Relativized separation of EQP from PNP

Abstract An oracle is constructed relative to which quantum polynomial time ( EQP ) is not polynomial-time Turing reducible to NP . That is, there is an A such that EQP A ⊈ P NP A . This generalizes and simplifies previous separations of EQP from NP and ZPP , due to Berthiaume and Brassard. A key element of the proof is the use of a special property of Grover's algorithm for database search, in order to show that the test language is in EQP A .