On the Reconstruction of Dark Energy Models

Mukherjee, Ankan (2017) On the Reconstruction of Dark Energy Models. PhD thesis, Indian Institute of Science Education and Research Kolkata.

PDF (PhD thesis of Ankan Mukherjee (10IP10)) thesis_ANKAN.pdf - Submitted Version Restricted to Repository staff only Download (4MB)

Abstract

The present work, which has been discussed in the following chapters, is devoted to the reconstruction of the dark energy models using diverse observational data sets. The parametric approach has been adopted for the reconstruction of cosmological models. The reconstruction of kinematical quantities and the possibility of interaction between dark energy and dark matter has also been emphasised. In first chapter, a brief introduction to cosmology has been presented. In the second chapter, a reconstruction of the dark energy equation of state parameter for a quintessence scalar field model has been discussed. The nature of evolution of the relevant cosmological parameters and the quintessence potential has also been studied for the reconstructed model. In the third chapter, a parametric reconstruction of the effective or total equation of state has been discussed. The reconstructed model mimics the LCDM model for a particular value of the model parameter, thus the reconstruction indicates the consistency or deviation form LCDM. A comparative study of the reconstructed model and the wCDM model has been done by representing both the models on the same parameter space. It has been shown that the reconstructed model ensures tighter constraints on the kinematic quantities like the deceleration parameter and the jerk parameter. In the fourth chapter, a kinematic approach in the reconstruction of dark energy model through the parametrization of the cosmological jerk parameter has been discussed. Four different parametric form of the jerk parameter have been studied. The evolution of the deceleration parameter, dark energy equation of state and also the nature of associated quintessence potential have been studied for these models. The fifth chapter is also about a kinematic approach to the reconstruction of dark energy. The reconstruction has been done with an assumption that the jerk parameter is a very slowly varying function. This model invokes the possibility of interaction between dark matter and the dark energy. The interaction term has also been reconstructed and it shows that the possibility of interaction is high in the past, but it is very small at the present time. The sixth chapter is devoted to the reconstruction of the interaction rate in holographic dark energy model. The interaction rate has been reconstructed for three different parametrization of the deceleration parameter. The evolution of the interaction rate, the nature of dark energy equation of state parameter etc. have been studied. The cosmic coincidence problem has also been addressed in the context of holographic dark energy. Finally, chapter seven contains the concluding remarks and relevant discussions regarding the overall work presented in the thesis.

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