  We describe a quantum scheme to ``color-code'' a set of objects in order to
record which one is which. In the classical case, N distinct colors are
required to color-code N objects. We show that in the quantum case, only N/e
distinct ``colors'' are required, where e = 2.71828 . . . If the number of
colors is less than optimal, the objects may still be correctly distinguished
with some success probability less than 1. We show that the success probability
of the quantum scheme is better than the corresponding classical one and is
information-theoretically optimal.
