Effects of Quantized Scalar Fields in Cosmological Spacetimes with Big Rip Singularities

TL;DR

This paper examines how quantized scalar fields behave near Big Rip singularities in cosmological models, analyzing their energy densities and potential to influence the fate of the universe.

Contribution

It provides the first detailed analysis of quantum scalar field energy densities in Big Rip scenarios, including numerical results for various field types and couplings.

Findings

Energy densities approach attractor states at late times.

Massive fields' energy densities asymptotically match massless fields.

Quantum effects may influence the Big Rip singularity.

Abstract

Effects of quantized free scalar fields in cosmological spacetimes with Big Rip singularities are investigated. The energy densities for these fields are computed at late times when the expansion is very rapid. For the massless minimally coupled field it is shown that an attractor state exists in the sense that, for a large class of states, the energy density of the field asymptotically approaches the energy density it would have if it was in the attractor state. Results of numerical computations of the energy density for the massless minimally coupled field and for massive fields with minimal and conformal coupling to the scalar curvature are presented. For the massive fields the energy density is seen to always asymptotically approach that of the corresponding massless field. The question of whether the energy densities of quantized fields can be large enough for backreaction effects to remove the Big Rip singularity is addressed.