Tidal effects and renormalization at fourth post-Minkowskian order

Abstract

We determine the adiabatic tidal contributions to the radiation reacted momentum impulse $\hat{I}”p_i^{\hat{I}}¼$ and scattering angle $\hat{I}¸$ between two scattered massive bodies (neutron stars) at next-to-next-to-leading post-Minkowskian (PM) order. The state-of-the-art three-loop (4PM) worldline quantum field theory toolkit using dimensional regularization is employed to establish the classical observables. We encounter divergent terms in the gravito-electric and gravito-magnetic quadrupolar sectors necessitating the addition of post-adiabatic counterterms in this classical theory. This leads us to include also the leading post-adiabatic tidal contributions to the observables. The resulting renormalization group flow of the associated post-adiabatic Love numbers is established and shown to agree with a recent gravito-electric third post-Newtonian analysis in the non-relativistic limit.

10 pages, 3 figures, v2: minor changes, published in PRD