论文标题
与电荷配对和Hubbard相互作用的Spin-1/2 Fermions的集成性
Integrability of the spin-1/2 fermions with charge pairing and Hubbard interaction
论文作者
论文摘要
在本文中，我们研究了自旋 - $ \ frac {1} {2} $的一维模型的精确解决方案，由最近的邻居三胞胎配对术语和现场Hubbard相互作用组成。我们认为，该模型通过映射到带有虚构跳动术语的哈伯德链的映射来接受贝特·安萨兹解决方案。 Bethe方程与Lieb和Wu \ cite {lw}所发现的方程相似，但取决于环大小的其他扭曲阶段。我们已经通过精确的对角线化研究了模型的频谱，并通过大型晶格大小的伯特方程进行了排斥相互作用。该模型的一个功能是，可以定义偶数和奇数晶格位点的电荷差距，并在无限尺寸限制中收敛到相同的值。我们将有限尺寸的校正分析为低覆盖的自旋激发，并认为它们等同于自旋 - $ \ frac {1} {2} $ isotropic Heisenberg模型，并具有边界转换，具体取决于晶格的平等。我们提出了经典的统计力学模型，其传输矩阵与模型hamiltonian通勤。为此，我们将Shastry \ Cite {Sha1，Sha2}使用的构造用于Hubbard模型。但是，就我们的情况而言，构建块是一个自由屈服的八个vertex型号，具有特定的无效重量。
In this paper we study the exact solution of a one-dimensional model of spin-$\frac{1}{2}$ electrons composed by a nearest-neighbor triplet pairing term and the on-site Hubbard interaction. We argue that this model admits a Bethe ansatz solution through a mapping to a Hubbard chain with imaginary kinetic hopping terms. The Bethe equations are similar to that found by Lieb and Wu \cite{LW} but with additional twist phases which are dependent on the ring size. We have studied the spectrum of the model with repulsive interaction by exact diagonalization and through the Bethe equations for large lattice sizes. One feature of the model is that it is possible to define the charge gap for even and odd lattice sites and both converge to the same value in the infinite size limit. We analyze the finite-size corrections to the low-lying spin excitations and argue that they are equivalent to that of the spin-$\frac{1}{2}$ isotropic Heisenberg model with a boundary twist depending on the lattice parity. We present the classical statistical mechanics model whose transfer matrix commutes with the model Hamiltonian. To this end we have used the construction employed by Shastry \cite{SHA1,SHA2} for the Hubbard model. In our case, however, the building block is a free-fermion eight-vertex model with a particular null weight.
