How one shutter can close N slits -: art. no. 042107

It is shown that a quantum shutter, preselected and postselected in particular quantum states, can close simultaneously arbitrary number of slits preventing the passage of a single photon in an arbitrary state. A set of K preselected and postselected shutters can close the slits preventing the passage of K or less photons. This result indicates that the surprising properties of preselected and postselected quantum systems are even more robust than previously expected.