Gravitational Wave Bursts as Harbingers of Cosmic Strings Diluted by Inflation

TL;DR

This paper shows that cosmic strings diluted by inflation can re-emerge to produce observable gravitational wave bursts, challenging the usual expectation that inflation erases such relics.

Contribution

It demonstrates that a network of cosmic strings can regrow after inflation and generate detectable GW bursts, providing a new observational window into early universe physics.

Findings

Diluted cosmic strings can produce observable GW bursts.

GW signals from these strings are distinguishable from background.

Potential detectability with current and future GW observatories.

Abstract

A standard expectation of primordial cosmological inflation is that it dilutes all relics created before its onset to unobservable levels. We present a counterexample to this expectation by demonstrating that a network of cosmic strings diluted by inflation can regrow to a level that is potentially observable today in gravitational waves~(GWs). In contrast to undiluted cosmic strings, whose primary GW signals are typically in the form of a stochastic GW background, the leading signal from a diluted cosmic string network can be distinctive bursts of GWs within the sensitivity reach of current and future GW observatories.