Consistent non-minimal couplings of massive higher-spin particles

Abstract

The mutual compatibility of the dynamical equations and constraints describing a massive particle of arbitrary spin, though essential for consistency, is generically lost in the presence of interactions. The conventional Lagrangian approach avoids this difficulty, but fails to ensure light-cone propagation and becomes very cumbersome. In this paper, we take an alternative route−the involutive form of the equations and constraints−to guarantee their algebraic consistency. This approach enormously simplifies the search for consistent interactions, now seen as deformations of the involutive system, by keeping manifest the causal propagation of the correct number of degrees of freedom. We consider massive particles of arbitrary integer spin in electromagnetic and gravitational backgrounds to find their possible non-minimal local couplings. Apart from easily reproducing some well-known results, we find restrictions on the backgrounds for consistent propagation of such a particle in isolation. The results can be altered by non-local interactions that may arise from additional massive states in the interacting theory.

Large-scale messengers from massive higher spin fields

“…In particular, their coupling to gravity or electromagnetism has proven to be a highly non-trivial task. Over the past few years there has been a noticeable progress toward a better understanding of higher spin fields, their interactions, as well as their behavior in external background fields, see [38][39][40][41][42][43][44][45] for a non-comprehensive list of references. In this work we argued that irrespective of these difficulties, general principles of Poincaré covrainace and analaticity of the Green's functions are enough to dictate the form of the energy-momentum tensor correlators and to conclude that the production of massive higher spin fields from vacuum is accompanied by large-scale signals that can be printed in the Cosmic Microwave Background (CMB) or detected in terrestrial or space-based gravitational wave interferometry (GWI) [46].…”

Mixed-symmetry fields in AdS(5), conformal fields, and AdS/CFT

“…Discussion of massive fields in gravitational backgrounds may be found, e.g., in refs. [45][46][47][48][49].…”

Higher-spin modes in a domain-wall universe

“…For ∇ µ R = 0, the latter condition is automatic. When ∇ µ R = 0, there are two possibilities: one is to start with a field whose trace is vanishing identically rather than just as an on-shell condition [36,38]. In this case, K µ 1 ...µ s−2 would never appear in the system and its reduced number of gauge identities.…”