Superstring Cosmology: Compactifying 7 Dimensions

[Kevin_Axion]

In Superstring Cosmology and Superstring Gas Cosmology they try to address the question as to how compactification occurs. Is it believed that possibly cosmic strings wrapped themselves around 7 dimensions and collapsed due to their tension? This isn't a personal theory just a curiosity as to how current Superstring Cosmologists propose compactification of 7 dimensions occurred. If this is incorrect I would be glad if you can provide a detailed explanation or link.

Thanks, Kevin

 

[nickthrop101]

I am not completely sure about this. But I do know that their is a theory that proclaims that 7 dimensions curl around into a tiny shape, about the plank size, named a calabi-yau shape.
These tiny shapes help the universe to survive, as any cut in space ( where space rips apart) they can mould into different shapes to almost glue that rip together and stop the cataclysmic affect
A good book on string theory is Brian Greens book " the elegant universe"
Hope that's useful :)

 

[Kevin_Axion]

Yea, thanks, I already know that I just wanted a more technical and mathematical perspective as to how only seven dimensional spaces become compactified within String Gas Cosmologies.

 

[Chronos]

I once watched a magician swallow a spool of thread and a pack of double edged razor blades. He then pulled the string out of his mouth with all the razor blades neatly tied to it.

 

[bapowell]

The original models of string gases don't involve cosmic strings but fundamental strings. The idea is that initially all the dimensions possesses winding modes -- strings that wrap around the dimension. By observing that p-dimensional objects generically intersect in 2p+1 dimensions, 1-dimensional winding modes will generically annihilate with 1-dimensional anti-winding modes in at most 3 dimensions. This annihilation 'frees-up' these dimensions -- hence a universe with 3 non-compact dimensions. The 1D winding modes do not annihilate efficiently in higher dimensions, and so these remain compactified. This reasoning is based on Brandenberger, Tsetylin and Vafa's original proposal based on toroidal compactification. It has since been studied under more complicated compactification schemes with varied outcomes -- some geometries/topologies result in more than 3 large dimensions. The role of cosmic strings and branes has also been investigated.

 

[Kevin_Axion]

Thanks.