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Null geodesics and gravitational lensing in a nonsingular spacetime
In this paper, the null geodesics and gravitational lensing in a nonsingular
spacetime are investigated. According to the nature of the null geodesics, the
spacetime is divided into several cases. In the weak deflection limit, we find
the influence of the nonsingularity parameter on the positions and
magnifications of the images is negligible. In the strong deflection limit, the
coefficients and observables for the gravitational lensing in a nonsingular
black hole background and a weakly nonsingular spacetime are obtained.
Comparing these results, we find that, in a weakly nonsingular spacetime, the
relativistic images have smaller angular position and relative magnification,
but larger angular separation than that of a nonsingular black hole. These
results might offer a way to probe the spacetime nonsingularity parameter and
put a bound on it by the astronomical instruments in the near future.Comment: 15 pages, 5 figures, 1 tabl
Gravity Localization and Effective Newtonian Potential for Bent Thick Branes
In this letter, we first investigate the gravity localization and mass
spectrum of gravity KK modes on de Sitter and Anti-de Sitter thick branes.
Then, the effective Newtonian gravitational potentials for these bent branes
are discussed by the two typical examples. The corrections of the Newtonian
potential turns out to be at small for both
cases. These corrections are very different from that of the Randall-Sundrum
brane model .Comment: 6 pages, 2 figure
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