The effect of kinematic constraints on multi-tension string network evolution

Understand

We consider the evolution of a network of strings in an expanding universe, allowing for the formation of junctions between strings of different tensions.

• By explicitly including, in the velocity-dependent evolution equations for the network, kinematic constraints associated with the formation of Y-shaped string junctions, we show how they lead to scaling solutions in regimes where they would not otherwise be found, thereby extending the range of parameters which lead to scaling.
• By incorporating these constraints we are able to study their general behaviour for networks with cosmic superstring interaction rules, and predict the scaling densities expected by these networks.