In a recent paper we provided an exact probabilistic expression for the real time or the imaginary time evolution of a Fermi system, in particular a Hubbard model, in terms of an associated stochastic dynamics of a collection of Poisson processes. Here, we generalize the result to the case of a Hubbard model with siteand spin-dependent hopping coefficients and site-dependent interactions. This ...

We consider the one-dimensional Hubbard model at half filling. We show that both excitation spectrum and S-matrix are determined by the SO(4) symmetry of the model. The complete set of excitations is given by the scattering states four elementary excitations, which form the fundamental representation of SO(4). We evaluate the exact S-matrix, which satisfies the Yang-Baxter relation. The results...

The Bose-Hubbard hamiltonian will be introduced and justified as an effective description of some relevant physical systems (dilute alkali gases in optical lattices, arrays of Josephson junctions). I will also show a mean field theory solution and the resulting phase diagram. Finally, I will describe in detail one of the more important experiments with an optical lattice of Rb atoms. 1. The Bos...

We propose a method to construct localized single-particle wave functions using imaginary time projection and thereby determine lattice Hamiltonian parameters. We apply the method to a specific disordered potential generated by an optical lattice experiment and calculate for each instance of disorder the equivalent lattice model parameters. The probability distributions of the Hubbard parameter...

We prove that approximating the ground energy of the antiferromagnetic XY model on a simple graph at fixed magnetization (given as part of the instance specification) is QMA-complete. To show this, we strengthen a previous result by establishing QMA-completeness for approximating the ground energy of the Bose-Hubbard model on simple graphs. Using a connection between the XY and Bose-Hubbard mod...

LiV2O4, a frustrated mixed valent metal (d 1 ↔ d2), is argued to undergo two spinscreening processes. The first quenches the effective spin to produce the spin 1 2 behavior seen below room temperature[1] , while the second produces the heavy fermi liquid character seen at low temperatures[2]. We present here a preliminary discussion of a t-J model with strong Hund’s coupling of the strongly cor...

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...

The new method of investigation of strongly correlated electronic system is presented. Using this method we have derived the superstring from 2D Hubbard model. The novel expression for generalized supercoherent state has been calculated. 1. Nowadays the Hubbard model attracts considerable attention. This model is incorporated in several profound theoretical projects, proposed in [1] for example...

Experiments on polarized fermion gases performed by trapping ultracold atoms in optical lattices allow the study of an attractive Hubbard model for which the strength of the on-site interaction is tuned by means of a Feshbach resonance. Using a well-known particle-hole transformation we discuss how results obtained for this system can be reinterpreted in the context of a doped repulsive Hubbard...

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 ...