Compact binaries in modified gravity

Summary:

I am studying the properties of compact objects, such as black holes, in the context of modified gravity. For my first year I am focusing on Gauss-Bonnet gravity, for which the Einstein-Hilbert action contains an additional quadratic (Gauss-Bonnet) curvature term. By coupling this term to a scalar field, one discovers that black holes can develop scalar hair. This violation of the no-hair theorem provides potential for observing new fundamental physics through imprints on gravitational waves from black hole collisions. Thus ultimately the aim of my project is to quantify the signature of this modified gravity on gravitational waves for experimental comparison.

Methodology:

Due to the high strength in curvature exhibited during black hole collisions my project is mostly numerical. It consists of decomposing the evolution equations of Gauss-bonnet gravity (initially at second-order in the coupling) into a 3+1 form such as the BSSN formalism. As a Cauchy problem one can then implement a code to evolve the system and extract results (I will likely be using the Einstein toolkit for this). For the time being the systems I will be evolving are single and binary black holes (with the corresponding coupled scalar field).