44,166 research outputs found
Pure geometric thick -branes: stability and localization of gravity
We study two exactly solvable five-dimensional thick brane world models in
pure metric gravity. Working in the Einstein frame, we show that these
solutions are stable against small linear perturbations, including the tensor,
vector, and scalar modes. For both models, the corresponding gravitational zero
mode is localized on the brane, which leads to the four-dimensional Newton's
law; while the massive modes are nonlocalized and only contribute a small
correction to the Newton's law at a large distance.Comment: 7 pages, 2 figures, improved version, accepted by Eur. Phys. J.
-field kinks: stability, exact solutions and new features
We study a class of noncanonical real scalar field models in
-dimensional flat space-time. We first derive the general criterion for
the classical linear stability of an arbitrary static soliton solution of these
models. Then we construct first-order formalisms for some typical models and
derive the corresponding kink solutions. The linear structures of these
solutions are also qualitatively analyzed and compared with the canonical kink
solutions.Comment: 14 pages, 3 figure
Tensor stability in Born-Infeld determinantal gravity
We consider the transverse-traceless tensor perturbation of a spatial flat
homogeneous and isotropic spacetime in Born-Infeld determinantal gravity, and
investigate the evolution of the tensor mode for two solutions in the early
universe. For the first solution where the initial singularity is replaced by a
regular geometric de Sitter inflation of infinite duration, the evolution of
the tensor mode is stable for the parameter spaces ,
and , . For the second solution where the
initial singularity is replaced by a primordial brusque bounce, which suffers a
sudden singularity at the bouncing point, the evolution of the tensor mode is
stable for all regions of the parameter space. Our calculation suggests that
the tensor evolution can hold stability in large parameter spaces, which is a
remarkable property of Born-Infeld determinantal gravity. We also constrain the
theoretical parameter by resorting to
the current bound on the speed of the gravitational waves.Comment: 14 pages, added a general discussion on the tensor stability in Sec.
3, and added Sec. 5 on the parameter constraint, published versio
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