Institute of Physics, Johannes Gutenberg University, 55099 Mainz, Germany.
Phys Rev Lett. 2010 Aug 6;105(6):065301. doi: 10.1103/PhysRevLett.105.065301. Epub 2010 Aug 3.
We study the magnetic ordering transition for a system of harmonically trapped ultracold fermions with repulsive interactions in a cubic optical lattice, within a real-space extension of dynamical mean-field theory. Using a quantum Monte Carlo impurity solver, we establish that antiferromagnetic correlations are signaled, at strong coupling, by an enhanced double occupancy. This signature is directly accessible experimentally and should be observable well above the critical temperature for long-range order. Dimensional aspects appear less relevant than naively expected.
我们在动态平均场理论的实空间扩展中，研究了在立方光学晶格中具有排斥相互作用的束缚超冷费米子系统的磁有序相变。通过量子蒙特卡罗杂质求解器，我们确定在强耦合下，反铁磁关联通过增强的双占据来表示。这种特征在实验中是直接可观测的，并且应该在长程有序的临界温度以上很好地观察到。维度方面的影响似乎不如预期的那么重要。
