Related papers: First order Quantum Hall to Wigner crystal phase t…
Experiments on chains of Rydberg atoms appear as a new playground to study quantum phase transitions in 1D. As a natural extension, we report a quantitative ground-state phase diagram of Rydberg atoms arranged in a two-leg ladder that…
We explore the quantum phase transitions between two ordered states in the infinite dimensional Hubbard-Holstein model at half filling. Our study is based on the dynamical mean field theory (DMFT) combined with the numerical renormalization…
We present a renormalization group theory for the onset of Ising-nematic order in a Fermi liquid in two spatial dimensions. This is a quantum phase transition, driven by electron interactions, which spontaneously reduces the point-group…
Recent experiments suggest that low carrier density three-dimensional (3D) metals ZrTe$_5$ and HfTe$_5$ exhibit the 3D quantum Hall (QH) effect with Hall resistivity plateaus and a metal-insulator transition in strong magnetic fields. The…
We study the phase diagram of quantum Hall bilayer systems with total filing $\nu_T=1/2+1/2$ of the lowest Landau level as a function of layer distances $d$. Based on numerical exact diagonalization calculations, we obtain three distinct…
Graphene and its multilayers have attracted considerable interest owing to the fourfold spin and valley degeneracy of their charge carriers, which enables the formation of a rich variety of broken-symmetry states and raises the prospect of…
A new kind of phase transition is proposed for lattice fermion systems with simplified f^2 configurations at each site. The free energy of the model is computed in the mean-field approximation for both the itinerant state with the Kondo…
We report experimental studies of disorder-induced transitions between quantum-Hall, metallic, and insulating states in a very dilute two-dimensional electron system in silicon at a magnetic field corresponding to Landau level filling…
The selection of the ground state among nearly degenerate states due to quantum fluctuations is studied for the S=1/2 XY-like Heisenberg antiferromagnets on the triangular lattice in the magnetic field applied along the hard axis, which was…
We study the phase transition between the quantum Hall liquid state and the insulating state within the framework of the Chern-Simons-Landau-Ginzburg theory of the quantum Hall effect. For the transition induced by a background periodic…
We study disorder induced transition between quantum Hall states and insulator state in a {\it lattice} model. We find the positions of the extended states do not change as disorder strength is varied. As a consequence, there are direct…
The triangular lattice of S=1/2 spins with XXZ anisotropy is a ubiquitous model for various frustrated systems in different contexts. We determine the quantum phase diagram of the model in the plane of the anisotropy parameter and the…
The ground state cohesive energies per electron of the composite fermion (CF) Fermi sea, the Laughlin state and the charge density wave (CDW) at higher Landau levels (LLs) are computed. It is shown that whereas for $n\geq 2$ LL, the CDW…
We study a bilayer GaAs hole system that hosts two distinct many-body phases at low temperatures and high perpendicular magnetic fields. The higher-density (top) layer develops a Fermi sea of composite fermions (CFs) in its half-filled…
A variety of analytical techniques suggest that quantum fluctuations lead to a fundamental instability of the Fermi liquid that drives ferromagnetic transitions first order at low temperatures. We present both analytical and numerical…
Ordering of the frustrated classical Heisenberg model on the triangular-lattice with an incommensurate spiral spin structure is studied under magnetic fields by means of a mean-field analysis and a Monte Carlo simulation. Several types of…
We have studied the ground states of two dimensional lattice model of Coulomb Glass via Monte Carlo annealing. Our results show a possibility of existence of a critical disorder (Wc) below which the system is in the charge ordered phase and…
We study the recently proposed D-brane configuration [hep-th/0010105] modeling the quantum Hall effect, focusing on the nature of the interactions between the charged particles. Our analysis indicates that the interaction is repulsive,…
The ground state properties of Hubbard model with or without long-range interactions in the regime with strongly repulsive on-site interaction are investigated by means of the exact diagonalization method. We show that the appearance of…
We consider a lattice model of itinerant electrons coupled to an array of localized classical Heisenberg spins. The nature of the ground state ordered magnetic phases that result from the indirect spin-spin coupling mediated by the…