Collective modes and the broken symmetry of a rotating attractive Bose gas in an anharmonic trap

Collin, A.

doi:10.1103/physreva.73.013611

Cited by 18 publications

(4 citation statements)

References 23 publications

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“…Moreover, low-lying excitations in such systems were addressed, for example in vortex lattices [26,193,194,195]. Furthermore, investigations were made on the decay of the counter-rotating quadrupole mode [196], on Tkachenko modes [197,198], on the twiston spectrum [199], or on excitations in anharmonic traps [200,201]. In the latter works, the mean-field excitations were calculated by utilizing the BdG theory.…”

Section: Rotating Bose-einstein Condensates In An Anharmonic Trapmentioning

confidence: 99%

Many-body effects in the excitations and dynamics of trapped Bose-Einstein condensates

Alon¹,

Beinke²,

Cederbaum³

2021

Preprint

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This review explores the dynamics and the low-energy excitation spectra of Bose-Einstein condensates (BECs) of interacting bosons in external potential traps putting particular emphasis on the emerging manybody effects beyond mean-field descriptions. To do so, methods have to be used that, in principle, can provide numerically exact results for both the dynamics and the excitation spectra in a systematic manner. Numerically exact results for the dynamics are presented employing the well-established multicongurational time-dependent Hartree for bosons (MCTDHB) method. The respective excitation spectra are calculated utilizing the more recently introduced linear-response theory atop it (LR-MCTDHB). The latter theory gives rise to an, in general, non-hermitian eigenvalue problem. The theory and its newly developed implementation are described in detail and benchmarked towards the exactly-solvable harmonic-interaction model. Several applications to BECs in one-and two-dimensional potential traps are discussed. With respect to dynamics, it is shown that both the out-of-equilibrium tunneling dynamics and the dynamics of trapped vortices are of many-body nature. Furthermore, many-body effects in the excitation spectra are presented for BECs in different trap geometries. It is demonstrated that even for essentially-condensed systems, the spectrum of the lowest-in-energy excitations computed at the many-body level can differ substantially from the standard mean-field description. In general, it is shown that bosons carrying angular momentum are more sensitive to many-body effects than bosons without. These effects are present in both the dynamics and the excitation spectrum.

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Section: Rotating Bose-einstein Condensates In An Anharmonic Trapmentioning

confidence: 99%

Many-body effects in the excitations and dynamics of trapped Bose-Einstein condensates

Alon¹,

Beinke²,

Cederbaum³

2021

Preprint

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“…For this reason, different theoretical studies [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] have considered traps with other functional forms, in which the trapping potential grows more rapidly than quadratically at a distance far away from the center of the cloud. In the control collapse experiment of achieving BEC [27][28][29], the trapping potential is well approximated by a superposition of quadratic and a small quartic potential resulting in confinement of the form ( ) ⁄ ( ⁄ ) , where m is the mass of the atom.…”

Section: Introductionmentioning

confidence: 99%

Study of Zero Temperature Ground State Properties of the Repulsive Bose-Einstein Condensate in an Anharmonic Trap

Debnath

2021

J. Sci. Res.

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The zero-temperature ground state properties of experimental 87Rb condensate are studied in a harmonic plus quartic trap [ V(r) = ½mω2r2 + λr4 ]. The anharmonic parameter (λ) is slowly tuned from harmonic to anharmonic. For each choice of λ, the many-particle Schrödinger equation is solved using the potential harmonic expansion method and determines the lowest effective many-body potential. We utilize the correlated two-body basis function, which keeps all possible two-body correlations. The use of van der Waals interaction gives realistic pictures. We calculate kinetic energy, trapping potential energy, interaction energy, and total ground state energy of the condensate in this confining potential, modelled experimentally. The motivation of the present study is to investigate the crucial dependency of the properties of an interacting quantum many-body system on λ. The average size of the condensate has also been calculated to observe how the stability of repulsive condensate depends on anharmonicity. In particular, our calculation presents a clear physical picture of the repulsive condensate in an anharmonic trap.

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“…Most theoretical works concentrated on the dynamics of the BEC system in the bichromatic OL potential, such as the quantum dynamics of a BEC, [2,3] the localization of a BEC, [4−6] symmetry breaking, [7] a BEC vortex, [8] and Anderson localization of pairs. [9] Likewise, the dynamics of a BEC in an anharmonic trap, whose potential is well approximated by a superposition of a quadratic and a small quartic potential, has attracted a great deal of interest both from the theoretical [10−20] and the experimental [21] points of view, and has been used to study such diverse phenomena as collective modes and the broken symmetry of a rotating Bose gas, [10] matter waves, [11] excited states, [12−17] dark soliton decay, [18] the Fermi-decay law of a BEC, [19] and rotational states of Bose gases. [20] Some dynamical issues related to a BEC vortical state, for example, the dynamics of a BEC vortex confined to a bichromatic OL [8] and anharmonic potentials, [10] have been investigated.…”

mentioning

confidence: 99%

“…[9] Likewise, the dynamics of a BEC in an anharmonic trap, whose potential is well approximated by a superposition of a quadratic and a small quartic potential, has attracted a great deal of interest both from the theoretical [10−20] and the experimental [21] points of view, and has been used to study such diverse phenomena as collective modes and the broken symmetry of a rotating Bose gas, [10] matter waves, [11] excited states, [12−17] dark soliton decay, [18] the Fermi-decay law of a BEC, [19] and rotational states of Bose gases. [20] Some dynamical issues related to a BEC vortical state, for example, the dynamics of a BEC vortex confined to a bichromatic OL [8] and anharmonic potentials, [10] have been investigated. However, so far the stability and the controlled manipulation dynamics of BEC vortical solitons trapped in an applied combined external potential has not yet been analyzed.…”

mentioning

confidence: 99%

Vortical Solitons of Three-Dimensional Bose—Einstein Condensates under Both a Bichromatic Optical Lattice and Anharmonic Potentials

Li¹,

Feng-De²,

Wang³

2013

Chinese Phys. Lett.

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We study Bose-Einstein condensate vortical solitons under both a bichromatic optical lattice and anharmonic potential. The vortical solitons are built in the form of a layer-chain structure made up of two fundamental vortices along the bichromatic optical lattice direction, which have not been reported before in the three-dimensional Bose-Einstein condensate. A variation approach is applied to find the optimum initial solutions of vortical solitons. The stabilities of the vortical solitons are confirmed by the numerical simulation of the time-dependent Gross-Pitaevskii equation. In particular, stable Bose-Einstein condensate vortical solitons with fundamental vortices of different atomic numbers in the external potential within a range of experimentally achievable timescales are found. We further manipulate the vortical solitons to an arbitrary position by steadily moving the bichromatic optical lattice, and find a stable region for the successful manipulation of vortical solitons without collapse. These results provide insight into controlling and manipulating the Bose-Einstein condensate vortical solitons for macroscopic quantum applications.

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Collective modes and the broken symmetry of a rotating attractive Bose gas in an anharmonic trap

Cited by 18 publications

References 23 publications

Many-body effects in the excitations and dynamics of trapped Bose-Einstein condensates

Many-body effects in the excitations and dynamics of trapped Bose-Einstein condensates

Study of Zero Temperature Ground State Properties of the Repulsive Bose-Einstein Condensate in an Anharmonic Trap

Vortical Solitons of Three-Dimensional Bose—Einstein Condensates under Both a Bichromatic Optical Lattice and Anharmonic Potentials

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