title: High-fidelity gates in a single josephson qubit.
abstract: We demonstrate new experimental procedures for measuring small errors in a superconducting quantum bit (qubit). By carefully separating out gate and measurement errors, we construct a complete error budget and demonstrate single qubit gate fidelities of 0.98, limited by energy relaxation. We also introduce a new metrology tool-- Ramsey interference error filter-that can measure the occupation probability of the state |2> which is outside the computational basis, down to 10{-4}, thereby confirming that our quantum system stays within the qubit manifold during single qubit logic operations.
authors.affiliation: Department of Physics, University of California at Santa Barbara, Broida Hall, Santa Barbara, California 93106, USA.
authors.forename: Erik
authors.initials: E
authors.lastname: Lucero
authors.forename: M
authors.initials: M
authors.lastname: Hofheinz
authors.forename: M
authors.initials: M
authors.lastname: Ansmann
authors.forename: Radoslaw C
authors.initials: RC
authors.lastname: Bialczak
authors.forename: N
authors.initials: N
authors.lastname: Katz
authors.forename: Matthew
authors.initials: M
authors.lastname: Neeley
authors.forename: A D
authors.initials: AD
authors.lastname: O'Connell
authors.forename: H
authors.initials: H
authors.lastname: Wang
authors.forename: A N
authors.initials: AN
authors.lastname: Cleland
authors.forename: John M
authors.initials: JM
authors.lastname: Martinis