I will present two experimental studies on strongly interacting ultracold Fermi gases of 6Li atoms. In a first experiment, we create the analogous of a Josephson junction by bisecting BEC-BCS crossover superfluids by a thin optical barrier. We observe coherent dynamics in both the population and in the relative phase . For large bias potentials across the junction, the superfluid dynamics exhibits both coherent oscillations and resistive flow due to phase-slippage events, arsing from vortices propagating into the bulk. We also enter the regime of strong dissipation when the junction operation is irreversibly affected by vortex proliferation, causing the loss of coherence between the superfluid reservoirs . In a second experiment, we investigate the impurity limit of large polarization in repulsive Fermi gases. We observe well-defined repulsive polarons even for strong interactions. We extract the quasi-particle properties and in particular we find the polaron energy to exceed the Fermi energy of the bath, indicating that the repulsive Fermi liquid state becomes energetically unstable .
 G. Valtolina et al., Science 350, 1505 (2015)
 A. Burchianti et al. in preparation
 F. Scazza et al., PRL 118, 083602 (2017)