We generalize the results of Montgomery for the Bochner Laplacian on high
tensor powers of a line bundle. When specialized to Riemann surfaces, this
leads to the Bergman kernel expansion and geometric quantization results for
semi-positive line bundles whose curvature vanishes at finite order. The proof
exploits the relation of the Bochner Laplacian on tensor powers with the
sub-Riemannian (sR) Laplacian