Non-linear dynamics of cosmic strings with non-scaling loops

Original · EN

At early stages the dynamics of cosmic string networks is expected to be influenced by an excessive production of small loops at the scales of initial conditions lmin. To understand the late time behavior we propose a very simple analytical model of strings with a non-scaling population of loops. The complicated non-linear dynamics is described by only a single parameter N 2/(1-C(lmin)) where C(l) is a correlation function of the string tangent vectors. The model predicts an appearance of two new length scales: the coherence length ξ t/N² and the cross-correlation length χ t/N. At the onset of evolution N 10 and at late times N is expected to grow logarithmically due to cosmological stretching and emission of small loops. The very late time evolution might be modified further when the gravitational back-reaction scale grows larger than lmin.