Self-tuning flat domain walls in 5d gravity and string theory

TL;DR

This paper constructs self-tuning flat domain wall solutions in 5d gravity models derived from string theory, demonstrating that quantum corrections to brane tension do not induce a 4D cosmological constant, thus addressing the cosmological constant problem.

Contribution

It introduces a class of self-tuning solutions in 5d string-inspired theories where quantum corrections do not generate a cosmological constant.

Findings

Existence of Poincare invariant solutions for arbitrary brane tension values.

Quantum corrections to brane tension do not lead to a 4d cosmological constant.

Examples from string theory support the naturalness of these solutions.

Abstract

We present Poincare invariant domain wall (``3-brane'') solutions to some 5-dimensional effective theories which can arise naturally in string theory. In particular, we find theories where Poincare invariant solutions exist for arbitrary values of the brane tension, for certain restricted forms of the bulk interactions. We describe examples in string theory where it would be natural for the quantum corrections to the tension of the brane (arising from quantum fluctuations of modes with support on the brane) to maintain the required form of the action. In such cases, the Poincare invariant solutions persist in the presence of these quantum corrections to the brane tension, so that no 4d cosmological constant is generated by these modes.