Dynamics of a tunable superfluid junction

L. J. LeBlanc, A. B. Bardon, J. McKeever, M. H. T. Extavour, D. Jervis, J. H. Thywissen, F. Piazza, A. Smerzi

We study the population dynamics of a Bose-Einstein condensate in a double-well potential with tunable barrier height. In the regime of weak inter-well coupling, we observe Josephson plasma oscillations as expected. However, in the strong-coupling regime, a second frequency enters the dynamics. We explain the amplitude, frequency, and nature of these two modes by with Gross-Pitaevskii calculations throughout the weak- to strong-coupling crossover. Our results interpolate between two standard paradigms of superfluidity: hydrodynamics and Josephson dynamics.

**Groupmeeting by Lindsay LeBlanc, September 22nd, 2010**