The evolution of circular loops of a cosmic string with periodic tension

TL;DR

This paper studies how cosmic string loops with periodically varying tension evolve in different spacetimes, showing they tend to oscillate rather than collapse into black holes under certain conditions.

Contribution

It introduces the analysis of cosmic string loops with periodic tension in Minkowski and Robertson-Walker spacetimes, revealing their oscillatory evolution.

Findings

Loops with periodic tension oscillate instead of collapsing.

Initial radius influences whether loops collapse or oscillate.

Cosmic string loops avoid black hole formation under specific conditions.

Abstract

In this paper the equation of circular loops of cosmic string with periodic tension is investigated in the Minkowski spacetime and Robertson-Walker universe respectively. We find that the cosmic string loops possessing this kind of time-varying tension will evolve to oscillate instead of collapsing to form a black hole if their initial radii are not small enough.