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arXiv 1107.3497cond-mat.str-el
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双带无自旋费米子和单带自旋1/2费米子模型的谱函数

Spectral functions of two-band spinless fermion and single-band spin-1/2 fermion models

Edmond Orignac, Masahisa Tsuchiizu, Yoshikazu Suzumura

摘要:

本文研究了具有不同速度和一般前向散射相互作用的一维双带无自旋费米子的零温单粒子谱函数。利用玻色化技术,将模型对角化为两个Tomonaga-Luttinger-liquid Hamilton算子,得到了谱函数的一般表达式,这些谱函数是用Appell超几何函数表示的.对于相同的双带费米子的情况下,对应于SU(2)对称的自旋1/2费米子与排斥相互作用,光谱函数可以表示为高斯超几何函数,并恢复双峰结构表明著名的“自旋-电荷”分离。通过调整两带费米子的速度差,我们澄清了从“自旋-电荷”分离到去耦费米子的谱函数的交叉。我们讨论了我们的结果的相关性自旋1/2哈伯德模型下的磁场,可以映射到双带无自旋费米子。

英文摘要:

We examine zero-temperature one-particle spectral functions for the one-dimensional two-band spinless fermions with different velocities and general forward-scattering interactions. By using the bosonization technique and diagonalizing the model to two Tomonaga-Luttinger-liquid Hamiltonians, we obtain general expressions for the spectral functions which are given in terms of the Appell hypergeometric functions. For the case of identical two-band fermions, corresponding to the SU(2) symmetric spin-1/2 fermions with repulsive interactions,the spectral functions can be expressed in terms of the Gauss hypergeometric functions and are shown to recover the double-peak structure suggesting the well-known "spin-charge" separation. By tuning the difference in velocities for the two-band fermions, we clarify the crossover in spectral functions from the "spin-charge" separation to the decoupled fermions. We discuss the relevance of our results to the spin-1/2 Hubbard model under a magnetic field which can be mapped onto two-band spinless fermions.

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