Effective relational cosmological dynamics from Quantum Gravity

TL;DR

This paper develops a relational approach to quantum gravity, deriving an effective cosmological dynamics that incorporates quantum effects and resolves classical singularities, advancing understanding of emergent spacetime.

Contribution

It concretely implements a relational strategy within tensorial group field theory, leading to a novel quantum cosmological model with a bounce and improved dynamics over previous approaches.

Findings

Quantum relational dynamics can produce a bounce that replaces the big bang singularity.

Quantum properties of the relational clock influence the emergent cosmological evolution.

The approach offers a consistent framework for emergent spacetime in quantum gravity.

Abstract

We discuss the relational strategy to solve the problem of time in quantum gravity and different ways in which it could be implemented, pointing out in particular the fundamentally new dimension that the problem takes in a quantum gravity context in which spacetime and geometry are understood as emergent. We realize concretely the relational strategy we have advocated in the context of the tensorial group field theory formalism for quantum gravity, leading to the extraction of an effective relational cosmological dynamics from quantum geometric models. We analyze in detail the emergent cosmological dynamics, highlighting the improvements over previous work, the contribution of the quantum properties of the relational clock to it, and the interplay between the conditions ensuring a bona fide relational dynamics throughout the cosmological evolution and the existence of a quantum bounce resolving the classical big bang singularity.