NLO gravitational quartic-in-spin interaction

A bstract In this paper we derive for the first time complete gravitational quartic-in-spin interaction of generic compact binaries at next-to-leading order in post-Newtonian (PN) expansion. The derivation builds on effective field theory gravitating spinning objects, and its recent extensions, which new type worldline couplings should be considered, as well extension action a particle to quadratic curvature. latter entails Wilson coefficient that appears sector. This work pushes precision frontier with spins fifth PN (5PN) maximally-spinning same informs us Compton scattering higher spins.