Effective-action model for dynamical scalarization beyond the adiabatic approximation

In certain scalar-field extensions to general relativity, scalar charges can develop on compact objects in an inspiraling binary-an effect known as dynamical scalarization. This effect can be modeled using effective-field-theory methods applied to the binary within the post-Newtonian approximation. Past analytic investigations focused on the adiabatic (or quasistationary) case for quasicircular orbits. In this work, we explore the full dynamical evolution around the phase transition to the scalarized regime. This allows for generic (eccentric) orbits and to quantify nonadiabatic (e.g., oscillatory) behavior during the phase transition. We also find that even in the circular-orbit case, the onset of scalarization can only be predicted reliably when taking the full dynamics into account, i.e., the adiabatic approximation is not appropriate. Our results pave the way for accurate post-Newtonian predictions for dynamical scalarization effects in gravitational waves from compact binaries.

Automated summary

In certain scalar-field extensions to general relativity, the effect of dynamical scalarization, where scalar charges develop on compact objects in an inspiraling binary, can be modeled using effective-field-theory methods applied to the binary within the post-Newtonian approximation. Previous studies focused on the adiabatic case for quasicircular orbits. This work explores the full dynamical evolution around the phase transition to the scalarized regime, considering generic orbits and quantifying nonadiabatic behavior. The results indicate that the full dynamics must be taken into account to reliably predict the onset of scalarization.