Related papers: Possible phases of two coupled n-component fermion…
We study a two species fermion mixture with different populations on a square lattice modeled by a Hubbard Hamiltonian with on-site inter-species repulsive interaction. Such a model can be realized in a cold atom system with fermionic atoms…
We present a systematic weak-coupling renormalization group (RG) technique for studying a collection of $N$ coupled one-dimensional interacting electron systems, focusing on the example of N-leg Hubbard ladders. For $N=2,3$, we recover…
We use bosonization approach to investigate quantum phases in mixtures of bosonic and fermionic atoms confined in one dimensional optical lattices. The phase diagrams can be well understood in terms of polarons, which correspond to atoms…
We investigate the SU($N$) Hubbard model for the multi-component fermionic optical lattice system, combining dynamical mean-field theory with the continuous-time quantum Monte Carlo method. We obtain the finite temperature phase diagrams…
Motivated by the problem of N coupled Hubbard chains, we investigate a generalisation of the Schulz-Shastry model containing two species of one-dimensional fermions interacting via a gauge field that depends on the positions of all the…
We obtain a phase diagram of the spin imbalanced Hubbard model on the Lieb lattice, which is known to feature a flat band in its single-particle spectrum. Using the BCS mean-field theory for multiband systems, we find a variety of…
We present a field theory analysis of a model of two SU(2n)-invariant magnetic chains coupled by a generic interaction preserving time reversal and inversion symmetry. Contrary to the SU(2)-invariant case the zero-temperature phase diagram…
White's density matrix renormalization group ({DMRG}) method has been applied to an $S= 1/2 + 1/2$ composite-spin model, which can also be considered as a two-leg ladder model. By appropriate choices of the coupling constants this model…
We study the renormalization group flow of the interactions in the two-dimensional t-t' Hubbard model near half filling in a N-patch representation of the whole Fermi surface. Starting from weak to intermediate couplings the flows are to…
One dimensional free-fermions and hard-core bosons are often considered to be equivalent. Indeed, when restricted to nearest-neighbor hopping on a chain the particles cannot exchange themselves, and therefore hardly experience their own…
We propose a lattice scale two-band generalized Hubbard model as a caricature of the electronic structure of twisted bilayer graphene. Various possible broken symmetry phases can arise, including a nematic phase (which is a form of orbital…
The one-dimensional Hubbard model with different on-site interactions is investigated by renormalization group technique. In the case of a 1/4-filled band the dynamical nonequivalence of sites leads to the appearance of Umklapp processes in…
The 2-leg t-J ladder forms a spin liquid at half-filling which evolves to a Luther-Emery liquid upon doping. Our aim is to obtain a complete phase diagram for isotropic coupling (i.e. rungs and legs equal) as a function of electron density…
Recently it has been suggested that fermions whose hopping amplitude is quenched to extremely low values provide a convenient source of local disorder for lattice bosonic systems realized in current experiment on ultracold atoms. Here we…
We consider a spinless $t$-$t'$ ionic Hubbard chain at 1/2 filling and large hopping ratio $t'/t$. In this limit the model adequately maps onto a weakly coupled triangular ladder with a potential interchain bias. The low-energy properties…
We consider a modified version of the one-dimensional Hubbard model, the t1-t2 Hubbard chain, which includes an additional next-nearest-neighbor hopping. It has been shown that at weak coupling this model has a Luttinger liquid phase or a…
Using Density-Matrix Renormalization Group, we investigate the general phase diagram of the frustrated two-leg ladder with Heisenberg interactions along legs, rungs and diagonals. We confirm that all antiferromagnetic gapped states belong…
We study the Hubbard model on the honeycomb lattice in the vicinity of the quantum critical point by means of a multiband formulation of the Dual Fermion approach. Beyond the strong local correlations of the dynamical mean field, critical…
We investigate an asymmetric zig-zag spin ladder with different exchange integrals on both legs using bosonization and renormalization group. When the leg exchange integrals and frustration both are sufficiently small, renormalization group…
We examine a two-dimensional Fermi liquid with a Fermi surface which touches the Umklapp surface first at the 4 points $(\pm \pi/2, \pm \pi/2)$ as the electron density is increased. Umklapp processes at the 4 patches near $(\pm \pi/2,…