  In a manner of Cornwal-Jackiw-Tomboulis effective action approach, the
density of condensate of a dilute Bose gas confined between two planar walls is
investigated within the framework of improved Hartree-Fock. Thereby, the
quantum fluctuations are taken into account with presence of high-order terms
in the momentum integrals. Our results show that the quantum fluctuations
significantly belittle the density of condensate compared with square of the
expectation value of the field operator. The comparison with relating results
of Gross-Pitaevskii theory is made.
