Light-Front Dynamics and AdS/QCD Correspondence: Gravitational Form Factors of Composite Hadrons

TL;DR

This paper demonstrates that the holographic mapping between AdS space and light-front QCD, originally established via electromagnetic currents, can also be derived using energy-momentum tensor matrix elements, confirming the consistency of the approach.

Contribution

It shows that the holographic mapping in AdS/QCD can be derived from energy-momentum tensor matrix elements, providing a new consistency check for the correspondence.

Findings

Electromagnetic and gravitational transition amplitudes agree in the holographic framework.

The energy-momentum tensor matrix elements correspond to string mode interactions with gravitons.

The results confirm the robustness of light-front holography in describing hadronic structure.

Abstract

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.