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arXiv 1111.2009cond-mat.str-el
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具有有限在位相互作用的半满Hubbard链的电荷动力学

Charge dynamics in half-filled Hubbard chains with finite on-site interaction

R. G. Pereira, K. Penc, S. R. White, P. D. Sacramento, J. M. P. Carmelo

摘要:

研究了具有有限在位排斥U的一维哈伯德模型在半填充时的电荷动力学结构因子。利用含时密度矩阵重整化群的计算结果与模型的精确谱进行了比较。作为U的函数的线形状的演变被解释在两个holon连续,占主导地位的限制U \to \infty和一个子集的两个holon-两个自旋子连续,重建的电子-空穴连续的限制U \to 0之间的相对转移的光谱重量。沿着谱边界线的幂律奇异性由有效杂质模型描述,该模型在自旋和η-自旋SU(2)旋转下是显式不变的。Mott-Hubbard金属-绝缘体转变反映在U=0处边缘奇异性指数的不连续变化中。在区域边界附近的动量谱中观察到的尖锐特征归因于作为可积性的结果而持续存在的范霍夫奇点。

英文摘要:

We study the charge dynamic structure factor of the one-dimensional Hubbard model with finite on-site repulsion U at half filling. Numerical results from the time-dependent density matrix renormalization group are analyzed by comparison with the exact spectrum of the model. The evolution of the line shape as a function of U is explained in terms of a relative transfer of spectral weight between the two-holon continuum that dominates in the limit U\to \infty and a subset of the two-holon-two-spinon continuum that reconstructs the electron-hole continuum in the limit U\to 0. Power-law singularities along boundary lines of the spectrum are described by effective impurity models that are explicitly invariant under spin and η-spin SU(2) rotations. The Mott-Hubbard metal-insulator transition is reflected in a discontinuous change of the exponents of edge singularities at U=0. The sharp feature observed in the spectrum for momenta near the zone boundary is attributed to a Van Hove singularity that persists as a consequence of integrability.

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