Speaker
David Dunsky
(New York University)
Description
Speaker: David Dunsky
Abstract: Multiple axions may emerge in the low-energy effective theory of Nature. In general, the potentials describing these axion fields are non-diagonal, leading to mass mixing between axion states and rich dynamics such as level-crossings. In this talk, I will discuss the cosmological evolution of such multi-axion systems, showing how their cosmological abundances can be determined even when their mass mixing changes rapidly (ie non-adiabatically) via the Landau-Zener formalism. From this, I will show how the standard misalignment abundance prediction for the usual QCD axion gets modified by the presence of an additional axion, and how it effects haloscope searches.