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Graciela S. Birman

Publications and source records attributed to Graciela S. Birman.

2 recordsLinked to original sources

Cylindrically symmetric spinning Brans-Dicke spacetimes with closed timelike curves

We present here three new solutions of Brans-Dicke theory for a stationary geometry with cylindrical symmetry in the presence of matter in rigid rotation with $T^μ_μ\neq 0$. All the solutions have eternal closed timelike curves in some region of the spacetime, the size of which depends on $ω$. Moreover, two of them do not go over a solution of general relativity in the limit $ω\to \infty$.

gr-qc↗

On Pseudospherically Symmetric Repulsive Gravitational Field

Solutions of Einstein vacuum equations, for a static pseudospherically symmetric system, are presented. They describe a naked singularity and a singular solution with many resemblances to the Schwartzschild solution but with two major differences: its static region, lying inside the null horizon, sees the singularity, and its effective gravitational field is repulsive. We shortly discuss on the phenomenological plausibility of this last solution as a self-consistent system living on a space-time domain, and discuss some features of particle geodesics in its gravitational field.

gr-qc↗