Effect of Dynamical Cosmological Constant in presence of Modified Chaplygin Gas for Accelerating Universe

TL;DR

This paper investigates how a time-dependent cosmological constant and gravitational constant, combined with Modified Chaplygin Gas, influence the accelerated expansion and evolution of the Universe across different epochs.

Contribution

It introduces phenomenological models for a dynamic cosmological constant and analyzes their effects on cosmic acceleration and evolution using statefinder diagnostics.

Findings

Models show accelerated expansion at present epoch

G and Lambda vary over the Universe's age

Evolution from radiation era to Lambda-CDM depicted

Abstract

In this paper we have considered the Universe to be filled with Modified Gas and the Cosmological Constant $\Lambda$ to be time-dependent with or without the Gravitational Constant $G$ to be time-dependent. We have considered various phenomenological models for $\Lambda$, viz., $\Lambda\propto\rho, \Lambda\propto\frac{\dot{a}^{2}}{a^{2}}$ and $\Lambda\propto\frac{\ddot{a}}{a}$. Using these models it is possible to show the accelerated expansion of the Universe at the present epoch. Also we have shown the natures of $G$ and $\Lambda$ over the total age of the Universe. Using the statefinder parameters we have shown the diagramamtical representation of the evolution of the Universe starting from radiation era to $\Lambda$CDM model.