Speaker
Description
Cold dark matter axions produced in the post-inflationary scenario serve as clear targets for their experimental detection, since it is in principle possible to give a sharp prediction for their mass once we understand precisely how they are produced from the decay of global cosmic strings in the early Universe. In recent years, multiple large scale numerical simulations of the cosmological evolution of the Peccei-Quinn (PQ) field were performed to measure the axion spectrum from global strings. This resulted in predictions for the axion dark matter mass in the μeV to meV range, with the largest uncertainties arising from extrapolations over several orders of magnitude in the string tension, necessitated by computational constraints.
We present a comprehensive study on the dynamics of global axion string loops and their decay spectrum. Using high-resolution numerical simulations that incorporate both, static grid and adaptive mesh refinement (AMR), along with analytical arguments, we investigate the evolution of cosmic axion strings and their energy loss mechanisms and discuss implications for the string network evolution.
