Two populations of axions can contribute to cold dark matter: the classical field produced via the misalignment mechanism, and the modes produced in the decay of strings. The classical field has extra pressure, as compared to WIMPs, which could have observable consequences in non-linear galaxy formation.
@article{arxiv.1410.4940,
title = {The Pressure of Misalignment Axions: a Difference from WIMPs in Galaxy Formation?},
author = {Sacha Davidson},
journal= {arXiv preprint arXiv:1410.4940},
year = {2014}
}
Comments
4 pages, contribution to the proceedings of PATRAS 2014