Cosmological Perturbations in Brane World - Brane view v.s. Bulk view -

TL;DR

This paper compares brane and bulk perspectives on cosmological perturbations, emphasizing the need for combined analysis to determine the system's evolution in brane world models.

Contribution

It demonstrates how brane and bulk analyses complement each other to fully understand cosmological perturbations in brane world scenarios.

Findings

Two types of extra data are essential for evolution.

Bulk equations help fix the extra data.

Both brane and bulk analyses are necessary.

Abstract

First, we will study the cosmological perturbations from the brane point of view. It turns out that two types of the extra data are necessary to know the evolution of the system. To fix these data, the analysis of the bulk is needed. So, we have solved equations of motion for the bulk gravity and determined the extra data. We would like to stress that, both analysis take complementary roles to achieve this goal.