arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1503.05549cond-mat.quant-gascond-mat.mtrl-scicond-mat.str-elquant-ph
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超冷费米子与离子哈伯德模型竞争密度序的探讨

Exploring competing density order in the ionic Hubbard model with ultracold fermions

Michael Messer, Rémi Desbuquois, Thomas Uehlinger, Gregor Jotzu, Sebastian Huber, Daniel Greif, Tilman Esslinger

摘要:

利用费米子原子与光晶格相互作用的双组分气体,实现并研究了离子哈伯德模型。二分晶格具有蜂窝状几何形状,其交错的能量偏移明确地破坏了反转对称性。使用原子动量分布的噪声相关测量确定不同的密度有序相。对于弱相互作用,几何形状诱导电荷密度波。对于强排斥的相互作用,我们检测到一个强大的抑制双占据的网站,如预期的莫特绝缘状态,和外部破坏反转对称性是不可见的密度分布。在不同的配置中的局部密度分布的特点是通过测量作为相互作用和能量偏移的函数的双重占据的晶格位置的数量。我们进一步探测的激发系统使用方向依赖调制光谱,并发现一个复杂的频谱,我们比较的理论模型。

英文摘要:

We realize and study the ionic Hubbard model using an interacting two-component gas of fermionic atoms loaded into an optical lattice. The bipartite lattice has honeycomb geometry with a staggered energy-offset that explicitly breaks the inversion symmetry. Distinct density-ordered phases are identified using noise correlation measurements of the atomic momentum distribution. For weak interactions the geometry induces a charge density wave. For strong repulsive interactions we detect a strong suppression of doubly occupied sites, as expected for a Mott insulating state, and the externally broken inversion symmetry is not visible anymore in the density distribution. The local density distributions in different configurations are characterized by measuring the number of doubly occupied lattice sites as a function of interaction and energy-offset. We further probe the excitations of the system using direction dependent modulation spectroscopy and discover a complex spectrum, which we compare with a theoretical model.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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