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arXiv 0912.1640cond-mat.quant-gas
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光晶格中强相互作用费米子的有效单带模型

Effective single-band models for strongly interacting fermions in an optical lattice

J. P. Kestner, L. -M. Duan

摘要:

为了检验光晶格中强相互作用费米子的有效哈密顿量,我们数值计算了双势阱中两个费米子通过费什巴赫共振相互作用的能谱。从频谱中,我们确定的失谐的范围内,该系统可以被描述为一个有效的晶格模型,以及如何模型参数与实验参数。我们发现,对于一系列的强相互作用的系统是很好地描述了一个有效的$t-J$模型,和有效的超交换项,$J$,可以顺利地调整通过零的任何一侧的酉。在么正性附近,一个有效的单带广义Hubbard模型是合适的,具有有限的和小的现场能量,由于在散射阈值处的原子与处于激发质心状态的弱束缚Feshbach分子之间的晶格诱导非谐耦合。

英文摘要:

To test effective Hamiltonians for strongly interacting fermions in an optical lattice, we numerically find the energy spectrum for two fermions interacting across a Feshbach resonance in a double well potential. From the spectrum, we determine the range of detunings for which the system can be described by an effective lattice model, and how the model parameters are related to the experimental parameters. We find that for a range of strong interactions the system is well described by an effective $t-J$ model, and the effective superexchange term, $J$, can be smoothly tuned through zero on either side of unitarity. Right at and around unitarity, an effective one-band general Hubbard model is appropriate, with a finite and small on-site energy, due to a lattice-induced anharmonic coupling between atoms at the scattering threshold and a weakly bound Feshbach molecule in an excited center of mass state.

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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