  In this paper, we investigate Casimir effect, Weyl anomaly and displacement
operator for boundary conformal field theory in general dimensions. We find
universal relations between them. In particular, they are all determined by the
central charge of boundary conformal field theory. We verify these relations by
studying free BCFTs and holographic BCFTs. As a byproduct, we obtain the
holographic two point function of stress tensor when the bulk boundary is
perpendicular to the AdS boundary.
