Modeling dynamical scalarization with a resummed post-Newtonian expansion

TL;DR

This paper develops a resummed post-Newtonian formalism to model dynamical scalarization in neutron-star binaries, enabling more accurate predictions of scalarization effects near merger in scalar-tensor theories.

Contribution

It introduces a novel resummation approach within post-Newtonian theory to better capture dynamical scalarization phenomena in gravitational-wave modeling.

Findings

Accurately predicts the onset of dynamical scalarization.

Matches well with quasi-equilibrium configuration calculations.

Provides a mathematically consistent framework for scalarization modeling.

Abstract

Despite stringent constraints set by astrophysical observations, there remain viable scalar-tensor theories that could be distinguished from general relativity with gravitational-wave detectors. A promising signal predicted in these alternative theories is dynamical scalarization, which can dramatically affect the evolution of neutron-star binaries near merger. Motivated by the successful treatment of spontaneous scalarization, we develop a formalism that partially resums the post-Newtonian expansion to capture dynamical scalarization in a mathematically consistent manner. We calculate the post-Newtonian order corrections to the equations of motion and scalar mass of a binary system. Through comparison with quasi-equilibrium configuration calculations, we verify that this new approximation scheme can accurately predict the onset and magnitude of dynamical scalarization.