title: Long-lived qubit memory using atomic ions.
abstract: We demonstrate experimentally a robust quantum memory using a magnetic-field-independent hyperfine transition in 9Be+ atomic ion qubits at a magnetic field B approximately = 0.01194 T. We observe that the single physical qubit memory coherence time is greater than 10 s, an improvement of approximately 5 orders of magnitude from previous experiments with 9Be+. We also observe long coherence times of decoherence-free subspace logical qubits comprising two entangled physical qubits and discuss the merits of each type of qubit.
authors.affiliation: National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA. clanger@boulder.nist.gov
authors.forename: C
authors.initials: C
authors.lastname: Langer
authors.forename: R
authors.initials: R
authors.lastname: Ozeri
authors.forename: J D
authors.initials: JD
authors.lastname: Jost
authors.forename: J
authors.initials: J
authors.lastname: Chiaverini
authors.forename: B
authors.initials: B
authors.lastname: Demarco
authors.forename: A
authors.initials: A
authors.lastname: Ben-Kish
authors.forename: R B
authors.initials: RB
authors.lastname: Blakestad
authors.forename: J
authors.initials: J
authors.lastname: Britton
authors.forename: D B
authors.initials: DB
authors.lastname: Hume
authors.forename: W M
authors.initials: WM
authors.lastname: Itano
authors.forename: D
authors.initials: D
authors.lastname: Leibfried
authors.forename: R
authors.initials: R
authors.lastname: Reichle
authors.forename: T
authors.initials: T
authors.lastname: Rosenband
authors.forename: T
authors.initials: T
authors.lastname: Schaetz
authors.forename: P O
authors.initials: PO
authors.lastname: Schmidt
authors.forename: D J
authors.initials: DJ
authors.lastname: Wineland