155 research outputs found
Critical Properties in Photoemmision Spectra for One Dimensional Orbitally Degenerate Mott Insulator
Critical properties in photoemission spectra for the one-dimensional Mott
insulator with orbital degeneracy are studied by exploiting the integrable {\it
t-J} model, which is a supersymmetric generalization of the SU() degenerate
spin model. We discuss the critical properties for the holon dispersion as well
as the spinon dispersions, by applying the conformal field theory analysis to
the exact finite-size energy spectrum. We study the effect of orbital-splitting
on the spectra by evaluating the momentum-dependent critical exponents.Comment: 8 pages, REVTeX, 2 figures(available upon request), accepted for
publication in JPSJ 68 (1999) No.
Exact Boundary Critical Exponents and Tunneling Effect in Integrable Models for Quantum Wires
Using the principles of the conformal quantum field theory and the finite
size corrections of the energy of the ground and various excited states, we
calculate the boundary critical exponents of single- and multicomponent Bethe
ansatz soluble models. The boundary critical exponents are given in terms of
the dressed charge matrix which has the same form as that of systems with
periodic boundary conditions and is uniquely determined by the Bethe ansatz
equations. A Luttinger liquid with open boundaries is the effective low-energy
theory of these models. As applications of the theory, the Friedel oscillations
due to the boundaries and the tunneling conductance through a barrier are also
calculated. The tunneling conductance is determined by a nonuniversal boundary
exponent which governs its power law dependence on temperature and frequency.Comment: REVTEX, submitted to PR
Animación sociocultural mediante el deporte en la Unidad de Salud Mental del establecimiento carcelario La Modelo de Bogotá
Servicio Social ComunitarioInvestigación realizada tuvo como objetivo la realización de una animación sociocultural en el establecimiento carcelario la Modelo ubicado en la ciudad de Bogotá- Colombia, específicamente en la unidad de salud mental, a través de metodologías participativas y alternativas de intervención como el Aprendizaje Servicio Solidario (ASS); de esta manera fue posible identificar en un primer momento algunas de las necesidades sentidas, percibidas e inferidas, tanto de la institución, como de las personas privadas de la libertad (PPL), a través del arte y el deporte. En un segundo momento se desarrolló una intervención a través de las metodologías ya mencionadas, utilizando el deporte como herramienta principal, buscando potencializar en los internos diferentes alternativas para la solución de problemas y la transformación de las necesidades evaluadas. En cuanto a este último objetivo de la intervención no todas las necesidades pudieron tener alguna modificación, puesto que algunas de ellas se encuentran vinculadas con lineamientos institucionales fuera del alcance de esta investigación. Para este estudio no se contó con una muestra estable, ya que para cada sesión los PPL podían elegir su participación de manera voluntaria y en casos particulares se evidenciaban traslados de patio o de establecimiento carcelario y, además, se presentaron situaciones de inseguridad en el patio, que no permitieron el desarrollo adecuado de las últimas sesiones de intervención.140 p.1. Marco Teórico
2. Marco Metodológico
3. Diseño Metodológico de la Intervención
4. Categorías de Análisis 5. Análisis de Contenido
6. Matriz Operativa del Proyecto
7. Análisis de Procesos
8. ReferenciasPregradoPsicólog
One-Dimensional Fermi liquids
I attempt to give a pedagogical overview of the progress which has occurred
during the past decade in the description of one-dimensional correlated
fermions. Fermi liquid theory based on a quasi-particle picture, breaks down in
one dimension because of the Peierls divergence and because of charge-spin
separation. It is replaced by a Luttinger liquid whose elementary excitations
are collective charge and spin modes, based on the exactly solvable Luttinger
model. I review this model and various solutions with emphasis on bosonization
(and its equivalence to conformal field theory), and its physical properties.
The notion of a Luttinger liquid implies that all gapless 1D systems share
these properties at low energies.
Chapters 1 and 2 of the article contain an introduction and a discussion of
the breakdown of Fermi liquid theory. Chapter 3 describes in detail the
solution of the Luttinger model both by bosonization and by Green's functions
methods and summarizes the properties of the model, expressed thorugh
correlation functions. The relation to conformal field theory is discussed.
Chapter 4 of the article introduces the notion of a Luttinger liquid. It
describes in much detail the various mappings applied to realistic models of 1D
correlated fermions, onto the Luttinger model, as well as important corrections
to the Luttinger model properties discussed in Ch.3. Chapter 5 describes
situations where the Luttinger liquid is not a stable fixed point, and where
spin or charge gaps open in at least one channel. Chapter 6 discusses
multi-band and multichain problems, in particular the stability of a Luttinger
liquid with respect to interchain hopping. Ch. 7 gives a brief summary of
experimental efforts to uncover Luttinger liquid correlations in quasi-1D
materials.Comment: uuencoded Latex files and postscript figures, one Readme-file approx
160 pages + 13 figures; to be published by Reports on Progress in Physic
Measurement of electroweak parameters from hadronic and leptonic decays of the Z 0
We have studied the reactions e + e − →hadrons, e + e − , μ + μ − and τ + τ − , in the energy range 88.2 GeV. A total luminosity of 5.5 pb −1 , corresponding to approximately 115000 hadronic and 10000 leptonic Z 0 decays, has been recorded with the L3 detector. From a simultaneous fit to all of our measured cross section data, we obtain assuming lepton universality:Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47890/1/10052_2005_Article_BF01475788.pd
Управление системой электрохимической защиты магистрального газопровода в условиях вечной мерзлоты
Объектом исследования подсистема коррозионного мониторинга электрохимической зашиты магистрального газопровода. Цель работы – проанализировать управление системой электрохимической зашиты магистрального газопровода в условиях вечной мерзлоты. В результате анализа установлено, что ПКМ-ТСТ-КонтКорр удовлетворяет требованиям системы управления техническим состоянием и целостностью площадных объектов организации.The object of study is the subsystem of corrosion monitoring of electrochemical protection of the main gas pipeline. The purpose of the work is to analyze the management of the system of electrochemical protection of the main gas pipeline in permafrost conditions. As a result of the analysis, it was established that PKM-TST-KontKorr satisfies the requirements of the system for managing the technical condition and integrity of the organization’s area facilities
Measurement of Z0 decays to hadrons, and a precise determination of the number of neutrino species
We have made a precise measurement of the cross section for e+e--->Z0-->hadrons with the L3 detector at LEP, covering the range from 88.28 to 95.04 GeV. From a fit to the Z0 mass, total width, and the hadronic cross section to be MZ0=91.160 +/- 0.024 (experiment) +/-0.030(LEP) GeV, [Gamma]Z0=2.539+/-0.054 GeV, and [sigma]h(MZ0)=29.5+/-0.7 nb. We also used the fit to the Z0 peak cross section and the width todetermine [Gamma]invisible=0.548+/-0.029 GeV, which corresponds to 3.29+/-0.17 species of light neutrinos. The possibility of four or more neutrino flavors is thus ruled out at the 4[sigma] confidence level.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28683/3/0000500.pd
A measurement of the Z0 leptonic partial widths and the vector and axial vector coupling constants
We have measured the partial widths of the Z0 into lepton pairs, and the forward-backward charge asymmetry for the process e+e--->[mu]+[mu]- using the L3 detector at LEP. We obtain an average [Gamma]ll of 83.0+/-2.1+/-1.1 MeV.From this result and the asymmetry measurement, we extract the values of the vector and axial vector couplings of the Z0 to leptons: grmv=-0.066-0.027+0.046 and grmA= -0.495-0.007+0.007.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28666/3/0000483.pd
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