论文标题
关键现象的连续相似性转换：易于轴抗铁磁XXZ模型
Continuous similarity transformation for critical phenomena: easy-axis antiferromagnetic XXZ model
论文作者
论文摘要
我们将连续的相似性转换（CST）应用于方格上的易于轴抗铁磁XXZ模型。 CST流动方程在动量空间中通过缩放维度$ d $截断，因此考虑了$ d \ le 2 $的所有贡献。在零，一单和两麦克农部门中分析了由此产生的四分之一耐镁的有效哈密顿量。通过这种方式，对于从间隙的ISING模型到无间隙的Heisenberg模型的各向异性，获得了对基态能量，一块杂散分散及其间隙以及其间隙以及两种束缚状态的定量描述。我们讨论了间隙截止的临界特性以及一块roton Mininum的演化。计算两麦克农结合状态的激发能，并通过反参与率确定它们进入两麦克农子连续体的衰减。
We apply continuous similarity transformations (CSTs) to the easy-axis antiferromagnetic XXZ-model on the square lattice. The CST flow equations are truncated in momentum space by the scaling dimension $d$ so that all contributions with $d\le 2$ are taken into account. The resulting quartic magnon-conserving effective Hamiltonian is analyzed in the zero-, one-, and two-magnon sector. In this way, a quantitative description of the ground-state energy, the one-magnon dispersion and its gap as well as of two-magnon bound states is gained for anisotropies ranging from the gapped Ising model to the gapless Heisenberg model. We discuss the critical properties of the gap closing as well as the evolution of the one-magnon roton mininum. The excitation energies of two-magnon bound states are calculated and their decay into the two-magnon continuum is determined via the inverse participation ratio.
