Speaker
Description
I will discuss keys aspects of the nature of radiation from global strings and its impact on the relic axion density, informed by studying the radiation emitted by perturbed straight strings in simulations. Particular attention is given to the difference between the overall phase of the field and the small perturbations about the string solution (which correspond to the axions). A significant correction is required to be sure that one is analysing the axions and not the self-field of the string.
I will also raise the question of how well the simple case of a single complex scalar can model the behaviour of axion strings in more complicated scenarios, such as the DFSZ model, where the phenomena of both fractional vortices and superconductivity may be relevant.
