Particle Production near an AdS Crunch

TL;DR

This study numerically explores how a dual field theory evolves near a cosmological singularity in an AdS spacetime, revealing energy transfer dynamics and the absence of a big crunch to big bang transition under certain boundary conditions.

Contribution

It provides a detailed numerical analysis of the boundary field theory dynamics near an AdS crunch, highlighting the energy conversion process and boundary condition effects.

Findings

Most potential energy converts into gradient energy during initial oscillation.

No transition from big crunch to big bang observed under studied boundary conditions.

Boundary conditions at infinity significantly influence the evolution of the singularity.

Abstract

We numerically study the dual field theory evolution of five-dimensional asymptotically anti-de Sitter solutions of supergravity that develop cosmological singularities. The dual theory is an unstable deformation of the N = 4 gauge theory on R $\times$ S3, and the big crunch singularity in the bulk occurs when a boundary scalar field runs to infinity. Consistent quantum evolution requires one imposes boundary conditions at infinity. Modeling these by a steep regularization of the scalar potential, we find that when an initially nearly homogeneous wavepacket rolls down the potential, most of the potential energy of the initial configuration is converted into gradient energy during the first oscillation of the field. This indicates there is no transition from a big crunch to a big bang in the bulk for dual boundary conditions of this kind.