Non-Riemannian Cosmic Walls as Boundaries of Spinning Matter

TL;DR

This paper presents a solution in Einstein-Cartan gravity modeling a cosmic wall boundary of spinning matter, highlighting the role of torsion and its relation to cosmic strings, with implications for non-Riemannian spacetime structures.

Contribution

It introduces a novel topological defect solution representing a cosmic wall with spinning matter in Einstein-Cartan theory, linking torsion to cosmic string configurations.

Findings

Solution models a cosmic wall boundary with spinning matter

Torsion is generated by static polarized spins along lines

Pure Riemannian cosmic wall is recovered when torsion is zero

Abstract

An example is given of a plane topological defect solution of linearized Einstein-Cartan (EC) field equation representing a cosmic wall boundary of spinning matter. The source of Cartan torsion is composed of two orthogonal lines of static polarized spins bounded by the cosmic plane wall. The Kopczy\'{n}ski- Obukhov - Tresguerres (KOT) spin fluid stress-energy current coincides with thin planar matter current in the static case. Our solution is similar to Letelier solution of Einstein equation for multiple cosmic strings. Due to this fact we suggest that the lines of spinning matter could be analogous to multiple cosmic spinning string solution in EC theory of gravity. When torsion is turned off a pure Riemannian cosmic wall is obtained.