Cosmic String Production Towards the End of Brane Inflation

TL;DR

This paper predicts the copious production of cosmic strings during the end of brane inflation in superstring theory, estimating their tension and potential observable effects in cosmic microwave background anisotropy and gravitational waves.

Contribution

It provides a detailed prediction of cosmic string formation from brane collision and estimates their tension, linking string theory to observable cosmological phenomena.

Findings

Cosmic strings produced during brane collision have tension Gμ ≈ 10^{-7}.

Cosmic strings contribute about 10% to CMB anisotropy.

Potential detection of cosmic strings via gravitational waves and pulsar timing.

Abstract

Towards the end of the brane inflationary epoch in the brane world, cosmic strings (but not texture, domain walls or monopoles) are copiously produced during brane collision. These cosmic strings are D$p$-branes with $(p-1)$ dimensions compactified. We elaborate on this prediction of the superstring theory description of the brane world. Using the data on the temperature anisotropy in the cosmic microwave background, we estimate the cosmic string tension $\mu$ to be around $G \mu \simeq 10^{-7}$. This in turn implies that the anisotropy in the cosmic microwave background comes mostly from inflation, but with a component (of order 10%) from cosmic strings. This cosmic string effect should also be observable in gravitational wave detectors and maybe even pulsar timing measurements. Keywords : Inflation, Brane World, Superstring Theory, Cosmic String, Cosmology