Quantum search on structured problems

This paper shows how a basic property of unitary transformations can be use d for meaningful computations. This approach immediately leads to search-ty pe applications where it improves the number of steps by a square-root; a s imple minded search that takes N steps can be improved to approximately roo t N steps. The quantum search algorithm is one of several immediate consequ ences of this framework. Several novel search-related applications are pres ented. (C) 1999 Elsevier Science Ltd. All rights reserved.