A Matrix Big Bang

TL;DR

This work presents a non-perturbative holographic framework for a cosmological big bang singularity using a light-like linear dilaton background in string theory. By formulating a Matrix string description on the Milne orbifold, it shows that the singularity corresponds to a UV regime of a (1+1)-D supersymmetric Yang–Mills theory and that spacetime emerges from the RG flow toward the IR, with gravity decoupled at the singularity. The authors provide a detailed DLCQ-based derivation, analyze the regime of validity, and discuss how time evolution maps to YM dynamics, while outlining several generalizations to IIA, IIB, and little string theory. This framework offers a controlled, non-perturbative avenue to study cosmological singularities and the emergence of spacetime in string theory. The approach highlights how non-geometric, matrix degrees of freedom can capture early-universe physics and suggests connections to broader holographic duals beyond AdS/CFT.

Abstract

The light-like linear dilaton background represents a particularly simple time-dependent 1/2 BPS solution of critical type IIA superstring theory in ten dimensions. Its lift to M-theory, as well as its Einstein frame metric, are singular in the sense that the geometry is geodesically incomplete and the Riemann tensor diverges along a light-like subspace of codimension one. We study this background as a model for a big bang type singularity in string theory/M-theory. We construct the dual Matrix theory description in terms of a (1+1)-d supersymmetric Yang-Mills theory on a time-dependent world-sheet given by the Milne orbifold of (1+1)-d Minkowski space. Our model provides a framework in which the physics of the singularity appears to be under control.