Consequences of U dualities for Intersecting Branes in the Universe

TL;DR

This paper explores how U dualities in M theory influence intersecting brane configurations, revealing relations among scale factors and suggesting that certain four-charge setups naturally evolve into a (3+1)-dimensional expanding universe.

Contribution

It introduces an ansatz for density and pressure in multi-charge brane systems that satisfies U duality relations and demonstrates the emergence of a (3+1)-dimensional universe from specific brane configurations.

Findings

U dualities impose relations among scale factors and densities.

An ansatz consistent with U dualities is proposed for multi-charge systems.

Four-charge configurations asymptotically lead to a (3+1)-dimensional universe.

Abstract

We consider N -- charge, intersecting brane antibrane configurations in M theory which are smeared uniformly in the common transverse space and may describe our universe. We study the consequences of U dualities and find that they imply relations among the scale factors. We find using Einstein's equations that U dualities also imply a relation among the density \rho and the pressure p_i for the single charge case. We present an ansatz for \rho and p_i for the N -- charge case which yields all the U duality relations among the scale factors. We then study configurations with identical charges, and also with net charges vanishing. We find among other things that, independent of the details of the brane antibrane dynamics, such four charge configurations lead asymptotically to an effective (3 + 1) -- dimensional expanding universe.