Scattering amplitudes provide a convenient strategy to calculate gravitational-wave observables characterizing compact binaries in the weak-field or post-Minkowskian (PM) regime, when the two objects remain far away from each other. Conversely, classical soft theorems encode exact information about the dynamics of such systems and do not rely on the PM expansion, while of course restricting to...
Non-conservative processes, such as gravitational radiation in
compact binaries, are inherently challenging to describe within traditional
action principles. To address this limitation, a useful strategy is to embed
the system into a higher dimensional manifold, which allows the variational
principle to be reframed via initial (causal) conditions. This approach has
been explored both in...
Exact solutions are crucial in our understanding of the gravitational field both for black hole and gravitational waves. In this talk, I will review the efforts in constructing exact solutions in modified gravity, focusing on the case of Degenerate Higher Order Scalar Tensor (DHOST) theories. I will underline the limitations we face so far to explore and organize the solution space of these...
