Multi-Brane Worlds and modification of gravity at large scales

TL;DR

This paper explores multi-brane models with positive and negative tensions, revealing how anomalously light KK states can modify gravity from 4D to higher dimensions at large scales, with potential resolutions for associated issues.

Contribution

It introduces a detailed study of a '+--+' brane configuration that interpolates between models with large-scale gravity modifications due to light KK states.

Findings

Gravity transitions from 4D to 5D at large distances

Negative tension branes lead to anomalously light KK states

Proposes a resolution for issues with negative tension branes

Abstract

We discuss the implications of multi-brane constructions involving combinations of positive and negative tension brane and show how anomalously light KK states emerge when negative tension ''-'' branes are sandwiched between ''+'' branes. We present a detailed study of a ''+--+'' brane assignment which interpolates between two models that have been previously proposed in which gravity is modified at large scales due to the anomalously light states. We show that it has the peculiar characteristic that gravity changes from four dimensional (4D) to 5D at large distances and returns to 4D at even larger scales. We also consider a crystalline universe which leads to a similar structure for gravity. The problems associated with intermediate negative tension branes are discussed and a possible resolution suggested.