  The quark gluon plasma which has been observed at RHIC is a strongly
interacting system and has been called sQGP. This is a system at high
temperatures and almost zero baryon chemical potential. A similar system with
high chemical potential and almost zero temperature may exist in the core of
compact stars. Most likely it is also a strongly interacting system. The strong
interactions may be partly due to non-perturbative effects, which survive after
the deconfinement transition and which can be related with the non-vanishing
gluon condensates in the sQGP. In this work, starting from the QCD Lagrangian
we perform a gluon field decomposition in low ("soft") and high ("hard")
momentum components, we make a mean field approximation for the hard gluons and
take the matrix elements of the soft gluon fields in the plasma. The latter are
related to the condensates of dimension two and four. With these approximations
we derive an analytical expression for the equation of state, which is compared
to the MIT bag model one. The effect of the condensates is to soften the
equation of state whereas the hard gluons significantly increase the energy
density and the pressure.
