Physical cosmology includes the scientific study of the origin, evolution and dynamics of the
universe. Due to impressive progress both on the theoretical and observational side, scientists
are able to resolve many of the puzzles of the universe. Nevertheless, many questions are not
answered completely. For instance, "What are the constituents of the universe?" and "How
does the dynamics of the universe evolve?" The curiosity to get convincing answers to these
questions, motivates one to work in this field.
According to the hot Big Bang model, the universe started from a bang and its properties change with
time. The discovery of the Cosmic Microwave Background Radiation (CMBR) by Penzias
and Wilson in 1965 was important in making the Big Bang model the accepted model of
the universe [5]. A landmark discovery in 1998 by two groups working independently on
Supernovae Ia was instrumental in changing the way we understand our universe. They
found that the expansion of the universe is accelerating [6, 7].
To explain the accelerated expansion of the universe, various models have been proposed. The
most widely accepted one is the Lambda Cold Dark Matter (ΛCDM) model [8]. According
to this model, the universe is flat and is expanding at an accelerated rate. It is composed of
baryonic matter, dark matter and dark energy. Dark energy is the name given to the cause
of the cosmic acceleration.
