Recent content by mitchell porter

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    I Can someone explain to me a flop transition in laymen's terms?

    A flop transition would be a particular kind of slight change in the shape of the extra dimensions in string theory. Without quantum mechanics it would be a discontinuous process, but quantum mechanics makes it smooth in a way that is of theoretical interest to Witten, Greene, etc. In string...
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    I Leptons and the Lorentz Group O(3,3)

    But e.g. when you rotate a physical system, there isn't a separate rotation group for each species of lepton. The same spatial rotation acts on everything at once. There are independent lepton family number symmetries but they are only U(1).
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    The wrong turn of string theory: our world is SUSY at low energies

    An inspiring paper mentioned early in this thread (#48) is Shifman and Vainshtein 2005 on diquarks. They argue that the color SU(3) of real-world QCD, should contain an echo of "SU(2) color", in which diquarks would be gauge-invariant objects on a par with pions. They posit an intermediate...
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    A Seeking the Standard Model in E8 plus Supersymmetry

    This is just a quick alert regarding a paper today https://arxiv.org/abs/2005.03048 Exceptional Unification of Families and Forces Alfredo Aranda, Francisco J. de Anda, Stephen F. King [Submitted on 6 May 2020] This work considers the remarkable suggestion that the three families of quarks and...
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    The wrong turn of string theory: our world is SUSY at low energies

    Last month Urs Schreiber tweeted about hadronic supersymmetry, eventually asking whether the WZW term from chiral perturbation theory has ever appeared in a hadronic-susy model. I think not. The WZW term is a phenomenon of field theory; the model of Brodsky et al employs supersymmetric quantum...
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    A The Wolfram Model & Wolfram Physics Project

    At the most concrete level, they don't look to be very similar. Abramsky's obstructions seem to be about preventing a kind of foliation, whereas GCT's obstructions prevent an embedding of one algebraic variety into another. In the first link he's only talking about complexity but not...
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    A The Wolfram Model & Wolfram Physics Project

    So can you show somewhere that he is using these methods, even if he doesn't call them by these names? I've studied geometric complexity theory. It is the proposed application of algebraic geometry to the separation of complexity classes (separation means, e.g., proving P is distinct from NP)...
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    A The Wolfram Model & Wolfram Physics Project

    So far I have not found any statement anywhere from him, which talks about using machine learning, evolutionary algorithms, etc, in order to choose among models. The only thing I have seen about computational complexity theory is a passing claim in the paper on "Some quantum mechanical...
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    A The Wolfram Model & Wolfram Physics Project

    I thought Wolfram was just proposing to base physics on a kind of cellular automaton. Is he using AI to search the possible rules? Where does he talk about this?
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    A Eric Weinstein's Geometric Unity theory

    I finally found a straightforward synopsis of the theory, between 02:11:07 and 02:12:34. "... starting with nothing other than a four-manifold, we built a bundle U. The bundle U had no metric, but it almost had a metric and had a metric up to a connection. There was another bundle on top of...
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    A Eric Weinstein's Geometric Unity theory

    Transcript of the video. There are some motivating remarks at 50 minutes, in which Einstein gravity, Yang-Mills theory, and a Dirac equation are described as the three ingredients of known physics, whose inconsistencies and tensions are to be examined, in order to find a deeper common...
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    A Eric Weinstein's Geometric Unity theory

    Eric Weinstein finally released a video of his 2013 Oxford talk on "geometric unity". There are many fans and skeptics out there, looking in vain for a genuinely informed assessment of the idea. I admit that so far I have only skimmed the transcript of the video, being very pressed for...
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    The wrong turn of string theory: our world is SUSY at low energies

    A year ago, while we were puzzling over what to do with single-flavor diquarks, I wrote Now Avner Karasik, mentioned in this thread at #269-270, has obtained the one-flavor eta membrane as a limit of a two-flavor skyrmion, by slightly amending the usual baryon current. He remarks (just after...
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    A New model of high-spin Baryons

    "Skyrmions, Quantum Hall Droplets, and one current to rule them all" by Avner Karasik obtains this unusual Nf=1 (one-flavor) model, as a limit of a more conventional Nf=2 skyrmion model, in which one flavor becomes heavy. The key technical development is in equation 4.9, a new current H which...
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    A M theory dimension change and large N_c, are they related?

    In terms of AdS/CFT, one has N (as in SU(N)) and g (gauge coupling) to work with. In string theory, the eleventh dimension emerges when string coupling is large, and string coupling is proportional to g^2. So at first glance there is no relationship, though in practice there are limits defined...
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