Speaker
Description
Axion-like particles coupled to the Standard Model photon are able to simultaneously generate a gravitational wave background and primordial magnetic fields, providing a multi-messenger probe of a promising dark matter candidate.
Mechanisms like trapped misalignment can delay the onset of oscillations, inducing a period of supercooling in the early Universe. The supercooling then allows for exponential production of photon quanta via a tachyonic instability, generating observable gravitational wave signatures.
In this talk, we show that reheating of the Standard Model plasma simultaneously produces strong, helical magnetic fields on intergalactic scales. The parameter space most promising for gravitational wave detection yields magnetic field strengths that exceed lower bounds from blazar observations.