The Interacting and Non-constant Cosmological Constant

TL;DR

This paper introduces a model of a time-varying cosmological constant that interacts with the universe's background, explaining the transition from inflation to dark energy-driven acceleration.

Contribution

It presents a novel interacting, non-constant cosmological constant model that evolves over cosmic history, aligning with observed acceleration phases.

Findings

The cosmological constant decreases from a large initial value to a small current value.

The model explains the universe's acceleration without a constant Lambda.

Interaction effects are significant only during certain cosmic epochs.

Abstract

We propose a time-varying cosmological constant with a fixed equation of state, which evolves mainly through its interaction with the background during most of the long history of the universe. However, such interaction does not exist in the very early and the late-time universe and produces the acceleration during these eras when it becomes very nearly a constant. It is found that after the initial inflationary phase, the cosmological constant, that we call as lambda parameter, rolls down from a large constant value to another but very small constant value and further dominates the present epoch showing up in form of the dark energy driving the acceleration.