Attractive Bose-Einstein condensates in anharmonic traps: Accurate numerical treatment and the intriguing physics of the variance

Alon, Ofir E.; Cederbaum, Lorenz S.

doi:10.1016/j.chemphys.2018.09.029

Cited by 14 publications

(15 citation statements)

References 123 publications

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“…Our results complement the recent findings, that the variances of observables are sensitive probes of correlations in the state of ultracold atomic systems [ 9 , 38 , 39 , 40 , 41 , 42 , 43 , 96 , 98 ].…”

Section: Discussionsupporting

confidence: 90%

Dynamics of Ultracold Bosons in Artificial Gauge Fields—Angular Momentum, Fragmentation, and the Variance of Entropy

Lode

Dutta

Lévêque

2021

Entropy

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We consider the dynamics of two-dimensional interacting ultracold bosons triggered by suddenly switching on an artificial gauge field. The system is initialized in the ground state of a harmonic trapping potential. As a function of the strength of the applied artificial gauge field, we analyze the emergent dynamics by monitoring the angular momentum, the fragmentation as well as the entropy and variance of the entropy of absorption or single-shot images. We solve the underlying time-dependent many-boson Schrödinger equation using the multiconfigurational time-dependent Hartree method for indistinguishable particles (MCTDH-X). We find that the artificial gauge field implants angular momentum in the system. Fragmentation—multiple macroscopic eigenvalues of the reduced one-body density matrix—emerges in sync with the dynamics of angular momentum: the bosons in the many-body state develop non-trivial correlations. Fragmentation and angular momentum are experimentally difficult to assess; here, we demonstrate that they can be probed by statistically analyzing the variance of the image entropy of single-shot images that are the standard projective measurement of the state of ultracold atomic systems.

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Section: Discussionsupporting

confidence: 90%

Dynamics of Ultracold Bosons in Artificial Gauge Fields—Angular Momentum, Fragmentation, and the Variance of Entropy

Lode

Dutta

Lévêque

2021

Entropy

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“…Here, it has recently been shown that the density and many-body variance in an anisotropic trap can exhibit opposite anisotropies, i.e., if the density along the y direction is wider than along the x direction, then the manybody variance along the y direction is smaller than along the x direction [16]. On the applications side, the many-body variance of BECs can be used as a sensitive diagnostic tool, for excitations of BECs [17] (also see [18]), for analyzing the impact of the range of interaction [19], and for assessing convergence of numerical simulations [20,21].…”

Section: Introductionmentioning

confidence: 99%

Condensates in annuli: dimensionality of the variance

Alon

2019

Molecular Physics

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Static and dynamic properties of Bose-Einstein condensates in annular traps are investigated by solving the many-boson Schrödinger equation numerically accurately using the multiconfigurational time-dependent Hartree for bosons method. We concentrate on weakly-interacting bosons exhibiting low depletion. Analysis of the mean-field position variance, which accounts for the shape of the density only, and the many-body position variance, which incorporates a tiny amount of excitations through the reduced two-particle density matrix, shows that the former behaves essentially as a quasi-one-dimensional quantity whereas the latter as a two-dimensional quantity. This brings another dimension to the physics of bosons in ring-shaped traps.

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“…6(f) and 6(h). We would like to place this observation in the context of the discussion in [37,68,[88][89][90].…”

Section: Comparison Of Methodsmentioning

confidence: 99%

“…We refer to the original article [35] for the equations of motion and the extensive literature for details. The method has proven particularly useful to study scenarios involving dynamical condensate fragmentation [36][37][38][39][40], scenarios generating entanglement [41][42][43][44], and few-body dynamics [45]. Here we use the open-MCTDHB package [46].…”

Section: B Multiconfigurational Time-dependent Hartree For Bosons (Mmentioning

confidence: 99%

Collisions of solitary waves in condensates beyond mean-field theory

et al. 2020

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Bright solitary waves in a Bose-Einstein condensate contain thousands of identical atoms held together despite their only weakly attractive contact interactions. They nonetheless behave like a compound object, staying whole in collisions, with their collision properties strongly affected by intersoliton quantum coherence. We show that separate solitary waves decohere due to phase diffusion, dependent on their effective ambient temperature, after which their initial mean-field relative phases are no longer well defined or relevant for collisions. In this situation, collisions occur predominantly repulsively and can no longer be described within mean-field theory. When considering the timescales involved in recent solitary wave experiments where nonequilibrium phenomena play an important role, these features could explain the predominantly repulsive collision dynamics observed in most condensate soliton train experiments.

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Attractive Bose-Einstein condensates in anharmonic traps: Accurate numerical treatment and the intriguing physics of the variance

Cited by 14 publications

References 123 publications

Dynamics of Ultracold Bosons in Artificial Gauge Fields—Angular Momentum, Fragmentation, and the Variance of Entropy

Dynamics of Ultracold Bosons in Artificial Gauge Fields—Angular Momentum, Fragmentation, and the Variance of Entropy

Condensates in annuli: dimensionality of the variance

Collisions of solitary waves in condensates beyond mean-field theory

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