论文标题
二维耦合对角线梯子上的量子海森堡抗fiferromagnet的散装和表面临界行为
Bulk and Surface Critical Behaviors of quantum Heisenberg antiferromagnet on a two-dimensional coupled diagonal ladders
论文作者
论文摘要
使用量子蒙特卡洛模拟，我们在通过耦合对角线梯子形成的二维晶格上研究了Spin-1/2海森堡模型。该模型具有抗铁磁néel相，一个梯级单线产物相和一个拓扑无容易的haldane相，由两个量子相变。我们表明，两个量子临界点全部在三维O（3）通用类中。研究了两个间隙相的特性，包括在haldane相中的弦序的有限大小行为。我们表明，梯子末端形成的表面是无间隙的，而沿梯子的表面在haldane相中是空白的。 相反，在张开的梯形旋转阶段中，前表面被覆盖，后者是无间隙的。我们证明，尽管两种无间隙模式的机制是不同的，但非凡的表面临界行为在无间隙表面上的两个关键点上都实现了通过简单地切割键而无需微调进行经典模型中多政治点所需的表面耦合而实现的。我们还表明，在间隙的表面上，表面临界行为在普通类中。
Using Quantum Monte Carlo simulations, we study the spin-1/2 Heisenberg model on a two-dimensional lattice formed by coupling diagonal ladders. The model hosts an antiferromagnetic Néel phase, a rung singlet product phase, and a topological none trivial Haldane phase, separated by two quantum phase transitions. We show that the two quantum critical points are all in the three-dimensional O(3) universality class. The properties of the two gapped phases, including the finite-size behavior of the string orders in the Haldane phase, are studied. We show that the surface formed by the ladders ends is gapless, while the surface exposed along the ladders is gapful, in the Haldane phase. Conversely, in the gapped rung singlet phase, the former surface is gapped, and the latter is gapless. We demonstrate that, although mechanisms of the two gapless modes are different, nonordinary surface critical behaviors are realized at both critical points on the gapless surfaces exposed by simply cutting bonds without fine-tuning the surface coupling required to reach a multicritical point in classical models. We also show that, on the gapped surfaces, the surface critical behaviors are in the ordinary class.
