On the back reaction of gravitational and particle emission and absorption from straight thick cosmic strings: A toy model

TL;DR

This paper investigates how gravitational and particle emissions from thick cosmic strings induce singularities along their symmetry axis, demonstrating that back reaction effects inevitably lead to scalar singularities that cannot be eliminated.

Contribution

It introduces a toy model analyzing emission and absorption effects on thick cosmic strings, revealing the universal formation of scalar singularities due to back reaction.

Findings

Back reaction causes the symmetry axis to become singular.

The singularity is scalar and cannot be removed.

Emission and absorption processes always lead to this singularity.

Abstract

The emission and absorption of gravitational waves and massless particles of an infinitely long straight cosmic string with finite thickness are studied. It is shown in a general term that the back reaction of the emission and absorption {\em always} makes the symmetry axis of the string singular. The singularity is a scalar singularity and cannot be removed.