  The quarkonium formation time in a quark-gluon plasma (QGP) is determined
from the space-time correlator of heavy quark vector currents using the
quarkonium in-medium mass and wave function obtained from heavy quark
potentials extracted from the lattice QCD. It is found that the formation time
of a quarkonium increases with the temperature of the QGP and diverges near its
dissociation temperature. Also, the quarkonium formation time is longer if the
heavy quark potential is taken to be the free energy from lattice calculations
for a heavy quark pair, compared to that based on the more negative internal
energy.
