Higher-Spin Theory and Space-Time Metamorphoses

TL;DR

Higher-spin gauge theories extend conventional gauge theories with an infinite tower of massless fields and infinite-dimensional symmetries, suggesting a spacetime description where Riemannian geometry is not fundamental. The framework employs unfolded dynamics and star-product formalisms (Vasiliev equations) in AdS backgrounds, enabling consistent nonlinear interactions and a holographic AdS_4/CFT_3 correspondence for HS currents. Key contributions include the central on-shell theorem for free HS fields, the nonlinear Vasiliev system, and the interpretation of spacetime metamorphoses via unfolded dynamics that relate theories in different dimensions. The work points to deep connections with quantum gravity and String Theory through multiparticle symmetries, and outlines future directions such as exact solutions, holographic RG flows, and potential cosmological implications of the HS scalar.

Abstract

Introductory lectures on higher-spin gauge theory given at 7 Aegean workshop on non-Einstein theories of gravity. The emphasis is on qualitative features of the higher-spin gauge theory and peculiarities of its space-time interpretation. In particular, it is explained that Riemannian geometry cannot play a fundamental role in the higher-spin gauge theory. The higher-spin symmetries are argued to occur at ultra high energy scales beyond the Planck scale. This suggests that the higher-spin gauge theory can help to understand Quantum Gravity. Various types of higher-spin dualities are briefly discussed.