Quantum effects near future singularities

TL;DR

This paper investigates whether quantum effects can prevent future cosmological singularities, finding they are significant near strong singularities like the big rip but negligible near milder singularities.

Contribution

It provides an analysis of quantum effects near different types of future singularities in cosmology, highlighting their importance in strong singularities.

Findings

Quantum effects are significant near big rip singularities.

Quantum effects are irrelevant near milder singularities like sudden singularities.

The relevance of quantum effects depends on the violation of energy conditions.

Abstract

General relativity allows a variety of future singularities to occur in the evolution of the universe. At these future singularities, the universe will end in a singular state after a finite proper time and geometrical invariants of the space time will diverge. One question that naturally arises with respect to these cosmological scenarios is the following: can quantum effects lead to the avoidance of these future singularities? We analyze this problem considering massless and conformally coupled scalar fields in an isotropic and homogeneous background leading to future singularities. It is shown that near strong, big rip-type singularities, with violation of the energy conditions, the quantum effects are very important, while near some milder classes of singularity like the sudden singularity, which preserve the energy conditions, quantum effects are irrelevant.