in the Anthropic Landscape" in Shifman, Vainshtein, and Wheater (eds.) From Fields to Strings: Circumnavigating Theoretical Physics (World Scientific, 2005). 1745-1749. [arXiv]
2. Books mentioned in this podcast:

3. Previous shows mentioned in this podcast:.



4. Related Shows:

5. 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.

<-- Previous (CPT Symmertry and Gravitation) (Metamaterial Stress Tensor) Next -->

Friday, August 10, 2018

CPT Symmetry and Gravitation

<-- Previous (Retrocausality) (The String Theory Landscape) Next -->


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.

-------------------------------------------

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.

<-- Previous (Retrocausality) (The String Theory Landscape) Next -->

Wednesday, July 25, 2018

Retrocausality

<-- Previous (Tunneling Time) (CPT Symmetry and Gravitation) Next -->


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.

-------------------------------------------

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. A popular book I recently read on the de Broglie-Bohm interpretation and endorsing non-locality is Jean Bricmont's Quantum Sense and Nonsense.

5. 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.

<-- Previous (Tunneling Time) (CPT Symmetry and Gravitation) Next -->

Friday, July 6, 2018

Tunneling Time

<-- Previous (Post-Newtonian Gravity) (Retrocausality) Next -->

(Retrocausality)
Recorded: 11/25/2017 Released: 7/6/2018

Jim and Randy discuss the tunneling time problem: just how long does quantum tunneling take? No definitive answer to this question exists, but people have been trying to answer it for at least eighty years -- with answers that span from instantaneous to subluminal. In this episode, we discuss several different ideas and how experiments at ETH-Zürich have helped clarify the issue.

-------------------------------------------

Notes:

1. The papers we read for this program:
2. The group responsible for the attoclock measurements at ETH-Zürich, including Landsman and Keller.

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.

<-- Previous (Post-Newtonian Gravity) (Retrocausality) Next -->

Friday, June 8, 2018

The Parameterized Post-Newtonian Framework

<-- Previous (Consistent Histories) (Tunneling Time) Next -->


Recorded: 11/12/2017 Released: 6/8/2018

Randy and Jim discuss the Parameterized Post-Newtonian Framework, a generalized way to compare metric theories of gravity to experiment in a standardized way. In this episode we discuss several theories of gravity and how they hold up under the light of experimental data.

-------------------------------------------

A Guide to the Parameters


  • γ (gamma) - Coupling of matter to curvature, GR = 1 , Newton = 0
  • β (beta) - Linearity of superposition, GR = 1 - Superposition linear
  • ξ (xi) - Preferred location effects, GR = 0 - Spatially homogeneous
  • α1 (alpha) - Preferred frame effects, GR = 0 - Lorentz invariant
  • α2 (alpha) - Preferred frame effects, GR = 0 - Lorentz invariant
  • α3 (alpha) - Preferred frame effects, GR = 0 - Lorentz invariant
  • ζ1 (zeta) - Momentum changes, GR = 0 - Momentum conserved
  • ζ2 (zeta) - Momentum changes, GR = 0 - Momentum conserved
  • ζ3 (zeta) - Momentum changes, GR = 0 - Momentum conserved
  • ζ4 (zeta) - Momentum changes, GR = 0 - Momentum conserved


-------------------------------------------

Notes:

1. The paper we read for this program (only sections 3 and 4):
2. My review of Will's book. This paper serves as something of an update of it. A true update is scheduled to come in December 2018.

3. Related Episodes of Physics Frontiers:

4. If you have any information about good packages for numerical relativity for Randy, please leave them in the comments.

5. 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.

<-- Previous (Consistent Histories) (Tunneling Time) Next -->

Thursday, May 24, 2018

The Consistent Histories Interpretation of Quantum Mechanics

<-- Previous (Alternatives to Dark Energy) (Post-Newtonian Gravitation) Next -->


Recorded: 10/29/2017 Released: 5/24/2018

Jim and Randy investigate the Consistent Histories interpretation of quantum mechanics. This highly logical interpretation was conceived of by Robert Griffiths and is based on bundling possible histories for a particle together and only using those histories that are consistent with the measurements we perform to winnow out the possible states of the particle. Although Griffiths calls this "Copenhagen done right," the interpretation is based on the idea the quantum particles have definite values for observables in the intervening space.

-------------------------------------------

Notes:

1. The papers we read for this program:

2. Griffith's book Consistent Quantum Theory, which we mention in the podcast because he continually refers to it in his papers.

3. My review of Speakable and Unspeakable in Quantum Mechanics by John Bell, which includes the paper in which he formulates Bell's Theorem -- the testable version of the EPR Paradox, which is based on the first tractable formulation of the paradox by David Bohm. I also recently reviewed a book on wave function realism, which seems to be a response to a response to Bell.

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.

<-- Previous (Alternatives to Dark Energy) (Post-Newtonian Gravitation) Next -->

Tuesday, May 15, 2018

Gravitational Alternatives to Dark Energy

<-- Previous (Quantum Vacuum and the Casimir Effect) (Consistent Histories) Next -->


Recorded: 10/15/2017 Released: 5/15/2018

Jim and Randy discuss the ways in which different modified gravities mimic the observed dark energy in the universe, contra a cosmological constant hypothesis. They talk about various forms of modified gravity theories and the particles associated with their "fifth fields."

-------------------------------------------

Notes:

1. The papers we read for this program:

2. My review of Will's book, which I talk about a little too much in this podcast.

3. Related Episodes of Physics Frontiers:

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.

<-- Previous (Quantum Vacuum and the Casimir Effect) (Consistent Histories) Next -->

Tuesday, April 24, 2018

The Quantum Vacuum and the Casimir Effect

<-- Previous (Gravitational Equivalence Principles) (Alternatives to Dark Energy) Next -->


Recorded: 9/16/2017 Released: 4/24/2018

Jim and Randy review two very convincing papers that make the claim that the Casimir effect is due to materials fluctuations and not the zero point energy

-------------------------------------------

Notes:

1. The papers we read for this program:

2. We discuss an earlier episode on the Casimir Effect and van der Waals forces repeatedly in this one.

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.

<-- Previous (Gravitational Equivalence Principles) (Alternatives to Dark Energy) Next -->

Saturday, April 14, 2018

The Gravitational Equivalence Principles

<-- Previous (Antimatter Production) (Quantum Vacuum and Casimir Effect) Next -->


Recorded: 9/10/2017 Released: 4/14/2018

Jim talks to Randy about the different ways in which the equivalence principle of general relativity can be formulated. More than just the equivalence of accelerations, the different possible meanings of the equivalence principle mean different things about how gravity works. From weak to strong, from Einstein's equivalence principle to Schiff's conjecture, the implications of these theories are explored.

-------------------------------------------

Notes:

1. The papers we read for this program:

2. My review of Will's book, which I talk about a little too much in this podcast.

3. Related Episodes of Physics Frontiers:

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.

<-- Previous (Antimatter Production) (Quantum Vacuum and Casimir Effect) Next -->


--------------------------------------------

A review of "Theory of Gravitation Theories" from the arXiv_plus subreddit:

This delightfully named paper explains the relationship between the equivalence principles – the three equivalence principles listed in Will’s book: weak, Einstein, and strong – and the modified gravities that serve as competitors to general relativity (GR) with a cosmological constant in the quest to explain dark energy. The meat of the text centers around showing that a theory of gravity is a cluster of mathematical representations of that theory that are linked in an analogous way as different gauges in electromagnetism, although no general method of transformation is given, and that in order to satisfy the intermediate level of equivalence only one of these representations must satisfy the metric postulates. This ambiguity in representation is reflected in the way in which the additional fields of modified gravities are represented: whether the field is additional “matter” or a coupling that changes the “geometry” is a matter of the representation, not the theory itself.

The metric postulates simply ask a theory to (1) produce a metric gmn that describes the geometry of space-time and (2) admit only stress-energy tensors whose covariant derivative is zero. This is what you have in GR. It has been shown that the weakest version of the equivalence principle, which in its simplest form means that gravitational provides a preferred set of trajectories for small, uncharged particles to take without reference to their mass, is not, in itself, sufficient to establish these metric postulates. Instead, two other postulates are required, both self-explanatory: Local Lorentz Invariance and Local Position Invariance. These three postulates together form the Einstein equivalence principle and, along with some reasonable limitations on the mathematics, are sufficient to create a general class of metric theories of gravity with an additional scalar field (scalar-tensor theories). Each theory itself will be a cluster of the mathematical representations of the same.

One of the take-aways from this paper is that common procedures for determining if a theory satisfies EEP have made an error of checking single mathematical representations in those clusters against the metric postulates or Local Lorentz Invariance and ignoring the equivalent representations. The main example in the text compares the Jordan and Einstein frames in scalar-tensor theories, showing that they are equivalent, but the Einstein representation does not satisfy the metric postulates. However, since the Jordan frame representation of a scalar-tensor theory does satisfy the metric postulates, the theory itself does. This does, however show an issue with the frames that do not satisfy the postulates: changes need to be made in interpreting their metric tensors or geodesic equations, or even the connection in that frame. For example, in moving to the Einstein frame, you add an additional term in the geodesic equations that can be interpreted as:

(1) The gradient of the scalar field

(2) The variation of the masses of elementary particles in space

(3) Changes in the “unit of mass” along the trajectory

Although I’m not sure if (2) and (3) are the same or that the relative masses also change, making a coherent standard impossible.

Unfortunately, according to the authors, only individual mathematical representations of modified gravities exist in the literature, not more general theories that encompass the all of the representations of those theories, and so miscategorizations are likely. More unfortunately, a way forward towards a more abstract definition of individual theory clusters is not given in the text.

Sunday, March 25, 2018

Antimatter Production at a Potential Boundary

<-- Previous (Gravitational Field Propulsion) (Gravitational Equivalence Principles) Next -->


Recorded: 6/17/2017 Released: 3/25/2017

Randy discusses a proposal for the production of antimatter without using supercolliders with Jim. This proposal would have used Klein's paradox for the production of electron-positron pairs at a very sharp, steep potential boundary produced through the Casimir effect.

-------------------------------------------

Notes:

1. The paper we read for this program:

2. The NASA Institute for Advanced Concepts no longer exists (apparently it closed down in 2007), but there is now a NASA Innovative Advanced Concepts, a program with the same acronym that seems to have a similar purpose (if not, tell me the salient difference in the comments).

3. Our listenership has increased markedly since we recorded this episode last June. We had 1,057 downloads in the first fifteen days of June 2017, and in the first two weeks of March we had 3,117. In both cases there were no podcasts published during the time interval (in the current case because this is my heavy semester at work and it eats into my free time).

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.

<-- Previous (Gravitational Field Propulsion) (Gravitational Equivalence Principles) Next -->

Thursday, March 15, 2018

Gravitational Field Propulsion

<-- Previous (Island of Stability) (Antimatter Production) Next -->



Randy introduces Jim to several ways in which people have theorized that gravity can be used to propel an object through space. In order of likelihood and in inverse order of coolness:
  • The Slingshot Effect -- Using a gravitational well to increase the energy available to an object. (In use)
  • The Penrose Process -- Using a rotating black hole to gain energy. (Penrose)
  • Negative Inertia Mass -- If mass has both a negative charge and inertia, then you can build a device that moves perpetually (RL Forward)
  • Induced Gravitational Dipoles -- Spinning half of a sphere will (supposedly) propel it in some direction or other. (Jeong)
  • The Alcubierre Drive -- A process that would sneak around the laws of relativity and allow someone to travel faster than light. (Alcubierre, White)


-------------------------------------------

Notes:

1. The papers we read for this program:


2. The slingshot effect is in common use and is a topic viable at the junior mechanics level in such books as Taylor's and Morin's.

3. There is a problem defining the center of mass in general relativity, and we've recorded at least one podcast related to the topic (although not directly addressing it) between the recording of this last June and its publication in March. But the problem is with defining mass, not the center of mass. And because of the simplicity of the space-time swimmers, I'm still not sure its as much of a problem as some people do.

4. Popular articles for this program:

5. The video Randy keeps talking about in the podcast he found linking through The Hammock Physicist Blog of Johannes Koelman. You can download it here from the IOP. I haven't yet found the article IOP attached it to.

6. I'll make a video of the non-commutative motion diagrams that I sent Randy and put a link up here.

7. 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.
>
<-- Previous (Island of Stability) (Antimatter Production) Next -->

Friday, February 23, 2018

The Island of Stability

<-- Previous (Dark Energy) (Gravitational Field Propulsion) Next -->



Randy tells Jim about the Island of Stability. This is a theoretically predicted region (or two, in one calculation) where the isotopes of atoms with heavy nuclei are stable. Jim and Randy talk about the islands, how they are attempting to get there, and some of the calculations people use to predict the stability of elements. Along the way, they mispronounce a lot of words.

-------------------------------------------

Notes:

1. The papers we read for this program:
2. The book I talked about on fluids that goes into the fluid model of the nucleus is Introduction to the Physics of Fluids and Solids by James S. Trefil, which is apparently no longer in print (I have a Dover edition, I love Dover). My favorite Modern Physics text is Rohlf, mostly because of its focus on scattering, but I taught from Serway, which is more standard.


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.

<-- Previous (Dark Energy) (Gravitational Field Propulsion) Next -->

Thursday, February 8, 2018

Dark Energy

<-- Previous (Weyl and Quasiparticles) (Island of Stability) Next -->



Randy helps Jim get a handle on dark energy. Why do we need it? Why do we want to believe in it now, but didn't earlier? How many different things could it be? What does it have to do with you? How close are we to knowing anything about it?

-------------------------------------------

Notes:

1. The papers we read for this program:
  • Carroll, S., "Dark Energy and the Preposterous Universe." [arXiv]
  • Turner, M., "Dark Energy and the New Cosmology." [arXiv]
  • Zwicky, F., "On the Masses of Nebulae and Clusters of Nebulae." Astrophys. J.  86, 217 (1937) [web]
  • Holsclaw, T., Alam, U., Sanso, B, Lee, H., Heitmann, K., Habib, S. and Higdon, D., "New Constraints on the Time-Variation of the Dark Energy Equation of State from Current Supernova Data." [web]
2.I'll review Oyvind Gron's book, Lecture Notes on the General Theory of Relativity soon. I've been meaning to for a couple of months now.

3. Previous Episodes Referenced:
4. Read my review of Cosmic Update, a book about cosmology in the accelerating universe.

5.If you or Dragan Hejdukovic wants to supply us with the background energy that would be predicted from virtual gravitational dipoles, please leave us a nice comment with smilies.

6. Our subreddit.

<-- Previous (Weyl and Quasiparticles) (Island of Stability) Next -->

Sunday, January 21, 2018

Weyl and Quasiparticles

<-- Previous (Origin of Inertia) (Dark Energy) Next -->



Jim and Randy discuss quasiparticles recently found in condensed matter systems that mirror particles theorized nearly a hundred years ago, but never found in the vacuum. Weyl particles are massless fermions, and once it was hoped that neutrinos would turn out to be this kind of particle, and Majorana fermions have real-valued wave functions and therefore many strange and possibly useful properties.

-------------------------------------------

Notes:

1. The papers we read for this program:
2.  Popular papers we may have read:
3. Original Papers:
4. I was wrong.  "Weyl" rhymes with "pile," not with "pail."

5. 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.

<-- Previous (Origin of Inertia) (Dark Energy) Next -->

Wednesday, January 10, 2018

The Origin of Inertia

<-- Previous (Exoplanets[Lost]) (Weyl and Quasiparticles) Next -->



Randy tells Jim about a scheme that uses Mach's Principle - the idea that there is a preferred background frame with respect to the fixed stars - to explain the origin of inertia. Why exactly does an object in motion stay in motion?

-------------------------------------------

Notes:

1. The papers we read for this program:

2. In addition, Randy sent me a lot of blog and other forum posts for background:


3. Our discussion on Gravitoelectromagnetism..

4. Our discussion of Aharonov and Rohrlich's Quantum Paradoxes, nine of the ten recorded episodes. I don't think we get into the retrocausal part of it.

5. 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.

<-- Previous (Exoplanets[Lost]) (Weyl and Quasiparticles) Next -->