A singularity problem for interacting massive vectors

TL;DR

This paper identifies a new consistency condition for interacting massive vector fields, revealing a potential singularity issue that could affect their cosmological and astrophysical applications.

Contribution

It derives a novel condition on the classical limit of massive vector theories, highlighting a singularity problem related to their non-trivial constraints.

Findings

Violation of the condition leads to singularities in the auxiliary component's time derivative.

The condition impacts the cosmic evolution and superradiance phenomena involving massive vectors.

The results suggest similar issues may exist in other constrained systems.

Abstract

Interacting massive spin-1 fields have been widely used in cosmology and particle physics. We obtain a new condition on the validity of the classical limit of these theories related to the non-trivial constraints that exist for vector field components. A violation of this consistency condition causes a singularity in the time derivative of the auxiliary component and could impact, for example, the field's cosmic history and superradiance around black holes. Such a condition is expected to exist generically in many other non-trivially constrained systems.