Polarization and speed of gravitational waves in hybrid metric-Palatini f(R)-gravity

TL;DR

This paper investigates the polarization states and propagation speed of gravitational waves in hybrid metric-Palatini f(R)-gravity, revealing the nature of scalar modes and their impact on wave behavior.

Contribution

It clarifies the polarization structure and calculates the wave speed in hybrid f(R)-gravity, advancing understanding of gravitational wave properties in modified gravity theories.

Findings

Scalar transverse breathing and longitudinal modes form a single polarization state.

The propagation speed of gravitational waves in hybrid f(R)-gravity is derived.

Scalar modes are a mixture of polarization states.

Abstract

The question of the correspondence between the number of degrees of freedom and the number of polarization states in hybrid metric-Palatini f(R)-gravity is considered. It is shown that the scalar transverse breathing and longitudinal modes are a mixture of one polarization state. The speed of gravitational waves propagation in hybrid f(R)-gravity is calculated.