# Physics Frontiers

## Science >

## Episodes

## The Einstein-Cartan Torsion Field Theory

10/29/2018

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Randy explains to Jim theories on how to incorporate a native angular momentum into general relativity. Show Notes: http://frontiers.physicsfm.com/37

Duration:00:35:24

## The Metamaterial Stress Tensor

10/14/2018

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Randy tells Jim about recent results in the description of the electromagnetic stress tensor in metamaterials. In particular, we discuss the efforts to computationally model the stress tensor in amorphous metamaterials. Show Notes: http://frontiers.physicsfm.com/36

Duration:00:42:27

## The String Theory Landscape

9/21/2018

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Jim and Randy explore the landscape of string theory in the anthropic manner put forward by Leonard Susskind. Show Notes: http:frontiers.physicsfm.com/35

Duration:00:42:28

## CPT Symmetry and Gravitation

8/10/2018

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CPT Symmetry is a fundamental symmetry in the standard model. Jim and Randy discuss what happens when it is applied to general relativity. Show Notes: frontiers.physicsfm.com/34 [Really sorry for the muted tracks on the first upload. The problem has been fixed. - J]

Duration:00:32:12

## Retrocausality

7/25/2018

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Jim and Randy look at how quantum mechanics is affected by time. Most importantly, what happens when temporal boundary conditions are used to create standing waves in the wave function of a particle? Show Notes: http://frontiers.physicsfm.com/33

Duration:00:34:49

## Tunneling Time

7/6/2018

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Jim talks to Randy about the amount of time it takes for an electron to tunnel through a forbidden region of space. Astoundingly, how quickly this happens has been a subject of debate for eighty years and is still unresolved. Show Notes: http://frontiers.physicsfm.com/32

Duration:00:47:16

## Post-Newtonian Gravitation

6/8/2018

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Jim discusses the Parameterized Post-Newtonian formalism with Randy. The PPN framework is a general, linearized metric theory of gravity that can simulate all metric theories of gravity and compare them to solar system sized experiments. Show Notes: http://frontiers.physicsfm.com/31

Duration:00:41:47

## The Consistent Histories Interpretation of Quantum Mechanics

5/24/2018

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Jim and Randy discuss the consistent histories interpretation of quantum mechanics. The brainchild of Robert Griffiths and with a surprisingly strong set of supporters, Consistent Histories seems to be a strong, logical description of what happens in the quantum world. Show Notes: http://frontiers.physicsfm.com/30

Duration:00:45:59

## Gravitational Alternatives to Dark Energy

5/15/2018

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Jim and Randy discuss how modifications to general relativity can be used to mimic the effects of dark energy. They discuss various forms of gravitational theory that can do the job, as well as the field particles that mediate their "fifth force." Show Notes: http://frontiers.physicsfm.com/29

Duration:00:46:56

## The Quantum Vacuum and the Casimir Effect

4/24/2018

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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. Show Notes: http://frontiers.physicsfm.com/28

Duration:00:41:21

## The Gravitational Equivalence Principles

4/14/2018

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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. Show Notes: http://frontiers.physicsfm.com/27

Duration:00:46:05

## Antimatter Production at a Potential Boundary

3/25/2018

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Randy shows Jim an idea for generating antimatter using the Casimir effect that doesn't require a collider. Show Notes: http://frontiers.physicsfm.com/26

Duration:00:39:32

## Gravitational Field Propulsion

3/15/2018

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Randy introduces Jim to several ways in which people have theorized that gravity can be used to propel an object through space. The slingshot effect is the only proven method here, but people have found many ways that theoretically could induce propulsion taking advantage of non-commutative motions in space-time, negative inertia, artificially-induced gravitational dipoles, and creating bubbles in space-time. Show Notes: http://frontiers.physicsfm.com/25

Duration:00:58:00

## The Island of Stability

2/23/2018

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Randy tells Jim about the island of stability: a theoretically predicted oasis of stable nuclear isotopes that researchers keep getting nearer and nearer to discovering. Randy and Jim talk about what they are, how researchers are trying to produce the isotopes, and the theoretical methods that predict their existence. Show Notes: http://frontiers.physicsfm.com/24

Duration:00:25:27

## Dark Energy

2/8/2018

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Randy helps Jim get a handle on Dark Energy. Why do we need it? What could it be? What does it have to do with you? How close are we to knowing anything about it? Show Notes: http://frontiers.physicsfm.com/23

Duration:00:45:55

## Weyl and Quasiparticles

1/21/2018

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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. Show Notes: http://frontiers.physicsfm.com/22

Duration:00:37:01

## The Origin of Inertia

1/10/2018

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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. Show Notes: http://frontiers.physicsfm.com/21

Duration:00:38:47

## Time Crystals

12/21/2017

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Jim talks to Randy about structures that are periodic in time like crystals are periodic in space. Show notes: http://frontiers.physicsfm.com/20

Duration:00:34:19

## The 2T Physics of Itzhak Bars

12/6/2017

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Randy tells Jim about a theory that complements other theories of fundamental physics based upon a phase space symmetry between the 4-position and the 4-momentum of a particle. The upshot of the theory is that there should be a second time dimension and a fourth space dimension, both macroscopic in extent, and the physics we see are 4D projections from the larger 6D space-time. Show notes: http://frontiers.physicsfm.com/18

Duration:00:44:54

## The Physics of Time Travel

11/24/2017

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Randy and Jim talk about traveling through through time, discussing relativity and, in particular, Kurt Goedel's solution for closed timelike curves in General Relativity. Show notes: http://frontiers.physicsfm.com/17

Duration:00:43:39