10 Dimensions

[steevey]

Is there any observable proof or any measurable proof of 10 dimensions in any way other than purely theoretical mathematics? What I heard, is that in 3 dimensional space, light grows dimmer by the square of the distance. In 4 dimensional space, light grows dimmer by the third power of the distance. In 10 dimensional space however, light grows dimmer by the fourth power of the distance, explaining why stars far a way look like dots. But otherwise, that's the most concrete thing I know of.

[ajb]

That is right, the "inverse square law" only applies in 3d space.

 

One possible signature of extra dimensions is the small scale modifications of gravity. Another could be the apparent non-conservation of energy as particles (gravitons or something else undiscovered) carries off the energy into the higher dimensions.

[steevey]

When you say "carried off into other dimensions", that doesn't make sense because all the dimensions would exist simultaneously, the only problem is we just can't see them ourselves if they are there.

[ajb]

To us, is it as if the extra dimensions are not there, either they are compactified or we live a a 3-brane (or maybe a combination of both).

 

So, lets assume we live on a 3-brane. Gravity can propagate in the bulk space-time, but we and all the forces of nature apart from gravity are trapped on this brane. In a collider experiment some of the energy could be carried by a graviton off our 3-brane and into the bulk. It would look like nonconservation of energy.

 

Energy entering our brane from the bulk is also a possibility.

Edited November 18, 2010 by ajb

[steevey]

To us, is it as if the extra dimensions are not there, either they are compactified or we live a a 3-brane (or maybe a combination of both).

 

So, lets assume we live on a 3-brane. Gravity can propagate in the bulk space-time, but we and all the forces of nature apart from gravity are trapped on this brane. In a collider experiment some of the energy could be carried by a graviton off our 3-brane and into the bulk. It would look like nonconservation of energy.

 

Energy entering our brane from the bulk is also a possibility.

 

There's no reason for energy which can normally always be accurately measured to all of a sudden disappear only when they do particle colliding. Chances are, there just just another unknown particle which they don't know how to detect, which get's released from the particle collision.

 

 

 

[ajb]

Chances are, there just just another unknown particle which they don't know how to detect, which get's released from the particle collision.

 

That would require some light neutral particle (like a moduli field?) to date unknown, that is a possibility. I assume that careful analysis of the collisions would shed light on if the loss of energy is due to a graviton or some other particle. Conservation of spin maybe a way to tackle that.

 

KK-particles could also be created at the LHC which would also be a signal of higher dimensions. People also suggest that careful analysis of gravitational waves could show the signature of higher dimensions. As I said before, careful analysis of gravity on the sub millimetre scale could also show higher dimensions. Micro blackholes could be created at the LHC, again these could suggest extra dimensions.

 

I am far from an expert on the experimental side of all this, but I know that people are thinking of ways to possibly probe extra dimensions. In particular they will all be looking for experiments that give very clear signals that can not be confused with something more "conventional". Doing a quick google or looking on the arXiv will give you an idea of the number of papers on this subject. Searching for "extra dimensions" in the abstracts of physics- phenomenology gave me over 1000 hits, the maximum it will display.

[steevey]

Have they ever tried colliding two entangled particles and seeing if anything happens? If there needs to be some weird dimensional thing for anything, it's entanglement.