Gravitational diffraction radiation

TL;DR

This paper proposes that particles in a universe modeled as a membrane in higher dimensions can emit gravitational waves due to spacetime inhomogeneities, analogous to electromagnetic diffraction radiation, with implications for brane-world scenarios.

Contribution

It introduces a general formula for gravitational diffraction radiation in higher-dimensional models and explores its potential to constrain brane perturbations.

Findings

Gravitational diffraction radiation can carry away significant particle energy.

The derived formula applies to flat compact extra dimensions.

Constraints on brane perturbation scales are established.

Abstract

We show that if the visible universe is a membrane embedded in a higher-dimensional space, particles in uniform motion radiate gravitational waves because of spacetime lumpiness. This phenomenon is analogous to the electromagnetic diffraction radiation of a charge moving near to a metallic grating. In the gravitational case, the role of the metallic grating is played by the inhomogeneities of the extra-dimensional space, such as a hidden brane. We derive a general formula for gravitational diffraction radiation and apply it to a higher-dimensional scenario with flat compact extra dimensions. Gravitational diffraction radiation may carry away a significant portion of the particle's initial energy. This allows to set stringent limits on the scale of brane perturbations. Physical effects of gravitational diffraction radiation are briefly discussed.