  We present tentative evidence for primordial clustering, manifested as an
excess of color-selected objects in the field of the QSO SDSS J1030+0524 at
redshift z=6.28. We have selected objects red in i_{775}-z_{850} on the basis
of Hubble Space Telescope Advanced Camera for Surveys imaging of a field
centered on the QSO. Compared to data at comparable depth obtained by the GOODS
survey, we find an excess of objects with (i_{775}-z_{850}) \geq 1.5 in the QSO
field. The significance of the detection is estimated to be ~97% on the basis
of the counts alone and increases to 99.4% if one takes into account the color
distribution. If confirmed this would represent the highest redshift example of
galaxy clustering and would have implications on models for the growth of
structure. Bias-driven clustering of first luminous objects forming in the
highest peaks of the primordial density field is expected in most models of
early structure formation. The redshift of one of the candidates has been found
to be z=5.970 by our spectroscopy with Keck I/LRIS, confirming the validity of
our color selection.
