Cosmological singularity resolution from quantum gravity: the emergent-bouncing universe

TL;DR

This paper proposes an 'emergent-bouncing universe' model within Quantum Reduced Loop Gravity, replacing the Big Bang singularity with a quantum oscillatory phase leading to a classical universe, offering new insights into early cosmology.

Contribution

It introduces a novel hybrid cosmological scenario combining emergent quantum phases with bouncing behavior in a quantum gravity framework.

Findings

Replaces Big Bang singularity with a short quantum bounce.

Universe undergoes oscillations before classical expansion.

Modified Friedmann equations support the emergent-bouncing scenario.

Abstract

Alternative scenarios to the Big Bang singularity have been subject of intense research for several decades by now. Most popular in this sense have been frameworks were such singularity is replaced by a bounce around some minimal cosmological volume or by some early quantum phase. This latter scenario was devised a long time ago and referred as an "emergent universe" (in the sense that our universe emerged from a constant volume quantum phase). We show here that within an improved framework of canonical quantum gravity (the so called Quantum Reduced Loop Gravity) the Friedmann equations for cosmology are modified in such a way to replace the big bang singularity with a short bounce {preceded by a metastable quantum phase in which the volume of the universe oscillates between a series of local maxima and minima}. We call this hybrid scenario an "emergent-bouncing universe" since after a pure oscillating quantum phase the classical Friedmann spacetime emerges. Perspective developments and possible tests of this scenario are discussed in the end.