Effective Dynamics of the Matrix Big Bang

TL;DR

The paper probes how cosmological singularities arise in a holographic Matrix-theory setting by studying maximally supersymmetric Yang-Mills on the Milne orbifold. Using a 1-loop analysis around a Cartan vacuum, it finds an attractive potential near the Big Bang that rapidly wanes at late times, aligning with the expected transition to perturbative string dynamics in the light-like dilaton background. At late times, the potential appears non-perturbative and D-brane–driven in string variables, suggesting an IR origin for features traditionally viewed as UV. The work highlights a subtle IR/UV interplay in time-dependent backgrounds and raises questions about general covariance and spontaneous Poincaré breaking in cosmological holography, offering a controlled window where Matrix theory captures aspects of singularity resolution and late-time string behavior.

Abstract

We study the leading quantum effects in the recently introduced Matrix Big Bang model. This amounts to a study of supersymmetric Yang-Mills theory compactified on the Milne orbifold. We find a one-loop potential that is attractive near the Big Bang. Surprisingly, the potential decays very rapidly at late times, where it appears to be generated by D-brane effects. Usually, general covariance constrains the form of any effective action generated by renormalization group flow. However, the form of our one-loop potential seems to violate these constraints in a manner that suggests a connection between the cosmological singularity and long wavelength, late time physics.