Gravitational wave polarization in exponential forms of f(R) gravity with coupling to matter

Abstract

We investigate polarizations of gravitational waves in generalized theories of gravity whose action contains a nonminimal coupling (NMC) between an exponential function of [Formula: see text] gravity and the matter field. Specifically, we consider two classes of such models. In the first case, we assume an explicit NMC between the matter Lagrangian density and curvature while in the second case, we consider the exponential [Formula: see text] gravity coupled to the trace of the stress-energy tensor of a scalar field. Using the Newman–Penrose quantities, we show that these models can be considered as suitable choices in order to produce new polarization modes.

Evolution of gravitational waves in non-minimal coupling between geometry and matter theories of gravity

“…The capability of gravitational waves to interact with matter has provided scientists with direct detection through laser interferometers. This motivated extensive study of gravitational waves in modified gravity theories, particularly the non-minimal ones to investigate the possible constraints on the number of polarization modes of gravitational waves and their associated propagation velocities [77][78][79][80][81][82][83].…”