Thermodynamics of Cosmic Defect Network Evolution

TL;DR

This paper derives a thermodynamic framework for cosmic defect evolution, extending the VOS model to include new interactions and degrees of freedom, and discusses potential observational implications.

Contribution

It introduces a thermodynamic approach to derive the VOS model for defects of any dimension, including new interaction terms and a dynamical degree of freedom.

Findings

Derived a thermodynamic basis for defect dynamics.

Extended the VOS model to include defect-field interactions.

Discussed potential observational effects of new degrees of freedom.

Abstract

We show that simple thermodynamic conditions determine, to a great extent, the equation of state and dynamics of cosmic defects of arbitrary dimensionality. We use these conditions to provide a more direct derivation of the Velocity-dependent One-Scale (VOS) model for the macroscopic dynamics of topological defects of arbitrary dimensionality in a $N+1$-dimensional homogeneous and isotropic universe. We parameterize the modifications to the VOS model associated to the interaction of the topological defects with other fields, including, in particular, a new dynamical degree of freedom associated to the variation of the mass per unit $p$-area of the defects, and compute the corresponding scaling solutions. The observational impact of this new dynamical degree of freedom is also briefly discussed.