Abstract: 

Dissipation in ultracold quantum gases can arise as a result of externally-induced perturbations or coupling of the condensate to the co-existing incoherent thermal cloud. In the main part of this talk I will discuss dissipative dynamics in two different settings, motivated by experimental investigations. In particular, I will highlight the origin and manifestations of dissipation in the context of Josephson junctions (LENS experiments), and atomic mixtures (Aarhus and Durham experiments), comparing predictions to experimental results and extending beyond them.

At the end of the talk I will briefly highlight how the tools developed to study ultracold atomic gases can become relevant in potentially addressing open cosmological structure formation challenges, through the 'alternative'​ -- but rapidly growing in popularity -- fuzzy dark matter model, which describes dark matter galaxies as effective superfluids of ultralight particles.