Cosmological space-times with resolved Big Bang in Yang-Mills matrix models

Understand

We present simple solutions of IKKT-type matrix models that can be viewed as quantized homogeneous and isotropic cosmological space-times, with finite density of microstates and a regular Big Bang (BB).

• The BB arises from a signature change of the effective metric on a fuzzy brane embedded in Lorentzian target space, in the presence of a quantized 4-volume form.
• The Hubble parameter is singular at the BB, and becomes small at late times.
• There is no singularity from the target space point of view, and the brane is Euclidean "before" the BB.