ed from previous theoretical studies. The symbols D1 Ref. 10 and D2 Ref. 13 represent the density-matrix renormalizationgroup DMRG calculations. Labels E Ref. 12 and H Ref. 14 correspond to the exact diagonalization method and hightemperature series expansion, respectively. FIG. 4. Color online The spin pairwise concurrence for the ground state L=8 site system as a function of x and y. CHEN et ...

We describe the evolution of the spectral density as we dope a Mott insulator within a dynamical mean field method. After giving an intuitive description of this Local Impurity Self-Consistent Approximation (LISA) for a model with several orbitals per unit cell, we illustrate its implementation in the context of the Hubbard model in infinite dimensions. For this purpose a new iterative perturba...

Two single-molecule magnets are coupled antiferromagnetically to form a supramolecule dimer. We study the coupling effect and tunneling process by means of the numerical exact diagonalization method, and apply them to the recently synthesized supramoleculer dimer [Mn4]2. The model parameters are calculated for the dimer based on the tunneling process. The absence of tunneling at zero field and ...

Computer simulations of decoherence in quantum spin systems require the solution of the time-dependent Schrödinger equation for interacting quantum spin systems over extended periods of time. We use exact diagonalization, the Chebyshev polynomial technique, four Suzuki-formula algorithms, and the short-iterative-Lanczos method to solve a simple model for decoherence of a quantum spin system by ...

Few-electron systems confined in two-dimensional parabolic quantum dots at high magnetic fields are studied by the Hartree-Fock (HF) and exact diagonalization methods. A generalized multicenter Gaussian basis is proposed in the HF method. A comparison of the HF and exact results allows us to discuss the relevance of the symmetry of the charge density distribution for the accuracy of the HF meth...

The exact numerical diagonalization of the Hamiltonian of a 2D circular quantum dot is performed for 2, 3, and 4 electrons.The results are compared with those of the perturbation theory.Our numerical results agree reasonably well for small values of the dimensionles coupling constant λ = a a B where a is the dot radius and a B is the effective Bohr radius.Exact diagonalization results are compa...

We explore the use of exact diagonalization methods for solving the self-consistent equations of the cellular dynamical mean field theory for the one-dimensional regular and extended Hubbard models. We investigate the nature of the Mott transition and convergence of the method as a function of cluster size as well as the optimal allocation of computational resources between bath and ‘‘cluster-i...