Radiation Reaction and Gravitational Waves at Fourth Post-Minkowskian Order

Area of Science:

• Gravitational physics
• General relativity
• Astrophysics

Background:

• Understanding binary mergers is crucial for gravitational wave astronomy.
• Previous calculations were limited in scope and order.
• Radiation-reaction effects are essential for accurate waveform modeling.

Purpose of the Study:

• To compute the total impulse in binary scattering at fourth post-Minkowskian order (O(G⁴)).
• To include linear, nonlinear, and hereditary radiation-reaction effects.
• To derive total radiated momentum and energy flux for gravitational wave observables.

Main Methods:

• Utilizing the Schwinger-Keldysh worldline effective field theory framework.
• Applying multiloop integration techniques from collider physics.
• Calculating scattering amplitudes for nonspinning binaries.

Main Results:

• The total impulse at O(G⁴) was obtained, incorporating radiation-reaction effects.
• The total radiated spacetime momentum and energy flux were derived.
• Results are consistent with existing partial calculations in post-Minkowskian and post-Newtonian expansions.

Conclusions:

• This work provides a significant advancement in calculating gravitational waveforms.
• The derived quantities are applicable to generic bound and unbound orbits.
• The findings enhance our ability to interpret gravitational wave signals from binary systems.