http://arxiv.org/abs/1711.06628
The search for extra dimensions is a challenging endeavor to probe physics beyond the Standard Model. The joint detection of gravity waves (GW) and electromagnetic (EM) signals from the merging of a binary system of compact objects like a neutron star (NS) can help constrain the geometry of extra dimensions. In particular, if our observable Universe is a 3+1 hypersurface or brane embedded in a higher 4+1 Anti-de Sitter (AdS$_5$) spacetime, in which gravity is the only field that propagates through the infinite bulk space while any other field is confined on the brane, then GW and EM signals between two points on the brane would in general travel different paths. This would result in a time lag between the detection of GW and EM signals emitted simultaneously from the same source, with the apparent measurement of a “superluminous” GW speed. Assuming the standard $\Lambda$-Cold Dark Matter ($\Lambda$CDM) scenario, we set a bound on the AdS$_5$ radius of curvature $\ell \lesssim 140\,$kpc, using the time lag $\delta t < 1.7\,$s between the measurement of the event GW170817 by the LIGO/VIRGO collaborations and the GRB170817A signal detected by the Fermi Gamma-ray Burst Monitor collaboration, both associated with a binary NS-NS infall.
L. Visinelli and N. Bolis
Thu, 23 Nov 17
1/52
Comments: 4 pages