Theory-agnostic framework for dynamical scalarization of compact binaries

Several classes of modified theories of gravity suggest that gravity may undergo a phase transition ---known as spontaneous scalarization--- in the strong-field regime. The detection of such a new phase would constitute a smoking-gun for corrections to general relativity at the classical level. Using a strong-field-agnostic effective-field-theory approach, we show that all theories that exhibit spontaneous scalarization can also manifest dynamical scalarization, a phase transition associated with symmetry breaking in a binary system. We derive an effective point-particle action that provides a simple parametrization describing both phenomena, which establishes a foundation for theory-agnostic searches for scalarization in gravitational-wave observations. This parametrization can be mapped onto any theory in which scalarization occurs; we demonstrate this point explicitly for binary black holes with modified electrodynamics.