EVOLUSI DARK ENERGY DENGAN POTENSIAL L-MODEL ?-ATTRACTOR

• Main Author: Taqiaturrahmah, Aulia
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/42954
• Institution: Institut Teknologi Bandung

Edwin Hubble's observation of the relation between the redshift and the distance of nearby galaxies shows that the universe is expanding. Furthermore, the observation of Supernova Ia on higher redshift shows that the expanding universe is accelerated as well. Various theories are put forward to explain this fact. One theory proposes a new entity besides matter and radiation, which is called dark energy. Various dark energy theories have been proposed. The simplest dark energy model is cosmological constant, which is vacuum energy that opposes the attractive force of gravity. However, there are two problems with this model, namely the energy scale problem and the matter-dark energy density equality problem that has been occurring near to the present. Another dark energy model is the scalar field. The scalar field is proposed to alleviate the cosmological constant problems, involving parameters that evolve with time. The scalar field has tracker properties driving its evolution converge towards present value following recent observations. However, there is a limitation in the range of initial values (basin of attraction) of the scalar field model, which enable a wide range of initial condition to evolve convergently towards the present value. A wide basin of attraction is preferred to reach the present value of dark energy parameters from different initial conditions. This Final Project discusses one scalar field model, namely ?-attractor. A compelling feature of ?-attractor is that they have a very wide basin of attraction. The evolution of L-model, which is an ?-attractor family of potentials, is derived analytically from cosmic dynamics equations. These dynamic equations lead to study L-model ?-attractor evolution throughout the age of the universe. As the results, this Final Project shows the equation of state of L-model ?-attractor plotted against the cosmic time.