LAUSR

We construct explicit mode expansions of various tree-level propagators in the Rindler–de Sitter universe, also known as the static (or compact) patch of the de Sitter spacetime. We construct in particular the Wightman functions for thermal states having a generic temperature T. We give a fresh simple proof that the only thermal Wightman propagator that respects the de Sitter isometry is the restriction to the Rindler–de Sitter wedge of the propagator for the Bunch-Davies state. It is the thermal state with T=(2π)-1 in the units of de Sitter curvature. We show that propagators with T≠(2π)-1 are only time translation invariant and have extra singularities on the boundary of the static patch. We also construct the expansions for the so-called alpha-vacua in the static patch and discuss the flat limit.