Second-order gravitational self-force -- a quick summary

TL;DR

This paper derives the second-order equation of motion for a small compact object in a vacuum spacetime, crucial for precise gravitational waveform modeling in extreme-mass-ratio binaries.

Contribution

It introduces a method to compute the second-order self-force using matched asymptotic expansions and defines an effective metric satisfying Einstein's equations.

Findings

Motion is geodesic in an effective metric satisfying Einstein's equations.

Provides a framework for numerical calculation of the effective metric.

Enhances accuracy of gravitational waveform predictions.

Abstract

In order to extract physical parameters from the waveform of an extreme-mass-ratio binary, one requires a second-order--accurate description of the motion of the smaller of the two objects in the binary. Using a method of matched asymptotic expansions, I derive the second-order equation of motion of a small, nearly spherical and non-rotating compact object in an arbitrary vacuum spacetime. I find that the motion is geodesic in a certain locally defined effective metric satisfying the vacuum Einstein equation through second order, and I outline a method of numerically calculating this effective metric.