How to simulate global cosmic strings with large string tension

Abstract

Global string networks may be relevant in axion production in the early Universe, as well as other cosmological scenarios. Such networks contain a large hierarchy of scales between the string core scale and the Hubble scale, ln(fa/H) ∼ 70, which influences the network dynamics by giving the strings large tensions T ≃ π fa2 ln(fa/H). We present a new numerical approach to simulate such global string networks, capturing the tension without an exponentially large lattice.