论文标题
螺旋价键阶段的多政治降低量子临界和LIFSHITZ点
Multicritical deconfined quantum-criticality and Lifshitz point of a helical valence-bond phase
论文作者
论文摘要
$ s = 1/2 $ quare-j $ j $ - $ q $型号在抗铁磁和二聚体（Valence-bond solid）基础状态之间进行了一个脱合的量子相变。我们在这里研究了该模型的两个变形 - 一个术语投影交错的单元，以及对$ j $项的调制，形成了强度和弱耦合的交替“楼梯”。第一个变形保留了所有晶格对称性。使用量子蒙特卡洛模拟，我们表明它仍然引入了第二个相关领域，这可能是由于产生拓扑缺陷而引入的。第二个变形诱导螺旋价池基阶。因此，我们将脱合的量子临界点识别为多政治LIFSHITZ点 - 螺旋相的终点，也是一阶转换线的终点。螺旋 - 抗铁磁转变形成了一系列通用降级量子量点的线。这些发现扩展了解剖量子关键性的范围，并解决了从共形启动方法绑定的先前不一致的关键 - 实心。
The $S=1/2$ square-lattice $J$-$Q$ model hosts a deconfined quantum phase transition between antiferromagnetic and dimerized (valence-bond solid) ground states. We here study two deformations of this model -- a term projecting staggered singlets as well as a modulation of the $J$ terms forming alternating "staircases" of strong and weak couplings. The first deformation preserves all lattice symmetries. Using quantum Monte Carlo simulations, we show that it nevertheless introduces a second relevant field, likely by producing topological defects. The second deformation induces helical valence-bond order. Thus, we identify the deconfined quantum critical point as a multicritical Lifshitz point -- the end point of the helical phase and also the end point of a line of first-order transitions. The helical-antiferromagnetic transitions form a line of generic deconfined quantum-critical points. These findings extend the scope of deconfined quantum criticality and resolve a previously inconsistent critical-exponent bound from the conformal-bootstrap method.
