A Discussion on Supersymmetric Cosmic Strings with Gauge-Field Mixing

In this paper, following a stream of investigation on supersymmetric gauge theories with cosmic string solutions, we contemplate the possibility of building up a D-and-F term cosmic string by means of a gauge-field mixing in connection with a U(1) x U(1)'-symmetry. The spontaneous break of both gauge symmetry and supersymmetry are thoroughly analysed and the fermion zero-modes are worked out. The role of the gauge-field mixing parameter is elucidated in connection with the string configuration that comes out. As an application of the model presented here, we propose the possibility that the supersimetric cosmic string yield production of fermionic charge carriers that may eject, at their late stages, particles that subsequently decay to produce cosmic rays of ultra-high energy. In our work, it turns out that massive supersymmetric fermionic partners may be produced for a susy breaking scale in the range 10^{11} to 10^{13} GeV, which is compatible with the phenomenology of a gravitino mass at the TeV scale. We also determine the range of the gauge-field mixing parameter, \alpha, in connection with the mass scales of the present model.Comment: 7 pages, no figures, ReVTex format, to appear in New Journal of Physic

Afeto composto / diálogos entre matéria e a memória familiar

O projeto pretende investigar, através de um processo recursivo de registros visuais, o espaço dimensional e temporal e o processo de transformação energética entre a materialidade de objetos relicários familiares e a imaterialidade do espaço afetivo memorial, buscando entender o processo de decomposição e recomposição orgânica e poética entre eles. Tudo isso se imprime e se apoia em cima do próprio contexto afetivo familiar do autor, através da documentação livre de uma série de objetos pessoais com uma enorme carga afetiva, ao mesmo tempo que estão sujeitos aos processos naturais ou artificiais que geram um desgaste, ou uma decomposição, que em sí expõem o estado orgânico desses objetos e suas relações, e os colocam em um papel-chave entre vida e morte. Através desse espaço, o autor explora os desdobramentos possíveis de conexão com esses membros familiares na busca de uma ruptura das micropolíticas existentes no âmbito familiar, gerando performances de confronto, que dialogam com os conceitos de memória, família e matéria, em busca de uma conexão não velada. Para que isso ocorra, o estudo pretende funcionar como um artifício de retomada do corpo e da memória. É através do processo de decomposição orgânica de frutas que o autor cria um corpo quase parasita, que penetra os objetos relicários e detentores da memória familiar e, num processo recorrente que dialoga entre a vida e a morte desse corpo, agrega novas marcas e formas de maneira exposta e passível ao tempo

Periodic squeezing in a polariton Josephson junction

The use of a Kerr nonlinearity to generate squeezed light is a well-known way to surpass the quantum noise limit along a given field quadrature. Nevertheless, in the most common regime of weak nonlinearity, a single Kerr resonator is unable to provide the proper interrelation between the field amplitude and squeezing required to induce a sizable deviation from Poissonian statistics. We demonstrate experimentally that weakly coupled bosonic modes allow exploration of the interplay between squeezing and displacement, which can give rise to strong deviations from the Poissonian statistics. In particular, we report on the periodic bunching in a Josephson junction formed by two coupled exciton-polariton modes. Quantum modeling traces the bunching back to the presence of quadrature squeezing. Our results, linking the light statistics to squeezing, are a precursor to the study of nonclassical features in semiconductor microcavities and other weakly nonlinear bosonic systems.Comment: 6 pages, 4 figure

Soil aggregation under different management systems

Considering that the soil aggregation reflects the interaction of chemical, physical and biological soil factors, the aim of this study was evaluate alterations in aggregation, in an Oxisol under no-tillage (NT) and conventional tillage (CT), since over 20 years, using as reference a native forest soil in natural state. After analysis of the soil profile (cultural profile) in areas under forest management, samples were collected from the layers 0-5, 5-10, 10-20 and 20-40 cm, with six repetitions. These samples were analyzed for the aggregate stability index (ASI), mean weighted diameter (MWD), mean geometric diameter (MGD) in the classes > 8, 8-4, 4-2, 2-1, 1-0.5, 0.5-0.25, and < 0.25 mm, and for physical properties (soil texture, water dispersible clay (WDC), flocculation index (FI) and bulk density (Bd)) and chemical properties (total organic carbon - COT, total nitrogen - N, exchangeable calcium - Ca2+, and pH). The results indicated that more intense soil preparation (M < NT < PC) resulted in a decrease in soil stability, confirmed by all stability indicators analyzed: MWD, MGD, ASI, aggregate class distribution, WDC and FI, indicating the validity of these indicators in aggregation analyses of the studied soil

Sistema de produção de leite à base de pastagens cultivada e nativa melhorada na região de Bagé.

bitstream/item/109817/1/SISTEMA-DE-PRODUCAO-DE-LEITE.pd