Scattering Amplitudes for Gravitational Wave Theory

Four years ago, the LIGO/Virgo observation of a black-hole binary mergerheralded the dawn of gravitational-wave astronomy.

The promise of futureobservations calls for an invigorated effort to underpin the theoreticalframework and supply the predictions needed for detecting future signals andexploiting them for astronomical and astrophysical studies.

Ampl2Einsteinwill take ideas and techniques from recent years' dramatic advances in QuantumScattering Amplitudes, creating new tools for taking their classical limitsand using it for gravitational physics.

The powerful `square root' relationbetween gravity and a generalization of electrodynamics known as Yang--Millstheory will play a key role in making this route simpler than direct classicalcalculation.

We will transfer these ideas to classical General Relativity tocompute new perturbative orders, spin-dependent observables, and thedependence on the internal structure of merging objects.

We will exploitsymmetries and structure we find in order to extrapolate to even higher ordersin the gravitational theory.

We will make such calculations vastly simpler,pushing the known frontier much further in perturbation theory and incomplexity of observables.

These advances will give rise to a new generationof gravitational-wave templates, dramatically extending the observing power ofdetectors.

They will allow observers to see weaker signals and will be key toresolving long-standing puzzles about the internal structure of neutron stars.We will apply novel technologies developed for scattering amplitudes tobound-state calculations in both quantum and classical theory.

Our researchwill also lead to a deeper understanding of the classical limit of quantumfield theory, relevant to gravitational-wave observations and beyond.

Thetransfer of ideas to the new domain of General Relativity will dramaticallyenhance our ability to reveal new physics encoded in the subtlest ofgravitational-wave signals.