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arXiv 2005.03539cond-mat.str-el
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半填充时$t-V-V'$格点费米子模型中相互作用驱动的极化位移:出射Half-Phase

Interaction driven polarization shift in the $t-V-V'$ lattice fermion model at half filling: emergent Haldane phase

Balázs Hetényi

摘要:

我们研究了一维半填充时的$t-V-V'$模型。已知对于足够大的$V$固定,随着$V'$变化,系统从电荷密度波进入Luttinger液体,然后是键序,然后是第二电荷密度波阶段。我们发现Luttinger液态进一步分裂为两个,分离的部分具有不同的多体极化Berry相值。在这个相位内,极化的变化在热力学极限下是无限的,这意味着即使极化不同,也无法测量。然而,在Luttinger液体的每一侧上的带隙相中,极化采取不同的可测量值,这意味着拓扑上的区别。关键的区别在于大- $V'$相位是链接反转对称的,而小- $V'$相位是位置反转对称的。我们发现大- $V'$相可以与一个$S=1$自旋链有关,并表现出Haldom相的许多特征.纠缠谱的最低态在两种情况下呈现出不同的简并性,并且在大- $V'$相位中我们还发现了弦序。我们还研究了在开边界条件下的系统,并建议缺陷的数量与拓扑结构。

英文摘要:

We study the $t-V-V'$ model in one dimension at half-filling. It is known that for large enough $V$ fixed, as $V'$ is varied, the system goes from a charge-density wave into a Luttinger liquid, then a bond-order, and then a second charge density wave phase. We find that the Luttinger liquid state is further split into two, separating parts with distinct values of the many-body polarization Berry phase. Inside this phase, the variance of the polarization is infinite in the thermodynamic limit, meaning that even if the polarization differs, it would not be measurable. However, in the gapped phases on each side of the Luttinger liquid, the polarization takes a different measurable value, implying topologically distinction. The key difference is that the large-$V'$ phases are link-inversion symmetric, while the small-$V'$ one is site-inversion symmetric. We show that large-$V'$ phase can be related to an $S=1$ spin chain, and exhibits many features of the Haldane phase. The lowest lying states of the entanglement spectrum display different degeneracies in the two cases, and we also find string order in the large-$V'$ phase. We also study the system under open boundary conditions, and suggest that the number of defects is related to the topology.

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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