Generalization of the U_q(gl(N)) algebra and staggered models

We develop a technique of construction of integrable models with a Z_2 grading of both the auxiliary (chain) and quantum (time) spaces. These models have a staggered disposition of the anisotropy parameter. The corresponding Yang-Baxter Equations are written down and their solution for the gl(N) case are found. We analyze in details the N=2 case and find the corresponding quantum group behind this solution. It can be regarded as quantum U_{q,B}(gl(2)) group with a matrix deformation parameter qB with (qB)^2=q^2. The symmetry behind these models can also be interpreted as the tensor product of the (-1)-Weyl algebra by an extension of U_q(gl(N)) with a Cartan generator related to deformation parameter -1.Comment: 12 pages ; Latex2

Integrable chain models with staggered R-matrices

The technique of construction on Manhattan lattice (ML) the fermionic action for Integrable models is presented. The Sign-Factor of 3D Ising model (SF of 3DIM) and Chalker-Coddington-s phenomenological model (CCM) for the edge excitations in Hall effect are formulated in this way. The second one demonstrates the necessity to consider the inhomogeneous models with staggered R-matrices. The disorder over the U(1) phases is taken into account and staggered Hubbard type of model is obtained. The technique is developed to construct the integrable models with staggered R-matrices. The disorder over the U(1) phases is taken into account and staggered Hubbard type of model is obtained. The technique is developed to construct the integrable models with staggered disposition of R-matrices.Comment: 12 pages, 2 figures, contribution to the proceedings of Advanced NATO Workshop on Statistical Field Theories, Como, June 18-23, 200

Absence of extended states in a ladder model of DNA

We consider a ladder model of DNA for describing carrier transport in a fully coherent regime through finite segments. A single orbital is associated to each base, and both interstrand and intrastrand overlaps are considered within the nearest-neighbor approximation. Conduction through the sugar-phosphate backbone is neglected. We study analytically and numerically the spatial extend of the corresponding states by means of the Landauer and Lyapunov exponents. We conclude that intrinsic-DNA correlations, arising from the natural base pairing, does not suffice to observe extended states, in contrast to previous claims.Comment: 4 RevTex pages, 4 figures include

Electron states in a one-dimensional random binary alloy

We present a model for alloys of compound semiconductors by introducing a one-dimensional binary random system where impurities are placed in one sublattice while host atoms lie on the other sublattice. The source of disorder is the stochastic fluctuation of the impurity energy from site to site. Although the system is one-dimensional and random, we demonstrate analytical and numerically the existence of extended states in the neighborhood of a given resonant energy, which match that of the host atoms.Comment: 11 pages, REVTeX, 3 PostScript figure