Neutrinos are the only known elementary particles that are Majorana fermion candidates, implying that they would be their own antiparticles. The most sensitive and perhaps only practical probe of the Majorana nature of neutrinos is an extremely rare nuclear decay process, the double beta decay without the emission of neutrinos. After an introduction to the physics of neutrinoless double beta decay, I will present the experimental techniques to search for this exceedingly rare process. I will show the latest results from leading experiments in the field, then discuss future projects and their prospects to probe the inverted neutrino mass ordering scenario.

In this talk, I will discuss the dynamics of a superfluid quantum Bose gas confined at the bottom of a shell rf-dressed trap. Weakly interacting quantum degenerate atoms present a superfluid behavior, characterized by several properties including the emergence of specific collective modes at low energy or the apparition of quantum vortices when the fluid is set into rotation. In the talk I will describe the collective dynamical behavior of the atoms confined in this very smooth potential, from the low excitation regime where the first collective modes are observed to the fast rotation limit where the bubble shape of the trap plays an essential role.