Condensed Matter
We develop a general variational approach to study the statistical properties of the tail states of a wide class of non-Hermitian operators. The utility of the method, which is a refinement of the instanton approach introduced by Zittartz…
We present an analytical and numerical study of the coherent exciton polarization including exciton-exciton correlation. The time evolution after excitation with ultrashort optical pulses can be divided into a slowly varying polarization…
We studied Li intercalated carbon nanotube ropes by using first principles methods. Our results show charge transfer between Li and C and small structural deformation of nanotube due to intercalation. Both inside of nanotube and the…
A class of exact solutions of Hele-Shaw flows without surface tension in a rotating cell is reported. We show that the interplay between injection and rotation modifies drastically the scenario of formation of finite-time cusp…
We study a system of one-dimensional t-J models coupled to a ladder system. A special choice of the interaction between neighbouring rungs leads to an integrable model with supersymmetry, which is broken by the presence of rung…
We study the phase diagram of a 2-leg bond-alternation spin-(1/2, 1) ladder for two different configurations using a quantum renormalization group approach. Although d-dimensional ferrimagnets show gapless behavior, we will explicitly show…
The damping of collective modes and the relaxation of temperature anisotropies in a trapped Bose gas is determined at temperatures above the Bose-Einstein condensation temperature in the collisionless regime. We demonstrate for both cases…
Ion conducting polymers have a biphasic character with crystalline as well as amorphous phases. There is moreover, a dynamic disorder due to motion of polymer chain segments. The PEO-NH$_4$ClO$_4$ system undergoes a crossover from a…
Within the framework of the quantized nesting model, we study the effect of umklapp scattering on the magnetic-field-induced spin-density-wave (SDW) phases which are experimentally observed in the quasi-one-dimensional organic conductors…
Transition temperature data obtained as a function of particle density in the $^4$He-Vycor system are compared with recent theoretical calculations for 3D Bose condensed systems. In the low density dilute Bose gas regime we find, in…
A discrete drift-diffusion model is derived from a microscopic sequential tunneling model of charge transport in weakly coupled superlattices provided temperatures are low or high enough. Realistic transport coefficients and novel contact…
We propose a simple and accurate model for the electron static structure factors (and corresponding pair-correlation functions) of the 3D unpolarized homogeneous electron gas. Our spin-resolved pair-correlation function is built up with a…
The energy levels of the fermions bound to the vortex core are considered for the general case of chiral superconductors. There are two classes of chiral superconductivity: in the superconducting state of class I the axisymmetric singly…
We report on experiments giving evidence for quantum effects of electromagnetic flux in barium alumosilicate glass. In contrast to expectation, below 100 mK the dielectric response becomes sensitive to magnetic fields. The experimental…
We find that the existence of self-organization of the members of a recently proposed minority game, depends on the type of update rules used. The resulting resource distribution is studied in some detail, and a related strategy scheme is…
A low energy crossover (see cond-mat/9711167) induced by Fermi liquid reservoirs in transport through a 1D Mott-Hubbard insulator of finite length $L$ is examined in the presence of impurity pinning. Under the assumption that the Hubbard…
In the framework of spherical geometry for jellium and local spin density approximation, we have obtained the equilibrium $r_s$ values, $\bar{r}_s(N,\zeta)$, of neutral and singly ionized "generic" $N$-electron clusters for their various…
Phase separation and a tendency to form inhomogeneous structures seems to be a generic property of systems with strongly correlated electrons. After shortly summarising the existing theoretical results in this direction, I concentrate on…
We study a complex formation between the DNA and cationic amphiphilic molecules. As the amphiphile is added to the solution containing DNA, a cooperative binding of surfactants to the DNA molecules is found. This binding transition occurs…
Electrical transport properties of DyAs epitaxial layers grown on GaAs have been investigated at various temperatures and magnetic fields up to 12T. The measured longitudinal resistances show two distinct peaks at fields around 0.2 and 2.5T…