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String Theory ... — Parallax Forums

String Theory ...

Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
edited 2013-10-02 06:59 in General Discussion
... set to "Bohemian Rhapsody"

I don't know any more about string theory now than before I watched the video, but I was highly entertained, nonetheless. And I thought the Albert Einstein sock puppet was a nice touch, too.

-Phil

Comments

  • Martin_HMartin_H Posts: 4,051
    edited 2013-10-02 06:35
    My knowledge of physics stops ad Physics III (Quantum Mechanics and Special Relativity). So I agree it was a fun romp, but he didn't explain theory as much as enumerate a few of the factors that lead to its invention. For example at 1:42 he mentioned renormalization which is a technique to work around the infinities created by point particles. The problem is that point particles inherently have no volume, so any math with them is just begging for a division by zero. String theories tiny multi-dimensional doughnuts side step the whole problem because they're not points at all.

    But that leaves String Theory in a bit of an odd place. Is it a mathematical artifact or does it describe the real world in any way? Normally scientists rely on experiments to solve such debates, but the energy levels required to test it are beyond any physics experiments humans can do at the present time.
  • ctwardellctwardell Posts: 1,716
    edited 2013-10-02 06:39
    I really like that.

    C.W.
  • Heater.Heater. Posts: 21,230
    edited 2013-10-02 06:59
    God I hate Queen.

    Last I heard string theory was out and "amplitudehedrons" were in.

    I have no idea what they are up to but I like their starting assumptions:

    1) "unitarity". Quantum mechanics describes the probabilities of particles being somewhere or somewhere else. It has always been assumed that the sum of all those probabilities is 1. That is to say a particle is sure to be somewhere.

    They threw that assumption out. Seems that particles near black holes end up with finite probability of not existing so it's a reasonable idea.

    2) "locality". Locality is the notion that particles can interact only from adjoining positions in space and time.

    They threw that idea out as well. Anyone who has done Young's experiments would also. I mean, an electron passing through a system of two "slits" has various probabilities of ending up here or there or elsewhere that look like they were the result of some wave interference mechanism.

    One might start to think about some "wave" being there, or one might see the obvious: All the particles in the system have interacted, non-locally, to figure out between them where that electron can be.

    Given these attractive assumptions they do a pile of maths, that happens to simplify calculating the interactions between subatomic particles by thousands of times and leads them to conclude:
    ...the new amplituhedron research suggests space-time, and therefore dimensions, may be illusory anyway.

    I love it :)

    https://www.simonsfoundation.org/quanta/20130917-a-jewel-at-the-heart-of-quantum-physics/
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