论文标题
一维延长的玻色 - 哈伯德模型中的宏观边界效应
Macroscopic boundary effects in the one-dimensional extended Bose-Hubbard model
论文作者
论文摘要
我们研究了不同开放边界条件对单位填充和附近一维延长玻色 - 哈伯德模型的绝缘接地状态的影响。为此，我们采用密度矩阵重新归一化组方法，系统尺寸高达250个站点。为了表征系统，计算各种订单参数和纠缠熵。当将相对的边缘电势添加到链的两端时，反转对称性被明确破坏，并且会出现常规的散装相。另一方面，简单的开放边界条件通常在链的中间表现出具有域壁的非分类基态，从而诱导了订单参数的符号。这样的域壁可以导致单个粒子密度矩阵的非对角线的代数行为。我们表明，这种代数行为仅增加了纠缠熵的有限贡献，随着系统大小的增加，该熵不会差异。因此，这不是超流相的迹象。我们通过基于域壁有效的哈密顿量的分析计算来确认这张图。
We study the effect of different open boundary conditions on the insulating ground states of the one-dimensional extended Bose-Hubbard model at and near unit filling. To this end, we employ the density matrix renormalization group method with system sizes up to 250 sites. To characterize the system, various order parameters and entanglement entropies are calculated. When opposite edge potentials are added to the two ends of the chain, the inversion symmetry is explicitly broken, and the regular bulk phases appear. On the other hand, simple open boundary conditions often exhibit non-degenerate ground states with a domain wall in the middle of the chain, which induces a sign-flip of an order parameter. Such a domain wall can lead to an algebraic behavior of the off-diagonals of the single particle density matrix. We show that this algebraic behavior adds only a finite contribution to the entanglement entropy, which does not diverge as the system size increases. Therefore, it is not an indication of a superfluid phase. We confirm this picture by analytical calculations based on an effective Hamiltonian for a domain wall.
