Related papers: Superconductivity in the Two-Dimensional $t$-$J$ M…
Recently two interesting candidate quantum phases --- the chiral spin density wave state featuring anomalous quantum Hall effect and the d+id superconductor --- were proposed for the Hubbard model on the honeycomb lattice at 1/4 doping.…
We studied underdoped high $T_c$ superconductors using a spinon-dopon approach (or doped-carrier approach) to $t$-$t'$-$t''$-$J$ model, where spinon carries spin and dopon carries both spin and charge. In this approach, the mixing of spinon…
A method to calculate the one-body Green's function for ground states of correlated electron materials is formulated by extending the variational Monte Carlo method. We benchmark against the exact diagonalization (ED) for the one- and…
A two chain ladder model is considered described by the strong coupling $t-t^\prime-J-J^\prime$ Hamiltonian. For the case of two holes moving in a background of antiferromagnetically interacting spins, exact, analytical results are derived…
Light localization by scattering is a fundamental mechanism driving phase transitions of wave transport in disordered systems. Characterizing the localization length in scattering systems is crucial yet challenging. In this Letter, we…
We study a Hamiltonian lattice version of the two-dimensional Wess-Zumino model. Preliminary results obtained by Quantum Monte Carlo with a many-parameter guiding wave function are presented. We analyze the pattern of supersymmetry breaking…
We study a two-dimensional t-J model close to the Ising limit in which charge inhomogeneity is stabilized by an on-site potential e_s, by using diagonalization in a restricted Hilbert space and finite temperature Quantum Monte Carlo. Both…
Magnetic and charge susceptibilities in the Kondo lattice are derived by the continuous-time quantum Monte Carlo (CT-QMC) method combined with the dynamical mean-field theory. For a weak exchange coupling J and near half filling of the…
We propose the projected BCS wave function as the ground state for the doped Mott insulator SrCu2(BO3)2 on the Shastry-Sutherland lattice. At half filling this wave function yields the exact ground state. Adding mobile charge carriers, we…
We study superconductivity on the honeycomb lattice close to the Mott state at half-filling. Due to the sixfold lattice symmetry and disjoint Fermi surfaces at opposite momenta, we show that several different fully gapped superconducting…
We study an extended Hubbard model with on-site repulsion and nearest neighbors attraction which tries to mimic some of the experimental features of doped cuprates in the superconducting state. We draw and discuss the phase diagram as a…
A microscopically based Hamiltonian of the generalized $t$-$t^\prime$-$J$ model is presented. Two types of the additional $t^\prime$-terms are discussed. The set of ranges of the additional $t^\prime$-terms for the real CuO$_2$ planes is…
Recent refinements of analytical and numerical methods have improved our understanding of the ground-state phase diagram of the two-dimensional (2D) Hubbard model. Here we focus on variational approaches, but comparisons with both Quantum…
The tunneling spectrum of an inhomogeneously doped extended Hubbard model is calculated at the mean field level. Self-consistent solutions admit both superconducting and antiferromagnetic order, which coexist inhomogeneously because of…
Routes to enhance superconducting instability are explored for doped Mott insulators. With the help of insights for criticalities of metal-insulator transitions, geometrical design of lattice structure is proposed to control the…
For a class of generalized Hubbard models, we determine the maximal stability region for the superconducting eta-pairing ground state. We exploit the Optimized Ground State (OGS) approach and the Lanczos diagonalization procedure to derive…
Spatial dependencies of the pair potential and the local density of states near the surfaces of $d_{x^{2}-y^{2}}$-wave superconductors are studied theoretically. The calculation is based on the t-J model within a mean-field theory with…
We study the evolution of the superconducting coherence length $\xi_0$ from weak to strong coupling, both within a s-wave and a d-wave lattice model. We show that the identification of $\xi_0$ with the Cooper-pair size $\xi_{pair}$ in the…
In the two-dimensional Kondo-Heisenberg lattice model away from half-filled, the local antiferromagnetic exchange coupling can provide the pairing mechanism of quasiparticles via the Kondo screening effect, leading to the heavy fermion…
Double-exchange model in infinite dimension is studied as the strong Hund's coupling limit $J\to\infty$ of the Kondo lattice model. Several quantities such as Green's function and the d.c.\ conductivity are calculated in analytical forms.…