  The heavy-quark potential is calculated in the framework of gauge/gravity
duality using the large-D approximation, where D is the number of dimensions
transverse to the flux tube connecting a quark and an antiquark in a flat
D+2-dimensional spacetime. We find that in the large-D limit the leading
correction to the ground-state energy, as given by an effective Nambu-Goto
string, arises not from the heavy modes but from the behavior of the massless
modes in the vicinity of the quark and the antiquark. We estimate this
correction and find that it should be visible in the near-future lattice QCD
calculations of the heavy-quark potential.
