22 research outputs found
Exact solution and exotic fluid in cosmology
We investigate cosmological consequences of nonlinear sigma model coupled
with a cosmological fluid which satisfies the continuity equation. The target
space action is of de Sitter type and is composed of four scalar fields. The
potential which is a function of only one of the scalar fields is also
introduced. We perform a general analysis of the ensuing cosmological equations
and give various critical points and their properties. Then, we show that the
model exhibits exact cosmological solution which yields a transition from
matter domination into dark energy and compare it with the CDM
behavior. Especially, we calculate the age of the Universe and show that it is
consistent with the observational value if the equation of the state
for the cosmological fluid is within the range of
Some implication of this result is also discussed.Comment: 13 pages, 1 table, 1 figure, published versio