论文标题
抗铁磁大规模状态中XXZ链的自旋电导率
Spin conductivity of the XXZ chain in the antiferromagnetic massive regime
论文作者
论文摘要
我们为在零温度下的抗铁磁大规模机制中XXZ链的局部自旋电流的动力学两点功能提供了一个串联表示。从本系列中，我们可以以很高的时间和较大的距离来计算相关函数。该系列中的每个术语都对应于偶数激发的所有散射状态的贡献。这些激发可以用相等数量的颗粒和孔来解释。该系列中的最低项包括一个孔和一个粒子的所有散射状态。该术语决定了可以从鞍点分析中明确获得的长期大距离渐近行为。电流在零动量下的两点函数的时空傅立叶变换给出了模型的光学自旋电导率。我们通过将数据转换我们的数据来获得该数量的高度准确的数值估计。对于单粒子的一孔贡献，等效地解释为两翼贡献，我们就已知的特殊功能获得了精确而明确的表达。对于足够大的各向异性，两翼的贡献承载了大部分光谱重量，可以通过计算F-SUM规则来看出。
We present a series representation for the dynamical two-point function of the local spin current for the XXZ chain in the antiferromagnetic massive regime at zero temperature. From this series we can compute the correlation function with very high accuracy up to very long times and large distances. Each term in the series corresponds to the contribution of all scattering states of an even number of excitations. These excitations can be interpreted in terms of an equal number of particles and holes. The lowest term in the series comprises all scattering states of one hole and one particle. This term determines the long-time large-distance asymptotic behaviour which can be obtained explicitly from a saddle-point analysis. The space-time Fourier transform of the two-point function of currents at zero momentum gives the optical spin conductivity of the model. We obtain highly accurate numerical estimates for this quantity by numerically Fourier transforming our data. For the one-particle, one-hole contribution, equivalently interpreted as a two-spinon contribution, we obtain an exact and explicit expression in terms of known special functions. For large enough anisotropy, the two-spinon contribution carries most of the spectral weight, as can be seen by calculating the f-sum rule.
