A general theory of flattened dipolar condensates

Baillie, D.; Blakie, P. B.

doi:10.1088/1367-2630/17/3/033028

Cited by 28 publications

(40 citation statements)

References 57 publications

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“…Crucially, the stability/instability regimes as a function of tilting angle α are found to be different for a uniform pancake condensate in the quasi-2D (Q2D) regime and a uniform 2D layer of dipoles, indicating that the extension of the BEC in the transverse direction is critical while characterizing the system. The tilting angle offers the possibility of an anisotropic roton-like Bo-goliubov spectrum [22] and we show that the roton momentum can be varied from very low magnitude to the order of the inverse-width of the transverse confinement. Then, we show that the roton may arise solely due to the anisotropic and the momentum dependence of DDI, in the absence of short-range contact interactions.…”

Section: Introductionmentioning

confidence: 79%

Dipolar condensates with tilted dipoles in a pancake-shaped confinement

Mishra

Nath

2016

Phys. Rev. A

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The effect of dipolar orientation with respect to the condensate plane on the mean-field dynamics of dipolar Bose-Einstein condensates in a pancake-shaped confinement is discussed. The stability of a quasi-two-dimensional condensate, with respect to the tilting angle, is found to be different from a two-dimensional layer of dipoles, indicating the relevance of the transverse extension while characterizing two-dimensional dipolar systems. An anisotropic excitation spectrum exhibiting a highly tunable, rotonlike minimum can arise entirely from the dipole-dipole interactions, by tilting the dipoles. At the magic angle and in the absence of contact interactions, the long-wavelength excitations are not phononlike and always unstable. The post-roton-instability dynamics, in contrast to phonon instability, in a uniform condensate, is featured by a transient, defect-free, stripe pattern, which eventually undergoes local collapses, and driving the condensate back into the stable regime can make them sustained for longer. Hopping between stripes has been observed before it melts into a uniform state in the presence of dissipation. Finally, we discuss a class of solutions, in which a quasi-two-dimensional condensate is self-trapped in one direction, as well as a regime of interaction parameters, including attractive short-range interactions, at which a two-dimensional anisotropic soliton can be stabilized, and we show that a chromium condensate with a relatively small number of atoms is well suited for this.Comment: 8 pages, 6 figure

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Section: Introductionmentioning

confidence: 79%

Dipolar condensates with tilted dipoles in a pancake-shaped confinement

Mishra

Nath

2016

Phys. Rev. A

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“…No assumptions are made about the density profile along the z direction and this must be solved numerically. With regard to this last point, it was demonstrated that accurate treatment of the tight direction can be crucial for providing qualitatively useful results [36].…”

Section: Formalismmentioning

confidence: 99%

Static-response theory and the roton-maxon spectrum of a flattened dipolar Bose-Einstein condensate

2019

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Important information for the roton-maxon spectrum of a flattened dipolar Bose-Einstein condensate is extracted by applying a static perturbation exhibiting a periodic in-plane modulation. By solving the Gross-Pitaevskii equation in the presence of the weak perturbation we evaluate the linear density response of the system and use it, together with sum rules, to provide a Feynman-like upperbound prediction for the excitation spectrum, finding excellent agreement with the predictions of full Bogoliubov calculations. By suddenly removing the static perturbation, while still maintaining the trap, we find that the density modulations -as well as the weights of the perturbation-induced side peaks of the momentum distribution -undergo an oscillatory behavior with double the characteristic frequency of the excitation spectrum. The measurement of the oscillation periods could provide an easy determination of dispersion relations. arXiv:1901.04875v2 [cond-mat.quant-gas]

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“…At ultralow temperatures, a dipolar BEC is described by the time-dependent GP equation with a nonlocal integral corresponding to the DDI [7,8,42,24,43] i ∂φ(r, t)…”

Section: The Mean-field Formalismmentioning

confidence: 99%

Effect of an oscillating Gaussian obstacle in a dipolar Bose-Einstein condensate

Sabari

Kumar

2018

Eur. Phys. J. D

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We study the dynamics of vortex dipoles in erbium ( 168 Er) and dysprosium ( 164 Dy) dipolar Bose-Einstein condensates (BECs) by applying an oscillating blue-detuned laser (Gaussian obstacle). For observing vortex dipoles, we solve a nonlocal Gross-Pitaevskii (GP) equation in quasi two-dimensions in real-time. We calculate the critical velocity for the nucleation of vortex dipoles in dipolar BECs with respect to dipolar interaction strengths. We also show the dynamics of the group of vortex dipoles and rarefaction pulses in dipolar BECs. In the dipolar BECs with Gaussian obstacle, we observe rarefaction pulses due to interaction of dynamically migrating vortex dipoles. PACS. 67.25.dk Vortices and turbulence -67.85.De Dynamic properties of condensates; excitations, and superfluid flow -03.75.-b Matter waves -47.37.+q Hydrodynamic aspects of superfluidity; quantum fluids arXiv:1809.07634v1 [cond-mat.quant-gas]

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A general theory of flattened dipolar condensates

Cited by 28 publications

References 57 publications

Dipolar condensates with tilted dipoles in a pancake-shaped confinement

Dipolar condensates with tilted dipoles in a pancake-shaped confinement

Static-response theory and the roton-maxon spectrum of a flattened dipolar Bose-Einstein condensate

Effect of an oscillating Gaussian obstacle in a dipolar Bose-Einstein condensate

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