Classical double copy and higher-spin fields

TL;DR

This paper extends the Kerr-Schild double copy framework to all free symmetric gauge fields in (A)dS spaces, revealing a spectrum organized by higher-spin symmetry and uncovering fine-tuned mass relations.

Contribution

It demonstrates that the classical double copy extends to higher-spin fields in (A)dS, revealing a structured multicopy pattern and fine-tuned mass relations.

Findings

Double copy extends to all free symmetric gauge fields in (A)dS.

Higher-spin multicopy includes zeroth, single, and double copies.

Mass relations are fine-tuned and organized by higher-spin symmetry.

Abstract

Kerr-Schild double copy is shown to extend naturally to all free symmetric gauge fields propagating on $(A)dS$ in any dimension. Similarly to the standard lower-spin case, the higher-spin multicopy comes along with the zeroth, single, and double copies. The mass-like term of the Fronsdal spin $s$ field equations fixed by gauge symmetry and the mass of the zeroth copy both appear to be remarkably fine-tuned to fit the multicopy pattern forming a spectrum organized by higher-spin symmetry. On the black hole side this curious observation fills up the list of miraculous properties of the Kerr solution.