Charged excitons in doped extended Hubbard model systems. Abstract We show that the charge transfer excitons in a Hubbard model system including nearest neighbor Coulomb interactions effectively attain some charge in doped systems and become visible in photoelectron and inverse photoelec-tron spectroscopies. This shows that the description of a doped system by an extended Hubbard model differs ...

A momentum-space approach of the density-matrix renormalization-group ~DMRG! method is developed. Ground-state energies of the Hubbard model are evaluated using this method and compared with exact diagonalization as well as quantum Monte Carlo results. It is shown that the momentum-space DMRG is a very useful numerical tool for studying the Hubbard model and other fundamental models of interact...

Quantum many-body systems are characterized by their correlations. While equal-time correlators and unequal-time commutators between operators standard observables, the direct access to anti-commutators poses a formidable experimental challenge. Here, we propose general technique for measuring using linear response of system non-Hermitian perturbation. We illustrate protocol at example Bose-Hub...

A consistent microscopic theory of superconductivity for strongly correlated electronic systems is presented within the extended t-J-V model where intersite Coulomb repulsion and electron-phonon interaction are taken into account. The exact Dyson equation normal anomalous (pair) Green functions derived projected (Hubbard) operators. solved in self-consistent Born approximation self-energy. We o...

Mott-Hubbard metal-insulator transitions in N -fold degenerate Hubbard models are studied within the Gutzwiller approximation. For any rational filling with x (integer) electrons per site it is found that metal-insulator transition occurs at a critical correlation energy Uc(N,x) = Uc(N, 2N − x) = γ(N,x)|ǭ(N,x)|, where ǭ is the band energy per particle for the uncorrelated Fermi-liquid state and...

In the present paper we study chemical potential of a generalized Hubbard model with correlated hopping at half-filling using a generalized mean-field approximation. For the special case of the model the approach reproduces the exact results: metalinsulator transition, ground state energy. Chemical potential of generelized Hubbard model with correlated hoppig as function of hopping integrals at...

We show that in the presence of a magnetic field the usual low-energy separation of the Hubbard chain is replaced by a “c” and “s” separation. Here c and s refer to small-momentum and low-energy independent excitation modes which couple both to charge and spin. Importantly, we find the exact generators of these excitations both in the electronic and pseudoparticle basis. In the limit of zero ma...

We construct XX-and Hubbard-like models based on unitary superalgebras gl(N |M) generalising Shastry's and Maassarani's approach of the algebraic case. We introduce the R-matrix of the gl(N |M) XX model and that of the Hubbard model defined by coupling two independent XX models. In both cases, we show that the R-matrices satisfy the Yang–Baxter equation, we derive the corresponding local Hamilt...

We employ density functional theory plus dynamical mean field theory and identify the physical origin of why two layers of SrVO(3) on a SrTiO(3) substrate are insulating: the thin film geometry lifts the orbital degeneracy, which in turn triggers a first-order Mott-Hubbard transition. Two layers of SrVO(3) are just at the verge of a Mott-Hubbard transition and hence ideally suited for technolog...

The combination of bandstructure theory in the local density approximation with dynamical mean field theory was recently successfully applied to V2O3 – a material which undergoes the famous Mott-Hubbard metal-insulator transition upon Cr doping. The aim of this short paper is to emphasize two aspects of our recent results: (i) the filling of the Mott-Hubbard gap with increasing temperature, and...