Gravitational Waves from Mesoscopic Dynamics of the Extra Dimensions

Recent models which describe our world as a brane embedded in a higher dimensional space introduce new geometrical degrees of freedom, associated with spatial variations in the position of the brane and the size of the extra dimensions, that can be coherently excited by symmetry breaking in the early universe even on “mesoscopic” scales as large as 1 mm. The characteristic frequency and intensity of resulting gravitational radiation backgrounds are estimated. Extra dimensions with scale between ${10}^{-14\mathrm{}}$ and 1 mm can produce detectable backgrounds at frequencies $f\approx {10}^3$ to ${10}^{-4\mathrm{}}\mathrm{Hz}$.