Maxwell-like Lagrangians for higher spins

TL;DR

This paper develops a simple, unified Lagrangian framework for describing massless bosons of any spin, applicable to flat and (A)dS spaces, extending to mixed-symmetry tensors and connecting to string theory spectra.

Contribution

It introduces a Maxwell-like Lagrangian formulation for higher-spin fields that is invariant under divergence-free gauge transformations, applicable to various backgrounds and tensor types.

Findings

Unified Lagrangian description for all spins

Applicable to flat and (A)dS backgrounds

Connections to tensionless string theory spectra

Abstract

We show how implementing invariance under divergence-free gauge transformations leads to a remarkably simple Lagrangian description of massless bosons of any spin. Our construction covers both flat and (A)dS backgrounds and extends to tensors of arbitrary mixed-symmetry type. Irreducible and traceless fields produce single-particle actions, while whenever trace constraints can be dispensed with the resulting Lagrangians display the same reducible, multi-particle spectra as those emerging from the tensionless limit of free open-string field theory. For all explored options the corresponding kinetic operators take essentially the same form as in the spin-one, Maxwell case.