| Abstract: |
Probing dark sector theories using a variety of cosmological techniques can lead to insight on the potential role of axion-like particles in the universe. First, I will discuss a framework for computing the gravitational wave (GW) spectrum generated by a magnetic field power spectrum produced at an arbitrary cosmological epoch. I will explain how the GW signal depends on the epoch of magnetogenesis, illustrating the broad applicability of the framework to cosmological magnetic field generation mechanisms. Then, I will show how a pseudoscalar axion can cause indirect parametric resonance of the electromagnetic field through Chern-Simons interactions to both an oscillating SU(2) dark matter condensate and an Abelian gauge sector. I will close by mentioning other work, including a Peccei-Quinn inflationary model involving an axion Chern-Simons coupling, non-minimally driven fields coupled to gravity, and a stochastic GW background from ultralight axion dark matter halos.
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