Einstein-Cartan Theory

TL;DR

The Einstein-Cartan Theory extends General Relativity by incorporating torsion in spacetime, linking it to intrinsic angular momentum, and offers a modified gravitational framework that predates the understanding of spin.

Contribution

It introduces a gravitational theory that includes torsion related to intrinsic angular momentum, expanding the geometric framework of spacetime beyond curvature.

Findings

Torsion is related to intrinsic angular momentum.

ECT generalizes Einstein's theory by including torsion.

Historical development predates the discovery of spin.

Abstract

The Einstein--Cartan Theory (ECT) of gravity is a modification of General Relativity Theory (GRT), allowing space-time to have torsion, in addition to curvature, and relating torsion to the density of intrinsic angular momentum. This modification was put forward in 1922 by Elie Cartan, before the discovery of spin. Cartan was influenced by the work of the Cosserat brothers (1909), who considered besides an (asymmetric) force stress tensor also a moments stress tensor in a suitably generalized continuous medium.