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arXiv 1201.5576cond-mat.quant-gascond-mat.str-el
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光晶格上冷费米子反铁磁关联和熵的普适探测

Universal probes for antiferromagnetic correlations and entropy in cold fermions on optical lattices

E. V. Gorelik, D. Rost, T. Paiva, R. Scalettar, A. Klümper, N. Blümer

摘要:

我们确定反铁磁(AF)签名的半填充哈伯德模型在强耦合的立方晶格和在较低的维度。在冷却时,从电荷激发区到AF海森堡区的转变通过双占有率在熵s=S/(Nk_B)=s*=ln(2)处的普遍最小值和次近邻(NNN)自旋关联函数(s<s*)的线性增加来指示。这种交叉,驱动的动能交换能量的增益,出现作为当前冷原子实验相关的基本AF物理。长程AF有序的开始(在立方晶格上的低s)在最近邻自旋相关与s中几乎不可见,但可以在NNN距离或超过NNN距离的自旋相关中检测到。

英文摘要:

We determine antiferromagnetic (AF) signatures in the half-filled Hubbard model at strong coupling on a cubic lattice and in lower dimensions. Upon cooling, the transition from the charge-excitation regime to the AF Heisenberg regime is signaled by a universal minimum of the double occupancy at entropy s=S/(N k_B)=s*=ln(2) per particle and a linear increase of the next-nearest neighbor (NNN) spin correlation function for s<s*. This crossover, driven by a gain in kinetic exchange energy, appears as the essential AF physics relevant for current cold-atom experiments. The onset of long-range AF order (at low s on cubic lattices) is hardly visible in nearest-neighbor spin correlations versus s, but could be detected in spin correlations at or beyond NNN distances.

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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