arXiv subjects

Ishwaree P. Neupane

Publications and source records attributed to Ishwaree P. Neupane.

39 records · Page 3Linked to original sources

arXiv2000

Consistency of Higher Derivative Gravity in the Brane Background

We consider the theory of higher derivative gravity with non-factorizable Randall-Sundrum type space-time and obtain the metric solutions which characterize the $p$-brane world-volume as a curved or planar defect embedded in the higher dimensions. We consider the string inspired effective actions of the dilatonic Gauss-Bonnet type in the brane background and show its consistency with the RS brane-world scenario and the conformal weight of the dilaton couplings in the string theory with apppropriate choice of Regge slope ($α'$) or Gauss-Bonnet coupling ($α$) or both. We also discuss a time dependent dilaton solution for a string-inspired fourth-derivative gravity.

hep-th↗

arXiv1999

Cosmological Constant in de-Sitter Spacetime

With the basic cosmological relations that agree with the recent observations, simple expressions are suggested concerning the value of cosmological constant($Λ$). A large contribution of quantum vacuum to the energy momentum tensor does not agree with the observed cosmos. However,one requires the presence of positive $Λ$ to make the various observations consistent. After a review of the effect of cosmological constant on the geodetic motions in the Schwarzschild de Sitter spacetime, some approaches to its solutions are briefly discussed. Also suggested is the very weak limit on $Λ$ from the planetary perturbations.

gr-qc↗

arXiv1999

Planetary Perturbation with Cosmological Constant

A contribution of quantum vacuum to the energy momentum tensor is inevitably experienced in the present universe. One requires the presence of non-zero cosmological constant ($Λ$) to make the various observations consistent. A case of $Λ$ in the Schwarzschild de Sitter space-time shows that precession of perihelion orbit provides a sensative solar test for non-zero $Λ$. Application of the relations involving $Λ$ to the planetery perturbation indicates the values near to the present bound on $Λ$. Also suggested are some relations in vacuum dominated flat universe with a positive $Λ$.

gr-qc↗