Emergent SU(3) symmetry in random spin-1 chains

We show that generic SU(2)-invariant random spin-1 chains have phases with an emergent SU(3) symmetry. We map out the full zero-temperature phase diagram and identify two different phases: (i) a conventional random singlet phase (RSP) of strongly bound spin pairs (SU(3) "mesons") and (ii) an unconventional RSP of bound SU(3) "baryons", which are formed, in the great majority, by spin trios located at random positions. The emergent SU(3) symmetry dictates that susceptibilities and correlation functions of both dipolar and quadrupolar spin operators have the same asymptotic behavior.Comment: 5 pages plus 3-page Supplemental Material, 5 figures; published versio

Localization transition in one dimension using Wegner flow equations

The flow equation method was proposed by Wegner as a technique for studying interacting systems in one dimension. Here, we apply this method to a disordered one dimensional model with power-law decaying hoppings. This model presents a transition as function of the decaying exponent $\alpha$. We derive the flow equations, and the evolution of single-particle operators. The flow equation reveals the delocalized nature of the states for $\alpha<1/2$. Additionally, in the regime, $\alpha>1/2$, we present a strong-bond renormalization group structure based on iterating the three-site clusters, where we solve the flow equations perturbatively. This renormalization group approach allows us to probe the critical point $\left(\alpha=1\right)$. This method correctly reproduces the critical level-spacing statistics, and the fractal dimensionality of the eigenfunctions.Comment: 19 pages, 16 figure

The use of jazz chants for children in the teaching-learning process of english

Nowadays it is very important for a teacher to know as many techniques as possible in order to improve the teaching - learning process. We focused our project on how to improve writing skills using good writing techniques. The use of a good writing technique in the class helps the students to write something in English easily. We chose two important ones, which are: Graphic organizers and note cards. The first one can be used as a warm up or feedback, and the second one as an instrument of evaluation. It is important to mention that we based our project on the Ausubel s theory of meaningful learning and previous knowledge. Students must know that learning English is really important and useful for their future, so every single word they learn in class is really important to build their knowledge. During the application we realized the students enjoy the new technique, so this helps the teacher to keep the students active in class, and the homework done by the students gives real evidence of what they have learnt in class. As a conclusion we can say that graphic organizers and note cards are really good tools to improve the teaching learning process and to help the students write easilyLicenciada en Ciencias de la Educación en la Especialización de Lengua y Literatura InglesaCuenc

Emergent SU(N) symmetry in disordered SO(N) spin chains

Strongly disordered spin chains invariant under the SO(N) group are shown to display random-singlet phases with emergent SU(N) symmetry without fine tuning. The phases with emergent SU(N) symmetry are of two kinds: one has a ground state formed of randomly distributed singlets of strongly bound pairs of SO(N) spins (a `mesonic' phase), while the other has a ground state composed of singlets made out of strongly bound integer multiples of N SO(N) spins (a `baryonic' phase). The established mechanism is general and we put forward the cases of $\mathrm{N}=2,3,4$ and $6$ as prime candidates for experimental realizations in material compounds and cold-atoms systems. We display universal temperature scaling and critical exponents for susceptibilities distinguishing these phases and characterizing the enlarging of the microscopic symmetries at low energies.Comment: 5 pages, 2 figures, Contribution to the Topical Issue "Recent Advances in the Theory of Disordered Systems", edited by Ferenc Igl\'oi and Heiko Riege

Highly-symmetric random one-dimensional spin models

The interplay of disorder and interactions is a challenging topic of condensed matter physics, where correlations are crucial and exotic phases develop. In one spatial dimension, a particularly successful method to analyze such problems is the strong-disorder renormalization group (SDRG). This method, which is asymptotically exact in the limit of large disorder, has been successfully employed in the study of several phases of random magnetic chains. Here we develop an SDRG scheme capable to provide in-depth information on a large class of strongly disordered one-dimensional magnetic chains with a global invariance under a generic continuous group. Our methodology can be applied to any Lie-algebra valued spin Hamiltonian, in any representation. As examples, we focus on the physically relevant cases of SO(N) and Sp(N) magnetism, showing the existence of different randomness-dominated phases. These phases display emergent SU(N) symmetry at low energies and fall in two distinct classes, with meson-like or baryon-like characteristics. Our methodology is here explained in detail and helps to shed light on a general mechanism for symmetry emergence in disordered systems.Comment: 26 pages, 12 figure

Integración con Cymdist de las redes de media tensión y subtransmisión del sistema de la Centrosur

El presente trabajo tiene un enfoque práctico e innovador de la explotación del software de simulación Cymdist, que persigue la integración de los sistemas de media tensión y subtransmisión de la E.E.R.C.S que actualmente se modelan en plataformas distintas como son Cymdist y DIgSILENT respectivamente. El enfoque de Cymdist para modelar redes de distribución frente a DIgSILENT con un enfoque a nivel de control y operación de SEP, concluyen en ventajas como es principalmente: la modelación detallada de subestaciones y redes secundarias con la posibilidad de referenciarles geográficamente, la implementación de algoritmos como son el método de caída de tensión en la resolución de flujos de carga y la distribución de carga. El gran potencial que ofrece Cymdist permitió que se modele los sistemas de media tensión y subtransmisión por separado, evaluando el sistema de forma tradicional, y a la hora de realizar la integración el sistema de subtransmisión creado se configuró de tal manera que la integración se realice en pocos segundos, con los alimentadores conectándose automáticamente a sus respectivas subestaciones. Finalmente se presenta en una sola plataforma las redes de media tensión y subtransmisión, eliminando así los equivalentes de red que actualmente se tienen en el sistema de media tensión, este sistema integrado permitirá un análisis de: planificación, diseño y funcionamiento del sistema de la CENTROSUR, ayudando a la toma de decisiones rápidas y efectivas en la parte operativa de las redes eléctricas.This paper has an approach practical and innovative of the exploitation of software of simulation Cymdist, which fallow the integration of the systems the half voltage and subtransmisión of E.E.R.C.S that currently the model in platforms different that are Cymdist and DIgSILENT respectively. The approach of Cymdist to model networks of distribution front of DIgSILENT with an approach a level of control and operation of SEP, conclude in advantages that is the first: the model details of substations and networks seconds with the possibility of references geographically, the implementation of algorithms that are the method of voltage drop in the resolution of the power flow and the load distribution. The great potential that gives Cymdist allowed is modeled half voltage systems and subtransmisión separately; evaluating the traditional system, system was configured so that the integration is performed in few seconds, with feeders automatically connecting to their respective substations. Finally we present on a single platform the networks of half voltage and subtransmisión, deleting that the networks equivalents currently have in the half voltage system, this integrated system will allow analysis of: planning, design and operation of the system of the CENTROSUR, helping to take decisions quick and effectives in the part operational of the electrics networks.Ingeniero EléctricoCuenc

Análisis del impacto de las remesas sobre el crecimiento económico ecuatoriano aplicando un modelo VAR para el período 2001-2012

El presente trabajo investigativo pretende contribuir en el análisis de las relaciones que guarda las remesas con el consumo, inversión y sobre todo con el crecimiento económico del Ecuador. Para el alcance de dicho objetivo se hizo uso de la metodología econométrica, llevando a cabo tres modelos VAR (Vectores auto-regresivos). Como resultado se encontró que las remesas tiene un efecto positivo sobre el crecimiento económico del Ecuador, el cual se pudo comprobar que dicho efecto se ejerce tanto a través del consumo como por medio de la inversión de las mismas. De igual modo, se comprobó que los migrantes ecuatorianos mantienen un sentimiento altruista con su familia, el cual los estimula a remitir con el fin de colaborar con el ingreso de su familia.This research work aims to contribute to the analysis of relationships that keeps remittances to consumption, investment and especially with the economic growth of Ecuador. To reach this goal was made use of econometric methodology, conducting three VAR (Vector Auto-Regressive) models. As a result it was found that remittances have a positive effect on economic growth in Ecuador, where it was found that this effect is exerted through both consumption and investment through the same. Similarly, it was found that Ecuadorian migrants maintain an altruistic feeling with his family, which encourages them to submit in order to assist the family income.EconomistaCuenc

Cuenca: su crecimiento urbano y paisajístico desde 1950-2008

Cuenca: su crecimiento urbano y paisajístico en los años de 1950- 2008 es un trabajo que busca plasmar los cambios ocurridos en la configuración urbana de Cuenca a largo de su historia, partiendo desde la concepción de ciudad para ir abordando los sucesos más relevantes de la historia urbana de la ciudad de Cuenca. Los momentos de la ocupación humana en su territorio hace que se plasman cambios sean en la infraestructura física (calles, veredas, alcantarillados, plazas), en la organización de la ciudad, en los tipos de uso del suelo, etc., referentes que ponen en manifiesto la constante intervención de diversos actores sociales. Y sin dejar de lado el crecimiento demográfico de la ciudad vemos que estos aspectos conllevan a cambios en el paisaje y en la proyección de Cuenca como ciudad. Dichos cambios en el paisaje permite conocer los trabajos realizados por ordenar el uso de suelo en la ciudad como también por controlar el desarrollo de Cuenca para hacer de ella una ciudad deseable para ser habitada e incluso ordenada de tal manera, que permita a sus habitantes acceder a los distintos servicios que presta y abastecer a la población de los servicios básicos requeridos. Esta tesis, muestra el rostro urbano y paisajístico de la ciudad de Cuenca desde su fundación hasta la actualidad.Licenciada en Ciencias de la Educación. Especialidad Historia y GeografíaCuenc