Topological to magnetically ordered quantum phase transition in antiferromagnetic spin ladders with long-range interactions
Topological to magnetically ordered quantum phase transition in antiferromagnetic spin ladders with long-range interactions
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DOI：
10.21468/scipostphys.13.3.060
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发表时间：
2020-12
期刊：
影响因子：
5.5
通讯作者：
Luhang Yang;P. Weinberg;A. Feiguin
中科院分区：
文献类型：
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作者：
Luhang Yang;P. Weinberg;A. Feiguin
我们研究了具有交错长程相互作用的广义量子自旋梯，它的衰变遵循指数为\alphaα的幂律.利用大尺度量子Monte Carlo（QMC）和密度矩阵重整化群（DMRG）模拟，我们证明了该模型经历了从以非局域弦序参量为特征的梯级二聚体相到对称破缺N'eel相的转变.我们发现的证据表明，过渡是二阶。在磁有序相，光谱表现出无隙模式，而在有隙相的激发很好地描述了在整个腿的自旋的三体束缚态。数值计算得到了动量分辨的自旋动力学结构因子，并发现了一个定义明确的三体子带，它在跃迁过程中演化为一个无带隙的磁振子色散。我们进一步讨论了在这个模型中解除临界的可能性。
We study a generalized quantum spin ladder with staggered long range interactions that decay as a power-law with exponent \alphaα. Using large scale quantum Monte Carlo (QMC) and density matrix renormalization group (DMRG) simulations, we show that this model undergoes a transition from a rung-dimer phase characterized by a non-local string order parameter, to a symmetry broken N'eel phase. We find evidence that the transition is second order. In the magnetically ordered phase, the spectrum exhibits gapless modes, while excitations in the gapped phase are well described in terms of triplons – bound states of spinons across the legs. We obtain the momentum resolved spin dynamic structure factor numerically and find a well defined triplon band that evolves into a gapless magnon dispersion across the transition. We further discuss the possibility of deconfined criticality in this model.