Spontaneous Lorentz violation and asymptotic flatness

TL;DR

This paper investigates spontaneous Lorentz violation within the minimal gravity sector of the SME, revealing that the $t$ term uniquely prevents asymptotically flat solutions in static, spherically symmetric spacetimes without matter.

Contribution

It demonstrates that the $t$ term in the minimal gravity sector uniquely obstructs asymptotic flatness, clarifying the $t$ puzzle in Lorentz-violating gravity models.

Findings

The $t$ term fixes the asymptotic behavior of the curvature tensor.

No asymptotically flat solutions exist for the $t$ term in the studied scenario.

The $t$ puzzle is linked to the unique properties of the $t$ term.

Abstract

The Standard Model Extension (SME) is a generic parametrization for Lorentz violation and the phenomenological consequences of the minimal gravity sector of the SME are usually studied using a post-Newtonian expansion that requires spacetime to be asymptotically flat. However, there is a term in this sector for which these approximations are unable to make predictions; this is known as the $t$ puzzle. The present paper studies a model of spontaneous Lorentz violation in the minimal gravity sector of the SME in a static and spherically symmetric situation, when no additional matter fields are present. It is shown that, under the above mentioned assumptions, $t$ is the only term in the minimal gravity sector for which no asymptotically flat solutions exist. This stems from the fact that the $t$ term fixes the asymptotic behavior of all the pieces of the curvature tensor.