Brane world=non-compact extra dimensions?

[arivero]

Just wondering. All this stuff of the brane world, where spacetime is a 3-brane inside a 10 dim world... is not the same than telling that we want to use non compact extra dimensions?

 

[cristo]

If you've got a braneworld scenario where the 3D brane is moving through the bulk then yes, the bulk is non-compact.

 

[arivero]

If you've got a braneworld scenario where the 3D brane is moving through the bulk then yes, the bulk is non-compact.

I was thinking so. On other hand, in order to have macroscopic gravity I imagine they need some finite "size" of the bulk.

 

[nrqed]

I was thinking so. On other hand, in order to have macroscopic gravity I imagine they need some finite "size" of the bulk.

There are different models, some with finite extra dimensions, some with infinite extra dimensions (the first two papers of Randall and Sundrum propose on of each type).
And by the way, in brane world papers they don't necessarily assume that the total number of spacetime dimensions is 10 or 11. In the papers by RS, they simply postulated a fifth dimension. Some other works consider 6 dimensions.