Gravitational field of a stationary circular cosmic string loop

TL;DR

This paper derives an exact solution for the gravitational field of a stationary circular cosmic string loop within full nonlinear Einstein gravity, revealing a singularity at a finite distance but regular elsewhere.

Contribution

It provides the first exact nonlinear Einstein solution for a stationary circular cosmic string loop with equal radial and tangential stresses.

Findings

Exact solution with a finite-distance singularity

Regular gravitational field away from the singularity

Insights into cosmic string loop gravitational properties

Abstract

Gravitational field of a stationary circular cosmic string loop has been studied in the context of full nonlinear Einstein's theory of gravity. It has been assumed that the radial and tangential stresses of the loop are equal to the energy density of the string loop. An exact solution for the system has been presented which has a singularity at a finite distance from the axis,but is regular for any other distances from the axis of the loop.