发表机构
P. J. Šafárik University（帕夫卢·约瑟夫·沙法里克大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过精确对角化和重整化群等方法，揭示了完全阻挫海森堡四腿管中维格纳磁振子晶体的涌现及其不连续量子相变，并探索了其作为量子斯特林热机工作介质的性能。
AI 中文摘要
我们使用精确对角化、密度矩阵重整化群和局域磁振子理论，研究了具有反铁磁plaquette内和plaquette间耦合常数J1和J2的完全阻挫自旋-1/2海森堡四腿管的基态、磁化曲线、低温热力学和热机性能。在无阻挫到弱阻挫区域J2/J1 << 2，系统表现出由场驱动的有能隙Haldane相与无能隙Tomonaga-Luttinger量子自旋液体之间的连续量子相变。在强阻挫区域J2/J1 > 2，系统反而表现出由场驱动的维格纳磁振子晶体之间的不连续量子相变，这些相变在零温磁化曲线中表现为在饱和磁化的零、四分之一、二分之一和四分之三处的中间平台。该区域的低温磁性和热力学性质可通过由局域单磁振子和双磁振子态构建的两个单体准粒子种类的有效相互作用晶格气体模型精确描述。最后，我们探索了以完全阻挫四腿管为工作介质的量子斯特林热机。在接近不连续场诱导相变时，功输出和效率受到强烈抑制，而在维格纳磁振子晶体的稳定区域内部达到显著的局部最大值。
英文摘要
The ground state, magnetization curves, low-temperature thermodynamics, and heat-engine performance of the fully frustrated spin-$1/2$ Heisenberg four-leg tube with antiferromagnetic inter- and intra-plaquette coupling constants J1 and J2 are examined using exact diagonalization, density matrix renormalization group, and localized-magnon theory. In the unfrustrated to weakly frustrated regime J2/J1 << 2, the system exhibits a continuous field-driven quantum phase transition between the gapped Haldane phase and a gapless Tomonaga-Luttinger quantum spin liquid. In the highly frustrated regime J2/J1 > 2, the system contrarily displays discontinuous field-driven quantum phase transitions between the Wigner magnon crystals, which are manifested in zero-temperature magnetization curves as intermediate plateaus at zero, one-quarter, one-half, and three-quarters of the saturation magnetization. The low-temperature magnetic and thermodynamic properties in this regime are accurately captured by an effective interacting lattice-gas model of two monomer quasi-particle species constructed from localized one- and two-magnon states. Finally, we explore a quantum Stirling heat engine using the fully frustrated four-leg tube as the working medium. The work output and efficiency are strongly suppressed near discontinuous field-induced transitions and reach pronounced local maxima well inside the stability regions of the Wigner magnon crystals.
Comments14 pages, 8 figures
