Quantum field theory

Scattering

Introduction to the mathematics of general relativity

Observable

Numerical relativity

Quantum

Quantum gravity

Physics

Gravitational field

Scattering amplitude

Gravitation

Pure mathematics

Mathematics

Theoretical physics

Quantum mechanics

Unitarity

General relativity

Theory of relativity

Field (mathematics)

Classical mechanics

Physical Review Letters

Weoutline the program to apply modern quantum field theory methods to calculate observables in classical general relativity through a truncation to classical terms of the multigraviton, two-body, on-shell scattering amplitudes between massive fields. Since only long-distance interactions corresponding to nonanalytic pieces need to be included, unitarity cuts provide substantial simplifications for both post-Newtonian and post-Minkowskian expansions. We illustrate this quantum field theoretic approach to classical general relativity by computing the interaction potentials to second order in the post-Newtonian expansion, as well as the scattering functions for two massive objects to second order in the post-Minkowskian expansion. We also derive an all-order exact result for gravitational light-by-light scattering.

General Relativity from Scattering Amplitudes