  A new method to compute correlation functions in AdS$_{d+1}$ in general
dimension is introduced, considering a particle quantised in the worldline
formalism of quantum field theory, coupled to bulk fields, in particular
gravity, quantised in the standard manner. This gives a systematic
two-parameter perturbative expansion organised by small parameters $G_N$ and
the inverse mass of the particle, complementary to the usual Witten diagram
expansion. This connects closely to CFT language, with the geodesic Witten
diagram representation of global conformal blocks emerging naturally, and for
two dimensions gives a bulk representation of the Virasoro block, with a
systematic method for computing quantum corrections. The global conformal block
and other contributions are shown to exponentiate in correlation functions in
any dimension, corresponding to pieces of Witten diagrams at arbitrary loop
order.
