Novel Properties of Massive Higher Spin Fields

TL;DR

This paper explores the unique properties and challenges of massive higher spin fields in cosmological backgrounds, revealing new phenomena in their degrees of freedom, unitarity, and interactions, with implications for supergravity.

Contribution

It introduces a novel phase diagram for higher spin fields in (m^2, Λ) space and discusses potential partial revival of de Sitter supergravity, clarifying interaction obstacles.

Findings

Identification of qualitative effects on degrees of freedom and unitarity

Causality issues in coupling to gravity and electromagnetism

Potential for partial resurrection of de Sitter supergravity

Abstract

I outline a series of results obtained in collaboration with A. Waldron on the properties of massive higher (s>1) spin fields in cosmological, constant curvature, backgrounds and the resulting unexpected qualitative effects on their degrees of freedom and unitarity properties. The dimensional parameter $\L$ extends the flat space m-line to a $(m^2,\L)$ "phase" plane in which these novel phenomena unfold. In this light, I discuss a possible partial resurrection of deSitter supergravity. I will also exhibit the well-known causality problems of coupling these systems to gravity and, for complex fields, to electromagnetism, systematizing some of the occasionally misunderstood obstacles to interactions, particularly for s = 3/2 and 2.