Massive gravity from Dirichlet boundary conditions

TL;DR

This paper introduces a novel non-linear massive gravity model using a compact extra dimension with specific boundary conditions, reproducing known gravitational phenomena and enabling studies of degravitation.

Contribution

It presents a new explicit non-linear realization of massive gravity via boundary conditions in an extra dimension, aligning with known linear and cubic interaction results.

Findings

Reproduces Fierz-Pauli amplitude at linear level

Demonstrates Vainshtein mechanism in cubic interactions

Supports flat geometry with cosmological constant

Abstract

We propose an explicit non-linear realization of massive gravity, which relies on the introduction of a spurious compact extra dimension, on which we impose half-Newmann and half-Dirichlet boundary conditions. At the linearized level, we recover the expected gravitational exchange amplitude between two sources mediated by a massive Fierz-Pauli spin-2 field, while cubic interactions in the additional helicity-0 mode give rise to the expected Vainsthein mechanism. We also show that this framework can accommodate for a flat four-dimensional geometry in the presence of a cosmological constant, putting this framework on a good footing for the study of degravitation.