Magneto-transport from momentum dissipating holography

We obtain explicit expressions for the thermoelectric transport coefficients of a strongly coupled, planar medium in the presence of an orthogonal magnetic field and momentum-dissipating processes. The computations are performed within the gauge/gravity framework where the momentum dissipation mechanism is introduced by including a mass term for the bulk graviton. Relying on the structure of the computed transport coefficients and promoting the parameters to become dynamical functions, we propose a holography inspired phenomenology open to a direct comparison with experimental data from the cuprates.Comment: 23 page

Analytic pseudo-Goldstone bosons

We consider the interplay between explicit and spontaneous symmetry breaking in strongly coupled field theories. Some well-known statements, such as the Gell-Mann-Oakes-Renner relation, descend directly from the Ward identities and have thus a general relevance. Such Ward identities are recovered in gauge/gravity dual setups through holographic renormalization. In a simple paradigmatic three dimensional toy-model, we find analytic expressions for the two-point correlators which match all the quantum field theoretical expectations. Moreover, we have access to the full spectrum, which is reminiscent of linear confinement.Comment: 20 pages, 4 figures, v2 minor correction

Electromagnetic response of strongly coupled plasmas

We present a thorough analysis of the electromagnetic response of strongly coupled neutral plasmas described by the gauge/gravity correspondence. The coupling of the external electromagnetic field with the tower of quasi-normal modes of the plasmas supports the presence of various electromagnetic modes with different properties. Among them we underline the existence of negative refraction with low dissipation for a transverse non-hydrodynamical mode. Previous hydrodynamical approaches have shown the ubiquitous character of negative refraction in charged plasmas and the absence thereof in neutral plasmas. Our results here extend the analysis for neutral plasmas beyond the hydrodynamical regime. As an application of these new insights we briefly discuss the case of the quark gluon plasma in the temperature dominated regime.Comment: 29 pages, 15 figure

Chasing the cuprates with dilatonic dyons

Magnetic field and momentum dissipation are key ingredients in describing condensed matter systems. We include them in gauge/gravity and systematically explore the bottom-up panorama of holographic IR effective field theories based on bulk Einstein-Maxwell Lagrangians plus scalars. The class of solutions here examined appear insufficient to capture the phenomenology of charge transport in the cuprates. We analyze in particular the temperature scaling of the resistivity and of the Hall angle. Keeping an open attitude, we illustrate weak and strong points of the approach.Comment: 30 pages, 2 figures, Version to appear in JHE

Analytic DC thermo-electric conductivities in holography with massive gravitons

We provide an analytical derivation of the thermo-electric transport coefficients of the simplest momentum-dissipating model in gauge/gravity where the lack of momentum conservation is realized by means of explicit graviton mass in the bulk. We rely on the procedure recently described by Donos and Gauntlett in the context of Q-lattices and holographic models where momentum dissipation is realized through non-trivial scalars. The analytical approach confirms the results found previously by means of numerical computations.Comment: 9 pages, no figures, minor comments added, version to appear on PR

How networks shape diversity for better or worse

Socio-diversity, the social analog of bio-diversity, is fundamental for innovation, productivity, and collective intelligence. How can it be promoted? This paper studies how social structure can promote and hinder socio-diversity, employing models of behavioral dynamics and numerical simulations. By introducing the structural diversity index, a quantifier revealing the propensity of a social structure to sustain diversity, we investigate how fundamental characteristics of social networks -- degree heterogeneity, clustering, distance, and size -- affect behavioral diversity. We show that degree-heterogeneity obstructs diversity, while clustering and distance favor it. These results open new perspectives for understanding how to change social structures to sustain more (behavioral) diversity and, thereby, societal innovation, collective intelligence, and productivity.Comment: 8 pages, 4 figure

A holographic perspective on phonons and pseudo-phonons

We analyze the concomitant spontaneous breaking of translation and conformal symmetries by introducing in a CFT a complex scalar operator that acquires a spatially dependent expectation value. The model, inspired by the holographic Q-lattice, provides a privileged setup to study the emergence of phonons from a spontaneous translational symmetry breaking in a conformal field theory and offers valuable hints for the treatment of phonons in QFT at large. We first analyze the Ward identity structure by means of standard QFT techniques, considering both spontaneous and explicit symmetry breaking. Next, by implementing holographic renormalization, we show that the same set of Ward identities holds in the holographic Q-lattice. Eventually, relying on the holographic and QFT results, we study the correlators realizing the symmetry breaking pattern and how they encode information about the low-energy spectrum.Comment: 31+1 pages, version accepted on JHE

Bounds on charge and heat diffusivities in momentum dissipating holography

Abstract: Inspired by a recently conjectured universal bound for thermo-electric diffusion constants in quantum critical, strongly coupled systems and relying on holographic analytical computations, we investigate the possibility of formulating Planckian bounds in different holographic models featuring momentum dissipation. For a certain family of solutions to a simple massive gravity dilaton model at zero charge density we find linear in temperature resistivity and entropy density alongside a constant electric susceptibility. In addition we explicitly find that the sum of the thermo-electric diffusion constants is bounded

Desarrollo de software para la simulación espacio-temporal de la dinámica poblacional de roedores transmisores de la fiebre hemorrágica argentina

Tesis (Lic. en Ciencias de la Computación)--Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física, 2008.El presente trabajo tiene por objetivo la creación de una herramienta software que a través de información extraída de imágenes satelitales, permita estudiar el comportamiento de roedores relacionados a enfermedades virales como la Fiebre Hemorrágica Argentina o el Síndrome Pulmonar por Hantavirus, resultando un medio educativo y de interés científico sobre patologías virales y su distribución. Dicho objeto de estudio se analiza desde dos puntos de vista, el espacio y el tiempo, dando lugar a la división de este trabajo en dos grandes módulos.Verónica Andrea Musso

"Cole al día": cuaderno de comunicados al digital

Numerosos estudios indican que la implicación de la familia en la educación es clave para el éxito escolar de los niños. Sin embargo, durante los últimos años se ha evidenciado un alejamiento entre la familia y la escuela, llegando incluso a situaciones de desacreditación y desconfianza mutua. Son reiterados los comentarios de los padres o tutores de niños en edad escolar sobre los desencuentros o falta de información en tiempo y forma; así como también la afirmación por parte de las instituciones educativas del bajo involucramiento de gran porcentaje de padres o tutores. Los motivos de esta situación son complejos, profundos y variados, pero no hay duda que una mejora en la comunicación es de vital importancia para su resolución. Es por ello que en el presente trabajo se decidió desarrollar el plan de negocios de Cole al Día, un emprendimiento que propone utilizar la tecnología para ayudar a establecer relaciones positivas y productivas entre la familia y la escuela, reemplazando el viejo cuaderno de comunicados por una aplicación móvil que facilite la comunicación y satisfaga las necesidades de ambas partes. Por medio de esta aplicación los padres reciben en su celular, en tiempo real, de manera centralizada y formal, toda la información administrativa, de progreso educativo y comunicados por parte de la institución, que es cargada por la misma en una moderna plataforma web. A continuación, se podrán encontrar definiciones y detalles sobre este producto, su negocio, sector y mercado. Se incluye además información financiera y el plan de trabajo para llevarlo a cabo.Fil: Musso, Verónica Andrea. Universidad Católica de Córdoba. Instituto de Ciencias de la Administración; Argentin