Formation and evolution of cosmic D-strings

TL;DR

The paper studies how D- and F-strings can form during brane-anti-brane annihilation at the end of brane inflation and how they evolve cosmologically. It argues that D-string formation from quantum de Sitter fluctuations is strongly suppressed by Ramond-Ramond field dynamics in compact dimensions, while F-strings can form through resonant gauge-field amplification on the unstable brane. It outlines alternative formation channels, including bulk reheating and resonant F-string production, and analyzes the distinctive four-dimensional properties of D-strings. It then investigates the evolution of independent and interacting D- and F-string networks and discusses observational implications such as gravitational lensing and gravitational waves, with signatures shaped by the extra-dimensional geometry and brane dynamics.

Abstract

We study the formation of D and F-cosmic strings in D-brane annihilation after brane inflation. We show that D-string formation by quantum de Sitter fluctuations is severely suppressed, due to suppression of RR field fluctuations in compact dimensions. We discuss the resonant mechanism of production of D and F-strings, which are formed as magnetic and electric flux tubes of the two orthogonal gauge fields living on the world-volume of the unstable brane. We outline the subsequent cosmological evolution of the D-F string network. We also compare the nature of these strings with the ordinary cosmic strings and point out some differences and similarities.