Ground-state properties of the one-dimensional attractive Hubbard model with confinement; A Comparative study

閉じ込めのある一次元引力ハバード模型の基底状態の性質; 比較研究

Hu, J.-H.*; Wang, J.-J.*; Xianlong, G.*; 奥村 雅彦*  ; 五十嵐 亮; 山田 進 ; 町田 昌彦 

Hu, J.-H.*; Wang, J.-J.*; Xianlong, G.*; Okumura, Masahiko*; Igarashi, Ryo; Yamada, Susumu; Machida, Masahiko

強相関電子の最もシンプルかつ代表的な1次元引力ハバード模型をベーテ仮説に基づく密度汎関数理論とDMRG法で粒子密度・相互作用を変化させつつ詳細に調べた結果について報告する。詳細な計算の結果、一次元引力ハバードモデルの基底状態の性質は、相互作用が弱から中程度の領域では、計算量の少ないベーテ仮説法に基づく密度汎関数理論で十分に記述できることがわかった。

We revisit the one-dimensional attractive Hubbard model by using the Bethe-ansatz-based density-functional theory and density-matrix renormalization method. The ground-state properties of this model are discussed in details for different fillings and different confining conditions in weak-to-intermediate coupling regime. We investigate the ground-state energy, energy gap, and pair-binding energy and compare them with those calculated from the canonical Bardeen-Cooper-Schrieffer approximation. We find that the Bethe-ansatz-based density-functional theory is computationally easy and yields an accurate description of the ground-state properties for weak-to-intermediate interaction strength, different fillings, and confinements.