Back reaction in the formation of a straight cosmic string

TL;DR

This paper models the formation of a straight cosmic string, calculates its gravitational field, and examines quantum back-reaction effects using semiclassical Einstein equations.

Contribution

It introduces a simple model for cosmic string formation, computes the quantum stress tensor, and analyzes back-reaction effects in a perturbative framework.

Findings

Quantum stress tensor computed to one-loop order.

Back-reaction effects on the gravitational field are quantified.

Model applies to both wiggly and unperturbed strings.

Abstract

A simple model for the formation of a straight cosmic string, wiggly or unperturbed is considered. The gravitational field of such string is computed in the linear approximation. The vacuum expectation value of the stress tensor of a massless scalar quantum field coupled to the string gravitational field is computed to the one loop order. Finally, the back-reaction effect on the gravitational field of the string is obtained by solving perturbatively the semiclassical Einstein's equations.