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Full-Text Articles in Physical Sciences and Mathematics

Approximately Self-Similar Critical Collapse In 2+1 Dimensions, Marco Cavaglia, Gerard Clement, Alessandro Fabbri Aug 2004

Approximately Self-Similar Critical Collapse In 2+1 Dimensions, Marco Cavaglia, Gerard Clement, Alessandro Fabbri

Physics Faculty Research & Creative Works

Critical collapse of a self-gravitating scalar field in a (2+1)-dimensional spacetime with negative cosmological constant seems to be dominated by a continuously self-similar solution of the field equations without cosmological constant. However, previous studies of linear perturbations in this background were inconclusive. We extend the continuously self-similar solutions to solutions of the field equations with negative cosmological constant, and analyze their linear perturbations. The extended solutions are characterized by a continuous parameter. A suitable choice of this parameter seems to improve the agreement with the numerical results. We also study the dynamics of the apparent horizon in the extended background.


Riemann Tensor Of The Ambient Universe, The Dilaton, And Newton’S Constant, Rossen Ivanov, Emil Prodanov Jan 2004

Riemann Tensor Of The Ambient Universe, The Dilaton, And Newton’S Constant, Rossen Ivanov, Emil Prodanov

Articles

We investigate a four-dimensional world, embedded into a five-dimensional spacetime, and find the five-dimensional Riemann tensor via generalisation of the Gauss (--Codacci) equations. We then derive the generalised equations of the four-dimensional world and also show that the square of the dilaton field is equal to the Newton's constant. We find plausable constant and non-constant solutions for the dilaton. Comment: 5 pages, revtex


Overlap Zones, Growth Faults, And Sedimentation: Using High Resolution Gravity Data, Livingston Parish, La, Carrie Alison Cazes Jan 2004

Overlap Zones, Growth Faults, And Sedimentation: Using High Resolution Gravity Data, Livingston Parish, La, Carrie Alison Cazes

LSU Master's Theses

In south Louisiana, parallel to the coast of the Gulf of Mexico, are belts of east-to-west trending, listric-normal faults with associated contemporaneous sedimentation and fault movement. The Tepetate-Baton Rouge Fault system in south-central Louisiana contains individual fault segments which are arcuate and overlap each other in map view, as seen on LiDAR data. Gravity survey data, with a sample spacing of 20 to 50 m, was collected across normal fault scarps. Structural ramps may form in the area between overlapping normal fault segments creating an east-to-west gradient. This gradient change may divert streams and provide areas for coarse-grained sediments to …