Axions are among the best motivated candidates for new physics. If the Peccei-Quinn symmetry associated with an axion has been ever restored after inflation, axion strings form and inevitably produce a contribution to the stochastic gravitational wave background. In this talk I will discuss the resulting gravitational wave spectrum by combining effective field theory analysis with numerical...
The cosmic microwave background (CMB) holds intriguing evidence of cosmic birefringence - an isotropic rotation of the polarization direction, manifesting in the CMB's parity odd spectra. This phenomenon finds a compelling explanation within axion physics, where a light scalar field interacts with the electromagnetic field through a Chern-Simons interaction, violating parity.
In this...
Axions and axion-like particles (ALPs) are among the most popular candidates that explain the origin of the mysterious dark matter. The most popular ALP production mechanism studied in the literature is the misalignment mechanism, where an ALP field with a quadratic or cosine potential has negligible kinetic energy initially, and it starts oscillating when its mass becomes comparable to the...
