One Dimensional Lattice Models of Electrons with 1/r^2 Hopping and Exchange
This talk reviews some recent progresses in the studies of low dimensional electronic models of strong correlations.
arXiv subjects
Publications and source records attributed to D. F. Wang.
This talk reviews some recent progresses in the studies of low dimensional electronic models of strong correlations.
The integrability of the one dimensional chiral Hubbard model is discussed in the limit of strong interaction, U=+\infty. The system is shown to be integrable in sense of existence of an infinite number of constants of motion. The system is related to a chiral Kondo lattice model at strong interaction J=+\infty
In this work, we exactly solve a Kondo lattice model in the thermodynamic limit. The system consists of an electronic conduction band described by unconstrained hopping matrix elements between the lattice sites. The conducting electrons interact with a localized impurity spin at each lattice cell. We have found the exact thermodynamics, the ground state energies of the system. At T=0, we explicitly demonstrate that the system exhibits a metal-insulator phase transition at half-filling. In the limit of strong coupling between the impurity spin and the electrons, J=\infty, we have solved the system on a lattice of any size L. The ground states are the resonating-valence-bond type Jastrow product wavefunctions. Various correlation functions may be computed for the impurity spins, and for the singlets formed by the electrons and impurities.
In this work, we introduce long range version of the extended Hubbard model. The system is defined on a non-uniform lattice. We show that the system is integrable. The ground state, the ground state energies, the energy spectrum are also found for the system. Another long range version of the extended Hubbard model is also introduced on a uniform lattice, and this system is proven to be integrable.
The Hofstadter problem is studied on hexagonal lattice. We first establish a relation between the spectra for the hexagonal lattice and for its dual he triangular lattice. Following the idea of Faddeev and Kashaev, we then obtain the Bethe-ansatz equations for this system.
In this work, the stability of the insulating phase of the 1D chiral Kondo lattice model is studied at half-filling, within the framework of self-consistent variational theory. It is found that arbitrarily small interaction would drive the system from a conducting phase to an insulating phase, in spite of the chirality of the conducting band.
In this remark, we note that the anyons, interacting with each other through pairwise potential in external magnetic field, exhibit a simple quantum group symmetry.
Revised version, a few typing errors that might cause confusion of physics argument in the article have been corrected.
We review some recent progresses in study of the 1D strongly correlated electron systems of long range hopping and exchange. The systems are completely integrable, with infinite number of constants of motions. The results of the physical properties, such as wavefunctions, the full excitation spectrum and the thermodynamics, are also reviewed.
In this work, we continue the study of the supersymmetric t-J model with 1/r^2 hopping and exchange without translational invariance. A set of Jastrow wavefunctions are obtained for the system, with eigenenergies explicitly calculated. The ground state of the t-J model is included in this set of wavefunctions. The spectrum of this t-J model consists of equal-distant energy levels which are highly degenerate.
We derive the spectrum and the thermodynamics of the one-dimensional supersymmetric t-J model with long range hopping and spin exchange using a set of maximal-spin eigenstates. This spectrum confirms the recent conjecture that the asymptotic Bethe-ansatz spectrum is exact. By empirical determining the spinon degeneracies of each state, we are able to explicitly construct the free energy.
In this work, we have studied the invariants of motion of two SU(N) supersymmetric t-J model of $1/r^2$ hopping and exchange in one dimension. The first model is defined on a lattice of equal spaced sites, and the second on a non-equal spacing lattice. Using the ``exchange operator formalism'', we are able to construct all the invariants for the models, by mapping the systems to mixtures of fermions and bosons. This identification shows that the supersymmetric t-J model on the chain with equal-spaced sites also belongs to Shastry-Sutherland's ``Super-Lax-Pair'' family. (IPT-EPFL 31/10/1993).
In this work we introduce one dimensional multi-component Hubbard model of 1/r hopping and U on-site energy. The wavefunctions, the spectrum and the thermodynamics are studied for this model in the strong interaction limit $U=\infty$. In this limit, the system is a special example of $SU(N)$ Luttinger liquids, exhibiting spin-charge separation in the full Hilbert space. Speculations on the physical properties of the model at finite on-site energy are also discussed.