Collective excitations of a trapped Bose-Einstein condensate in the presence of weak disorder and a two-dimensional optical lattice

Hu, Ying; Liang, Zhaoxin; Hu, Bambi

doi:10.1103/physreva.81.053621

Cited by 8 publications

(5 citation statements)

References 58 publications

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“…So far much attention has been devoted to studies of the disorder-induced damping of motion in Bose [5][6][7][8][9][10] and Fermi [11] gases, classical localization [12][13][14][15][16][17][18][19][20], spatial diffusion [19][20][21][22][23][24][25], and Anderson localization in regimes where interactions can be neglected [18,21,24,[26][27][28][29][30][31][32][33][34][35][36][37][38][39]. The effects of disorder in interacting quantum systems have also been studied in a variety of contexts, such as transport in weakly interacting Bose-Einstein condensates [40][41][42][43][44][45][46][47]…”

Section: Introductionmentioning

confidence: 99%

Localization of Bogoliubov quasiparticles in interacting Bose gases with correlated disorder

Lugan

Sanchez-Palencia

2011

Phys. Rev. A

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Published versionInternational audienceWe study the Anderson localization of Bogoliubov quasiparticles (elementary many-body excitations) in a weakly interacting Bose gas of chemical potential $\mu$ subjected to a disordered potential $V$. We introduce a general mapping (valid for weak inhomogeneous potentials in any dimension) of the Bogoliubov-de Gennes equations onto a single-particle Schrödinger-like equation with an effective potential. For disordered potentials, the Schrödinger-like equation accounts for the scattering and localization properties of the Bogoliubov quasiparticles. We derive analytically the localization lengths for correlated disordered potentials in the one-dimensional geometry. Our approach relies on a perturbative expansion in $V/\mu$, which we develop up to third order, and we discuss the impact of the various perturbation orders. Our predictions are shown to be in very good agreement with direct numerical calculations. We identify different localization regimes: For low energy, the effective disordered potential exhibits a strong screening by the quasicondensate density background, and localization is suppressed. For high-energy excitations, the effective disordered potential reduces to the bare disordered potential, and the localization properties of quasiparticles are the same as for free particles. The maximum of localization is found at intermediate energy when the quasicondensate healing length is of the order of the disorder correlation length. Possible extensions of our work to higher dimensions are also discussed

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Section: Introductionmentioning

confidence: 99%

Localization of Bogoliubov quasiparticles in interacting Bose gases with correlated disorder

Lugan

Sanchez-Palencia

2011

Phys. Rev. A

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“…[20] On the other hand, the successful control of ultracold atoms in an optical lattice has made it an ideal playground to explore a variety of fascinating quantum phenomena. [21][22][23][24][25] Especially, the tunneling of atoms of the BEC in an optical lattice can be controlled by the potential barrier. [26][27][28][29] Optical lattices provide a possible method to investigate ultracold atoms, but small random impurities or defects always exist, which can be induced by additional lasers and/or magnetic fields.…”

Section: Introductionmentioning

confidence: 99%

Periodically modulated interaction effect on transport of Bose–Einstein condensates in lattice with local defects

Zhu¹,

Yu²,

Gao³

et al. 2019

Chinese Phys. B

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We theoretically investigate the periodically modulated interaction effect on the propagation properties of a traveling plane wave in a Bose-Einstein condensate (BEC) trapped in a deep annular lattice with local defects both analytically and numerically. By using the two-mode ansatz and the tight-binding approximation, a critical condition for the system preserving the superfluidity is obtained analytically and confirmed numerically. We find that the coupled effects of periodic modulated atomic interactions, the quasi-momentum of the plane wave, and the defect can control the superfluidity of the system. Particularly, when we consider the periodic modulation in the system with single defect, the critical condition for the system entering the superfluid regime depends on both the defect and the momentum of the plane wave. This is different from the case for the system without the periodic modulation, where the critical condition is only determined by the defect. The modulation and quasi-momentum of the plane wave can enhance the system entering the superfluid regime. Interestingly, when the modulated amplitude/frequency, the defect strength, and the quasi-momentum of the plane wave satisfy a certain condition, the system will always be in the superfluid region. This engineering provides a possible means for studying the periodic modulation effect on propagation properties and the corresponding dynamics of BECs in disordered optical lattices.

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“…It indicates possible fractional Chern insulators [33][34][35] and stabilizes superfluid [36][37][38][39] or superconductor [40][41][42][43][44][45][46][47][48][49][50] phases in flat-band systems. For trapped interacting bosonic atoms in optical lattices [51][52][53][54][55], quantum geometric effects on hydrodynamic equations have been proposed [56,57]. However, the spatial density fluctuation of atoms is comparable with the lattice for a ground state, so it is improper to treat the interaction as a slowly varying mean-field potential as in the literature.…”

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confidence: 99%

Physics on Ultracold Quantum Gases

Han

Zhang

2018

Peking University-World Scientific Advanced Physics Series

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Collective excitations of a trapped Bose-Einstein condensate in the presence of weak disorder and a two-dimensional optical lattice

Cited by 8 publications

References 58 publications

Localization of Bogoliubov quasiparticles in interacting Bose gases with correlated disorder

Localization of Bogoliubov quasiparticles in interacting Bose gases with correlated disorder

Periodically modulated interaction effect on transport of Bose–Einstein condensates in lattice with local defects

Physics on Ultracold Quantum Gases

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