Dynamics of F/D networks: the role of bound states

TL;DR

This paper investigates how bound states influence the evolution and scaling behavior of cosmic superstring networks composed of F-strings, D-strings, and their bound states, revealing an energy loss mechanism that promotes network scaling.

Contribution

It introduces a numerical approach with controlled initial bound state abundance to study their impact on network evolution and identifies a new energy loss mechanism involving bound state formation.

Findings

All network components scale independently of initial conditions.

Bound state formation leads to an additional energy loss mechanism.

The network maintains scaling due to this energy loss process.

Abstract

We study, via numerical experiments, the role of bound states in the evolution of cosmic superstring networks, being composed by p F-strings, q D-strings and (p,q) bound states. We find robust evidence for scaling of all three components of the network, independently of initial conditions. The novelty of our numerical approach consists of having control over the initial abundance of bound states. This indeed allows us to identify the effect of bound states on the evolution of the network. Our studies also clearly show the existence of an additional energy loss mechanism, resulting to a lower overall string network energy, and thus scaling of the network. This new mechanism consists of the formation of bound states with an increasing length.