The O(3) symmetric Anderson model is an example of a system which has a stable low energy marginal Fermi liquid fixed point for a certain choice of parameters. It is also exactly equivalent, in the large U limit, to a localized model which describes the spin degrees of freedom of the linear...

We discuss the solution of the Mott transition problem in a fully frustrated lattice with a semicircular density of states in the limit of infinite dimensions from the point of view of a Landau free energy functional. This approach provides a simple relation between the free energy of the...

We study the effect of a magnetic field on the dimensional crossover of weakly coupled two-leg Hubbard ladders under pressure. Our model is based on the perturbative renormalization approach (PRG) with two cut-off parameters, the bandwidth E <Subscript>0</Subscript> and a characteristic magnetic energy ω <Subscript>c</Subscript>. We...</subscript></subscript>

We study the magnetic excitation spectrum of the spin-1 chain with Hamiltonian <Emphasis FontCategory="NonProportional">H=Σ<Subscript> i </Subscript> cos θ <Emphasis Type="Bold">S <Subscript> i </Subscript> · <Emphasis Type="Bold">S <Subscript> i+1</Subscript> + sin θ(<Emphasis Type="Bold">S <Subscript> i </Subscript> · <Emphasis Type="Bold">S <Subscript> i+1</Subscript>)<Superscript>2</Superscript>. We focus on the range 0 ≤ θ ≤ + π/4 where the spin chain is in the gapped Haldane phase. The excitation spectrum and static structure factor is studied...</superscript></subscript></emphasis></subscript></emphasis></subscript></emphasis></subscript></emphasis></subscript></emphasis>

We investigate polaron formation in a many-electron system in the presence of a local repulsion sufficiently strong to prevent local-bipolaron formation. Specifically, we consider a Hubbard-Holstein model of interacting electrons coupled to dispersionless phonons of frequency ω <Subscript>0</Subscript>. Numerically...</subscript>