Dynamical System Analysis of Dark Energy Models

Chakraborty, Abhijit (2017) Dynamical System Analysis of Dark Energy Models. Masters thesis, Indian Institute of Science Education and Research Kolkata.

PDF (MS dissertation of Abhijit Chakraborty (12MS079)) 12MS079.pdf - Submitted Version Restricted to Repository staff only Download (834kB)

Abstract

The thesis is divided into two parts. The main aim of this thesis is to carry out dynamical system stability analysis for two dark energy models: Quintessence and K-essence. Quintessence models can be categorised into two types: Tracking and Thawing. Tracking model suggests that the equation of state parameter is gradually decreasing and approaching the value -1. Thawing model states that the equation of state parameter is gradually increasing from -1 following a slow rolling potential. For the first part of this thesis, the focus is on finding the preferable model between tracking and thawing models using stability analysis. The second part focuses on the stability analysis of another model, K-essence. In K-essence, the kinetic part is non-canonical. The Lagrangian for the K-essence model discussed in this thesis is a second order polynomial of X = ½ ϕ² with co-efficients taken as the functions of the scalar field. The stable solutions for this system are investigated and the conditions on the coefficients of the polynomial are determined.

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