arXiv:1312.7315 · Physical Review Letters
One-Dimensional Transport of Bosons between Weakly Linked Reservoirs
D. P. Simpson, Dimitri M. Gangardt, Igor V. Lerner, P. Krüger
Abstract
We study a flow of ultracold bosonic atoms through a one-dimensional channel that connects two macroscopic three-dimensional reservoirs of Bose-condensed atoms via weak links implemented as potential barriers between each of the reservoirs and the channel. We consider reservoirs at equal chemical potentials so that a superflow of the quasicondensate through the channel is driven purely by a phase difference $2\mathrm{\ensuremath{\Phi}}$ imprinted between the reservoirs. We find that the superflow never has the standard Josephson form $\ensuremath{\sim}\mathrm{sin}2\mathrm{\ensuremath{\Phi}}$. Instead, the superflow discontinuously flips direction at $2\mathrm{\ensuremath{\Phi}}=\ifmmode\pm\else\textpm\fi{}\mathrm{\ensuremath{\pi}}$ and has metastable branches. We show that these features are robust and not smeared by fluctuations or phase slips. We describe a possible experimental setup for observing these phenomena.