Symmetron Fields: Screening Long-Range Forces Through Local Symmetry Restoration

TL;DR

This paper introduces a screening mechanism for scalar fields that allows long-range gravitational forces to exist in the universe while remaining undetectable in high-density local environments, by restoring symmetry locally.

Contribution

It proposes a novel symmetry-restoration screening mechanism for scalar fields that enables long-range forces without conflicting with local gravity tests.

Findings

Predicts deviations from general relativity within next-generation experimental reach.

Foresees observable violations of the equivalence principle.

Distinguishes from other modified gravity theories through specific experimental signatures.

Abstract

We present a screening mechanism that allows a scalar field to mediate a long range (~Mpc) force of gravitational strength in the cosmos while satisfying local tests of gravity. The mechanism hinges on local symmetry restoration in the presence of matter. In regions of sufficiently high matter density, the field is drawn towards \phi = 0 where its coupling to matter vanishes and the \phi-> -\phi symmetry is restored. In regions of low density, however, the symmetry is spontaneously broken, and the field couples to matter with gravitational strength. We predict deviations from general relativity in the solar system that are within reach of next-generation experiments, as well as astrophysically observable violations of the equivalence principle. The model can be distinguished experimentally from Brans-Dicke gravity, chameleon theories and brane-world modifications of gravity.