Gravitational waves in warped compactifications

Abstract

We study gravitational waves propagating on a warped Minkowski space-time with D −4 compact extra dimensions. While Kaluza-Klein scales are typically too high for any current detection, we analyse how the warp factor changes the Kaluza-Klein spectrum of gravitational waves. To that end we provide a complete and explicit expression for the warp factor on a d-dimensional torus. This expression differs from that of braneworld models and should find further uses in string compactifications. We then evaluate the Kaluza-Klein spectrum of gravitational waves. Our preliminary numerical results indicate not only a deviation from the standard toroidal spectrum, but also that the first masses get lowered due to the warp factor.

Gravitational radiation from a binary system in odd-dimensional spacetime

“…The non-vanishing components of its derivative have the form From Eqs. (V. 16) and (V.17) we find the non-zero components of A ij (x)…”

“…(III.14-III. 16) and introducing the spacelike vector s(t ) defined by Eq. (III.18) (here we replaced the proper time with coordinate one), we obtain the non-relativistic approximation of the emitted part of the gravitatonal field up to the leading order in small parameters |z|/r, |v|, |s| 1 as…”

“…Extra dimensions are intrinsically present in the string theory [1], holography [2,3], and various models proposed to solve the hierarchy problem [4][5][6] and puzzles of cosmology [7][8][9][10][11] (for review see, e.g., [12][13][14]). New tools in astrophysics, such as gravitational-wave astronomy and black hole shadows, are opening up new ways to experimentally explore extra dimensions [15][16][17][18][19][20][21][22] as was anticipated about two decades ago [23]. Presence of extra dimensions can manifest itself in a number of ways in gravitational-wave observations (for review see, e.g., [24]).…”

“…One of the most common for different theories sign of extra dimensions is the additional polarisations of the gravitational waves [15], the experimental observation of which will become available when more gravitationalwave observatories will start operation. For compact extra dimensions, gravitational-wave signals acquire, also, the tower of massive, high-frequency Kaluza-Klein modes [15][16][17]23], which, however, are currently unavailable for observation. In some theories, gravitational waves detected by the observer on the brane are modified due to the additional contributions into the source term in the effective Einstein equations for the induced metric on the brane [25][26][27][28].…”

Dark matter and the early Universe: A review

“…To hide the extra-dimensions, one generally considers that they are compactified with very small radii much below the scales we are sensitive to. It is often assumed that Standard Model particles are confined outside the extra-dimensions, but gravity may enter them, leading for example to the modification of the speed of gravitational waves [64]. The existence of such extra-dimensions could give birth to effective scalar fields in our 4-dimensional world, such as dilatons [65,66], or other new particles [67,68].…”