Informal Pizza Seminar

Quantum Resolution of Cosmological Singularities using AdS/CFT

Ben Craps

Vrije University & Solvay Institute

The AdS/CFT correspondence is used to describe five-dimensional cosmology with a big crunch singularity in terms of N=4 supersymmetric SU(N) gauge theory on R times S³ deformed by an unstable potential. The big crunch singularity in the bulk corresponds in the boundary theory to a scalar field rolling to infinity in finite time. We generalize the method of self-adjoint extensions to define consistent unitary quantum evolution in the boundary theory. The quantum mechanical spread of the wave function for the homogeneous mode on the sphere suppresses the creation of high energy particles as the scalar field rolls down the potential and bounces back. This leads to the prediction that a quantum transition from the big crunch to a big bang is the most probable outcome of cosmological evolution, for a specific parameter range. We briefly comment on cosmological perturbations.