Field theory approach to one-dimensional electronic systems

In this talk I describe a recently introduced field-theoretical approach that can be used as an alternative framework to study one-dimensional systems of highly correlated particles.Comment: 25 pages, latex, no figures. Talk delivered at Trends in Theoretical Physics - CERN - Santiago de Compostela - La Plata Meeting, La Plata, April-May 1997, to be published. Abstract modifie

Factored coset approach to bosonization in the context of topological backgrounds and massive fermions

We consider a recently proposed approach to bosonization in which the original fermionic partition function is expressed as a product of a $G/G$-coset model and a bosonic piece that contains the dynamics. In particular we show how the method works when topological backgrounds are taken into account. We also discuss the application of this technique to the case of massive fermions.Comment: 10 pages, latex, no figures, To appear in Mod.Phys.Lett.

Two-Dimensional Bosonization from Variable Shifts in the Path Integral

A method to perform bosonization of a fermionic theory in (1+1) dimensions in a path integral framework is developed. The method relies exclusively on the path integral property of allowing variable shifts, and does not depend on the explicit form of Greens functions. Two examples, the Schwinger model and the massless Thirring model, are worked out.Comment: 4 page

Los procedimientos administrativos en materia de transferencias internacionales de datos de carácter personal

Este artículo tiene por objeto el análisis de los procedimientos administrativos en materia de transferencias internacionales de datos de carácter personal. Estos procedimientos se encuentran sometidos (además de a las reglas generales de los procedimientos administrativos) a determinadas reglas especiales, contenidas en los artículos 137 a 144 del Reglamento de desarrollo de la Ley Orgánica de protección de datos de carácter personal. ¿Qué valoración merece esta regulación especial? ¿Se ha enfrentado a las particularidades de la materia y las ha regulado con el alcance y precisión exigidos? Para responder a tales preguntas, el artículo trata, en particular: (a) qué normas son aplicables a los procedimientos relacionados con las transferencias internacionales de datos personales, (b) el procedimiento de autorización de transferencias internacionales (incluida su iniciación, instrucción y terminación), (c) las cuestiones procedimentales relativas a la autorización de trasferencias internacionales sobre la base de «reglas corporativas vinculantes», y (d) el procedimiento de suspensión de transferencias internacionales, incluido el procedimiento para el levantamiento de la suspensión

A gauge invariant and string independent fermion correlator in the Schwinger model

We introduce a gauge invariant and string independent two-point fermion correlator which is analyzed in the context of the Schwinger model (QED_2). We also derive an effective infrared worldline action for this correlator, thus enabling the computation of its infrared behavior. Finally, we briefly discuss possible perspectives for the string independent correlator in the QED_3 effective models for the normal state of HTc superconductors.Comment: 14 pages, LaTe

Numerical study of the critical behavior of the Ashkin-Teller model at a line defect

We consider the Ashkin-Teller model on the square lattice, which is represented by two Ising models ($\sigma$ and $\tau$) having a four-spin coupling of strength, $\epsilon$, between them. We introduce an asymmetric defect line in the system along which the couplings in the $\sigma$ Ising model are modified. In the Hamiltonian version of the model we study the scaling behavior of the critical magnetization at the defect, both for $\sigma$ and for $\tau$ spins by density matrix renormalization. For $\epsilon>0$ we observe identical scaling for $\sigma$ and $\tau$ spins, whereas for $\epsilon<0$ one model becomes locally ordered and the other locally disordered. This is different of the critical behavior of the uncoupled model ($\epsilon=0$) and is in contradiction with the results of recent field-theoretical calculations.Comment: 6 pages, 4 figure

Multiflavor Correlation Functions in non-Abelian Gauge Theories at Finite Density in two dimensions

We compute vacuum expectation values of products of fermion bilinears for two-dimensional Quantum Chromodynamics at finite flavored fermion densities. We introduce the chemical potential as an external charge distribution within the path-integral approach and carefully analyse the contribution of different topological sectors to fermion correlators. We show the existence of chiral condensates exhibiting an oscillatory inhomogeneous behavior as a function of a chemical potential matrix. This result is exact and goes in the same direction as the behavior found in QCD_4 within the large N approximation.Comment: 28 pages Latex (3 pages added and other minor changes) to appear in Phys.Rev.

Universal structure of the edge states of the fractional quantum Hall states

We present an effective theory for the bulk fractional quantum Hall states on the Jain sequences on closed surfaces and show that it has a universal form whose structure does not change from fraction to fraction. The structure of this effective theory follows from the condition of global consistency of the flux attachment transformation on closed surfaces. We derive the theory of the edge states on a disk that follows naturally from this globally consistent theory on a torus. We find that, for a fully polarized two-dimensional electron gas, the edge states for all the Jain filling fractions $\nu=p/(2np+1)$ have only one propagating edge field that carries both energy and charge, and two non-propagating edge fields of topological origin that are responsible for the statistics of the excitations. Explicit results are derived for the electron and quasiparticle operators and for their propagators at the edge. We show that these operators create states with the correct charge and statistics. It is found that the tunneling density of states for all the Jain states scales with frequency as $|\omega|^{(1-\nu)/\nu}$.Comment: 10 page

Yield prediction of retail product from beef carcasses in Argentina.

Currently the Argentine beef industry does not have an objective system of quality control at purchase, with which to guide production by means of differential prices. The objective of this work was to develop equations to predict the yield of retail cuts of the pistol hind quarter (Kg retail cuts/kg carcass, RC). For this purpose 343 pistol hind quarters (PHQ), of six biotypes were evaluated: BB, British (123); BC, Britsh x Continental (39); BI, British x Bos indicus (113); HH, Argentine Holstein (25); CC, Continental (20); and CI, Continental, Bos indicus (23). Multiple linear regressions were used to develop prediction equations for RC by biotype. Independent variables used were warm carcass side weight (CW); percentage of PHQ (kg PHQ/kg carcass, % PHQ); percentage of kidney knob and pelvic fat (% KPH); and dental classification (0, 2, 4 or 6 permanent incisors, DC). Equations to predict, RC based on these variables, for the different biotypes, were obtained. We conclude that a proposal to adopt these prediction equations is justified; with subsequent validations, this would enable the industry to apply objective criteria of yields in its purchases, thus guiding produces, through differential prices, to adjust the offer to market requirements

Erratum to: Targeting the association of calgranulin B (S100A9) with insulin resistance and type 2 diabetes

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