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arXiv · 1007.0435

How higher-spin gravity surpasses the spin two barrier: no-go theorems versus yes-go examples

Xavier Bekaert·Nicolas Boulanger·Per Sundell
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Abstract

Aiming at non-experts, we explain the key mechanisms of higher-spin extensions of ordinary gravity. We first overview various no-go theorems for low-energy scattering of massless particles in flat spacetime. In doing so we dress a dictionary between the S-matrix and the Lagrangian approaches, exhibiting their relative advantages and weaknesses, after which we high-light potential loop-holes for non-trivial massless dynamics. We then review positive yes-go results for non-abelian cubic higher-derivative vertices in constantly curved backgrounds. Finally we outline how higher-spin symmetry can be reconciled with the equivalence principle in the presence of a cosmological constant leading to the Fradkin--Vasiliev vertices and Vasiliev's higher-spin gravity with its double perturbative expansion (in terms of numbers of fields and derivatives).

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Xavier Bekaert, Nicolas Boulanger, Per Sundell. 2010-07-02. How higher-spin gravity surpasses the spin two barrier: no-go theorems versus yes-go examples. https://doi.org/10.1103/revmodphys.84.987

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