On the emergence of an expanding universe from a Lorentzian matrix model

TL;DR

This paper provides evidence that a Lorentzian matrix model can explain the emergence of an expanding universe and introduces an effective metric that describes a finite-curvature (3+1)-dimensional spacetime.

Contribution

It demonstrates how classical equations from the Lorentzian IIB matrix model relate to universe expansion and proposes a new effective metric for the emergent spacetime.

Findings

Numerical results suggest universe expansion from the matrix model.

An effective metric with finite curvature scalars is proposed.

Heuristic discussion on the universe's origin within the model.

Abstract

We present evidence that recent numerical results from the reduced classical equations of the Lorentzian IIB matrix model can be interpreted as corresponding to the emergence of an expanding universe. In addition, we propose an effective metric to describe the emerging (3+1)-dimensional spacetime. This metric gives, at all times, finite values for the Ricci and Kretschmann curvature scalars. With these results, we are able to give a heuristic discussion of the origin of the Universe in the context of the IIB matrix model.