Quintessence behavior via matter creation cosmology
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Regular Article - Theoretical Physics
Quintessence behavior via matter creation cosmology C. P. Singha , Ajay Kumarb Department of Applied Mathematics, Delhi Technological University, Bawana Road, Delhi 110 042, India
Received: 3 October 2019 / Accepted: 24 January 2020 © The Author(s) 2020
Abstract We study the matter creation cosmology as an alternative theory to explain the dark energy phenomena. We discuss the matter-dominated Universe in a flat FriedmannRobertson-Walker line element by adopting the thermodynamics of open systems, in which the matter creation irreversible processes may take place at a cosmological scale. We propose a new form of the matter creation rate, Γ = 3α H0 + 3β H + 3γ aa¨˙ , which generalizes some of the previous models in the literature. Exact solutions of the field equations are found and discussed the evolution of the Universe. Constraints on the model parameters are obtained from Markov Chain Monte Carlo (MCMC) analysis using the Supernova distance modulus data, observational measurements of Hubble parameter, Baryon acoustic oscillation data. The trajectories of the evolution of the scale factor, deceleration parameter and equation of state parameter are plotted by using best-fit values of the parameters. It is observed that the model shows accelerating behavior and behaves quintessence like (ω > −1). The age of the Universe is obtained which is in good agreement with ΛCDM model. We examine the model using two independent diagnostic parameters, namely statefinder and Om. We apply Akaike information criterion (AI C) and Bayesian information criterion (B I C) to discriminate the model based on the penalization associated to the number of parameters. The analysis shows that the model has close resemblance to the ΛC D M cosmology. We also discuss the thermodynamics of the model and find that the model satisfies the generalized second law of thermodynamics with certain constraints.
1 Introduction The observations such as Type Ia Supernovae (SNe) [1–3], Baryon Acoustic Oscillations (BAO) [4], Large Scale Struca e-mail:
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tures (LSS) [5] and Cosmic Microwave Background (CMB) [6] provide strong evidence that the Universe at present is undergoing an accelerated expansion rather than deceleration (as predicted by the standard cosmology). Since the discovery of the accelerating Universe, people are trying to explain this observational fact in two different ways - either by modifying the Einstein gravity itself or by introducing some unknown kind of matter in the framework of Einstein gravity. Most models consider accelerated expansion as due to a component of the Universe that behaves opposite to gravity, the so called dark energy(DE). The origin and nature of the DE is still unknown, though some of its properties are widely accepted, namely the fact that it has a negative pressure. Cosmological constant is the common choice for this unknown matter but it suffers the serious fine-tuning and cosmic coincidence prob
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