A Non-Inflationary Axion and ALP Misalignment Mechanism

Abstract: Based on considerations of quantum gravity, global symmetries which lead to axions as pseudo Nambu-Goldstone bosons after low scale symmetry breaking cannot be exact at the Planck scale. Here, we show that Planck-suppressed terms which yield this symmetry breaking may provide a non-inflationary misalignment mechanism which can generate coherent oscillations of the axion and axion-like particle (ALP) fields at low temperatures.