Cosmic Gravitational Microwave Backgrounds (CGMB) and the Cosmology of the dilaton-Einstein-Gauss-Bonnet theory
ABSTRACT
We begin by presenting the motivation for frameworks beyond Einstein's gravity and the ΛCDM paradigm, both from the theoretical and observational aspects. Sources and detectors of Gravitational Waves (GWs) are briefly reviewed with GWs as a tool for testing or constraining theories especially beyond Einstein's General Relativity theory. The main focus is on the CGMB from the hot plasmas in the early universe whose pea frequency is close to 100GHz. Next, our discussion will be on the cosmology of dilaton-Einstein-Gauss-Bonnet (DEGB) gravity . This represents one of the simplest extensions through the inclusion of higher-curvature terms. Particular attention is given to the emergence of a novel phase within dEGB cosmology at high temperatures, supplementing the established radiation, matter, and dark energy-dominated phases characteristic of the ΛCDM model. Out of the many implication of dEGB cosmology, we describe the impact to the CGMB from the hot plasmas consisting of the standard model particle s in the early universe . The sources and propagation of the GWs depend on the gravity theory. We point out that CGMB can be enhanced up to the visible range for the detectors near future with the present technology. This should lead either to the new discovery of the Ultra High Frequency gravitational waves of CGMB or the constraints to the DEGB theory if not .
