arXiv:2007.13102 · New Journal of Physics

Dynamical phase diagram of ultracold Josephson junctions

Klejdja Xhani, Luca Galantucci, Carlo F. Barenghi, G. Roati, Andrea Trombettoni, Nick P. Proukakis

Published Nov 10, 2020• 22 citations

Abstract

Abstract We provide a complete study of the phase diagram characterising the distinct dynamical regimes emerging in a three-dimensional Josephson junction in an ultracold quantum gas. Considering trapped ultracold superfluids separated into two reservoirs by a barrier of variable height and width, we analyse the population imbalance dynamics following a variable initial population mismatch. We demonstrate that as the chemical potential difference is increased, the system transitions from Josephson plasma oscillations to either a dissipative (in the limit of low and narrow barriers) or a self-trapped regime (for large and wider barriers), with a crossover between the dissipative and the self-trapping regimes which we explore and characterize for the first time. This work, which extends beyond the validity of the standard two-mode model, connects the role of the barrier width, vortex rings and associated acoustic emission with different regimes of the superfluid dynamics across the junction, establishing a framework for its experimental observation, which is found to be within current experimental reach.

DOI: 10.1088/1367-2630/abc8e4

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