Orateur
Description
Compact binaries are the primary sources of gravitational waves measured by gravitational-wave detectors. In this context, obtaining the equations of motion in different approximation schemes is essential for producing waveform templates with the accuracy required by future LISA detections.
In this presentation, I derive the gravitational radiation-reaction force on a compact binary system at the fourth-and-a-half post-Newtonian (4.5PN) order of general relativity, i.e., 2PN orders beyond the leading 2.5PN radiation-reaction term in harmonic coordinates. This result is derived using the 4.5PN gravitational radiation-reaction force obtained recently in the Burke–Thorne (BT) coordinate system.
This represents a significant improvement, as harmonic coordinates provide a manifestly Lorentz-invariant formulation, and offer a much simpler expression compared to the BT coordinates. Moreover, they pave the way for comparisons with other approximation schemes (such as post-Minkowskian) at 4.5PN.
Using the harmonic radiation-reaction acceleration, we also derive from first principles the flux-balance laws and the center-of-mass position, in a general frame up to the 4.5PN order.