# $D$-brane and 5th dimensions

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While I was looking up the 5th dimension of the Randall-Sandram model, I have wondered whether Kaluza Klein theory can be applied to the $D$-brane or $p$-brane.

Can the $D$-brane and $p$-brane wrapped as compactification of the dimensions?

If so, what is the main difference between $D$- and $p$-brane?

This post imported from StackExchange Physics at 2014-10-14 10:43 (UTC), posted by SE-user user44629
Have you tried the obvious Google searches? If so, can you be more specific about what you're asking?

This post imported from StackExchange Physics at 2014-10-14 10:43 (UTC), posted by SE-user John Rennie
Main question was whether the D-brane and P-brane can be wrapped up or not . It seems the answer can be accessed through the Google Search if you say so.

This post imported from StackExchange Physics at 2014-10-14 10:43 (UTC), posted by SE-user user44629
The "p" in p-brane stands in for the number of spatial dimensions that a brane covers. The "D" in D-brane stands for something quite different: It states that this brane provides "Dirichlet" boundary conditions for the strings roaming around in space.

This post imported from StackExchange Physics at 2014-10-14 10:43 (UTC), posted by SE-user Siva

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The answer is yes, branes (both $D$ and $p$) can be wrapped around compactified dimensions. There is little difference between the two types of branes with regard to compactification.

This post imported from StackExchange Physics at 2014-10-14 10:44 (UTC), posted by SE-user Frederic Brünner
answered Oct 13, 2014 by (1,120 points)
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Can the D-brane and p-brane wrapped as compactification of the dimensions?

String theories are consistent in 26 (bosonic string theory), 10 (superstring theories) and 11 (M-theory) dimensions. To get our world (4D) one needs to compactify the extra-dimensions. In general $D$ branes are extended $p+1$ dimensional objects with $p$ spatial and one time dimension. Obviously, if $p>d$ (here $d$ is the dimension of theory you want to get after compactification) then some of D brane dimensions are compact. For example, compactifying superstring theory to 4D we have 6 compact dimensions and if there is a brane with $p>4$ then it has some compact coordinates. So the answer on your first question is Yes.

If so, what is the main difference between D- and p-brane?

From the definition that I gave above, you see that if you want to specify the dimension of $D$ brane you call it $Dp$ brane. Now why $D$? Actually there are two other types of branes - $NS$ and $M$ branes, so that is why we need a letter $D$ - to distinguish different types of branes.

This post imported from StackExchange Physics at 2014-10-14 10:44 (UTC), posted by SE-user g3n1uss
answered Oct 13, 2014 by (20 points)

Well, actually if you look at the literature, the term p-brane is much older than the term D-brane. I think it was Horowitz and Strominger (correct me if wrong) who found various type II SUGRA solutions which they called (black) p-branes. Only later Polchinski came to realize that p-branes are the low energy version of the Dirichelt p-branes which are the non-pertub. string theory states. When talking about SUGRA, strictly speaking you are talking about p-branes.

The earliest reference I found is a paper titled "Super p-branes" from 1987 by A. Achucarro, J.M. Evans, P.K. Townsend, D.L. Wiltshire http://inspirehep.net/record/22286?ln=en I think Townsend came up with the name as  play on "pea-brains".

My comment is not an answer to the question!

Hi @suresh, I have converted it into a comment.

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