Viscous Dark Energy Models with Variable G and Lambda

TL;DR

This paper explores a cosmological model with bulk viscosity and variable cosmological and gravitational constants, showing inflation driven by viscosity and dark energy without a fixed equation of state, and suggesting matter creation during inflation.

Contribution

It introduces a novel cosmological model with variable G and Lambda, demonstrating inflation driven by viscosity and matter creation without standard dark energy assumptions.

Findings

Inflation driven by bulk viscosity without $p=-\rho$

Exponential increase of G and Lambda over time

Mass creation during inflation is significant

Abstract

We consider a cosmological model with bulk viscosity ($\eta$) and variable cosmological $(\Lambda\propto \rho^{-\alpha}, \alpha=\rm const.$) and gravitational ($G$) constants. The model exhibits many interesting cosmological features. Inflation proceeds du to the presence of bulk viscosity and dark energy without requiring the equation of state $p=-\rho$. During the inflationary era the energy density ($\rho$) does not remain constant, as in the de-Sitter type. Moreover, the cosmological and gravitational constants increase exponentially with time, whereas the energy density and viscosity decrease exponentially with time. The rate of mass creation during inflation is found to be very huge suggesting that all matter in the universe was created during inflation.