Doing without the Equivalence Principle

TL;DR

This paper demonstrates that teleparallel gravity, a gauge theory of translation, can describe gravitation consistently without relying on the weak equivalence principle, unlike Einstein's general relativity.

Contribution

It shows that teleparallel gravity remains consistent as a gravitational theory even when the weak equivalence principle does not hold.

Findings

Teleparallel gravity can be formulated without the weak equivalence principle.

The theory describes gravity as a force similar to electromagnetism.

It remains consistent and predictive without the universality of free-fall.

Abstract

In Einstein's general relativity, geometry replaces the concept of force in the description of the gravitation interaction. Such an approach rests on the universality of free-fall--the weak equivalence principle--and would break down without it. On the other hand, the teleparallel version of general relativity, a gauge theory for the translation group, describes the gravitational interaction by a force similar to the Lorentz force of electromagnetism, a non-universal interaction. It is shown that, similarly to the Maxwell's description of electromagnetism, the teleparallel gauge approach provides a consistent theory for gravitation even in the absence of the weak equivalence principle.