This paper presents numerical studies of the single hole <InlineEquation ID="Equ1"> <EquationSource Format="TEX">$tt't''J$</EquationSource> </InlineEquation> model that address the interplay between the kinetic energy of itinerant electrons and the exchange energy of local moments as of interest to doped Mott insulators. Due to this interplay, two different spin correlations coexist...</equationsource></inlineequation>

Phonon anomalies observed in various high T<Subscript>c</Subscript> cuprates are analyzed theoretically within the Hubbard-Holstein model in the limit of strong local electron correlations and in presence of long-range Coulomb interaction. The phonon self-energy is evaluated by taking into account the charge...</subscript>

A recently developed renormalization approach is used to study the electron-phonon coupling in many-electron systems. By starting from an Hamiltonian which includes a small gauge symmetry breaking field, we directly derive a BCS-like equation for the energy gap from the renormalization approach....

We present the in-plane and c-axis penetration depths of the underdoped cuprates. The pseudogap phase is addressed within the framework of the ordered d-density wave (DDW). The above scenario is considered using a mean-field calculation of the tight binding model which incorporates two types of...

We suggest and implement a new Monte Carlo strategy for correlated models involving fermions strongly coupled to classical degrees of freedom, with accurate handling of quenched disorder as well. Current methods iteratively diagonalise the full Hamiltonian for a system of N sites with...