Fixing the dynamical evolution in scalar-Gauss-Bonnet gravity

Understand

One of the major obstacles to testing alternative theories of gravity with gravitational-wave data from merging binaries of compact objects is the formulation of their field equations, which is often mathematically ill-suited for time evolutions.

• A possible way to address these delicate shortcomings is the fixing-the-equations approach, which was developed to control the behaviour of the high-frequency modes of the solutions and the potentially significant flow towards ultra-violet modes.
• This is particularly worrisome in gravitational collapse, where even black hole formation might be insufficient to shield regions of the spacetime where these pathologies might arise.
• Here, we focus (as a representative example) on scalar-Gauss-Bonnet gravity, a theory which can lead to ill-posed dynamical evolutions, but with intriguing stationary black hole physics.