  Light-front holography is a remarkable feature of the AdS/CFT correspondence
between gravity in AdS space and conformal field theories in physical
space-time; it allows string modes $\Phi(z)$ in the anti-de Sitter (AdS) fifth
dimension to be precisely mapped to the light-front wavefunctions of hadrons in
physical space-time in terms of a specific light-front impact variable $\zeta$
which measures the separation of the quark and gluonic constituents within the
hadron. This mapping was originally obtained by matching the exact expression
for electromagnetic current matrix elements in AdS space with the corresponding
exact expression for the current matrix element using light-front theory in
physical space-time. In this paper we show that one obtains the identical
holographic mapping using matrix elements of the energy-momentum tensor. To
prove this, we show that there exists a correspondence between the matrix
elements of the energy-momentum tensor of the fundamental hadronic constituents
in QCD with the transition amplitudes describing the interaction of string
modes in AdS space with an external graviton field which propagates in the AdS
interior. The agreement of the results for electromagnetic and gravitational
hadronic transition amplitudes provides an important consistency test and
verification of holographic mapping from AdS to physical observables defined on
the light-front.
