Screening Vector Field Modifications of General Relativity

TL;DR

This paper introduces a screening mechanism for vector-tensor modifications of general relativity, utilizing a conformal factor that varies with environmental density, leading to suppression of fifth forces and Lorentz violations.

Contribution

It proposes a novel screening mechanism based on a conformal factor dependent on the vector field norm, addressing both cosmological and local constraints.

Findings

The screening mechanism effectively suppresses fifth forces in high-density regions.

The model predicts Lorentz violations in low-density environments.

Cosmological and local constraints are consistent with the proposed mechanism.

Abstract

A screening mechanism for conformal vector-tensor modifications of general relativity is proposed. The conformal factor depends on the norm of the vector field and makes the field to vanish in high dense regions, whereas drives it to a non-null value in low density environments. Such process occurs due to a spontaneous symmetry breaking mechanism and gives rise to both the screening of fifth forces as well as Lorentz violations. The cosmology and local constraints are also computed.