Quantum search on structured problems

This paper shows how a basic property of unitary transformations can be used for meaningful computations. This approach immediately leads to search-type applications where it improves the number of steps by a square-root; a simple minded search that takes N steps can be improved to approximately root N steps. The quantum search algorithm is one of several immediate consequences of this framework. Several novel search-related applications are presented. (C) 1999 Elsevier Science Ltd. All rights reserved.