Exact solutions and particle creation for nonconformal scalar fields in homogeneous isotropic cosmological models

TL;DR

This paper derives exact solutions for nonconformal scalar fields in homogeneous isotropic cosmological models, revealing how nonconformal couplings influence particle creation during cosmic evolution.

Contribution

It provides explicit solutions for scalar fields with nonconformal couplings, including Gauss-Bonnet type, and analyzes their impact on particle creation in cosmology.

Findings

Exact solutions relate nonconformal to conformal scalar fields.

Nonconformal couplings can dominate particle creation effects.

Explicit integral expressions for scale factor dependence.

Abstract

The problem is solved of describing scale factors of a homogeneous isotropic spaces-time such that the exact solution for the scalar field with a nonconformal coupling to curvature can be obtained from solutions for the conformally coupled field by redefining the mass and momentum. Explicit expressions for dependence of time from the large-scale factor are presented in the form of Abelian integrals in these cases. The exact solution for a scalar field with Gauss-Bonnet type coupling with curvature is received and it is shown that the corresponding nonconformal additions can dominate at the particles creation by gravitational field.