Single-field model of gravitational-scalar instability. I. Evolution of perturbations

TL;DR

This paper develops a numerical model to study gravitational-scalar instability in a cosmological setting with fermions and scalar interactions, revealing how scalar charge influences instability development and identifying four distinct perturbation types.

Contribution

It introduces a new numerical model for gravitational-scalar perturbations in a one-component fermionic cosmological system with scalar interaction, highlighting the role of scalar charge.

Findings

Instability arises at small scalar charges during early expansion.

Four types of perturbations and instability are identified.

Numerical models show large amplitude growth of perturbations.

Abstract

On the basis of the previously formulated mathematical model of a statistical system with a scalar interaction of fermions and the theory of gravitational-scalar instability of a cosmological model based on a two-component statistical system of scalarly charged degenerate fermions, a numerical model of the cosmological evolution of gravitational-scalar perturbations for a one-component cosmological system with a canonical scalar interaction is constructed and studied. The influence of the magnitude of the scalar charge of fermions on the differential and integral parameters of the instability is revealed. It is shown that the gravitational-scalar instability in the early stages of expansion in the model under study arises at sufficiently small scalar charges. 4 fundamentally different types of perturbations are identified, as well as 4 types of gravitational-scalar instability, determined by the fundamental parameters of the model. Examples of numerical models are given that provide large values of the increments of the increase in the amplitude of perturbations.