MHV amplitudes and BCFW recursion for Yang-Mills theory in the de Sitter static patch

Understand

We study the scattering problem in the static patch of de Sitter space, i.e.

• the problem of field evolution between the past and future horizons of a de Sitter observer.
• We formulate the problem in terms of off-shell fields in Poincare coordinates.
• This is especially convenient for conformal theories, where the static patch can be viewed as a flat causal diamond, with one tip at the origin and the other at timelike infinity.