Supergravity Inspired Warped Compactifications and Effective Cosmological Constants

TL;DR

This paper derives a supergravity-based effective action for brane-world scenarios, explaining the origin and quantization of cosmological constants in the bulk and on the brane, and linking them to physical quantities like brane charge.

Contribution

It introduces a supergravity inspired derivation of Randall-Sundrum type actions, showing how cosmological constants naturally emerge and are quantized from fundamental theory.

Findings

Cosmological constants are derived parameters, not arbitrary inputs.

Bulk and brane cosmological constants are related to brane charge and quantized.

Explicit example with supersymmetric D3-branes in type IIB superstring theory.

Abstract

We propose a supergravity inspired derivation of a Randall-Sundrum's type action as an effective description of the dynamics of a brane coupled to the bulk through gravity only. The cosmological constants in the bulk and on the brane appear at the classical level when solving the equations of motion describing the bosonic sector of supergravities in ten and eleven dimensions coupled to the brane. They are related to physical quantities like the brane electric charge and thus inherit some of their physical properties. The most appealing property is their quantization: in d_\perp extra dimensions, Lambda_brane goes like N and Lambda_bulk like N^{2/(2-d_perp)}. This dynamical origin also explains the apparent fine-tuning required in the Randall-Sundrum scenario. In our approach, the cosmological constants are derived parameters and cannot be chosen arbitrarily; instead they are determined by the underlying Lagrangian. Some of the branes we construct that support cosmological constant in the bulk have supersymmetric properties: D3-branes of type IIB superstring theory provide an explicit example.