论文标题
Cutic Ferromagnet和Emergent $ U（1）$对称性在其相边界上
Cubic ferromagnet and emergent $U(1)$ symmetry on its phase boundary
论文作者
论文摘要
我们通过平均场分析和张量网络计算研究了最简单的量子晶格自旋模型。尽管两种方法在检测相关阶段都会产生相似的结果，但2D无限投影纠缠状态（IPEP）计算提供了更准确的过渡点值。此外，在相边界附近，我们的IPEPS结果表明，固定磁性易于轴的方向更加困难，我们将其解释为易于轴的软化。这种现象意味着连续$ u（1）$对称性的出现，这是由低能量有效模型指示的，并已通过现场理论进行了分析表明。我们的模型和研究提供了一个具体的示例，用于利用临界区域附近的IPEP，表明生活在关键点上的新兴现象已经被IPEP捕获的，具有相当小的键尺寸。
We study the simplest quantum lattice spin model for the two-dimensional (2D) cubic ferromagnet by means of mean-field analysis and tensor network calculation. While both methods give rise to similar results in detecting related phases, the 2D infinite projected entangled-pair state (iPEPS) calculation provides more accurate values of transition points. Near the phase boundary, moreover, our iPEPS results indicate that it is more difficult to pin down the orientation of magnetic easy axes, and we interpret it as the easy-axis softening. This phenomenon implies an emergence of continuous $U(1)$ symmetry, which is indicated by the low-energy effective model and has been analytically shown by the field theory. Our model and study provide a concrete example for utilizing iPEPS near the critical region, showing that the emergent phenomenon living on the critical points can already be captured by iPEPS with a rather small bond dimension.
