论文标题
Chebyshev伪材料矩阵产品状态方法用于电子 - 音波耦合系统的光谱函数
Chebyshev pseudosite matrix product state approach for the spectral functions of electron-phonon coupling systems
论文作者
论文摘要
电子音波（$ e $ -ph）耦合系统通常具有大量的声子自由度，其光谱函数在数值上很难使用矩阵乘积状态（MPS）形式主义计算。为了解决这个问题，我们提出了一种新的实用方法，该方法将Chebyshev MPS和伪材料密度基质矩阵恢复归一化组（DMRG）算法结合在一起。 Chebyshev向量由具有全局$ u（1）$ fermion对称的伪材料MP代表，该Maps $ 2^{n_p} $ Bosonic Freedom of Freedom of Freedom of Freedom of Freedom of Freedom of $ n_p $ pseudosites，每个自由度都有两个州。这种方法可以处理任意$ e $ ph耦合的汉密尔顿人，其中伪源性DMRG的性能有效。我们使用这种方法来研究掺杂的延长哈伯德 - 荷尔斯坦模型的光谱函数，这是在强烈的库仑排斥力方面，以前尚未对此进行过广泛的研究。激发光谱的关键特征以适中的计算成本捕获。我们的结果表明，较弱的$ e $ ph耦合可以在低声子频率下增加Holon折叠分支的光谱重量，这与一维（1D）callate的角度分辨光发射观测一致。
The electron-phonon ($e$-ph) coupling system often has a large number of phonon degrees of freedom, whose spectral functions are numerically difficult to compute using matrix product state (MPS) formalisms. To solve this problem, we propose a new and practical method that combines the Chebyshev MPS and the pseudosite density matrix renormalization group (DMRG) algorithm. The Chebyshev vector is represented by a pseudosite MPS with global $U(1)$ fermion symmetry, which maps $2^{N_p}$ bosonic degrees of freedom onto $N_p$ pseudosites, each with two states. This approach can handle arbitrary $e$-ph coupling Hamiltonians where pseudosite DMRG performs efficiently. We use this method to study the spectral functions of the doped extended Hubbard-Holstein model in a regime of strong Coulomb repulsion, which has not been studied extensively before. Key features of the excitation spectra are captured at a modest computational cost. Our results show that weak extended $e$-ph couplings can increase the spectral weight of the holon-folding branch at low phonon frequencies, in agreement with angle-resolved photoemission observations on one-dimensional (1D) cuprates.
