Related papers: Superconductivity with hard-core repulsion: BCS-Bo…
The nature of superconductivity in heavy-fermion materials is a subject under intense debate, and controlling this many-body state is central for its eventual understanding. Here, we examine how proximity effects may change this phenomenon,…
The direct transition from an insulator to a superconductor (SC) in Fermi systems is a problem of long-standing interest, which necessarily goes beyond the standard BCS paradigm of superconductivity as a Fermi surface instability. We…
We consider a mixture of a two-component Fermi gas and a single-component dipolar Bose gas in a square optical lattice and reduce it into an effective Fermi system where the Fermi-Fermi interaction includes the attractive interaction…
We study the limit of large onsite repulsion of the one-dimensional Bose-Hubbard model at low densities, and derive a strong-coupling effective Hamiltonian. By taking the lattice parameter to zero, the Hamiltonian becomes a continuum model…
We analyze a superfluid state of two species gas of fermions trapped in a quasi-1D harmonic potential and interacting via attractive s-wave collisions. It is shown that the gap equation posesses a self consistent solution with an…
Systems of fermions described by the three-dimensional (3D) repulsive Hubbard model on a cubic lattice have recently attracted considerable attention due to their possible experimental realization via cold atoms in an optical lattice.…
We investigate the electronic phases of an effective Hubbard model on the body-centered-cubic lattice, motivated by alkali-doped fulleride molecular solids. The model incorporates renormalized on-site interactions and an effective inverted…
We study the system of multi-body interacting bosons on a two dimensional optical lattice and analyze the formation of bound bosonic pairs in the context of the Bose-Hubbard model. Assuming a repulsive two-body interaction we obtain the…
In this work we use functional integral techniques to examine the nearest neighbour attractive Hubbard model on a quasi-2D lattice. It is a simple phenomenological model for the high-Tc cuprates that allows both extended (non-local) s- and…
We revisit the issue of superconductivity at the quantum-critical point (QCP) between a 2D paramagnet and a spin-density-wave metal with ordering momentum (\pi,\pi). This problem is highly non-trivial because the system at criticality…
We study the ground state properties of a frustrated two-species mixture of hard-core bosons on a triangular lattice, as a function of tunable amplitudes for tunnelling and interactions. By combining three different methods, a…
Quantum-degenerate Fermi gases provide a remarkable opportunity to study strongly interacting fermions. In contrast to other Fermi systems, such as superconductors, neutron stars or the quark-gluon plasma, these gases have low densities and…
Both FeSe and cuprate superconductors are quasi 2D materials with high transition temperatures and local fermion pairs. Motivated by such systems, we investigate real space pairing of fermions in an anisotropic lattice model with intersite…
We show that in a superconductor where two or more bands cross the Fermi level it is possible, in the framework of the conventional (s-wave) BCS theory, that the sign of the superconducting gap is different on the different sheets of the…
In our model, spinless fermions (or hardcore bosons) on a square lattice hop to nearest neighbor sites, and also experience a hard-core repulsion at the nearest neighbor separation. This is the simplest model of correlated electrons and is…
We review briefly the properties of a mixture of mutually interacting bosons (bound electron pairs) and itinerant fermions on a lattice (the boson-fermion model). The calculations of the superconducting phase transition temperature…
We revisit the stability of the superconducting state within mean-field theory in the presence of repulsive pairing interactions, focusing on multiband systems where such channels naturally arise. We show that, when repulsion is present,…
The Kondo lattice model enlarged by an antiferromagnetic coupling $J_{\rm AF}$ between the localized spins is here investigated using computational techniques. Our results suggest the existence of a d-wave superconducting phase close to…
The properties of ultracold atomic Bose-Fermi mixtures in external potentials are investigated and the existence of gap solitons of Bose-Fermi mixtures in optical lattices demonstrated. Using a self-consistent approach we compute the energy…
Ultra-cold atom experiments offer the unique opportunity to study mixing of different types of superfluid states. Our interest is in superfluid mixtures comprising particles with different statistics- Bose and Fermi. Such scenarios occur…