Massive gravitational waves from the Cosmic Defect theory

TL;DR

This paper explores the linearized Cosmic Defect theory, revealing that it predicts massive gravitational waves with Yukawa-like potentials and additional polarization modes, consistent with experimental constraints.

Contribution

It introduces a linearized version of the Cosmic Defect theory, showing it predicts massive gravitational waves with unique polarization modes and aligns with observational data.

Findings

Yukawa-like gravitational potential in the weak field limit

Presence of massive and longitudinal gravitational wave modes

Consistency with Solar system and galactic scale constraints

Abstract

The Cosmic Defect theory (CD), which is presented elsewhere in this conference, introduces in the standard Einstein-Hilbert Lagrangian an elastic term accounting for the strain of space-time viewed as a four-dimensional physical continuum. In this framework the Ricci scalar acts as the kinetical term of the strain field whose potential is represented by the additional terms. Here we are presenting the linearised version of the theory in order to analyze its implications in the weak field limit. First we discuss the recovery of the Newtonian limit. We find that the typical static weak field limit imposes a constraint on the values of the two parameters (Lame coefficients) of the theory. Once the constraint has been implemented, the typical gravitational potential turns out to be Yukawa-like. The value for the Yukawa parameter is consistent with the constraints coming from the experimental data at the Solar system and galactic scales. We then come to the propagating solutions of the linearised Einstein equations in vacuo, i.e. to gravitational waves. Here, analogously with other alternative or extended theories of gravity, the presence of the strain field produces massive waves, where massive (in this completely classical context) means subluminal. Furthermore longitudinal polarization modes are allowed too, thus lending, in principle, a way for discriminating these waves from the plane GR ones.