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    A Conservation of Quantum Information

    So "quantum information" is a bit of a pop science buzz word it sounds like. It's unfortunate that I've been trying to puzzle it out then. However, some good came from this discussion and I think you all for your time. Specifically, the mention of Weyl quantization (by others) and symmetry...
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    A Conservation of Quantum Information

    I can't seem to wrap my head around the notion of conservation of quantum information. One thing that might help that is if someone can tell me what the associated symmetry is. For example, phase symmetry leads to conservation of electric charge according to Noether's theorem; a fact that...
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    B Is there anything left after a black hole is done evaporating?

    Suppose a black hole isn't sucking in any new material. Then it is doomed to evaporate due to Hawking radiation and become smaller and smaller over time. Is there anything left when it's done evaporating?
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    A Chern-Simons Invariant

    I've been studying the Witten-Reshetikhin-Turaev (WRT) invariant of 3-manifolds but have almost zero background in physics. The WRT of a 3-manifold is closely related to the Chern-Simons (CS) invariant via the volume conjecture. My question is, what does the CS invariant of a 3-manifold...
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    A Black Hole Topology

    It seems that in order to make my question less muddy I would need to study GR a bit myself first.
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    A Black Hole Topology

    Well, add the point at infinity to the real line and you are in business. I have no idea if that makes any physical sense though. The space S^2xS^1 is the complement of the unknot with no framing. The associated invariants are easy to compute. Unfortunately nothing interesting falls out as I...
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    A Black Hole Topology

    I want to understand the topology of a black hole so that I can think about how (or if it's even possible) to compute its Witten-Reshetikhin-Turaev invariant.
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    A Black Hole Topology

    I'm not sure about the physics term so maybe I should have stuck with the math. By cross section, I mean one of the boundaries of a cobordism between two 3-manifolds.
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    A Black Hole Topology

    Can a black hole be presented as a Heegaard decomposition or as the complement of a knot? I'll try and elaborate: If I understand correctly, the cross section of spacetime near a black hole can be thought of topologically as a manifold. What manifold is it? Can the manifold be decomposed?
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    A Quantum Invariants of 3-Manifolds

    If I understand the theory of quantum invariants of 3-manifolds correctly (possibly I don't), TQFTs on different presentations of closed 3-manifolds produce different values. However, the same quantum invariants (Reshetikhin-Turaev invariants for example) are produced on a closed manifold...
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    A Reshetikhin-Turaev Invariant of Manifolds

    I stumbled onto the answer to my own question. I'm sufficiently motivated now. Anyway, the Reshetikhin-Turaev Invariant of a 3-manifold obtained from surgery on a link in #S^3# are colored jones polynomials of the link. Roughly (very roughly), calculate the Reshetikhin-Turaev Invariant of a...
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    A Reshetikhin-Turaev Invariant of Manifolds

    The Reshetikhin-Turavev construction comes with an invariant that is sometimes called the Reshetikhin-Turaev Invariant. I'm currently attempting to wrap my head around this construction but was hoping for a sneak peak to help motivate me. My question is, what does the Reshetikhin-Turaev...
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    A Topological Quantum Field Theory: Help reading a paper

    You can disregard this question. I figured it out.
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    A Topological Quantum Field Theory: Help reading a paper

    https://www.ma.utexas.edu/users/dafr/OldTQFTLectures.pdf I'm reading the paper linked above (page 10) and have a simple question about notation and another that's more of a sanity check. Given a space ##Y## and a spacetime ##X## the author talks about the associated Quantum Hilbert Spaces...
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    A Gauge Theory: Principal G Bundles

    That's quite possible. So then, what are characteristic numbers, how are characteristic numbers related to Dijkgraaf-Witten theory and what physical quantity (if any) do they correspond to in the real world? The only type of characteristic numbers I'm aware of come from representation theory...
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    A Gauge Theory: Principal G Bundles

    Definitely! Don't hold your breath though. I have a heavy course load starting in the fall =/
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    A Gauge Theory: Principal G Bundles

    I like where your intuition is going with that. Unfortunately I would need to study the theorem of Noether you mention more extensively before even beginning to consider what you suggest. I do understand enough to see why you might suggest that though.
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    A Gauge Theory: Principal G Bundles

    I don't think I articulated my question very well. Let me try again: The number of principal G bundles of a manifold is a topological invariant. What I would like to know is, does that invariant correspond to any physical quantity?
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    A Gauge Theory: Principal G Bundles

    I've been studying TQFT and gauge theory. Dijkgraaf-Witten theory in particular. One learns that a topological field theory applied to a manifold outputs the number of principal G bundles of a manifold. My question is for the Physicists in the room, why do you want to know the number of...
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    A TQFT From Purely Mathematical Considerations

    I worked my way through this paper http://www.math.harvard.edu/theses/senior/lee/lee.pdf as part of a mathematics reading project and believe I have a fairly good understanding of the material. There is virtually no physics in this paper yet we seem to arrive at Dijkgraaf-Witten Theory quite...
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    I Simple GR Question

    OK, I think I get it now. Thanks everyone!
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    I Simple GR Question

    I'm referring to ##g## in two different contexts which is what I think made my question unclear. So, let ##g## be the metric from GR and let ##d## be the metric from math class. Does defining ##g## on a differentiable manifold automatically induce ##d##? As an aside, this is interesting to me...
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    I Simple GR Question

    You're right, I suppose I should make that precise. The metric topology I'm referring to has as open sets ##B_r(m_0)=\{m_0\in M : g(m_0,m)<r\ \forall m\in M \text{ where } r>0\}##
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    I Simple GR Question

    Is it fair to say, when talking about spacetime with a given metric, it would be redundant to state that the associated set has the metric topology placed on it. In other words, let ##M## be a set, ##O## the metric topology, ##\nabla## a connection, ##g## a metric, and ##T## be the direction of...
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    Algebraic Topology: SO(3)/A5

    I was watching this video on Abstract Algebra and the professor was discussing how at one point a few mathematicians conjectured the special orthogonal group in ##\mathbb{R}^3## mod the symmetries of an icosahedron described the shape of the universe (near the end of the video). My question is...
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    Trying To Learn Category Theory

    So I cleaned my solution up a little based on the comments but I also worked through mathwonks solution which is much nicer. It used some mathematics that were a little beyond where I'm at currently but I managed to get a handle on those mechanics by "reading ahead." Anyway, if anyone is...
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    Trying To Learn Category Theory

    Thanks mathwonk and fresh_42 for the great comments. I've read them and will rework this problem shortly. Seems like it needs a lot of work though so it might take a day or two.
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    Trying To Learn Category Theory

    I'm trying to learn Category Theory; this isn't homework or anything. I've attached a problem from the text "Basic Homological Algebra" by Osborne and I show my attempt at a solution. My solution doesn't seem exactly correct and I state why in the attachment as well. Can someone take a look...
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    Tensor Product Functor

    That's along the lines of what I was guessing. I suppose an idea for a paper would be to carry this line of thought out and make it precise. I suppose I would have to learn some GR which seems rather daunting.
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    Tensor Product Functor

    At the risk of sounding ignorant I'd like to propose a question to someone well versed in Homological Algebra and General Relativity. I'm starting to study the tensor product functor in the context of category theory because I'm interested in possibly doing a paper on TQFT for a directed...
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