Stochastic gravitational wave background from smoothed cosmic string loops

TL;DR

This paper provides a comprehensive calculation of the expected stochastic gravitational wave background from cosmic string loops, incorporating realistic loop populations, smoothing effects, and cosmological evolution to predict observable signals.

Contribution

It introduces a detailed model that combines simulation data, gravitational back reaction smoothing, and cosmological propagation to accurately estimate the gravitational wave background from cosmic strings.

Findings

Predicted gravitational wave spectrum from cosmic strings.

Quantified effects of early universe physics on the background.

Estimated contribution of rare bursts to the stochastic background.

Abstract

We do a complete calculation of the stochastic gravitational wave background to be expected from cosmic strings. We start from a population of string loops taken from simulations, smooth these by Lorentzian convolution as a model of gravitational back reaction, calculate the average spectrum of gravitational waves emitted by the string population at any given time, and propagate it through a standard model cosmology to find the stochastic background today. We take into account all known effects, including changes in the number of cosmological relativistic degrees of freedom at early times and the possibility that some energy is in rare bursts that we might never have observed.