  The correlation function in Ads/CFT are correlation of the operator
insertions on the boundary (at CFT) through the complete geometry of bulk.
These are represented by Witten diagrams which at tree level doesn't have any
quantum corrections. Generally, correlation functions are of low scaling (or
conformal) dimension, $\Delta$, which is related to the mass of insertion of
the scalar operator by, $\Delta(\Delta - 1) = m^2 L_{AdS}^2$. At low scaling
dimensions the operator insertion on the CFT boundary does not back-react the
metric of the geometry. On the other hand, at large scaling dimensions which
scale with central charge the operator is considered heavy. This leads to an
interesting question of what in the dual bulk (AdS) geometry of such heavy
operators. At the heavy limit $\Delta = m L_{AdS}$, which means that the mass
of the operator insertion is large too. The two-point function of
heavy-operator is assumed to be Black hole in $(d+1)$-dimensions and the
two-point form of CFT is recovered by calculating the action. In $3$-dimension
we have more control over the geometry because of existence of exact metric
called Ba\~nados metric with boundary stress-tensor insertion along with a map
which maps it to Euclidean Poincare upper half plane. These methods are used to
find the geometry for three-point function. The geometry is not simply of a
black-hole but a wormhole solution for whose action is calculated which
recovers the "square" of the classical DOZZ formula. We review the recent work
of arXiv:2306.15105 and arXiv:2307.13188 in this thesis to form an
understanding of heavy operators in the context of AdS/CFT.
