We develop an efficient method to perform density matrix renormalization group simulations of the SU(N) Heisenberg chain with open boundary conditions taking full advantage of the SU(N) symmetry of the problem. This method is an extension of the method previously developed for exact diagonalizations and relies on a systematic use of the basis of standard Young tableaux. Concentrating on the model with the fundamental representation at each site (i.e. one particle per site in the fermionic formulation), we have benchmarked our results for the ground state energy up to N = 8 and up to 420 sites by comparing them with Bethe ansatz results on open chains, for which we have derived and solved the Bethe ansatz equations. The agreement for the ground state energy is excellent for SU(3) (12 digits). It decreases with N , but it is still satisfactory for N = 8 (6 digits). Central charges c are also extracted from the entanglement entropy using the Calabrese-Cardy formula, and agree with the theoretical values expected from the SU(N)1 Wess-Zumino-Witten CFTs.
Density Matrix Renormalization Group simulations of the SU(N) Fermi-Hubbard chain implementing the full SU(N) symmetry via Semi-Standard Young Tableaux and Unitary Group Subduction Coefficients
Emergent Spin Excitations in a Bethe Lattice at Percolation
研究了稀释到逾渗阈值的Bethe晶格上自旋为1/2的量子海森堡反铁磁体。稀释产生偶数/奇数亚晶格不平衡区域，导致“悬挂自旋”（L。Wang和A. W. Sandvik，Phys. Rev. 97，117204（2006）; Phys. Rev. B 81，054417（2010））。这些共同作为“涌现”自旋1/2自由度，并负责创造一组低洼的“quasidegenerate状态”。使用密度矩阵重整化群（DMRG）计算，我们检测到这些新兴的自旋的存在和位置。我们找到了这些涌现自旋的有效哈密顿量，海森堡相互作用随它们之间的距离呈指数衰减。
Ground-state properties of the symmetric single-impurity Anderson model on a ring from Density-Matrix Renormalization Group, Hartree-Fock, and Gutzwiller theory
A spin chain with non-Hermitian $\mathscr{PT}-$symmetric boundary couplings: exact solution, dissipative Kondo effect, and phase transitions on the edge
Multiple impurities and combined local density approximations in Site-Occupation Embedding Theory
占位嵌入理论（SOET）是密度泛函理论在理论上对模型哈密顿量的精确多行列式推广。SOET最近发展的各种扩展[Senjean等人，Phys. Rev. B 97，235105（2018）]在这项工作中进行了探索。向前迈出的重要一步是将理论推广到多个杂质位置。我们还提出了一种新的单杂质密度泛函近似（DFA），它将二能级（2L）Hubbard系统的密度泛函杂质相关能与Bethe局域密度近似（BALDA）结合起来，计算（无限）哈伯德模型的全相关能.为了检验新的分布函数，用密度矩阵重整化群方法（DMRG）自洽地计算了杂质相互作用的波函数。双占领和每个网站的能量表达式已被推导和实施的一维情况下。的结果进行了详细的分析，特别关注的错误引起的能量泛函单独或自洽收敛密度。在所有的DFA（包括以前提出的），组合2L-BALDA是一个在所有的相关性和密度制度，表现最好的。最后，扩展在新的方向，如分区DFT型重新制定SOET，基于投影的SOET方法，或SOET与格林函数的组合，简要讨论了作为一个角度。
