I will present two complementary ideas to look for sub-MeV dark matter: superfluid helium-4 and anti-ferromagnetic materials. I will discuss advantages and possible difficulties, and argue that a prominent theoretical tool to tackle these problems should be Goldstone’s theorem for spontaneously broken spacetime symmetries.
The QCD axion is a compelling target for physics beyond the Standard Model which offers also a characteristic imprint in the Early Universe as a hot relic. In this talk we present a state-of-the-art bound on the QCD axion from Cosmology by confronting momentum-dependent Boltzmann equations against up-to-date measurements of the CMB – including ground-based telescopes – and abundances from BBN. We conclude presenting forecasts using dedicated likelihoods for future cosmological surveys and recent non-perturbative computations at the crossover from lattice QCD.
In this talk, three topics concerning aspects of cosmology and particle physics will be discussed: 1) primordial black hole production during the early universe; 2) higher-order computations of cosmological correlators in non-single-clock inflation, and 3) QCD axion dynamics and the role of gravitational anomalies.