Cosmic strings from pure Yang-Mills theory

TL;DR

This paper explores the formation, properties, and gravitational wave signatures of cosmic strings arising from pure Yang-Mills theories, linking theoretical physics, holography, and observational prospects.

Contribution

It demonstrates that pure Yang-Mills theories can produce cosmic F- and D-strings without extra dimensions, and analyzes their gravitational wave signals for detection.

Findings

Cosmic strings from pure YM theories are dual to fundamental strings or D-branes.

Reconnection probabilities are suppressed by factors depending on N.

Gravitational wave signals could be detectable by SKA and LISA if the confinement scale is sufficiently high.

Abstract

We discuss the formation of cosmic strings or macroscopic color flux tubes at the phase transition from the deconfinement to confinement phase in pure Yang-Mills (YM) theory, such as SU($N$), Sp($N$), SO($N$), and Spin($N$), based on the current understanding of theoretical physics. According to the holographic dual descriptions, the cosmic strings are dual to fundamental strings or wrapped D-branes in the gravity side depending on the structure of the gauge group, and the reconnection probability is suppressed by $\mathcal{O}(N^{-2})$ and $e^{-\mathcal{O}(N)}$, respectively. The pure YM theory thus provides a simple realization of cosmic F- and D-strings without the need for a brane-inflationary scenario or extra dimension. We also review the stability of cosmic strings based on the concept of 1-form symmetry, which further implies the existence of a baryon vertex in some YM theory. We calculate the gravitational wave spectrum that is emitted from the cosmic strings based on an extended velocity-dependent one-scale model and discuss its detectability based on ongoing and planned gravitational-wave experiments. In particular, the SKA and LISA can observe gravitational signals if the confinement scale is higher than $\mathcal{O}(10^{12})\,\mathrm{GeV}$ and $\mathcal{O}(10^{10})\,\mathrm{GeV}$ for SU($N$) with $N = \mathcal{O}(1)$, respectively.