74 citations · 364 across the 11 of their papers we have counts for
11 papers
Neural network ensembles: Evaluation of aggregation algorithms
P. M. Granitto, P. F. Verdes, H. A. Ceccatto
Ensembles of artificial neural networks show improved generalization capabilities that outperform those of single networks. However, for aggregation to be effective, the individual…
Phase diagram of the chain at half filling
M. E. Torio, A. A. Aligia, H. A. Ceccatto
We study the half filled Hubbard chain including next-nearest-neighbor hopping . The model has three phases: one insulating phase with dominant spin-density-wave correlations a…
Phase diagram of the Hubbard chain with two atoms per cell
M. E. Torio, A. A. Aligia, H. A. Ceccatto
We obtain the quantum phase diagram of the Hubbard chain with alternating on-site energy at half filling. The model is relevant for the ferroelectric perovskites and organic mixed-…
Phase diagram of the extended Hubbard chain with charge-dipole interactions
M. E. Torio, A. A. Aligia, K. Hallberg +1
We consider a modified extended Hubbard model (EHM) which, in addition to the on-site repulsion U and nearest-neighbor repulsion V, includes polarization effects in second-order pe…
Stability of homogeneous magnetic phases in a generalized t-J model
L. O. Manuel, H. A. Ceccatto
We study the stability of homogeneous magnetic phases in a generalized t-J model including a same-sublattice hopping t' and nearest-neighbor repulsion V by means of the slave fermi…
Magnetic and quantum disordered phases in triangular-lattice Heisenberg antiferromagnets
L. O. Manuel, H. A. Ceccatto
We study, within the Schwinger-boson approach, the ground-state structure of two Heisenberg antiferromagnets on the triangular lattice: the J1-J2 model, which includes a next-neare…
The Heisenberg model on the 1/5-depleted square lattice and the CaV4O9 compound
L. O. Manuel, M. I. Micheletti, A. E. Trumper +1
We investigate the ground state structure of the Heisenberg model on the 1/5-depleted square lattice for arbitrary values of the first- and second-neighbor exchange couplings. By u…
Rotational invariance and order-parameter stiffness in frustrated quantum spin systems
L. O. Manuel, A. E. Trumper, H. A. Ceccatto
We compute, within the Schwinger-boson scheme, the Gaussian-fluctuation corrections to the order-parameter stiffness of two frustrated quantum spin systems: the triangular-lattice…
Numerical Study of the Incommensurate Phase in Spin-Peierls Systems
A. E. Feiguin, J. A. Riera, A. Dobry +1
We analyze several properties of the lattice solitons in the incommensurate phase of spin-Peierls systems using exact diagonalization and quantum Monte Carlo. These systems are mod…
Superconductivity and incommensurate spin fluctuations in a generalized t-J model for the cuprates
C. D. Batista, L. O. Manuel, H. A. Ceccatto +1
We consider the slave-fermion Schwinger-boson decomposition of an effective model obtained through a systematic low-energy reduction of the three-band Hubbard Hamiltonian. The mode…
Schwinger-boson approach to quantum spin systems: Gaussian fluctuactions in the "natural" gauge
A. E. Trumper, L. O. Manuel, C. J. Gazza +1
We compute the Gaussian-fluctuation corrections to the saddle-point Schwinger-boson results using collective coordinate methods. Concrete application to investigate the frustrated…