Einstein's Other Gravity and the Acceleration of the Universe

TL;DR

This paper explores f(T) gravity, an extension of teleparallel theory where torsion replaces curvature, leading to second-order field equations capable of explaining cosmic acceleration.

Contribution

It introduces and analyzes f(T) gravity theories as a viable alternative to general relativity for explaining the universe's accelerated expansion.

Findings

f(T) theories produce second-order field equations

f(T) models can account for cosmic acceleration

Unique features distinguish f(T) from other gravity theories

Abstract

Spacetime curvature plays the primary role in general relativity but Einstein later considered a theory where torsion was the central quantity. Just as the Einstein-Hilbert action in the Ricci curvature scalar R can be generalized to f(R) gravity, we consider extensions of teleparallel, or torsion scalar T, gravity to f(T) theories. The field equations are naturally second order, avoiding pathologies, and can give rise to cosmic acceleration with unique features.