Dynamics of a Tunable Superfluid Junction

Abstract

We study the population dynamics of a Bose-Einstein condensate in a double-well potential throughout the crossover from Josephson dynamics to hydrodynamics. At barriers higher than the chemical potential, we observe slow oscillations well described by a Josephson model. In the limit of low barriers, the fundamental frequency agrees with a simple hydrodynamic model, but we also observe a second, higher frequency. A full numerical simulation of the Gross-Pitaevskii equation giving the frequencies and amplitudes of the observed modes between these two limits is compared to the data and is used to understand the origin of the higher mode. Implications for trapped matter-wave interferometers are discussed.

Josephson dynamics of a spin-orbit-coupled Bose-Einstein condensate in a double-well potential

“…For l 0 ∼ √ 2b, we have ξ T ∼ 0 and ξ V ∼h 2 4mb 2 , and [20], b and l 0 to be on the order of micrometers [50,51]. In fact, in the regime of b 2 /l 2 0 ∼ [0.5, 2], we find that…”

“…where the parameters a and b are both tunable in the experiments [51]. Expanding V (x) near x = ±b, one obtains its harmonic form as V (2) (x) .…”

“…Thus we have ε L = ε R and g (L) σσ ′ = g (R) σσ ′ . Such kind of double well potential can be generated in experiments [51] with the form…”

“…The weakly interacting BECs provide a further context [46][47][48] for JEs in superconductor systems because they display a nonlinear generalization of typical d.c. and a.c. JEs and macroscopic quantum selftrapping, all of which have been observed in experiments [49][50][51]. Apart from the conventional single-species BECs [45][46][47][48], the Josephson dynamics of two-species BECs [52] and spinor BECs without SO coupling [53] have also been studied [54][55][56][57]; however, the dynamics of SO coupled BECs is yet to be explored.…”

Triangular Bose-Hubbard trimer as a minimal model for a superfluid circuit

“…The experimental study of Bose-Einstein Condensates (BECs) allows the realization of ultracold atomic superfluid circuits [1][2][3][4][5][6][7][8][9][10][11][12][13][14] and the incorporation of a laserinduced weak-link (a bosonic Josephson junction) within them [15]. By rotating such a barrier it is possible to induce current [16] and to drive phase-slips between quantized superfluid states of a low dimensional toroidal ring [15].…”