Dynamical Systems and Superstring Phases in the Early Universe

TL;DR

This paper explores the dynamics of superstring loops during the early universe, revealing a new attractor solution where most energy is stored in stable cosmic superstring loops, influenced by the scalar field's evolution.

Contribution

It introduces a novel string loop attractor tracker solution within the LVS potential, showing a dominant energy component in stable superstring loops during early cosmological phases.

Findings

75% of energy density in superstring loops on the tracker

Loops remain stable due to decreasing string tension

Mixed radiation-loop trackers can occur in non-LVS potentials

Abstract

We study the string theory dynamics of the volume scalar rolling down an exponential potential during the period between inflation and reheating, in a background of cosmic superstring loops. In the context of the LVS potential, we demonstrate the existence of a novel string loop attractor tracker solution, in which 75% of the energy density of the universe is in the form of a gas of fundamental cosmic superstring loops (a configuration preferred over the standard radiation tracker). On this tracker, it is the continual reduction in the string tension as the volume scalar evolves that makes the loops stable against decay. For more general non-LVS potentials, mixed radiation-loop trackers can also occur.