  We compute the Szeg\"o kernels of the unit circle bundles of homogeneous
negative line bundles over a compact Hermitian symmetric space. We prove that
their logarithmic terms vanish in all cases and, further, that the circle
bundles are not diffeomorphic to the unit sphere in $\CC^n$ for Grassmannian
manifolds of higher ranks. In particular they provide an infinite family of
smoothly bounded strictly pseudo-convex domains on complex manifolds for which
the log terms in the Fefferman expansion of the Szeg\"o kernel vanish and which
are not diffeomorphic to the sphere. The analogous results for the Bergman
kernel are also obtained.
