The Production, Spectrum and Evolution of Cosmic Strings in Brane Inflation

TL;DR

This paper investigates production, spectrum, and evolution of cosmic strings in brane inflation. It argues that in brane-world scenarios, tachyon condensation at the end of inflation naturally yields cosmic strings, with a spectrum of tensions due to brane wrapping and KK modes, unlike single-tension field theory strings. The authors show that some strings may dissolve into flux or lower-dimensional branes, while others persist as a network whose interaction rate is reduced by extra dimensions, leading to a potentially large enhancement in string density. They provide a stability analysis of possible brane configurations, compute tension estimates for various scenarios, and apply a one-scale network model to predict scaling with enhanced density, with observational implications for G mu and rho.

Abstract

Brane inflation in superstring theory predicts that cosmic strings (but not domain walls or monopoles) are produced towards the end of the inflationary epoch. Here, we discuss the production, the spectrum and the evolution of such cosmic strings, properties that differentiate them from those coming from an abelian Higgs model. As D-branes in extra dimensions, some type of cosmic strings will dissolve rapidly in spacetime, while the stable ones appear with a spectrum of cosmic string tensions. Moreover, the presence of the extra dimensions reduces the interaction rate of the cosmic strings in some scenarios, resulting in an order of magnitude enhancement of the number/energy density of the cosmic string network when compared to the field theory case.