A Portal Special Presentation- Geometric Unity: A First Look: Difference between revisions
A Portal Special Presentation- Geometric Unity: A First Look (edit)
Revision as of 17:08, 25 April 2020
, 25 April 2020→The Levi-Civita Connection
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<p>[01:20:01] Okay. What is it that we get for the Levi-Civita connection? Well, not much. One thing we get is that normally the space of connections is an affine space ($$\mathcal(A)$$). Not a vector space, but an affine space. Almost a vector space, a vector space up to a choice of origin. But with the Levi-Civita connection, rather than having an infinite plane with an ability to take differences, but no real ability to have a group structure. | <p>[01:20:01] Okay. What is it that we get for the Levi-Civita connection? Well, not much. One thing we get is that normally the space of connections is an affine space ($$\mathcal(A)$$). Not a vector space, but an affine space. Almost a vector space, a vector space up to a choice of origin. But with the Levi-Civita connection, rather than having an infinite plane with an ability to take differences, but no real ability to have a group structure. | ||
<p>[01:20:35] You pick out one point, which then becomes the origin. That means that any connection $$A$$ has a torsion tensor, $$T_A$$, which is equal to the connection, $$A$$ minus the Levi-Civita connection ($$\nabla^{LC}$$. So we get a tensor that we don't usually have. Gauge potentials are not usually well-defined. They're are only defined up to a choice of gauge. | <p>[01:20:35] You pick out one point, which then becomes the origin. That means that any connection $$A$$ has a torsion tensor, $$T_A$$, which is equal to the connection, $$A$$ minus the Levi-Civita connection ($$\nabla^{LC}$$). So we get a tensor that we don't usually have. Gauge potentials are not usually well-defined. They're are only defined up to a choice of gauge. | ||
<p>[01:21:00] So that's one of the things we get for our Levi-Civita connection, but because the gauge group is going to go missing, this has terrible properties from with respect to the gauge group. It almost looks like a representation. But, in fact, if we let the gauge group act, there's going to be an affine shift. | <p>[01:21:00] So that's one of the things we get for our Levi-Civita connection, but because the gauge group is going to go missing, this has terrible properties from with respect to the gauge group. It almost looks like a representation. But, in fact, if we let the gauge group act, there's going to be an affine shift. | ||
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<p>[01:21:48] [The] first thing we need to do is we still have the right to choose intrinsic field content. [We] have an intrinsic field theory. So, if you consider the structure bundle of the spinors; we built the chimeric bundle, so we can define Dirac spinors on the chimeric bundle if we're in Euclidean signature. A 14-dimensional manifold has Dirac spinors of dimension-two to the dimension of the space divided by two. | <p>[01:21:48] [The] first thing we need to do is we still have the right to choose intrinsic field content. [We] have an intrinsic field theory. So, if you consider the structure bundle of the spinors; we built the chimeric bundle, so we can define Dirac spinors on the chimeric bundle if we're in Euclidean signature. A 14-dimensional manifold has Dirac spinors of dimension-two to the dimension of the space divided by two. | ||
<p>[01:22:20] Right? So 2^14 over 2^7 is 128, so we have a map into a structured group of U(128) | <p>[01:22:20] Right? So $$2^14$$ over $$2^7$$ is $$128$$, so we have a map into a structured group of $$U(128)$$ | ||
<p>[01:22:36] At least in Euclidean signature. We can get to mixed signatures later. From that, we can form the associated bundle. | <p>[01:22:36] At least in Euclidean signature. We can get to mixed signatures later. From that, we can form the associated bundle. | ||