Technical Report No Quantum computing Beyond the limits of conventional computation

The quantum model of computation not only o ers entirely new ways to manipulate information but also allows information process ing tasks to be formulated in unconventional genuine quantum me chanical terms We show that the task of distinguishing among en tangled quantum states combines entanglement and non determinism in a way that makes the quantum solution impossible to simulate on any classical machine even one equipped with the same measurement capabilities as the quantum computational device A new class of information processing tasks is thus uncovered whose members are readily carried out by a quantum computer yet are impossible to per form on any classical machine whether deterministic or probabilistic In the broad unconventional context created by quantum mechanics the computational power of a quantum computer is therefore strictly greater than that of a classical computer This research was supported by the Natural Sciences and Engineering Research Coun