Double copy theory

Double copy theory is a theory in theoretical physics that hypothesizes a perturbative duality between gauge theory and gravity. The theory says that scattering amplitudes in non-Abelian gauge theories can be factorized such that replacement of the color factor by additional kinematic dependence factor, in a well-defined way, automatically leads to gravity scattering amplitudes. It was first written down by Zvi Bern, John Joseph Carrasco and Henrik Johansson in 2010 [1] and was sometimes known as the BCJ duality after its creators[2] or as "gravity = gauge x gauge".[3]

The theory can be used to make calculations of gravity scattering amplitudes simpler by instead calculating the Yang–Mills amplitude and following the double copy prescription.[4] This was proven to work at tree level and at higher orders,[1] including at fourth post-Minkowskian order.[5] The theory has been applied to black holes.[6]