4 votes

Compactification in String Theory and Compactification in Topology are they the same thing?

I don't know much about compactification in string theory, but the idea is based on the compactification in (4+1) D Kaluza-Klein theory, proposed in the years after the theory of general realtivity ...
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4 votes

Compactification in String Theory and Compactification in Topology are they the same thing?

No, different concepts. The compactification in string theory is the process of taking a theory with extra infinitely extended dimensions (w.r.t. the canonical 3+1 dimensions) and modifying it so that ...
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  • 4,390
4 votes

Assuming FLRW is correct, can it be 3-torus?

The assumption underlying the FLRW metric is that space is homogeneous and locally isotropic. Schur’s Theorem states that a connected Riemann manifold of dimension $n>2$ that is locally isotropic ...
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  • 99
2 votes

Compactification in String Theory and Compactification in Topology are they the same thing?

No, it is not. We compactify $\mathbb{R}$ to become a $\mathbb{S}^1$ by gluing $x\sim x+2\pi$, which is an universal covering $j:\mathbb{R}\rightarrow \mathbb{S}^1$.
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  • 5,375
1 vote

Assuming FLRW is correct, can it be 3-torus?

FLRW cosmology postulates that there exists a frame in which space is isotropic and homogenous, but a 3-torus is not globally isotropic. You can see this in that if you head along a (spatial) geodesic ...
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  • 1,045

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