  We perform an updated analysis on a long-lived axion domain wall (DW)
network. By simulating the axion field on a 3D lattice and fitting an
analytical model for the DW evolution, we identify the leading energy loss
mechanisms of the DWs and compute the spectrum of axions emitted from the
network. The contribution from the DWs to axion dark matter (DM) density is
derived, with viable parameter space given. The application to both QCD axions
and general axion-like particles (ALPs) are considered. Due to the new
approaches taken, while our results bear consistency with earlier literature,
notable discrepancies are also revealed, such as the prediction for DM
abundance, which may have a profound impact on axion phenomenology at large.

High Energy Physics - Phenomenology;Cosmology and Nongalactic Astrophysics;High Energy Physics - Lattice