论文标题
无限和巨大的1D单重分散频道在无限的自旋1/2梯子中---无限的准1D纠缠理论激发理论
Gapless and Massive 1D Singlet Dispersion Channel in Infinite Spin-1/2 Ladders ---Infinite Quasi-1D Entanglement Perturbation Theory for Excitation
论文作者
论文摘要
我们通过扩展最近开发的无限准准1D纠缠扰动理论来解决无限准1D量子晶格中的基本激发。激发态的波函数是通过优化群集操作的叠加来确定的，每个群集操作的叠加由晶格位点的块内的同时现场操作组成，以平面波的形式处于基础状态。相对于波数的激发能提供了基本激发的光谱。我们的方法是免费的，是免费的，并且适合各种准粒子图片。 Using the triplet spectrum, the application to $\infty$-by-$N$ antiferromagnetic spin-$\frac{1}{2}$ ladders for $N=2, 4, 6, 8$, and $10$ confirms a previous report that there is a quantum dimensional transition, namely, the lattice transits from quasi-1D to 2D at a finite critical value $N_c=10$. $ \左（π，π\右）$的无质量三重散布看到一个消失的差距。我们的结果在三重态频谱中检测到$ \左（π，0 \右）的异常，与宏观样本的非弹性中子散射测量非常吻合。令人惊讶的是，我们的结果还揭示了一个无间隙和庞大的一维单元色散通道，该通道远低于三重态激发。但是，我们注意到，尺寸的转变取决于无质量的三重态分散。
We solve for the elementary excitation in infinite quasi-1D quantum lattices by extending the recently developed infinite quasi-1D entanglement perturbation theory. The wave function of an excited state is variationally determined by optimizing superposition of cluster operation, each of which is composed of simultaneous on-site operation inside a block of lattice sites, on the ground state in a form of plane wave. The excitation energy with respect to the wave number gives the spectra for an elementary excitation. Our method is artificial broadening free and is adaptive for various quasi-particle pictures. Using the triplet spectrum, the application to $\infty$-by-$N$ antiferromagnetic spin-$\frac{1}{2}$ ladders for $N=2, 4, 6, 8$, and $10$ confirms a previous report that there is a quantum dimensional transition, namely, the lattice transits from quasi-1D to 2D at a finite critical value $N_c=10$. The massless triplet dispersion at $\left( π, π\right)$ sees a vanishing gap. Our results detect the anomaly at $\left(π,0\right)$ in the triplet spectrum, agreeing well with the inelastic neutron scattering measurement of a macroscopic sample. Surprisingly, our results also reveal a gapless and massive 1D singlet dispersion channel that is much lower than the triplet excitation. We note, however, the dimensional transition is determined by the massless triplet dispersion.
