@article{oai:oist.repo.nii.ac.jp:00001142,
 author = {David, Adrian and Fischer, Nico and Neiman, Yasha},
 issue = {4},
 journal = {Physical Review D},
 month = {Aug},
 note = {We consider massless fields of arbitrary spin in de Sitter space. We introduce a spinor-helicity formalism, which encodes the field data on a cosmological horizon. These variables reduce the free S-matrix in an observer’s causal patch, i.e., the evolution of free fields from one horizon to another, to a simple Fourier transform. We show how this result arises via twistor theory, by decomposing the horizon↔horizon problem into a pair of (more symmetric) horizon↔twistor problems.},
 title = {Spinor-helicity variables for cosmological horizons in de Sitter space},
 volume = {100},
 year = {2019}
}