The horizon area and curvature of three-charge BPS black strings are studied
in the D-brane ensemble for the stationary black string. The charge
distributions along the string are used to translate the classical expressions
for the horizon area and curvature of BPS black strings with waves into
operators on the D-brane Hilbert space. Despite the fact that any `wavy' black
string has smaller horizon area and divergent curvature, the typical values of
the horizon area and effects of the horizon curvature in the D-brane ensemble
deviate negligibly from those of the original stationary black string in the
limit of large integer charges. Whether this holds in general will depend on
certain properties of the quantum bound states.Comment: 13 pages, RevTex, small errors corrected, some interpretation changed
in light of new result
