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arXiv 2411.08095cond-mat.stat-mechcond-mat.str-elhep-th
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$J_1$-$J_2$自旋链中临界反铁磁相之间的跃迁

Transition between critical antiferromagnetic phases in the $J_1$-$J_2$ spin chain

International Centre for Theoretical Physics(国际理论物理中心);Centre for Fluid and Complex Systems, Coventry University(考文垂大学流体与复杂系统中心);London Centre for Nanotechnology, University College London(伦敦纳米技术中心,伦敦大学学院)

Adam J. McRoberts, Chris Hooley, A. G. Green

AI总结:

本研究针对$J_1$-$J_2$自旋链,发现其存在两种不同的临界反铁磁相,分别对应Affleck-Haldane相和Zirnbauer相,二者二聚场与对偶场角色互换,并用密度矩阵重整化群计算验证了该结论。

摘要:

$J_1$-$J_2$自旋链是量子磁学的经典模型之一,长期以来人们已知其存在自旋关联呈幂律衰减的临界反铁磁相。我们在这篇快报中证明,实际上存在两种截然不同的临界反铁磁相,其中局域二聚场及其对偶场的角色发生了互换:靠近海森堡点$J_2=0$的是“Affleck-Haldane相”,该相中参数化局域单态序的二聚场是无隙的,并且是联合$O(4)$奈尔-单态序参量的一部分;另一种是“Zirnbauer相”,出现在铁磁性$J_2$足够大的情况下,该相中二聚场被打开能隙,而其对偶场——即$O(3)$奈尔场的瞬子密度——变为临界的。这两个相如此命名,是因为它们分别实现了带拓扑theta项的$O(3)$非线性sigma模型重整化到$\boldsymbol{\text{su}}(2)_1$ Wess-Zumino-Witten模型的两种相互竞争的物理图像之一。我们通过密度矩阵重整化群计算为这些预测提供了支持。

英文摘要:

The $J_1$-$J_2$ spin chain is one of the canonical models of quantum magnetism, and has long been known to host a critical antiferromagnetic phase with power-law decay of spin correlations. We show in this Letter that there are, in fact, \textit{two} distinct critical antiferromagnetic phases, where the roles of the local dimer field and its dual field are interchanged: the `Affleck-Haldane' phase near the Heisenberg point $J_2 = 0$, where the dimer field that parametrises local singlet order is gapless and part of a joint $O(4)$ Néel-singlet order parameter; and the `Zirnbauer' phase which appears at sufficiently large ferromagnetic $J_2$, where the dimer field is gapped out and its \textit{dual} field -- the instanton density of the $O(3)$ Néel field -- is critical instead. The phases are so-named because each realises one of the competing pictures for how the $O(3)$ non-linear sigma model with a topological theta term renormalises to the $\mathfrak{\hat{su}}(2)_1$ Wess-Zumino-Witten model. We support these predictions with density matrix renormalisation group calculations.

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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