If there are a plethora of 4 in 1 Can Cooler axions in nature, they may have a complicated potential and create an axion landscape.We study a possibility that one of the axions is so light that it is cosmologically stable, explaining the observed dark matter density.In particular we focus on a case in which two (or more) shift-symmetry breaking terms conspire to make the axion sufficiently light at the potential minimum.
In this case the axion has a Light Guards flat-bottomed potential.In contrast to the case in which a single cosine term dominates the potential, the axion abundance as well as its isocurvature perturbations are significantly suppressed.This allows an axion with a rather large mass to serve as dark matter without fine-tuning of the initial misalignment, and further makes higher-scale inflation to be consistent with the scenario.