  Traditional idea of Pomeron/Reggeon description for hadron scattering is now
being given theoretical foundation in gravity dual descriptions, where Pomeron
corresponds to exchange of spin-j\in 2Z states in the graviton trajectory.
Deeply virtual compton scattering (DVCS) is essentially a 2 to 2 scattering
process of a hadron and a photon, and hence one should be able to study
non-perturbative aspects (GPD) of this process by the "Pomeron" process in
gravity dual. We find, however, that even the most developed formulation of
gravity dual Pomeron (Brower--Polchinski--Strassler--Tan (BPST) 2006) is not
able to capture skewness dependence of GPD properly. Conformal operator product
expansion allows us to determine DVCS amplitude in terms of matrix elements of
primary operators, which should then be given by wavefunctions on warped
spacetime. We determined all the necessary wavefunctions on AdS$_5$ as an
expression holomorphic in $j$, which will then be used (in our forthcoming
publication) to determine GPD through inverse Mellin transformation. This
approach will extend the formulation of BPST.
