  Quantum chromodynamics (QCD) predicts the existence of both nonperturbative
intrinsic and perturbative extrinsic heavy quark contributions to the
fundamental structure of hadrons. The existence of intrinsic charm at the
3-standard-deviation level in the proton has recently been established from
structure function measurements by the NNPDF Collaboration. Here we revisit the
physics of intrinsic heavy quarks using light-front holographic QCD (LFHQCD) -
a novel comprehensive approach to hadron structure which provides detailed
predictions for dynamical properties of the hadrons, such as form factors,
distribution amplitudes, structure functions, etc. We will extend this
nonperturbative light-front QCD approach to study the heavy quark-antiquark
contribution to the electromagnetic properties of nucleon. Our framework is
based on a study of the eigenfunctions of the QCD light-front Hamiltonian, the
frame-independent light-front wave functions (LFWFs) underlying hadron
dynamics. We analyze the heavy quark content in the proton, induced either
directly by the nonperturbative $|uud+Q\bar Q\rangle$ Fock state or by the
$|uud+g\rangle$ Fock state, where the gluon splits into a heavy quark-antiquark
pair. The specific form of these LFWFs are derived from LFHQCD. Using these
LFWFs, we construct light-front representations for the heavy quark-antiquark
asymmetry, the electromagnetic form factors of nucleons induced by heavy
quarks, including their magnetic moments and radii.
