Condensed Matter
We develop a theory to calculate exciton binding energies of both two- and three-dimensional spin polarized exciton gases within a mean field approach. Our method allows the analysis of recent experiments showing the importance of the…
Using a microscopic numerical approach suitable to describe disordered antiferromagnets, with application to $Fe_{x}Zn_{1-x}F_{2}$, it is shown that the characteristics of the spin glass phase found for $x=0.25$ is much in agreement with…
We find a solvable limit to the problem of the 1D electron gas interacting with a lattice of Kondo scattering centers. In this limit, we present exact results for the problems of incommensurate filling, commensurate filling, impurity…
Selfconsistent equations which describe the order parameter and chemical potential behaviour in $2D$ metalic system as functions of external magnetic field, $H$, temperature, $T$, and carrier density, $n$, are obtained. It is shown that for…
A new class of nano-structure devices is suggested, based on interference from the order parameter phase gradient of a single superconductor (S) in contact with a single normal metallic lead (N). By solving the Bogoliubov - de Gennes…
We present a novel approach for a systematic large--spin expansion of the $t$-$J$ Hamiltonian which enables us to work without the constraint of no double occupancy. In our scheme we can perform the large--spin limit ensuring that the low…
We consider the possibility that instabilities of the Abrikosov-Suhl resonance lead to new fixed point behavior of the Kondo effect in a lattice environment. In one scenario, a pairing component to the resonant scattering develops in the…
In this work, we study the wavefunctions of the one dimensional $1/r$ Hubbard model in the strong interaction limit $U =\infty$. A set of Gutzwiller-Jastorw wavefunctions are shown to be eigen-functions of the Hamiltonian. The entire…
The late-stage demixing following spinodal decomposition of a three-dimensional symmetric binary fluid mixture is studied numerically, using a thermodynamicaly consistent lattice Boltzmann method. We combine results from simulations with…
We compute the spectral function rho(q,omega) of the one- dimensional Luttinger model. We discuss the distinct influences of charge-spin separation and of the anomalous dimensions of the fermion operators and their evolution with…
We present a study of a microtwinned single crystal of LaMnO$_3$ by means of implanted muons. Two muon stopping sites are identified from the symmetry of the internal field in the ordered phase. The temperature dependence of these fields…
The equilibrium superfluid phase of 3He impregnated into high-porosity silica aerogels appears to be a non-equal-spin-pairing state in zero field at all pressures, which is generally assumed to be the Balian-Werthamer (BW) phase modified by…
A new method of the phase determination in X-ray crystallography is proposed. The method is based on the so-called "minimum charge" principle, recently suggested by Elser. The electron density function $\rho$ is sought in the form…
The time-dependent pair correlation functions for a degenerate ideal quantum gas of charged particles in a uniform magnetic field are studied on the basis of equilibrium statistics. In particular, the influence of a flat hard wall on the…
The free energy of the Coulomb Gap problem is expanded as a set of Feynman diagrams, using the standard diagrammatic methods of perturbation theory. The gap in the one-particle density of states due to long-ranged interactions corresponds…
We show that band-structure effects are likely to prevent superfluidity in semiconductor electron-hole double-layer systems. We suggest the possibility that superfluidity could be realized by the application of uniaxial pressure…
Quantum Monte Carlo methods are used to calculate various ground state properties of charged bosons in two dimensions, throughout the whole density range where the fluid phase is stable. Wigner crystallization is predicted at $r_s\simeq…
By using algebraic Bethe ansatz method, we give the Hamitonian of the spin-1 XXX chain associated with $sl_2$ with two boundary impurities.
We derive a microscopic theory of the composite fermion type quasiparticles describing the low-lying edge excitations in the fractional quantum Hall liquid with $\nu=1/m$. Using the composite fermion transformation, one finds that the edge…
The transport properties of a ferromagnet-superconductor (FS) junction are studied in a scattering formulation. Andreev reflection at the FS interface is strongly affected by the exchange interaction in the ferromagnet. The conductance G_FS…