de Sitter super-gravity in ambient space formalism

TL;DR

This paper develops a formalism for de Sitter supergravity using ambient space techniques, showing gauge invariance of massless fields and constructing a unitary supergravity theory on the Bunch-Davies vacuum.

Contribution

It introduces a novel ambient space formalism for de Sitter supergravity, demonstrating gauge invariance of massless higher-spin fields and constructing a consistent supergravity model.

Findings

Massless fields with spin ≥ 1 are gauge invariant in this formalism.

A unitary de Sitter supergravity is constructed on the Bunch-Davies vacuum.

The formalism separates fields into scalar and polarization parts, simplifying analysis.

Abstract

In the de Sitter ambient space formalism the massless fields, which include the linear gravity and massless minimally coupled scalar field, can be written in terms of two separate parts: a massless conformally coupled scalar field and a polarization tensor(-spinor) part. Therefore due to the massless conformally coupled scalar field, there exist an unique Bunch-Davies vacuum state for quantum field theory in the de Sitter space time. In the de Sitter ambient space formalism one can show that the massless fields with spin $s\geq 1$ are gauge invariant. By coupling the massless gauge spin-$2$ and the massless gauge spin-$3/2$ fields and using the super-symmetry algebra in de Sitter ambient space formalism, one can naturally construct a unitary de Sitter super-gravity on Bunch-Davies vacuum state.