Anomalous Transport in Holographic Chiral Superfluids via Kubo Formulae

We study anomalous conductivities in Chiral Superfluids in the framework of two different holographic models, by means of Kubo formulae. In addition, we point out the existence of an anomalous transport phenomenon that consists in the presence of a charge density when the superfluid velocity is aligned with a magnetic field. It has been pointed out recently that certain chiral conductivities in holographic superfluids exhibit universal behavior at zero temperature. We show that anomalous conductivities always stabilize at low temperatures in our setup. Even though the particular value they acquire is model-dependent, it seems to be robust and determined solely by the interplay between the broken symmetries and the anomalies.Comment: 23 pages, 22 figures. v2: references added, minor typos corrected. v3: footnotes added; published versio

Second Order Transport Coefficient from Chiral Anomaly at Weak Coupling: Diagrammatic Resummation

We compute one of the second order transport coefficients arising from the chiral anomaly in a high temperature weakly coupled regime of quark-gluon plasma. This transport coefficient is responsible for the CP-odd current that is proportional to the time derivative of the magnetic field, and can be considered as a first correction to the chiral magnetic conductivity at finite, small frequency. We observe that this transport coefficient has a non-analytic dependence on the coupling as $\sim 1/(g^4 \log(1/g))$ at weak coupling regime, which necessitates a re-summation of infinite ladder diagrams with leading pinch singularities to get a correct leading log result: a feature quite similar to that one finds in the computation of electric conductivity. We formulate and solve the relevant CP-odd Schwinger-Dyson equation in real-time perturbation theory that reduces to a coupled set of second order differential equations at leading log order. Our result for this second order transport coefficient indicates that chiral magnetic current has some resistance to the time change of magnetic field, which may be called "chiral induction effect". We also discuss the case of color current induced by color magnetic field.Comment: 54 pages, 8 figure

Análisis espacial de la composición florística de huertos familiares en Malinalco, Tenancingo y Villa Guerrero, Estado de México

TESIS DE MAESTRÍAEl objetivo de este trabajo se realizó mediante un análisis espacial de la composición florística y de la distribución biogeográfica de los huertos familiares en Malinalco, Tenancingo y Villa Guerrero, enriquecido con la perspectiva etnobotánica. Para tal fin se hizo uso del análisis espacial basado en fotointerpretación cartográfica a partir de imágenes de satélite, procesos en campo, un análisis comparativo, el cálculo de la composición florística y un análisis de factores que inciden en los procesos de cambio. El análisis espacial de la composición florística de huertos familiares que responde al problema de la diversidad biológica y cultural de México es resultado de la forma, ubicación y topografía de su territorio, así como de las relaciones entre los grupos humanos y los ecosistemas. De acuerdo con las condiciones geográficas, la mayor parte de la Región Sur del Estado de México, de donde los municipios de Malinalco, Tenancingo y Villa Guerrero se encuentran localizados, pertenece al ecosistema de bosque subtropical caducifolio, donde la interacción de los factores fisiográficos, biológicos y socioculturales favorece una amplia agrobiodiversidad en los distintos ambientes. Los huertos suelen ser espacios contiguos a las residencias de sus propietarios (Vogl et al., 2004) aunque algunas veces se encuentren a una cierta distancia de las mismas. Se trata de espacios complejos donde convergen numerosos elementos culturales, ecológicos, sociales y económicos (Gispert et al., 2004). La distribución espacial y estructura de los huertos no es uniforme en las viviendas de las comunidades de la región, tampoco es uniforme la composición florística, ni la superficie. Mediante la información obtenida, se diagnostico el cambio, la pérdida y/o beneficios de comunidades vegetales dentro de la zona y se obtuvo información actualizada sobre el estado vegetal correspondiente a parte de la zona sur del estado. Los datos satelitales nos proporcionaron una perspectiva más amplia de la situación actual de la zona y aportó un conocimiento más detallado para la implementación de estrategias, para mejorar estos agroecosistemas, como beneficio local, regional y global. El estudio encuentra sustento teórico en: Los Agroecosistemas (Altieri y Merrick, 1987; Gutiérrez, 2007, 2011 y 2012); los Sistemas Agroforestales Indígenas (Alcorn, 1990); Los Huertos de Traspatio (Méndez y Gliessman, 2002), la Organización y el Ordenamiento Espacial de los Individuos (Pielou, 1979). Las plantas alimentarias, ornamentales y medicinales, ocupan los tres primeros lugares de importancia en los agro ecosistemas con huertos familiares. Las investigaciones que se realizaron en los espacios geográficos que ocupan los huertos familiares, proporcionaron elementos valiosos de análisis para reconsiderar la importancia de las funciones y utilización de las partes de las plantas existentes.CONACY

Anomalous magnetoconductivity and relaxation times in holography

We study the magnetoconductivity induced by the axial anomaly via the chiral magnetic effect in strongly coupled holographic models. An important ingredient in our models is that the axial charge is non-conserved beyond the axial anomaly. We achieve this either by explicit symmetry breaking via a non-vanishing non-normalisable mode of an axially charged scalar or using a Stuckelberg field to make the AdS-bulk gauge field massive. The DC magnetoconductivites can be calculated analytically. They take a universal form in terms of gauge field mass at the horizon and quadratic dependence on the magnetic field. The axial charge relaxation time grows linearly with magnetic field in the large $B$ regime. Most strikingly positive magnetoconductivity is still present even when the relaxation times are short $\tau_5 \approx 1/(\pi T)$ and the axial charge can not be thought of as an approximate symmetry. In the $U(1)_A$ explicit breaking model, we also observe that the axial magnetic conductivity in the limit of strong symmetry breaking approaches the same universal value as for anomalous holographic superconductors in the zero temperature limit.Comment: 44 pages, 12 figures; v2: refs added, sec. 2.3 expande

Holographic Plasmon Relaxation with and without Broken Translations

We study the dynamics and the relaxation of bulk plasmons in strongly coupled and quantum critical systems using the holographic framework. We analyze the dispersion relation of the plasmonic modes in detail for an illustrative class of holographic bottom-up models. Comparing to a simple hydrodynamic formula, we entangle the complicated interplay between the three least damped modes and shed light on the underlying physical processes. Such as the dependence of the plasma frequency and the effective relaxation time in terms of the electromagnetic coupling, the charge and the temperature of the system. Introducing momentum dissipation, we then identify its additional contribution to the damping. Finally, we consider the spontaneous symmetry breaking (SSB) of translational invariance. Upon dialing the strength of the SSB, we observe an increase of the longitudinal sound speed controlled by the elastic moduli and a decrease in the plasma frequency of the gapped plasmon. We comment on the condensed matter interpretation of this mechanism.Comment: v2: improved discussions, added results in the SSB section, references added; matching the published version in JHE

Holographic s+p Superconductors

We study the phase diagram of a holographic model realizing a U(2) global symmetry on the boundary and show that at low temperature a phase with both scalar s and vector p condensates exists. This is the s+p-wave phase where the global U(2) symmetry and also the spatial rotational symmetry are spontaneously broken. By studying the free energy we show that this phase is preferred when it exists. We also consider unbalanced configurations where a second chemical potential is turned on. They present a rich phase diagram characterized by the competition and coexistence of the s and p order parameters.Comment: 6 pages, 4 figures; v3: published version, clarifications and references adde

Holographic quenches and anomalous transport

We study the response of the chiral magnetic effect due to continuous quenches induced by time dependent electric fields within holography. Concretely, we consider a holographic model with dual chiral anomaly and compute the electric current parallel to a constant, homogeneous magnetic field and a time dependent electric field in the probe approximation. We explicitly solve the PDEs by means of pseudospectral methods in spatial and time directions and study the transition to an universal "fast" quench response. Moreover, we compute the amplitudes, i.e.,~residues of the quasi normal modes, by solving the (ODE) Laplace transformed equations. We investigate the possibility of considering the asymptotic growth rate of the amplitudes as a well defined notion of initial time scale for linearized systems. Finally, we highlight the existence of Landau level resonances in the electrical conductivity parallel to a magnetic field at finite frequency and show explicitly that these only appear in presence of the anomaly. We show that the existence of these resonances induces, among others, a long-lived AC electric current once the electric field is switched off.Comment: 34 pages, 10 figure

Holographic Type II Goldstone bosons

The Goldstone theorem implies the appearance of an ungapped mode whenever a continuous global symmetry is spontaneously broken. In general it does not say anything about the precise form of the dispersion relation nor does it imply that there is one massless mode for each broken symmetry generator. It is a well-established fact that even for relativistic field theories in the presence of a chemical potential Goldstone modes with quadratic dispersion relation, the type II Goldstone bosons, appear in the spectrum. We develop two holographic models that feature type II Goldstone modes as part of the quasinormal mode spectrum. The models are based on simple generalizations with U(2) symmetry of the well-studied holographic s-wave superfluid. Our results include Goldstone modes without broken generators but with unusual realization of symmetries and a frequency dependent conductivity of striking resemblance to the one of Graphene.Comment: 47 pages, 21 figures; v2: references and clarifications added, typos correcte

La influencia que ejerce la atención al cliente en la competitividad de las pequeñas y medianas empresas en la ciudad de Matagalpa, durante el año 2010

El tema general para llevar a cabo este trabajo investigativo, radica en la competitividad de las pequeñas y medianas empresas en la ciudad de Matagalpa. Del tema general se desglosa el Sub _ tema: La influencia que ejerce la atención al cliente en la competitividad de las pequeñas y medianas empresas (PYMES) en la ciudad de Matagalpa, durante el año 2010. En la actualidad se vuelve indispensable que las pequeñas y medianas empresas (PYMES) opten por aplicar estrategias, identificar los factores, e implementar principios de atención al cliente como retos de competitividad. Una de las principales metas del presente documento, es analizar el papel importante que juega el aplicar una adecuada atención al cliente y por ende los beneficios que esta genera a cada empresa. En esta investigación se abordan los factores que inciden, estrategias aplicadas y principios que deben implementarse con el objetivo de lograr beneficios y una buena atención al cliente, así como información de conceptos básicos, importancia, principios, factores y etapas de competitividad, además información general de las PYMES, tomando como referencia los sectores: metal mecánica y comercio de la ciudad de Matagalpa. Las PYMES evaluadas, implementan de forma inconsciente o no planificada los factores que inciden en la atención al cliente así como las estrategias y principios. Además han logrado una buena atención al cliente y competitivida