title: Cryogenic setup for trapped ion quantum computing.
abstract: We report on the design of a cryogenic setup for trapped ion quantum computing containing a segmented surface electrode trap. The heat shield of our cryostat is designed to attenuate alternating magnetic field noise, resulting in 120 dB reduction of 50 Hz noise along the magnetic field axis. We combine this efficient magnetic shielding with high optical access required for single ion addressing as well as for efficient state detection by placing two lenses each with numerical aperture 0.23 inside the inner heat shield. The cryostat design incorporates vibration isolation to avoid decoherence of optical qubits due to the motion of the cryostat. We measure vibrations of the cryostat of less than ±20 nm over 2 s. In addition to the cryogenic apparatus, we describe the setup required for an operation with40Ca+and88Sr+ions. The instability of the laser manipulating the optical qubits in40Ca+is characterized by yielding a minimum of its Allan deviation of 2.4 ⋅ 10-15at 0.33 s. To evaluate the performance of the apparatus, we trapped40Ca+ions, obtaining a heating rate of 2.14(16) phonons/s and a Gaussian decay of the Ramsey contrast with a 1/e-time of 18.2(8) ms.
authors.affiliation: Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25, A-6020 Innsbruck, Austria.
authors.forename: M F
authors.initials: MF
authors.lastname: Brandl
authors.affiliation: Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25, A-6020 Innsbruck, Austria.
authors.forename: M W
authors.initials: MW
authors.lastname: van Mourik
authors.affiliation: Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25, A-6020 Innsbruck, Austria.
authors.forename: L
authors.initials: L
authors.lastname: Postler
authors.affiliation: Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25, A-6020 Innsbruck, Austria.
authors.forename: A
authors.initials: A
authors.lastname: Nolf
authors.affiliation: Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25, A-6020 Innsbruck, Austria.
authors.forename: K
authors.initials: K
authors.lastname: Lakhmanskiy
authors.affiliation: Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25, A-6020 Innsbruck, Austria.
authors.forename: R R
authors.initials: RR
authors.lastname: Paiva
authors.affiliation: Department of Physics, University of California, Berkeley, California 94720, USA.
authors.forename: S
authors.initials: S
authors.lastname: Möller
authors.affiliation: Department of Physics, University of California, Berkeley, California 94720, USA.
authors.forename: N
authors.initials: N
authors.lastname: Daniilidis
authors.affiliation: Department of Physics, University of California, Berkeley, California 94720, USA.
authors.forename: H
authors.initials: H
authors.lastname: Häffner
authors.affiliation: QUANTUM, Institut für Physik, Universität Mainz, Staudingerweg 7, 55128 Mainz, Germany.
authors.forename: V
authors.initials: V
authors.lastname: Kaushal
authors.affiliation: QUANTUM, Institut für Physik, Universität Mainz, Staudingerweg 7, 55128 Mainz, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Ruster
authors.affiliation: QUANTUM, Institut für Physik, Universität Mainz, Staudingerweg 7, 55128 Mainz, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Warschburger
authors.affiliation: QUANTUM, Institut für Physik, Universität Mainz, Staudingerweg 7, 55128 Mainz, Germany.
authors.forename: H
authors.initials: H
authors.lastname: Kaufmann
authors.affiliation: QUANTUM, Institut für Physik, Universität Mainz, Staudingerweg 7, 55128 Mainz, Germany.
authors.forename: U G
authors.initials: UG
authors.lastname: Poschinger
authors.affiliation: QUANTUM, Institut für Physik, Universität Mainz, Staudingerweg 7, 55128 Mainz, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Schmidt-Kaler
authors.affiliation: Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25, A-6020 Innsbruck, Austria.
authors.forename: P
authors.initials: P
authors.lastname: Schindler
authors.affiliation: Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25, A-6020 Innsbruck, Austria.
authors.forename: T
authors.initials: T
authors.lastname: Monz
authors.affiliation: Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25, A-6020 Innsbruck, Austria.
authors.forename: R
authors.initials: R
authors.lastname: Blatt