2,495 research outputs found

    Non-Markovian qubit dynamics in a circuit-QED setup

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    We consider a circuit-QED setup that allows the induction and control of non-Markovian dynamics of a qubit. Non-Markovianity is enforced over the qubit by means of its direct coupling to a bosonic mode which is controllably coupled to other qubit-mode system. We show that this configuration can be achieved in a circuit-QED setup consisting of two initially independent superconducting circuits, each formed by one charge qubit and one transmission-line resonator, which are put in interaction by coupling the resonators to a current-biased Josephson junction. We solve this problem exactly and then proceed with a thorough investigation of the emergent non-Markovianity in the dynamics of the qubits. Our study might serve the context for a first experimental assessment of non-Markovianity in a multi-element solid-state device.Comment: 8 pages, 7 figures, slightly changed titl

    COOPERATION IN LARGE NETWORKS: AN EXPERIMENTAL

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    We present a new design of a simple public goods experiment with a large number of players, where up to 80 people in a computer lab have the possibility to connect with others in the room to induce more cooperators to contribute to the public good and overcome the social dilemma. This experimental design explores the possibility of social networks to be used and institutional devices to create the same behavioral responses we observe with small groups (e.g. commitments, social norms, reciprocity, trust, shame, guilt) that seem to induce cooperativebehavior in the private provision of public goods. The results of our experiment suggest that the structure of the network affects not only the players´ ability to communicate, but their willingness to do so as well. Finally, we find that the local connectivity structure of the network has an important role as determinant of the willingness of the players to engage in a more costly type of collective action, namely the endogenous creation of new links to individuals previously out of reach.Social capital, social networks, collective action, cooperation, VCM,experiments, public goods provision

    Sturm-Liouville boundary conditions for a second order ODE

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    We study the semilinear second order ODE u00 + g(t, u) = 0 under the following Sturm- Liouville boundary condition au(0) + bu0(0) = u0 and cu(T) + du0(T) = uT . We obtain solutions by topological methods. Moreover, we show that a solution may be constructed recursively, under appropriate conditions

    Resonance enhancement of particle production during reheating

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    We found a consistent equation of reheating after inflation, which shows that for small quantum fluctuations the frequencies of resonance are slighted different from the standard ones. Quantum interference is taken into account and we found that at large fluctuations the process mimics very well the usual parametric resonance but proceed in a different dynamical way. The analysis is made in a toy quantum mechanical model and we discuss further its extension to quantum field theory.Comment: 4 pages, 4 figures(eps), using RevTe

    Inflation as a response to protect the Holographic Principle

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    A model where the inflationary phase emerges as a response to protect the Fischler-Susskind holographic bound is described. A two fluid model in a closed universe inflation picture is assumed, and a discussion on conditions under which is possible to obtain an additional exponential expansion phase as those currently observed is given.Comment: 6 pages, 2 figures. Accepted for publication in MPL

    Evaluación de Capacidad Adsortiva del Carbón Activado Industrial Darco en Agente Surfactante Dodecil Benceno en Detergentes,realizados en los Laboratorios de Química UNAN-MANAGUA, de Marzo a Noviembre del 2012

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    Se realizó un estudio experimental evaluando la capacidad adsortiva del carbón activado industrial DARCO, en presencia de agentes surfactantes, Dodecil benceno sulfonato de sodio lineal, presente en la marca de detergente FAB,disuelto en 250 ml de agua. El carbón fue sometido a un proceso de pruebas con el fin de conocer sus propiedades físico-químicas (%ceniza, % de humedad, densidad aparente y porosidad) según las normas de la Sociedad Americana para pruebas y materiales, así como la determinación del porcentaje de remoción y la cuantificación de su capacidad adsortiva Se realizaron ensayos de adsorción en fase liquida con dos tipos de concentraciones una de 80,000 ppm y 40,000 ppm con distintos tiempos de agitación de 30-60 min a una temperatura de 25ºC, el indicador que se empleó para este análisis fue azul de metileno, donde la variable dependiente es la capacidad adsortiva del carbón activado DARCO y las independientes son el tiempo de retención y concentración Para el orden aleatorio de las pruebas fue ajustado por el programa Statgraphcs Plus 5.1 empleando el método multinivel . Para la calibración del Espectrofotómetro Espectrónico Termo de 20 GENESYS serial RS-232-C de UV se realizaron las lecturas de adsorbancia del azul de metileno en una longitud de onda de 652 nm, con el fin de obtener la curva de calibración, lo cual permitió obtener un rango de respuesta lineal para la cuantificación de la adsorbancia del Dodecil benceno sulfonato de sodio lineal. En la adsorción del Dodecil benceno sulfonato de sodio lineal, se determinó que en los dos tiempos de contacto estipulados, el carbón activado presento una gran adsorción ante los dos tipos de concentraciones, el porcentaje de remoción con respecto los tiempos versus concentración osciló entre el 60% y 99%, presente en las muestra. El análisis estadístico que se empleo para comprobar la eficiencia de remoción fue el método de prueba de igualdad de varianza empleando el programa estadístico SPSS, ratificando que no hay diferencia significativa en base a las concentraciones de las muestras de aguas

    Comprehensive transient-state study for CARMENES-NIR high thermal stability

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    CARMENES has been proposed as a next-generation instrument for the 3.5m Calar Alto Telescope. Its objective is finding habitable exoplanets around M dwarfs through radial velocity measurements (m/s level) in the near-infrared. Consequently, the NIR spectrograph is highly constraint regarding thermal/mechanical requirements. As a first approach, the thermal stability has been limited to \pm 0.01K (within year period) over a working temperature of 243K. This can be achieved by means of several temperature-controlled rooms. The options considered to minimise the complexity of the thermal design are here presented, as well as the transient-state thermal analyses realised to make the best choice

    Chitosan gel film bandages: correlating structure, composition, and antimicrobial properties

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    Chitosan gel films were successfully obtained by evaporation cast from chitosan solutions in aqueous acidic solutions of organic acids (lactic and acetic acid) as gel film bandages, with a range of additives that directly influence film morphology and porosity. We show that the structure and composition of a wide range of 128 thin gel films, is correlated to the antimicrobial properties, their biocompatibility and resistance to biodegradation. Infrared spectroscopy and solid-state 13C nuclear magnetic resonance spectroscopy was used to correlate film molecular structure and composition to good antimicrobial properties against 10 of the most prevalent Gram positive and Gram negative bacteria. Chitosan gel films reduce the number of colonies after 24 h of incubation by factors of ∼105–107 CFU/mL, compared with controls. For each of these films, the structure and preparation condition has a direct relationship to antimicrobial activity and effectiveness. These gel film bandages also show excellent stability against biodegradation with lysozyme under physiological conditions (5% weight loss over a period of 1 month, 2% in the first week), allowing use during the entire healing process. These chitosan thin films and subsequent derivatives hold potential as low-cost, dissolvable bandages, or second skin, with antimicrobial properties that prohibit the most relevant intrahospital bacteria that infest burn injuries
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