Anisotropic Inflation in a 5D Standing Wave Braneworld and Dimensional Reduction

TL;DR

This paper presents an exact 5D cosmological solution demonstrating how anisotropic primordial metrics can induce inflation in some dimensions while shrinking others, potentially explaining dimensional reduction in higher-dimensional theories.

Contribution

It introduces a novel dynamical mechanism in a 5D standing wave braneworld model that links anisotropic inflation to dimensional reduction.

Findings

Exact 5D solution with anisotropic inflation

Mechanism for dimensional reduction via shrinking dimensions

Relevance for string theory and higher-dimensional models

Abstract

We investigate a cosmological solution within the framework of a 5D standing wave braneworld model generated by gravity coupled to a massless scalar phantom-like field. By obtaining a full exact solution of the model we found a novel dynamical mechanism in which the anisotropic nature of the primordial metric gives rise to i) inflation along certain spatial dimensions, and ii) deflation and a shrinking reduction of the number of spatial dimensions along other directions. This dynamical mechanism can be relevant for dimensional reduction in string and other higher dimensional theories in the attempt of getting a 4D isotropic expanding space-time.