2002/07/31 by Sugumi Kanno, Jiro Soda
Physics and Astronomy · #Black Holes and Theoretical Physics #Cosmology and Gravitation Theories #Quantum Electrodynamics and Casimir Effect #gr-qc #hep-th
paper · pdf · doi:10.1103/physrevd.66.083506
published as Phys.Rev. D66 (2002) 083506 · Revtex4, 18 pages, revised version, conclusions unchanged, references added
arxiv created 2002/08/02 · openalex publication_date 2002/10/16 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The low energy effective theory for the Randall-Sundrum two-brane system is investigated with an emphasis on the role of the nonlinear radion in the brane world. The equations of motion in the bulk are solved using a low energy expansion method. This allows us, through the junction conditions, to deduce the effective equations of motion for gravity on the brane. It is shown that the gravity on the brane world is described by a quasi-scalar-tensor theory with a specific coupling function \ensuremathω(\ensuremathΨ)=3\ensuremathΨ/2(1\ensuremath-\ensuremathΨ) on the positive tension brane and \ensuremathω(\ensuremathΦ)=\ensuremath-3\ensuremathΦ/2(1+\ensuremathΦ) on the negative tension brane, where \ensuremathΨ and \ensuremathΦ are nonlinear realizations of the radion on the positive and negative tension branes, respectively. In contrast with the usual scalar-tensor gravity, the quasi-scalar-tensor gravity couples with two kinds of matter; namely, the matter on both positive and negative tension branes, with different effective gravitational coupling constants. In particular, the radion disguised as the scalar fields \ensuremathΨ and \ensuremathΦ couples with the sum of the traces of the energy-momentum tensor on both branes. In the course of the derivation, it is revealed that the radion plays an essential role in converting the nonlocal Einstein gravity with generalized dark radiation to local quasi-scalar-tensor gravity. For completeness, we also derive the effective action for our theory by substituting the bulk solution into the original action. It is also shown that quasi-scalar-tensor gravity works as a hologram at low energy in the sense that the bulk geometry can be reconstructed from the solution of quasi-scalar-tensor gravity.