Crosstalk between DGP branes

TL;DR

This paper explores how overlapping DGP branes with U(1) gauge theories can lead to modified electromagnetic interactions, potentially observable effects on cosmic signals and structure formation.

Contribution

It introduces a model of crosstalk between overlapping DGP branes affecting Coulomb interactions and cosmological signals, a novel mechanism in brane-world scenarios.

Findings

Modified Coulomb potentials in overlap regions

Potential observable effects on Lyman-alpha forest signals

Impacts on structure formation through radiative cooling

Abstract

If two DGP branes carry U(1) gauge theories and overlap, particles of one brane can interact with the photons from the other brane. This coupling modifies in particular the Coulomb potentials between charges from the same brane in the overlapping regions. The coupling also introduces Coulomb interactions between charges from the different branes which can generate exotic bound states. The effective modification of the fine structure constant in the overlap region generates a trough in signals at the redshift of the overlap region and an increase at smaller or larger redshift, depending on the value of the crosstalk parameter. This implies potentially observable perturbations in the Lyman-alpha forest if our 3-brane overlapped with another 3-brane in a region with redshift z<6. Crosstalk can also affect structure formation by enhancing or suppressing radiative cooling.