Institute for Quantum Electronics, ETH Zurich, 8093 Zurich, Switzerland.
Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA.
Phys Rev Lett. 2015 Dec 31;115(26):260401. doi: 10.1103/PhysRevLett.115.260401. Epub 2015 Dec 23.
We report on the observation of antiferromagnetic correlations of ultracold fermions in a variety of optical lattice geometries that are well described by the Hubbard model, including dimers, 1D chains, ladders, isolated and coupled honeycomb planes, as well as square and cubic lattices. The dependence of the strength of spin correlations on the specific geometry is experimentally studied by measuring the correlations along different lattice tunneling links, where a redistribution of correlations between the different lattice links is observed. By measuring the correlations in a crossover between distinct geometries, we demonstrate an effective reduction of the dimensionality for our atom numbers and temperatures. We also investigate the formation and redistribution time of spin correlations by dynamically changing the lattice geometry and studying the time evolution of the system. Time scales ranging from a sudden quench of the lattice geometry to an adiabatic evolution are probed.
我们报告了在各种光学晶格几何形状中观察到的超冷费米子的反铁磁关联，这些晶格几何形状可以很好地用 Hubbard 模型来描述，包括二聚体、1D 链、 ladder、孤立和耦合的蜂窝平面以及方形和立方晶格。通过测量不同晶格隧穿链接之间的关联，实验研究了自旋关联强度对特定几何形状的依赖性，在该过程中观察到不同晶格链接之间的关联重新分布。通过在不同几何形状之间的交叉处测量关联，我们证明了对于我们的原子数和温度，有效降低了维度。我们还通过动态改变晶格几何形状并研究系统的时间演化，研究了自旋关联的形成和重新分布时间。探测了从晶格几何形状的突然淬火到绝热演化的时间尺度。
