Related papers: Quasi-Spin-Charge Separation and the Spin Quantum …
The quantum spin Hall state can be understood in terms of spontaneous O(3) symmetry breaking. Topological skyrmion configurations of the O(3) order parameter vector carry a charge 2e, and as shown previously, when they condense, a…
Quantum phase transition in the one-dimensional period-two and uniform quantum compass model are studied by using the pseudo-spin transformation method and the trace map method. The exact solutions are presented, the fidelity, the…
We obtain the field-theory representations of several network models that are relevant to 2D transport in high magnetic fields. Among them, the simplest one, which is relevant to the plateau transition in the quantum Hall effect, is…
We define supersymmetric spin networks, which provide a complete set of gauge invariant states for supergravity and supersymmetric gauge theories. The particular case of Osp(1/2) is studied in detail and applied to the non-perturbative…
We present results of numerical studies of spin quantum Hall transitions in disordered superconductors, in which the pairing order parameter breaks time-reversal symmetry. We focus mainly on p-wave superconductors in which one of the spin…
Dynamical mean field theory is used to study the quantum critical point (QCP) in the doped Hubbard model on a square lattice. The QCP is characterized by a universal scaling form of the self energy and a spin density wave instability at an…
Using quantum Monte Carlo and numerical analytic continuation methods, we study the dynamic spin structure factor and the single-hole spectral function of a two-dimensional quantum magnet ($J$-$Q$ model) at its quantum phase transition…
We have investigated chiral edges of a quantum Hall(QH) liquid at filling factor \nu=2. We find that spin and charge separate in the presence of the long-range Coulomb interaction, and the tunneling density of states(DOS) is given by…
During the last years there has been much interest, and theoretical discussion, about the possibility to use spin-orbit coupling to control the carriers spins in two-dimensional semiconducting heterostructures. Spin polarization at the…
We consider the spin-1/2 Ising chain in a regularly alternating transverse field to examine the effects of regular alternation on the quantum phase transition inherent in the quantum Ising chain. The number of quantum phase transition…
A careful study of the supersymmetric version of Pruisken's nonlinear sigma model for the integer quantum Hall effect is presented. The lattice regularized model is cast in Hamiltonian form by taking the anisotropic limit and interpreting…
We propose a series of paired spin-singlet quantum Hall states, which exhibit a separation of spin and charge degrees of freedom. The fundamental excitations over these states, which have filling fraction \nu=2/(2m+1) with m an odd integer,…
We study spin-polarized quasiparticle transport in a mesoscopic superconductor with a spin- splitting field in the presence of co-flowing supercurrent. In such a system, the nonequilibrium state is characterized by charge, spin, energy and…
We develop a strong-disorder renormalization group to study quantum phase transitions with continuous O$(N)$ symmetry order parameters under the influence of both quenched disorder and dissipation. For Ohmic dissipation, as realized in…
Unlike that of SO(3) or SU(2), the Lie algebra for SO(2), which defines intermediate spin, comprises only $S_{z}$ and implies $S^{\pm}$ commute. In general, $S_{z}$ has a continuous spectrum. This intermediate spin scheme can realized for…
In this paper, we present our studies of the phase diagram of the cuprate superconductors performed in recent years. We describe how a few field-theoretical concepts can be used to account for the puzzling properties of these compounds.…
Based on the finite-size analysis of the spectrum of the quantum group invariant deformation of the $OSp(3|2)$ superspin chain we identify the operator content of the conformal field theory describing the model in its scaling limit. We find…
The quantum Hall regime in a smooth random potential is considered when two disorder-broadened Zeeman levels overlap strongly. Spin-orbit coupling is found to cause a drastic change in the percolation network which leads to a strong…
The equilibration between quantum Hall edge modes is known to depend on the disorder potential and the steepness of the edge. Modern samples with higher mobilities and setups with lower electron temperatures call for a further exploration…
A theory of electronic properties of a spin-singlet quantum Hall droplet at filling factor $\nu=2$ in a parabolic quantum dot is developed. The excitation spectrum and the stability of the droplet due to the transfer of electrons into the…