发表机构
Graduate School of China Academy of Engineering Physics; School of Physics, Nankai University（中国工程物理研究院研究生院; 南开大学物理学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文通过精确解析解与大规模DMRG计算，确定了交错磁场下XXZ链的相图，发现精确基态位于铁磁与无能隙Luttinger液体相边界，并揭示一级相变。
AI 中文摘要
我们研究了自旋-1/2 XXZ海森堡链在交错磁场中的相图。在相边界处获得了精确解，其中交换各向异性和交错场强度满足精确的解析关系，产生了一个具有非对角长程序的基态高度简并流形。我们证明了这些精确基态位于铁磁相和无能隙Luttinger液体相之间的边界上。当进一步减小各向异性时，无能隙相最终让位于有能隙的量子无序相。大规模密度矩阵重正化群计算证实了这一相结构，并表明跨越精确边界的相变为一级相变。我们的结果为理解一维量子自旋系统中由交错磁场驱动的量子相变提供了精确基准。
英文摘要
We study the phase diagram of the spin-1/2 XXZ Heisenberg chain in a staggered magnetic field. An exact solution is obtained along the phase boundary, where the exchange anisotropy and the staggered-field strength satisfy an exact analytical relation, yielding a highly degenerate manifold of ground states with off-diagonal long-range order. We demonstrate that these exact ground states lie on the boundary between the ferromagnetic phase and a gapless Luttinger liquid phase. Upon further decreasing the anisotropy, the gapless phase eventually gives way to a gapped quantum-disordered phase. Large-scale density-matrix renormalization group calculations confirm this phase structure and indicate that the transition across the exact boundary is of first order. Our results provide an exact benchmark for understanding quantum phase transitions driven by staggered magnetic fields in one-dimensional quantum spin systems.
Comments8 pages, 4 figures
