Higher spin de Sitter quasinormal modes

TL;DR

This paper constructs higher spin quasinormal modes in de Sitter space algebraically, revealing their representation structure and connection to boundary currents, with implications for understanding higher spin fields in cosmological backgrounds.

Contribution

It introduces an algebraic method to construct higher spin quasinormal modes in de Sitter space and links their spectrum to Harish-Chandra characters of SO(1,D) representations.

Findings

Quasinormal modes form two nonunitary lowest-weight representations.

Massless higher spin modes are generated by boundary conserved currents.

Quasinormal spectrum is encoded in Harish-Chandra characters.

Abstract

We construct higher spin quasinormal modes algebraically in $D$-dimensional de Sitter spacetime using the ambient space formalism. The quasinormal modes fall into two nonunitary lowest-weight representations of $\mathfrak{so}(1, D)$. From a local QFT point of view, the lowest-weight quasinormal modes of massless higher spin fields are produced by gauge-invariant boundary conserved currents and boundary higher-spin Weyl tensors inserted at the southern pole of the past boundary. We also show that the quasinormal spectrum of a massless/massive spin-$s$ field is precisely encoded in the Harish-Chandra character corresponding to the unitary massless/massive spin-$s$ $\text{SO}(1, D)$ representation.