Eur. Phys. J. C 25, 157-164 (2002)
DOI: 10.1007/s10052-002-0981-3
Cosmological evolution in compactified Horava-Witten theory induced by matter on the branes
U. EllwangerLaboratoire de Physique Théorique (Unité Mixte de Recherche - CNRS - UMR 8627) , Université de Paris XI, Bâtiment 210, 91405 Orsay Cedex, France
(Received: 8 April 2002 / Published online: 26 July 2002 )
Abstract
The combined Einstein equations and scalar equation of motion
in the
Horava-Witten scenario of the strongly coupled heterotic
string
compactified on a Calabi-Yau manifold are solved in the presence
of additional matter densities on the branes. We take into account
the
universal Calabi-Yau modulus
with potentials in the
5-
d
bulk and on the 3-branes, and allow for an arbitrary coupling
of the
additional matter to
and an arbitrary equation of state.
No
ad hoc stabilization of the five dimensional radius is assumed.
The
matter densities are assumed to be small compared to the potential
for
on the branes; in this approximation we find solutions
in the
bulk which are exact in
y and
t. Depending on the coupling
of
the
matter to
and its equation of state, various solutions
for
the metric on the branes and in the 5-
d bulk are obtained:
solutions
corresponding to a "rolling radius", and solutions with a
static 5-
d radius, which reproduce the standard cosmological
evolution.
© Società Italiana di Fisica, Springer-Verlag 2002
