Publications (17)
Spatially homogeneous ground state of the two-dimensional Hubbard model
F. Becca, M. Capone, S. Sorella
We investigate the stability with respect to phase separation or charge density-wave formation of the two-dimensional Hubbard model for various values of the local Coulomb repulsio…
Charge-density-waves and superconductivity as an alternative to phase separation in the infinite-U Hubbard-Holstein model
F. Becca, M. Tarquini, M. Grilli +1
We investigate the density instabilities present in the infinite-U Hubbard-Holstein model both at zero and finite momenta as well as the occurrence of Cooper instabilities with a s…
Magnetic Superstructure in the Two-Dimensional Quantum Antiferromagnet SrCu2(BO3)2
K. Kodama, M. Takigawa, M. Horvatic +6
We report the observation of magnetic superstructure in a magnetization plateau state of SrCu2(BO3)2, a frustrated quasi-two-dimensional quantum spin system. The Cu and B nuclear m…
Inhomogeneous Gutzwiller approximation with random phase fluctuations for the Hubbard model
G. Seibold, F. Becca, J. Lorenzana
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-li…
Time-dependent Gutzwiller theory of magnetic excitations in the Hubbard model
G. Seibold, F. Becca, P. Rubin +1
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 metho…
Ising transition driven by frustration in a 2D classical model with SU(2) symmetry
C. Weber, L. Capriotti, G. Misguich +3
We study the thermal properties of the classical antiferromagnetic Heisenberg model with both nearest () and next-nearest () exchange couplings on the square lattice by e…
Theory of antibound states in partially filled narrow band systems
G. Seibold, F. Becca, J. Lorenzana
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 agreemen…
The Quantum Compass Model on the Square Lattice
J. Dorier, F. Becca, F. Mila
Using exact diagonalizations, Green's function Monte Carlo simulations and high-order perturbation theory, we study the low-energy properties of the two-dimensional spin-1/2 compas…
Magnetic field-induced transition in a quantum magnet described by the Quantum Dimer Model
A. Ralko, F. Becca, D. Poilblanc
The effect of a magnetic field on a gapped quantum magnet is described within the framework of the Quantum Dimer Model. A minimal model describing the proliferation of itinerant sp…
The emergence of Resonating Valence Bond physics in spin-orbital models
F. Mila, F. Vernay, A. Ralko +3
We discuss how orbital degeneracy, which is usually removed by a cooperative Jahn-Teller distortion, could under appropriate circumstances lead rather to a Resonating Valence Bond…
Charge fluctuations close to phase separation in the two dimensional t-J model
M. Calandra, F. Becca, S. Sorella
We have studied the t-J model using the Green Function Monte Carlo technique. We have obtained accurate energies well converged in the thermodynamic limit, by performing simulation…
Time-dependent Gutzwiller theory of pairing fluctuations in the Hubbard model
G. Seibold, F. Becca, J. Lorenzana
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…
Spectral properties of incommensurate charge-density wave systems
G. Seibold, F. Becca, F. Bucci +3
The concept of frustrated phase separation is applied to investigate its consequences for the electronic structure of the high T_c cuprates. The resulting incommensurate charge den…
The incommensurate charge-density-wave instability in the extended three-band Hubbard model
F. Becca, F. Bucci, M. Grilli
The infinite-U three-band Hubbard model is considered in order to describe the CuO_2 planes of the high temperature superconducting cuprates. The charge instabilities are investiga…
A chiral spin liquid wave function and the Lieb-Schulz-Mattis theorem
S. Sorella, L. Capriotti, F. Becca +1
We study a chiral spin liquid wave function defined as a Gutwziller projected BCS state with a complex pairing function. After projection, spontaneous dimerization is found for any…
Superconductivity in the two-dimensional t-J model
S. Sorella, G. B. Martins, F. Becca +4
Using computational techniques, it is shown that pairing is a robust property of hole doped antiferromagnetic (AF) insulators. In one dimension (1D) and for two-leg ladder systems,…
Metallic charge density waves and surface Mott insulators for adlayer structures on semiconductors: extended Hubbard modeling
G. Santoro, S. Sorella, F. Becca +2
Motivated by the recent experimental evidence of commensurate surface CDW in Pb/Ge(111) and Sn/Ge(111) -adlayer structures, as well as by the insulating states found on K…