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arXiv 2602.17029cond-mat.str-elcond-mat.stat-mech
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耦合伊辛链和SO($N$)对称自旋链中的相变

Phase transitions in coupled Ising chains and SO($N$)-symmetric spin chains

University of Tokyo(东京大学);Ritsumeikan University(立命馆大学);Univ Toulouse, CNRS, Laboratoire de Physique Théorique(图卢兹大学,法国国家科学研究中心,理论物理实验室);Center for Computational Quantum Physics, Flatiron Institute(扁平研究所计算量子物理中心);Laboratoire de Physique Théorique et Modélisation, CNRS, CY Cergy Paris Université(理论物理与建模实验室,法国国家科学研究中心,CY塞尔吉巴黎大学)

Yohei Fuji, Sylvain Capponi, Lukas Devos, Philippe Lecheminant

AI总结:

研究了耦合伊辛链和SO($N$)对称自旋链中的相变,发现N≥4时相变变为一级,修正了SPT相临界性猜想。

摘要:

我们研究了一个由N个伊辛共形场论组成的(1+1)维场论中的量子相变性质,这些场论通过竞争的相关扰动相互作用。该场论描述了质量项与涉及N个序参数场乘积的相互作用之间的竞争,这例如在耦合伊辛链、双腿自旋阶梯和SO($N$)对称自旋链中得以实现。通过结合微扰重整化群分析和大规模矩阵积态模拟,我们系统地确定了相变的性质作为N函数的函数。对于N=2和N=3,我们确认相变是连续的,分别属于伊辛和四态Potts universality类。相反,对于N≥4,我们的结果提供了强有力的证据表明相变变为一级。我们进一步将这些发现应用于具有SO($N$)对称性的特定晶格模型,包括具有自旋-1/2和自旋-1的双腿阶梯,这些模型实现了从SO($N$)对称保护拓扑相到平凡相的直接过渡。我们的结果修正了最近关于SPT相之间临界性的猜想。

英文摘要:

We investigate the nature of quantum phase transitions in a (1+1)-dimensional field theory composed of $N$ copies of the Ising conformal field theory interacting via competing relevant perturbations. The field theory governs the competition between a mass term and an interaction involving the product of $N$ order-parameter fields, which is realized, e.g. in coupled Ising chains, two-leg spin ladders, and SO($N$)-symmetric spin chains. By combining a perturbative renormalization group analysis and large-scale matrix-product state simulations, we systematically determine the nature of the phase transition as a function of $N$. For $N=2$ and $N=3$, we confirm that the transition is continuous, belonging to the Ising and four-state Potts universality classes, respectively. In contrast, for $N \ge 4$, our results provide compelling evidence that the transition becomes first order. We further apply these findings to specific lattice models with SO($N$) symmetry, including spin-$1/2$ and spin-$1$ two-leg ladders, that realize a direct transition between an SO($N$) symmetry-protected topological phase and a trivial phase. Our results refine a recent conjecture regarding the criticality of transitions between SPT phases.

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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