Quantum Partial Search of a Database with Several Target Items——All the target itemsare asymmetrically divided into two target block
Guo Guang-Can
By quantum Grover search algorithm,people can find a target item in a database faster than any classical algorithm.In this search algorithm the initial state is the equally weighted superposition of all basis states,which is operated by the unitary operator repeatedly.Consequently,non-target states transfer their amplitude to the target state,so we can find the target item with larger probability.However,sometimes we just want to know partial information,so we only need to find the subdatabase(a block) containing the target item,which is partial search.A partial search algorithm was suggested by Grover and Radhakrishnan,which is denoted as Grover-Radhakrishnan Algorithm of Partial Search(GRK),in which they considered the database contains one target item.In our paper,we study the database which contains several target items,and they are randomly distributed in two target blocks.Our algorithm is based on GRK.We minimize the number of queries to the oracle for blocks of large size,and compare this case with the one that each target block contains the same number of target items.
Acta Sinica Quantum Optica•Jan 1, 2008•0 citations