|Title:||Coherent driving and freezing of bosonic matter wave in an optical Lieb lattice|
|Authors:||Taie, Shintaro |
|Author's alias:||田家, 慎太郎|
ultracold atomic gases
|Publisher:||American Association for the Advancement of Science|
|Journal title:||Science Advances|
|Abstract:||Although kinetic energy of a massive particle generally has quadratic dependence on its momentum, a flat, dispersionless energy band is realized in crystals with specific lattice structures. Such macroscopic degeneracy causes the emergence of localized eigenstates and has been a key concept in the context of itinerant ferromagnetism. We report the realization of a “Lieb lattice” configuration with an optical lattice, which has a flat energy band as the first excited state. Our optical lattice potential has various degrees of freedom in its manipulation, which enables coherent transfer of a Bose-Einstein condensate into the flat band. In addition to measuring lifetime of the flat band population for different tight-binding parameters, we investigate the inter-sublattice dynamics of the system by projecting the sublattice population onto the band population. This measurement clearly shows the formation of the localized state with the specific sublattice decoupled in the flat band, and even detects the presence of flat-band breaking perturbations, resulting in the delocalization. Our results will open up the possibilities of exploring the physics of flat bands with a highly controllable quantum system.|
|Description:||レーザーで作る光の結晶格子で平坦バンドを実現 -難解な磁性の問題の解明へ新たな道を拓く-. 京都大学プレスリリース. 2015-11-25.|
|Rights:||© 2015, The Authors|
This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial license, which permits use, distribution, and reproduction in any medium, so long as the resultant use is not for commercial advantage and provided the original work is properly cited.
|Appears in Collections:||Journal Articles|
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