Topic: Beyond Einstein Gravity with Gauss-Bonnet Term- Black Hole, Astroparticle, and Cosmology

Speaker: Prof. Bum-Hoon Lee

Coordinates: PCFT C1124, 16:00, Tuesday, April 14

Abstract: 

We start with the motivation for the Gravity Theory beyond Einstein from the view point of the theoretical arguments and the recent observational data challenge the ΛCDM (Lambda (dark energy) Cold Dark Matter) cosmology model.
With higher curvature terms anticipated, we primarily focus on the Einstein- dilaton-Gauss-Bonnet (EdGB) Gravity in four dimensions, as it represents the simplest extension. We are going to present the properties of the EdGB theory through black holes, astroparticles, and cosmological implications in brief.
A notable feature of EdGB Black holes, unlike Einstein's gravity, is the presence of a minimum mass threshold below which a black hole cannot form. Another property is that a single black hole can be splitted into two in some parameter range.
We provide a brief overview of the universe's evolution. The different time evolution affects many phenomena well known in the standard cosmology. One example is the application to the WIMP physics, which can be used to contrain the EdGB model. We also show that there exists another phase with the attractor property in the high enough temperature range in addition to the phases dominated by radiation, matter, and the cosmological constant. As one of the implication, we show the possibility of the enhancement of the Cosmic Gravitational Microwave Background.