Testing metric-affine f(R)-gravity by relic scalar gravitational waves

TL;DR

This paper investigates scalar gravitational waves in metric-affine f(R)-gravity, proposing a method to distinguish it from metric theories through polarization analysis and assessing detectability with current interferometers.

Contribution

It extends cross correlation analysis to include scalar polarization modes and evaluates the potential for detecting relic scalar gravitational waves.

Findings

Scalar gravitational waves can be distinguished in metric-affine f(R)-gravity.

The detectable energy density of relic scalar gravitons is calculated.

Detection prospects are discussed for VIRGO, LIGO, and LISA.

Abstract

We discuss the emergence of scalar gravitational waves in metric-affine f(R)-gravity. Such a component allows to discriminate between metric and metric-affine theories The intrinsic meaning of this result is that the geodesic structure of the theory can be discriminated. We extend the formalism of cross correlation analysis, including the additional polarization mode, and calculate the detectable energy density of the spectrum for cosmological relic gravitons. The possible detection of the signal is discussed against sensitivities of VIRGO, LIGO and LISA interferometers.