Gravitational back reaction on piecewise linear cosmic string loops

TL;DR

This paper calculates the gravitational back reaction on piecewise linear cosmic string loops, showing how it affects loop size, shape, and kink sharpness, with implications for gravitational wave emission.

Contribution

It provides a detailed analysis of gravitational back reaction effects on piecewise linear cosmic string loops, including the evolution of kinks and loop evaporation behavior.

Findings

Back reaction reduces loop size consistent with gravitational wave emission.

Square loops evaporate without shape change, others develop less sharp kinks.

Loop shape influences evaporation rate and kink smoothing.

Abstract

We calculate the metric and affine connection due to a piecewise linear cosmic string loop, and the effect of gravitational back reaction for the Garfinkle-Vachaspati loop with four straight segments. As expected, back reaction reduces the size of the loop, in accord with the energy going into gravitational waves. The "square" (maximally symmetric) loop evaporates without changing shape, but for all other loops in this class, the kinks become less sharp and segments between kinks become curved. If the loop is close to the square case, it will evaporate before its kinks are significantly changed, if it is far from square, the opening out of the kinks is much faster than evaporation of the loop.