Signatures of extra dimensions in gravitational waves

[kodama]

Signatures of extra dimensions in gravitational waves
David Andriot, Gustavo Lucena Gómez
(Submitted on 24 Apr 2017)
Considering gravitational waves propagating on the most general 4+N-dimensional space-time, we investigate the effects due to the N extra dimensions on the four-dimensional waves. All wave equations are derived in general and discussed. On Minkowski4 times an arbitrary Ricci-flat compact manifold, we find: a massless wave with an additional polarization, the breathing mode, and extra waves with high frequencies fixed by Kaluza-Klein masses. We discuss whether these two effects could be observed.
Comments: 21 pages + appendices, comments welcome!
Subjects: High Energy Physics - Theory (hep-th); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph)
Cite as: arXiv:1704.07392 [hep-th]
(or arXiv:1704.07392v1 [hep-th] for this version)

Any evaluation of this proposal? GR in 4 D has one prediction and non observation of additional polarization implies GR in 4D is correct, no extra dimensions.

In string theory, are the extra 6 spatial dimenions considered frozen, immutable for all eternity, while the 3 large spatial dimensions can curve as described by Einstein?

Were those extra 6 dimensions frozen from the very beginning of time or does string theory state the universe start out as 10 flat dimensions then at some time 6 became compactified and 3 remain large and 1 became time?

 

[AndyW]

I find this proposal to be intriguing and worth further investigation. The idea of extra dimensions affecting gravitational waves is a fascinating concept that could provide valuable insights into the nature of our universe.

In terms of evaluating this proposal, I believe that conducting experiments and observations to test for the predicted effects of extra dimensions on gravitational waves would be the best approach. If these effects are observed, it could provide strong evidence for the existence of extra dimensions.

However, as you mentioned, the non-observation of these effects would not necessarily disprove the existence of extra dimensions, but rather support the idea that our current understanding of gravity in 4 dimensions is correct.

In terms of string theory, the extra dimensions are considered to be compactified, meaning that they are curled up and too small to be observed in our everyday experience. These dimensions are not frozen or immutable, but rather they can interact with the 3 large dimensions in a way that affects the behavior of gravity.

The exact nature of how and when these extra dimensions became compactified is still a topic of debate in string theory. Some theories suggest that these dimensions were always compactified, while others propose that they became compactified at some point in the early universe.

Overall, I believe that this proposal has the potential to provide valuable insights into the fundamental nature of our universe and should be further explored through experiments and observations.