 |
Quantum phase slips are the primary excitations in one-dimensional superfluids and superconductors at low temperature, but haven’t been so far detected in ultracold quantum gases. We have now studied experimentally the nucleation rate of phase slips in one-dimensional superfluids realized with ultracold quantum gases, owing along a periodic potential. We have observed a crossover between a regime of temperature-dependent dissipation at small velocity and interaction and a second regime of velocity-dependent dissipation at larger velocity and interaction. This behavior is consistent with the predicted crossover from thermally-assisted quantum phase slips to purely quantum phase slips. L. Tanzi, et al., |
Quantum simulations with a tunable Bose-Einstein condensate… We use BECs made of potassium-39 atoms, with interaction tunable via Feshbach resonances, to explore open problems in condensed-matter and few-body physics. Recently we have been studying quantitatively Anderson localization of non-interacting matter waves in disordered potentials, the interplay of disorder and interactions in low-dimensional systems, and superfluidity in bosonic wires.