768 research outputs found
Gravitational Phase Transition in Neutron Stars
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
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
We are able to show that BF theories naturally emerge from the coadjoint
orbits of and 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 contributions
to gravity which can be associated with the anomaly. We comment on the
relationship to gravitational monopoles.Comment: 14 page
Case study: Class diagram restructuring
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
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
Alien Registration- Lano, George (Portland, Cumberland County)
https://digitalmaine.com/alien_docs/31767/thumbnail.jp
Alien Registration- Lano, George (Portland, Cumberland County)
https://digitalmaine.com/alien_docs/31767/thumbnail.jp
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