Competing orders in FeAs layers (2008)
Lorenzana, J., Seibold, G., Ortix, C., Grilli, M.
Using the unrestricted Hartree-Fock approximation and Landau theory we identify possible phases competing with superconductivity in FeAs layers. We find that close to half-filling the transition from...
Charge instabilities and electron-phonon interaction in the Hubbard-Holstein model (2008)
Di Ciolo, A., Lorenzana, J., Grilli, M., Seibold, G.
We consider the Hubbard-Holstein model in the adiabatic limit to investigate the effects of electron-electron interactions on the electron-phonon coupling. To this aim we compute at any momentum and...
Time-dependent Gutzwiller theory of pairing fluctuations in the Hubbard model (2008)
Seibold, G., Becca, F., Lorenzana, J.
We present a method to compute pairing fluctuations on top of the Gutzwiller approximation (GA). Our investigations are based on a charge-rotational invariant GA energy functional which is expanded...
Ortix, C., Lorenzana, J., Di Castro, C.
Using numerical techniques and asymptotic expansions we obtain the phase diagram of a paradigmatic model of Coulomb frustrated phase separation in systems with negative short-range compressibility....
Coarse grained models in Coulomb-frustrated phase separation (2007)
Ortix, C., Lorenzana, J., Di Castro, C.
Competition between interactions on different length scales leads to self-organized textures in classical as well as quantum systems. This pattern formation phenomenon has been invoked to explain...
Theory of antibound states in partially filled narrow band systems (2007)
Seibold, G., Becca, F., Lorenzana, J.
We present a theory of the dynamical two-particle response function in the Hubbard model based on the time-dependent Gutzwiller approximation. The results are in excellent agreement with exact...
Intermediate scale phenomena in cuprates (2007)
After 20 years of research the low energy physics of cuprates remains a mystery. It is generally accepted that a three band Hamiltonian with Cu's and O's orbitals should contain the essential physics...
Charge inhomogeneity coexisting with large Fermi surfaces (2007)
Di Ciolo, A., Grilli, M., Lorenzana, J., Seibold, G.
We discuss how stripes in cuprates can be compatible with a Fermi-liquid-like Fermi surface and, at the same time, they give rise to a one-dimensional-like pseudo Fermi surface in the momentum...
Quantum Lifshitz point in the infinite dimensional Hubbard model (2006)
Günther, F., Seibold, G., Lorenzana, J.
We show that the Gutzwiller variational wave function is surprisingly accurate for the computation of magnetic phase boundaries in the infinite dimensional Hubbard model. This allows us to...
Screening effects in Coulomb frustrated phase separation (2006)
Ortix, C., Lorenzana, J., Beccaria, M., Di Castro, C.
We solve a model of phase separation among two competing phases frustrated by the long-range Coulomb interaction in two and three dimensions (2D/3D) taking into account finite compressibility...
Unified description of charge and spin excitations of stripes in cuprates (2006)
We study stripes in cuprates within the one-band and the three-band Hubbard model. Magnetic and charge excitations are described within the time-dependent Gutzwiller approximation. A variety of...
Checkerboard and stripe inhomogeneities in cuprates (2006)
Seibold, G., Lorenzana, J., Grilli, M.
We systematically investigate charge-ordering phases by means of a restricted and unrestricted Gutzwiller approximation to the single-band Hubbard model with nearest ($t$) and next-nearest neighbor...
Effective electron-electron and electron-phonon interactions in the Hubbard-Holstein model (2006)
Aprea, G., Di Castro, C., Grilli, M., Lorenzana, J.
We investigate the interplay between the electron-electron and the electron-phonon interaction in the Hubbard-Holstein model. We implement the flow-equation method to investigate within this model...
Thermodynamics of volume collapse transitions in cerium and related compounds (2005)
Bustingorry, S., Jagla, E. A., Lorenzana, J.
We present a non-linear elastic model of a coherent transition with discontinuous volume change in an isotropic solid. The model reproduces the anomalous thermodynamics typical of coherent...
Doping dependence of spin excitations in the stripe phase of high-Tc superconductors (2005)
Based on the time-dependent Gutzwiller approximation for the extended Hubbard model we calculate the energy and momentum dependence of spin excitations for striped ground states. Our starting point...
Freeman, P. G., Boothroyd, A. T., Prabhakaran, D., Lorenzana, J.
We have studied the magnetization of a series of spin-charge ordered La(2-x)Sr(x)NiO(4+delta) single crystals with 0 < x < 0.5. For fields applied parallel to the ab plane there is a large...
Frustrated phase separation in two-dimensional charged systems (2005)
Ortix, C., Lorenzana, J., Di Castro, C.
We study phase separation frustrated by the long-range Coulomb interaction in two dimensional electronic systems with emphasys in the case of a metallic and an insulating phase. We find that...
Where is the spectral weight in magnetic neutron scattering in the cuprates? (2005)
Lorenzana, J., Seibold, G., Coldea, R.
We present estimates in the Hubbard and Heisenberg models for the spectral weight in magnetic neutron scattering experiments on the cuprates. With the aid of spin-wave theory and the time dependent...
Effect of mesoscopic inhomogeneities on local tunnelling density of states (2004)
Dell'Anna, L., Lorenzana, J., Capone, M., Castellani, C., Grilli, M.
We carry out a theoretical analysis of the momentum dependence of the Fourier-transformed local density of states (LDOS) in the superconducting cuprates within a model considering the interference of...
Magnetic fluctuations from stripes in cuprates (2004)
Within the time-dependent Gutzwiller approximation for the Hubbard model we compute the magnetic fluctuations of vertical metallic stripes with parameters appropriate for...
First principle computation of stripes in cuprates (2004)
Anisimov, V. I., Korotin, M. A., Mylnikova, A. S., Kozhevnikov, A. V., Lorenzana, J.
We present a first principle computation of vertical stripes in $La_{15/8}Sr_{1/8}CuO_4$ within the LDA+U method. We find that Cu centered stripes are unstable toward O centered stripes. The metallic...
Time-dependent Gutzwiller theory of magnetic excitations in the Hubbard model (2003)
Seibold, G., Becca, F., Rubin, P., Lorenzana, J.
We use a spin-rotational invariant Gutzwiller energy functional to compute random-phase-approximation-like (RPA) fluctuations on top of the Gutzwiller approximation (GA). The method can be viewed as...
Stability of metallic stripes in the extended one-band Hubbard model (2003)
Based on an unrestricted Gutzwiller approximation (GA) we investigate the stripe orientation and periodicity in an extended one-band Hubbard model. A negative ratio between next-nearest and nearest...
Solid-solid volume collapse transitions are zeroth order (2003)
Bustingorry, S., Jagla, E. A., Lorenzana, J.
We present an exactly solvable non-linear elastic model of a volume collapse transition in an isotropic solid. Integrity of the lattice through the transition leads to an infinite-range...
Inhomogeneous Gutzwiller approximation with random phase fluctuations for the Hubbard model (2002)
Seibold, G., Becca, F., Lorenzana, J.
We present a detailed study of the time-dependent Gutzwiller approximation for the Hubbard model. The formalism, labelled GA+RPA, allows us to compute random-phase approximation-like (RPA)...
Dynamics of metallic stripes in cuprates (2002)
We study the dynamics of metallic vertical stripes in cuprates within the three-band Hubbard model based on a recently developed time dependent Gutzwiller approximation. As doping increases the...
Metallic mean-field stripes, incommensurability and chemical potential in cuprates (2002)
We perform a systematic slave-boson mean-field analysis of the three-band model for cuprates with first-principle parameters. Contrary to widespread believe based on earlier mean-field computations...
Advanced Composite Cost Estimating Manual. Volume I (2002)
LeBlanc, Donald J., Lorenzana, J., Kokawa, A., Bettner, T., Timson, F.
This program concentrated on the development of a computerized system that estimates the recurring costs associated with the fabrication of advanced composite detail parts and components. The system...
Advanced Composite Cost Estimating Manual. Volume II. Appendix (2002)
LeBlanc, Donald J., Lorenzana, J., Kokawa, A., Bettner, T., Timson, F.
Contents: Computer Program Listing; Permanent Input Data Sets; Job Control Language and Sample Estimates.
Advanced Composite Cost Estimating Manual. Volume II (2002)
LeBlanc, Donald J., Lorenzana, J., Kokawa, A., Bettner, T., Timson, F.
Contents: Input Forms; Keypunching Data Cards; and Estimating Equations.
Phase separation frustrated by the long range Coulomb interaction II: Applications (2001)
Lorenzana, J., Castellani, C., Di Castro, C.
The theory of first order density-driven phase transitions with frustration due to the long range Coulomb (LRC) interaction develop on paper I of this series is applied to the following physical...
Phase separation frustrated by the long range Coulomb interaction I: Theory (2000)
Lorenzana, J., Castellani, C., Di Castro, C.
We analyze the combined effect of the long range Coulomb (LRC) interaction and of surface energy on first order density-driven phase transitions in the presence of a compensating rigid background. We...
Time-dependent Gutzwiller approximation for the Hubbard model (2000)
We develop a time-dependent Gutzwiller approximation (GA) for the Hubbard model analogous to the time-dependent Hartree-Fock (HF) method. The formalism incorporates ground state correlations of the...
Optical Absorption of CuO$_3$ antiferromagnetic chains at finite temperatures (1999)
Gagliano, Eduardo, Lema, Fabian, Bacci, Silvia, Vicente, Juan José, Lorenzana, J.
We use a high-statistic quantum Monte Carlo and Maximum Entropy regularization method to compute the dynamical energy correlation function (DECF) of the one-dimensional (1D) $S=1/2$ antiferromagnetic...
The interaction Hamiltonian for a system of polarons a la Feynman in the presence of long range Coulomb interaction is derived and the dielectric function is computed in mean field. For large enough...
Lorenzana, J., Eroles, J., Sorella, S.
We compute the absorption spectrum for multimagnon excitations assisted by phonons in insulating layered cuprates using exact diagonalization in clusters of up to 32 sites. The resulting line shape...
Published in: Phys. Rev. B 55 (1997) 3358-3361 Citing articles (CrossRef) citations recorded in [Science Citation Index] Abstract: We use numerical and analytical results to construct a simple ansatz...
We use numerical and analytical results to construct a simple ansatz for the energy dynamical correlation function of the 1D antiferromagnetic Heisenberg model. This is applied to compute the phonon...
Lorenzana, J., Sawatzky, G. A.
We calculate the effective charge for multimagnon infrared (IR) absorption assisted by phonons in a perovskite like antiferromagnet and we compute the spectra for two magnon absorption using...
Lorenzana, J., Sawatzky, G. A.
We calculate the effective charge for multimagnon infrared (IR) absorption assisted by phonons in the parent insulating compounds of cuprate superconductors and the spectra for two-magnon absorption...
Polaron Formation in the Three-Band Peierls-Hubbard Model for Cuprate Superconductors (1994)
Exact diagonalization calculations show a continuous transition from delocalized to small polaron behavior as a function of intersite electron-lattice coupling. A transition, found previously at...
Polaronic Self-Localization Effects in the Three Band Peierls Hubbard Model (1993)
Dobry, A., Greco, A., Lorenzana, J., Riera, J.
We have studied the three-band Peierls-Hubbard model describing the Cu-O layers in high-T$_c$ superconductors by using Lanczos diagonalization and assuming infinite mass for the ions. When the system...