Scale Factor Dualities in Anisotropic Cosmologies

TL;DR

This paper investigates scale factor dualities in various anisotropic vacuum Brans-Dicke cosmologies, revealing that such symmetries depend on the specific Bianchi type and spatial curvature, with some models exhibiting dualities and others not.

Contribution

It identifies the presence or absence of scale factor dualities across different anisotropic cosmological models, highlighting the influence of anisotropy and spatial curvature.

Findings

Dualities exist for Bianchi types I, II, VI_0, VII_0.

No dualities for types VIII, IX, and V.

Certain models like Kantowski-Sachs show duality symmetry.

Abstract

The concept of scale factor duality is considered within the context of the spatially homogeneous, vacuum Brans-Dicke cosmologies. In the Bianchi class A, it is found that duality symmetries exist for the types I, II, VI_0, VII_0, but not for types VIII and IX. The Kantowski-Sachs and locally rotationally symmetric Bianchi type III models also exhibit a scale factor duality, but no such symmetries are found for the Bianchi type V. In this way anisotropy and spatial curvature may have important effects on the nature of such dualities.