Hereditary Effects in Eccentric Compact Binary Inspirals to Third Post-Newtonian Order

TL;DR

This paper derives the first closed-form analytic expressions for hereditary effects in eccentric compact binary inspirals at third post-Newtonian order, enabling precise and efficient gravitational wave modeling across all eccentricities.

Contribution

It provides novel closed-form, analytic formulas for hereditary effects in eccentric binaries at third post-Newtonian order, surpassing previous numerical and small-eccentricity approaches.

Findings

Superasymptotic series achieve >10^-3 accuracy at all eccentricities.

Hyperasymptotic expressions improve accuracy to >10^-8.

Analytic flux expressions match numerical Bessel sum calculations.

Abstract

While there has been much success in understanding the orbital dynamics and gravitational wave emission of eccentric compact binaries in the post-Newtonian formalism, some problems still remain. The largest of these concerns hereditary effects: non-linear phenomena related to the scattering off of the background curved spacetime (tails) and to the generation of gravitational waves by gravitational waves (memory). Currently, these hereditary effects are only known numerically for arbitrary eccentricity through infinite sums of Bessel functions, with closed-form, analytic results only available in the small eccentricity limit. We here calculate, for the first time, closed-form, analytic expressions for all hereditary effects to third post-Newtonian order in binaries with arbitrary eccentricity. For the tails, we first asymptotically expand all Bessel functions in high eccentricity and find a superasymptotic series for each enhancement factor, accurate to better than $10^{-3}$ relative to post-Newtonian numerical calculations at all eccentricities. We further improve the small-eccentricity behavior of the superasymptotic series by generating hyperasymptotic expressions for each enhancement factor, typically accurate to better than $10^{-8}$ at all eccentricities. For the memory, we discuss its computation within the context of an osculating approximation of the binary's orbit and the difficulties that arise. Our closed-form analytic expressions for the hereditary fluxes allow us to numerically compute orbital phases that are identical to those found using an infinite sum of Bessel functions to double numerical precision.