Perdurance of multiply connected de Sitter space

TL;DR

This paper investigates the stability of a multiply connected de Sitter spacetime under classical and quantum perturbations, concluding classical stability but quantum stability only at Planck-scale sizes, impacting cosmological boundary conditions.

Contribution

It provides a detailed analysis of the stability of Gott and Li's multiply connected de Sitter spacetime against both classical and quantum perturbations, highlighting size-dependent quantum stability.

Findings

Classical perturbations do not destabilize the spacetime.

Quantum fluctuations destabilize the spacetime unless the region is Planck-scale.

Supports boundary conditions based on universe self-creation or creation from nothing.

Abstract

This paper deals with a study of the effects that spherically symmetric first-order metric perturbations and vacuum quantum fluctuations have on the stability of the multiply connected de Sitter spacetime recently proposed by Gott and Li. It is the main conclusion of this study that although such a spacetime is stable to the classical metric perturbations for any size of the nonchronal region, it is only stable against the quantum fluctuations of vacuum if the size of the multiply connected region is of the order the Planck scale. Therefore, boundary conditions for the state of the universe based on the notion that the universe created itself in a regime where closed timelike curves were operative and stable, still appear to be physically and philosophically so well supported as are those boundary conditions relying on the notion that the universe was created out of nothing.