Instead, it becomes a complex quantum state containing contributions from zero photons through arbitrarily high photon numbers. To the left of a narrow transition region, measurements give the same statistics as a normal single-photon state. Rather, observers restricted to one side of the transition region cannot distinguish the truncated state from those simpler states using local measurements. According to the University of Oslo team, the high photon-number content is concentrated in the narrow transition region created while the reflector is being removed. At the same time, the complete state requires components with arbitrarily high photon numbers, even when the reflector is removed gradually.