Abstract

The observed positive cosmological constant implies that spatial infinity is forever beyond our reach. We must learn to dial down our attachment to observables defined on the boundary of spacetime. While this is ultimately a very hard problem for quantum-gravity reasons, we can begin flexing our muscles within well-understood theory. In this talk, I’ll describe an S-matrix-like calculation of field evolution between the past and future horizons of a de Sitter static patch, i.e. of a largest observable region in de Sitter space. The field theory we’ll consider is a conformally massless scalar with cubic coupling, intended as a simple case with similarities to perturbative GR. I will present a general strategy for the calculation, by decomposing it into a pair of Poincare-patch evolutions, sewn together by a coordinate inversion. As an intermediate step, I’ll present some apparently new results on the inversion of plane waves in Minkowski space.