Particle physics today faces the challenge of explaining the mystery of dark matter, the origin
of matter over anti-matter in the Universe, the origin of the neutrino masses, the apparent …

I present an introduction and topical review on axions as a dark matter candidate. Emphasis
is placed on issues surrounding the cosmology of axion dark matter that are relevant for …

High-frequency gravitational waves (HFGWs) are predicted in various exotic scenarios
involving both cosmological and astrophysical sources. These elusive signals have recently …

Cold dark matter axions produced in the post-inflationary Peccei-Quinn symmetry breaking
scenario serve as clear targets for their experimental detection, since it is in principle …

Several Pulsar Timing Array (PTA) collaborations have recently reported the evidence for a
stochastic gravitational-wave background (SGWB), which can unveil the formation of …

It has long been established that axions could have been produced within the nascent proto-
neutron star formed following the type II supernova SN1987A, escaped the star due to their …

In the scenario in which QCD axion dark matter is produced after inflation, the Universe is
populated by large inhomogeneities on very small scales. Eventually, these fluctuations will …

With axions now a primary candidate for dark matter, understanding their indirect
astrophysical signatures is of paramount importance. Key to this is the production of photons …

A traveling wave parametric amplifier has been integrated in the haloscope of the QUAX
experiment. A search for dark matter axions has been performed with a high-Q dielectric …

In the near future BabyIAXO will be the most powerful axion helioscope, relying on a custom‐
made magnet of two bores of 70 cm diameter and 10 m long, with a total available magnetic …