Anomalous dispersion in gravity theories

Altas, Emel
Kilicarslan, Ercan
Tekin, Bayram
A wave pulse (be it a gravitational wave or a light wave) undergoes anomalous dispersion in a vacuum in flat spacetimes with an even number of spatial dimensions even if all the frequencies move at the same speed. Such an anomalous dispersion does not occur in spacetimes with an odd number of spatial dimensions. We study various gravity theories and show that dispersion-free propagation is possible in even number of spatial dimensions if the background is not the Minkowski but the de Sitter spacetime and the gravity theory is massive gravity with a tuned mass in terms of the cosmological constant. Mass and the cosmological constant conspire to get rid of the anomalous dispersion and restore Huygens's principle.


Higher dimensional metrics of colliding gravitational plane waves
Gurses, M; Kahya, EO; Karasu, Atalay (2002-07-15)
We give a higher even dimensional extension of vacuum colliding gravitational plane waves with the combinations of collinear and noncollinear polarized four-dimensional metrics. The singularity structure of space-time depends on the parameters of the solution.
Equivariant Reduction of Gauge Theories over Fuzzy Extra Dimensions
Kürkcüoğlu, Seçkin (IOP Publishing, 2012-2-8)
In SU(N) Yang-Mills theories on a manifold M, which are suitably coupled to a set of scalars, fuzzy spheres may be generated as extra dimensions by spontaneous symmetry breaking. This process results in gauge theories over the product space of the manifold M and the fuzzy spheres with smaller gauge groups. Here we present the SU(2)- and SU(2) x SU(2)-equivariant parametrization of U(2) and U(4) gauge fields on S-F(2), and S-F(2), x S-F(2), respectively and outline the dimensional reduction of these theories...
The effect of rotation, up to second order, on the oscillation frequencies of some delta-scuti stars
Doğan, Gülnur; Kırbıyık, Halil; Department of Physics (2007)
In this work, the effect of rotation on the oscillation frequencies of some radially and nonradially oscillating Delta-Scuti stars have been explored. Rotation has been considered as a perturbation and treated up to the second order. Series of evolutionary models have been calculated for the oscillating stars in question and compared with the observational parameters. Three stars are considered: V350 Peg with no rotation, CC And with a rotational velocity Vsini=20 km/s, and BS Tuc with Vsini=130 km/s. We fi...
Topological black holes and momentum four-vector
Pirinccioglu, Nurettin; Binbay, Figen; AÇIKGÖZ, İRFAN; Aydogdu, Oktay (World Scientific Pub Co Pte Lt, 2007-07-30)
We consider the energy momentum definition of the Moller in both general relativity and teleparallel gravity to evaluate the energy distribution (due to both matter and fields including gravitation) associated with the topological black holes with a conformally coupled scalar field. Our results show that the energy depends on the mass M and charge Q of the black holes and cosmological constant Lambda. In some special limits, the expression of the energy reduces to the energy of the well-known spacetimes. Th...
Black hole collisions at the speed of light
Şentürk, Çetin; Karasu, Atalay; Department of Physics (2010)
The main purpose of this work is to study the collision of two black holes and the energy loss due to the gravitational waves emitted during this collision in the framework of general relativity. For this purpose we first study plane wave geometries and their collisions. More realistic collisions are the pp-wave collisions. As an analytic treatment of this problem, we investigate the head-on collision of two ultra-relativistic black holes. Treating the problem perturbatively, we extract the news function to...
Citation Formats
E. Altas, E. Kilicarslan, and B. Tekin, “Anomalous dispersion in gravity theories,” PHYSICAL REVIEW D, vol. 105, no. 6, pp. 0–0, 2022, Accessed: 00, 2022. [Online]. Available: