The standard LCDM cosmological model of structure formation provides an amazing description of a wide range of astrophysical and astronomical data. However, there are a few statistically significant anomalies and tensions between observations at early and late cosmological time that can indicate a failure of the LCDM model. I will show briefly these tensions, with a particular focus on the...
The Hubble tension is relieved if the sound horizon at decoupling, r, is reduced. This can happen as a result of the enhanced recombination induced by primordial magnetic fields or caused by more exotic new physics. However, when trying to bring the H0 value measured from CMB into a complete agreement with SH0ES by reducing r alone, one runs into a disagreement with either the BAO or the...
The origin of the baryon asymmetry of the Universe (BAU) and the nature of dark matter are two of the most challenging problems in cosmology. I will present a scenario in which the gravitational collapse of large inhomogeneities at the QCD epoch generates both the baryon asymmetry and the dark matter in the form of primordial black holes (PBHs). It would naturally explains the observed BAU and...
Profound evidence for the existence of dark matter has been collected throughout the past 100 years. However, its exact nature remains elusive. A large effort is being put into the search for direct detection of weakly interacting massive particles (WIMPs), which arise as dark matter particle candidates in various theories. The search is led by dual-phase liquid xenon time projection chambers...
The calculation of tunneling actions, that control the exponential
suppression of the decay of metastable phases (like the unstable
electroweak vacuum), can be reformulated as an elementary variational
problem in field space. This alternative approach circumvents the use of
bounces in Euclidean space by introducing an auxiliary function, a
tunneling potential Vt that connects smoothly the...
I will introduce the concept of standard siren, reviewing the methodologies that one can apply to probe the cosmic expansion using gravitational wave observations. I will then outline the gravitational wave sources that can be used as standard sirens for both Earth-based (LIGO/Virgo/3G) and space-based (LISA) detectors, pointing out for which of them an electromagnetic counterpart is expected...
