Figure 1:
(Top) Dizzy Dean throws curveballs made of ordinary unentangled single baseballs (photons) at a target, and his probability of hitting the bull’s eye improves only as 1/√N, where N=4 is the number of balls thrown. (Bottom) Here Dean throws a single quantum ball composed of N=2 photons in a spatially entangled N00N state, and with a little postprocessing carried out by a computer at the target, the chances of hitting the bull’s eye now scales like 1/N.