Modified Gravitational Waves Across Galaxies from Macroscopic Gravity

Understand

We analyze the propagation of gravitational waves in a medium containing bounded subsystems ("molecules"), able to induce significant Macroscopic Gravity effects.

• We establish a precise constitutive relation between the average quadrupole and the amplitudes of a vacuum gravitational wave, via the geodesic deviation equation.
• Then we determine the modified equation for the wave inside the medium and the associated dispersion relation.
• A phenomenological analysis shows that anomalous polarizations of the wave emerge with an appreciable experimental detectability if the medium is identified with a typical galaxy.