Massive particle pair production and oscillation in Friedman Universe: its effect on inflation

TL;DR

This paper investigates how massive particle pairs produced during inflation influence the universe's expansion, linking quantum particle dynamics with cosmological observations like the spectral index and tensor-to-scalar ratio.

Contribution

It introduces a model combining classical Friedman equations with quantum particle production, revealing how massive pairs affect inflation and observable cosmic parameters.

Findings

Massive particle pairs are produced and oscillate during inflation.

The resulting pair plasma influences the universe's expansion and observable spectra.

The model aligns with recent cosmic microwave background observations.

Abstract

We study the classical Friedman equations for the time-varying cosmological term $\tilde\Lambda$ and Hubble function $H$, together with quantised field equations for the production of massive $M\gg H$ particles, namely, the $\tilde\Lambda$CDM scenario of dark energy and matter interactions. Classical slow components ${\mathcal O}(H^{-1})$ are separated from quantum fast components ${\mathcal O}(M^{-1})$. The former obeys the Friedman equations, and the latter obeys a set of nonlinear differential equations. Numerically solving equations for quantum fast components, we find the production and oscillation of massive particle-antiparticle pairs in microscopic time scale ${\mathcal O}(M^{-1})$. Their density and pressure averages over microscopic time do not vanish. It implies the formation of a massive pair plasma state in macroscopic time scale ${\mathcal O}(H^{-1})$, whose effective density and pressure contribute to the Friedman equations. Considering the inflation driven by the time-varying cosmological term and slowed down by the massive pair plasma state, we obtain the relation of spectral index and tensor-to-scalar ratio in agreement with recent observations. We discuss the singularity-free pre-inflation, the CMB large-scale anomaly, and dark-matter density perturbations imprinting on power spectra.