Related papers: Gutzwiller variational wave function for multi-orb…
The Hubbard model on the fcc lattice is studied in the limit of infinite spatial dimensions. At sufficiently strong interaction finite temperature Quantum Monte Carlo calculations yield a second order phase transition to a highly polarized…
We calculate the interaction-induced deformation of the Fermi surface in the two-dimensional Hubbard model within second order perturbation theory. Close to half-filling, interactions enhance anisotropies of the Fermi surface, but they…
We calculate the Landau interaction function f(k,k') for the two-dimensional t-t' Hubbard model on the square lattice using second and higher order perturbation theory. Within the Landau-Fermi liquid framework we discuss the behavior of…
We study itinerant ferromagnetism in a $t_{2g}$ multi-orbital Hubbard system in the cubic lattice, which consists of three planar oriented orbital bands of $d_{xy}$, $d_{yz}$, and $d_{zx}$. Electrons in each orbital band can only move…
We implement the Gutzwiller wave function for attractive SU(3) fermion systems on a quantum computer using a quantum-classical hybrid scheme based on the discrete Hubbard-Stratonovich transformation. In this approach, the nonunitary…
A single-band Hubbard model with nearest and next-nearest neighbour hopping is studied for $d=1$, 2, 3, using both analytical and numerical techniques. In one dimension, saturated ferromagnetism is found above a critical value of $U$ for a…
In order to resolve the long-standing issue of how the itinerant ferromagnetism is affected by the lattice structure and Hund's coupling, we have compared various three-dimensional lattice structures in the single- and multiorbital Hubbard…
We present a method to compute pairing fluctuations on top of the Gutzwiller approximation (GA). Our investigations are based on a charge-rotational invariant GA energy functional which is expanded up to second order in the pair…
We investigate the possibility and stability of bandferromagnetism in the single-band Hubbard model. This model poses a highly non-trivial many-body problem the general solution of which has not been found up to now. Approximations are…
We present a systematic stability analysis for the two-dimensional Hubbard model, which is based on a new renormalization group method for interacting Fermi systems. The flow of effective interactions and susceptibilities confirms the…
The 2D Hubbard model is extended by placing 2S orbitals at each lattice site and studied in a systematic 1/S expansion. The 1/S results for the magnetic susceptibility and the spectra of spin-wave excitations at half-filling are consistent…
We introduce a novel approach for the investigation of spin-wave excitations in itinerant ferromagnets. Our theory is based on a variational treatment of general multi-band Hubbard models which describe elements and compounds of transition…
We study the Gutzwiller method for the spinless fermion model in one dimension, which is one of the simplest models that incorporates the intersite Coulomb interaction. The Gutzwiller solution of this model has been studied in the…
It is investigated, on the basis of the fluctuation exchange approximation, how the shape of the Fermi surface is modified in two-dimensional $t-t'-U$ Hubbard model at half filling as strength of the onsite Coulomb interaction $U$ is…
We investigate the competing Fermi surface instabilities in the Kagome tight-binding model. Specifically, we consider onsite and short-range Hubbard interactions in the vicinity of van Hove filling of the dispersive Kagome bands where the…
We investigate spin and orbital states of the two-orbital Hubbard model on a square lattice by using a variational Monte Carlo method at quarter-filling, i.e., the electron number per site is one. As a variational wave function, we consider…
A systematic diagrammatic expansion for Gutzwiller-wave functions (DE-GWF) proposed very recently is used for the description of superconducting (SC) ground state in the two-dimensional square-lattice $t$-$J$ model with the hopping electron…
We measure the band structure of nickel along various high-symmetry lines of the bulk Brillouin zone with angle-resolved photoelectron spectroscopy. The Gutzwiller theory for a nine-band Hubbard model whose tight-binding parameters are…
In this work, a two-dimensional one-band Hubbard model is investigated within a two-pole approximation. The model presents a non-local attractive potential $U (U<0)$ that allows the study of d-wave superconductivity and also includes…
We study weak itinerant ferromagnetism in one-dimensional Fermi systems using perturbation theory and bosonization. We find that longitudinal spin fluctuations propagate ballistically with velocity v_m << v_F, where v_F is the Fermi…