Persistent current oscillations in a double-ring quantum gas

Bland, Thomas; Yatsuta, Igor; Edwards, Mark; O., Nikolaieva, Y.; Oliinyk, Artem; Yakimenko, A. I.; Proukakis, N. P.

doi:10.1103/physrevresearch.4.043171

Cited by 9 publications

(2 citation statements)

References 59 publications

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“…Interestingly, in a many-body description of trapped BECs, it is possible to recognize the presence of "phantom vortices", topological defects of the spatial coherence, but not of the density [27]. Ghost vortices play a crucial role also in some recent technological applications, where coherent matter waves can be conveniently employed to realize high-precision accelerometers [28,29], and to characterize the current-phase relationship of quantum devices [30].…”

Section: Introductionmentioning

confidence: 99%

Making ghost vortices visible in two-component Bose-Einstein condensates

Chaika¹,

Richaud²,

Yakimenko³

2023

Preprint

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Ghost vortices constitute an elusive class of topological excitations in quantum fluids since the relevant phase singularities fall within regions where the superfluid density is almost zero. Here we present a platform that allows for the controlled generation and observation of such vortices. Upon rotating an imbalanced mixture of two-component Bose-Einstein condensates (BECs), one can obtain necklaces of real vortices in the majority component whose cores get filled by particles from the minority one. The wavefunction describing the state of the latter is shown to harbour a number of ghost vortices which are crucial to support the overall dynamics of the mixture. Their arrangement typically mirrors that of their real counterpart, hence resulting in a "dual" ghostvortex necklace, whose properties are thoroughly investigated in the present paper. We also present a viable experimental protocol for the direct observation of ghost vortices in a 23 Na + 39 K ultracold mixture. Quenching the inter-component scattering length, some atoms are expelled from the vortex cores and, while diffusing, swirl around unpopulated phase singularities, thus turning them directly observable.

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Section: Introductionmentioning

confidence: 99%

Making ghost vortices visible in two-component Bose-Einstein condensates

Chaika¹,

Richaud²,

Yakimenko³

2023

Preprint

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“…The confinement provided by the potential barrier surrounding the vortex core makes even multi-charged (q > 1) metastable vortex states highly robust. The generation and stability of these atomic flows in condensates with toroidal topology have been extensively explored both experimentally [33][34][35][36][37][38][39][40][41][42][43][44][45][46][47] and theoretically [48][49][50][51][52][53][54][55][56][57][58][59]. These investigations have revealed their topological protection in the absence of external driving, highlighting their robust nature.…”

Section: Introductionmentioning

confidence: 99%

Engineering phase and density of Bose–Einstein condensates in curved waveguides with toroidal topology

Nikolaieva,

Salasnich,

Yakimenko

2023

New J. Phys.

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We investigate the effects of ellipticity-induced curvature on atomic Bose-Einstein condensates confined in quasi-one-dimensional closed-loop waveguides. Our theoretical study reveals intriguing phenomena arising from the interplay between curvature and interactions. Density modulations are observed in regions of high curvature, but these modulations are suppressed by strong repulsive interactions. Additionally, we observe phase accumulation in regions with the lowest curvature when the waveguide with persistent current is squeezed. Furthermore, waveguides hosting persistent currents exhibit dynamic transformations between states with different angular momenta. These findings provide insights into the behaviour of atomic condensates in curved waveguides, with implications for fundamental physics and quantum technologies. The interplay between curvature and interactions offers opportunities for exploring novel quantum phenomena and engineering quantum states in confined geometries.

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Vortex Depinning in a Two-Dimensional Superfluid

Liu,

Prasad,

Baggaley

et al. 2024

J Low Temp Phys

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We employ the Gross–Pitaevskii theory to model a quantized vortex depinning from a small obstacle in a two-dimensional superfluid due to an imposed background superfluid flow. We find that, when the flow’s velocity exceeds a critical value, the vortex drifts orthogonally to the flow before subsequently moving parallel to it away from the pinning site. The motion of the vortex around the pinning site is also accompanied by an emission of a spiral-shaped sound pulse. Through simulations, we present a phase diagram of the critical flow velocity for vortex depinning together with an empirical formula that illustrates how the critical velocity increases with the height and width of the pinning site. By employing a variety of choices of initial and boundary conditions, we are able to obtain lower and upper bounds on the critical velocity and demonstrate the robustness of these results.

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Persistent current oscillations in a double-ring quantum gas

Cited by 9 publications

References 59 publications

Making ghost vortices visible in two-component Bose-Einstein condensates

Making ghost vortices visible in two-component Bose-Einstein condensates

Engineering phase and density of Bose–Einstein condensates in curved waveguides with toroidal topology

Vortex Depinning in a Two-Dimensional Superfluid

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