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Why gravity gets weak as it "arrives" at our weak brane can be explained by looking at the warped AdS space given by $ ds^2 = e^{-2\phi}\eta_{\mu\nu}\, dx^{\mu} dx^{\nu} + d\phi^2$ The flat Minkow …

The compactification of a spatial dimension, say $x^1$ given by the identification $x \sim x^1 + 2\pi R$ is said to be related to the lightlike compactification by a Lorentz boost : $$ \left( \beg …

There can not only, there have to be heavy higher dimensional objects (as for example D-branes) in string theory, as Joseph Polchinski discovered. So it is strictly speaking no longer appropriate to t …

As Cumrun Vafa explains in the video linked to below the picture of him in this article, F-theory works in a total of $10+2$ dimensions. The signature of the last two infinitesimal dimensions is ambig …

In addition to what John Rennie said, meaning by the number of dimensions the universe has the number of large dimensions, there are (yep somewhat wild) suggestions how the number of these could chang …

In addition to Qmechanic's nice answer, in string theory the wick rotation changes the Lagrangian such that the equations of motion are given by the Laplace equation instead of the conventional wave e …

To compactify 2 open dimensions to a torus, the method of identification written down for this example as $$ (x,y) \sim (x+2\pi R,y) $$ $$ (x,y) \sim (x, y+2\pi R) $$ can be applied. What are the …

In addition to what dmckee said, another hint at ("large") extra dimensions would be the detection of Kaluza-Klein particles at the LHC for example. Kaluza-Klein particles are in principle nothing bu …

In bosonic string theory, to obtain the photon as the first excited state, the ground state must have a negative mass (tachyon). By applying $1 + 2 + 3 + \cdots = -1/12$, it can be shown (in a simplif …

In this blog post, a paper that derives by dimensional reduction well known super Yang-Mills (SYM) theories, such as N=1 SYM in 9+1 dimensions and N=4 SYM in 3+1 dimensions among other things using a …