A quantum no-reflection theorem and the speeding up of Grover's search algorithm
Low Temperature Laboratory, Aalto University - P.O. Box 15100, FI-00076 Aalto, Finland, EU
Accepted: 10 January 2011
We prove that it is impossible to built a universal quantum machine that produces reflections about an unknown state. We then point out a connection between this result and the optimality of Grover's search algorithm: if such reflection machines were available, it would be possible to accelerate Grover's search algorithm to exponential speedups.
PACS: 03.67.Ac – Quantum algorithms, protocols, and simulations
© EPLA, 2011