47th Annual IEEE Symposium on Foundations of Computer Science
Event
FOCS2006, 47th Annual IEEE Symposium on Foundations of Computer Science, Berkeley, CA
Pages (from-to)
411-419
Organisations
Faculty of Science (FNWI) - Korteweg-de Vries Institute for Mathematics (KdVI)
Interfacultary Research - Institute for Logic, Language and Computation (ILLC)
Abstract
We show that quantum circuits cannot be made fault-tolerant against a depolarizing noise level of approximately 45%, thereby improving on a previous bound of 50% (due to Razborov). Our precise quantum circuit model enables perfect gates from the Clifford group (CNOT, Hadamard, S, X, Y, Z) and arbitrary additional one-qubit gates that are subject to that much depolarizing noise. We prove that this set of gates cannot be universal for arbitrary (even classical) computation, from which the upper bound on the noise threshold for fault-tolerant quantum computation follows.