Aspects of Duality in Cosmology

TL;DR

This paper explores scale factor duality in a class of f(R) gravity theories derived from string theory, showing they exhibit properties similar to Pre-Big Bang cosmology, with implications for understanding early universe dynamics.

Contribution

It demonstrates that a specific class of f(R) theories from string theory can exhibit scale factor duality, connecting modified gravity to string cosmology models.

Findings

f(R) theories can be derived from string theory effective actions

The models exhibit scale factor duality similar to Pre-Big Bang scenarios

Noether symmetry approach reveals duality properties in these theories

Abstract

In the first part of this article, given the intent to stay at a popular level, it has been introduced and explained briefly basic concepts of Einstein's General Relativity, Dark Matter, Dark Energy, String Theory, Quantum Gravity and Extended Theories of Gravity. The core of this research is based on selecting a class of f(R) theories of gravity, which exhibits scale factor duality transformations. The starting point of this theory is the effective theory of gravity derived from Bosonic String Theory, which is called tree level effective theory of gravity. It is shown that this theory can be cast in a class of f(R) theories of gravity (modified theories of Einstein's General Relativity). It is imposed that FLRW metric be solution of this class of $f(R)$ theories, and, using the Noether symmetry approach, it is found that the cosmological model has scale factor duality like the Pre-Big Bang cosmology of Gasperini and Veneziano.