Oscillating Quantum Droplets From the Free Expansion of Logarithmic One-dimensional Bose Gases

Rodríguez-López, Omar Abel; Castellanos, Elías

doi:10.1007/s10909-021-02601-y

Cited by 6 publications

(2 citation statements)

References 42 publications

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“…The other term F (ln) |Ψ| 2 ∝ ln |Ψ| 2 /n describes the logarithmic fluid part in the wave equation. Nonlinearity of this type often occurs in theories containing quantum Bose liquids and condensates [8,[10][11][12][13][14][15][16][17][18]. The reason for such universality is that logarithmically nonlinear terms readily emerge in evolution equations for those dynamical systems in which interparticle interaction energies dominate kinetic ones, see Ref.…”

Section: The Modelmentioning

confidence: 99%

Resolving the puzzle of sound propagation in a dilute Bose–Einstein condensate

Zloshchastiev

2022

Int. J. Mod. Phys. B

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A unified model of a dilute Bose–Einstein condensate is proposed, combining the logarithmic and Gross–Pitaevskii (GP) nonlinear terms in a wave equation, where the GP term describes two-body interactions, as suggested by the standard perturbation theory; while the logarithmic term is essentially nonperturbative, and takes into account quantum vacuum effects. The model is shown to have excellent agreement with sound propagation data in the condensate of cold sodium atoms known since the now classic works by Andrews and collaborators. The data also allowed us to place constraints on two of the unified model’s parameters, which describe the strengths of the logarithmic and GP terms. Additionally, we suggest an experiment constraining the value of the third parameter (the characteristic density scale of the logarithmic part of the model), using the conjectured attraction–repulsion transition of many-body interaction inside the condensate.

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Section: The Modelmentioning

confidence: 99%

Resolving the puzzle of sound propagation in a dilute Bose–Einstein condensate

Zloshchastiev

2022

Int. J. Mod. Phys. B

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“…Thus, adding or removing particles to the logarithmic condensate is energetically favorable in two of the four regions {n ≷ n c , T ≷ T c }, and unfavorable in the others. This, of course, has a crucial influence upon the stability of the free logarithmic condensate [10,21,22].…”

Section: The Modelmentioning

confidence: 99%

Acoustic oscillations in cigar-shaped logarithmic Bose-Einstein condensate in the Thomas-Fermi approximation

Zloshchastiev

2022

Preprint

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We consider the dynamical properties of density fluctuations in the cigar-shaped Bose-Einstein condensate described by the logarithmic wave equation with a constant nonlinear coupling by using the Thomas-Fermi and linear approximations. It is shown that the propagation of small density fluctuations along the long axis of a condensed lump in a strongly anisotropic trap is essentially onedimensional, while the trapping potential can be disregarded in the linear regime. Depending on the sign of nonlinear coupling, the fluctuations either take the form of translationally symmetric pulses and standing waves, or become oscillations with varying amplitudes. We also study the condensate in an axial harmonic trap, by using elasticity theory's notions. Linear particle density and energy also behave differently depending on the nonlinear coupling's value. If it is negative, the density monotonously grows along with lump's radius, while energy is a monotonous function of density. For the positive coupling, the density is bound from above, whereas energy grows monotonously as a function of density until it reaches its global maximum.

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