论文标题
通过改进的水平光谱法检测到的切斯特里 - 泽兰模型中的量子自旋液相
Quantum spin liquid phase in the Shastry-Sutherland model detected by an improved level spectroscopic method
论文作者
论文摘要
我们通过与周期性边界条件的群集的确切对角线化研究了旋转$ 1/2 $二维的二维 - 泽特式旋转模型。我们使用具有不同量子数的状态之间的能量差距开发了一种改进的水平光谱技术。某些相对（复合）间隙的交叉点的有限尺寸漂移比仅相对基态定义的正常使用的间隙弱得多，从而可以精确确定量子临界点，即使在小簇中也可以进行量子临界点。我们的结果支持了旋转液相的图片，介入众所周知的plaquette-singlet和防铁磁接地状态之间，相位边界几乎完全一致，并且使用了最近的密度矩阵重质化组研究，其中使用了大量较大的圆柱形晶格[J. J. Yang等人，物理。修订版B {\ bf 105}，L060409（2022）]。使用复合材料低能差距来减少缩放校正的方法在量子临界现象的数值研究中具有广泛的应用。
We study the spin-$1/2$ two-dimensional Shastry-Sutherland spin model by exact diagonalization of clusters with periodic boundary conditions. We develop an improved level spectroscopic technique using energy gaps between states with different quantum numbers. The crossing points of some of the relative (composite) gaps have much weaker finite-size drifts than the normally used gaps defined only with respect to the ground state, thus allowing precise determination of quantum critical points even with small clusters. Our results support the picture of a spin liquid phase intervening between the well known plaquette-singlet and antiferromagnetic ground states, with phase boundaries in almost perfect agreement with a recent density matrix renormalization group study, where much larger cylindrical lattices were used [J. Yang et al., Phys. Rev. B {\bf 105}, L060409 (2022)]. The method of using composite low-energy gaps to reduce scaling corrections has potentially broad applications in numerical studies of quantum critical phenomena.
