Improved calculation of the gravitational wave spectrum from kinks on infinite cosmic strings

TL;DR

This paper presents a numerical method to accurately compute the gravitational wave spectrum from kinks on infinite cosmic strings, improving previous analytical estimates and aiding future gravitational wave detection efforts.

Contribution

It introduces a numerical approach to solve the evolution of kink sharpness distribution, refining the spectral predictions for gravitational waves from cosmic strings.

Findings

Number of small-sharpness kinks is larger than previous estimates

Spectral shape of gravitational waves is affected by kink distribution

Provides more precise predictions for future gravitational wave experiments

Abstract

Gravitational wave observations provide unique opportunities to search for cosmic strings. One of the strongest sources of gravitational waves is discontinuities of cosmic strings, called kinks, which are generated at points of intersection. Kinks on infinite strings are known to generate a gravitational wave background over a wide range of frequencies. In this paper, we calculate the spectrum of the gravitational wave background by numerically solving the evolution equation for the distribution function of the kink sharpness. We find that the number of kinks for small sharpness is larger than the analytical estimate used in a previous work, which makes a difference in the spectral shape. Our numerical approach also helps to avoid the use of analytic approximations, and enables us to make a more precise prediction on the spectral amplitude for future gravitational wave experiments.