The Cosmological Bootstrap: Weight-Shifting Operators and Scalar Seeds
  A key insight of the bootstrap approach to cosmological correlations is the
fact that all correlators of slow-roll inflation can be reduced to a unique
building block---the four-point function of conformally coupled scalars,
arising from the exchange of a massive scalar. Correlators corresponding to the
exchange of particles with spin are then obtained by applying a spin-raising
operator to the scalar-exchange solution. Similarly, the correlators of
massless external fields can be derived by acting with a suitable
weight-raising operator. In this paper, we present a systematic and highly
streamlined derivation of these operators (and their generalizations) using
tools of conformal field theory. Our results greatly simplify the theoretical
foundations of the cosmological bootstrap program.
