768 research outputs found

    Gravitational Phase Transition in Neutron Stars

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    The possibility of a gravitational phase transition, especially with respect to neutron stars is investigated. First, a semiclassical treatment is given, predicting a gravitational London penetration depth of 12km for neutron stars. Second, the problem is considered from a Ginzburg-Landau point of view. A gravitational Meissner effect, a gravitational Aharanov-Bohm type effect and a gravitational ferromagnetic type phase are predicted. Finally, a field theoretic consideration predicts a mass term for the graviton below a certain critical temperature.Comment: 19 pages, standard LaTe

    Yang-Mills, Gravity, and String Symmetries

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    In this work we use constructs from the dual space of the semi-direct product of the Virasoro algebra and the affine Lie algebra of a circle to write a theory of gravitation which is a natural analogue of Yang-Mills theory. The theory provides a relation between quadratic differentials in 1+1 dimensions and rank two symmetric tensors in higher dimensions as well as a covariant local Lagrangian for two dimensional gravity. The isotropy equations of coadjoint orbits are interpreted as Gauss law constraints for a field theory in two dimensions, which enables us to extend to higher dimensions. The theory has a Newtonian limit in any space-time dimension. Our approach introduces a novel relationship between string theories and 2D field theories that might be useful in defining dual theories. We briefly discuss how this gravitational field couples to fermions.Comment: To Appear in Phys. Lett. B, In memory of Emma Meuric

    Applications of W-algebras to BF theories, QCD and 4D Gravity

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    We are able to show that BF theories naturally emerge from the coadjoint orbits of W2W_2 and ww_\infty algebras which includes a Kac-Moody sector. Since QCD strings can be identified with a BF theory, we are able to show a relationship between the orbits and monopole-string solutions of QCD. Furthermore, we observe that when 4D gravitation is cast into a BF form through the use of Ashtekar variables, we are able to get order \hbar contributions to gravity which can be associated with the W2W_2 anomaly. We comment on the relationship to gravitational monopoles.Comment: 14 page

    Case study: Class diagram restructuring

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    This case study is an update-in-place refactoring transformation on UML class diagrams. Its aim is to remove clones of attributes from a class diagram, and to identify new classes which abstract groups of classes that share common data features. It is used as one of a general collection of transformations (such as the removal of redundant inheritance, or multiple inheritance) which aim to improve the quality of a specification or design level class diagram. The transformation is a typical example of a model refactoring, and illustrates the issues involved in such transformations.Comment: In Proceedings TTC 2013, arXiv:1311.753

    Solving the Petri-Nets to Statecharts Transformation Case with UML-RSDS

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    This paper provides a solution to the Petri-Nets to statecharts case using UML-RSDS. We show how a highly declarative solution which is confluent and invertible can be given using this approach.Comment: In Proceedings TTC 2013, arXiv:1311.753

    Global warming

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    Alien Registration- Lano, George (Portland, Cumberland County)

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    https://digitalmaine.com/alien_docs/31767/thumbnail.jp

    Alien Registration- Lano, George (Portland, Cumberland County)

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    https://digitalmaine.com/alien_docs/31767/thumbnail.jp

    Global warming

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