Browsing by Author "Brown, KR"

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    A hybrid ion-atom trap with integrated high resolution mass spectrometer
    (Review of Scientific Instruments, 2019-10-01) Jyothi, S; Egodapitiya, KN; Bondurant, B; Jia, Z; Pretzsch, E; Chiappina, P; Shu, G; Brown, KR
    © 2019 Author(s). In this article, we describe the design, construction, and implementation of our ion-atom hybrid system incorporating a high resolution time of flight mass spectrometer (TOFMS). Potassium atoms (39K) in a magneto optical trap and laser cooled calcium ions (40Ca+) in a linear Paul trap are spatially overlapped, and the combined trap is integrated with a TOFMS for radial extraction and detection of reaction products. We also present some experimental results showing interactions between 39K+ and 39K, 40Ca+ and 39K+, as well as 40Ca+ and 39K pairs. Finally, we discuss prospects for cooling CaH+ molecular ions in the hybrid ion-atom system.
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    Error compensation of single-qubit gates in a surface-electrode ion trap using composite pulses
    (Physical Review A - Atomic, Molecular, and Optical Physics, 2015-12-16) Mount, E; Kabytayev, C; Crain, S; Harper, R; Baek, SY; Vrijsen, G; Flammia, ST; Brown, KR; Maunz, P; Kim, J
    © 2015 American Physical Society.The fidelity of laser-driven quantum logic operations on trapped ion qubits tend to be lower than microwave-driven logic operations due to the difficulty of stabilizing the driving fields at the ion location. Through stabilization of the driving optical fields and use of composite pulse sequences, we demonstrate high-fidelity single-qubit gates for the hyperfine qubit of a Yb+171 ion trapped in a microfabricated surface-electrode ion trap. Gate error is characterized using a randomized benchmarking protocol and an average error per randomized Clifford group gate of 3.6(3)×10-4 is measured. We also report experimental realization of palindromic pulse sequences that scale efficiently in sequence length.
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    Two-qubit entangling gates within arbitrarily long chains of trapped ions
    (Physical Review A, 2019-08-26) Landsman, KA; Wu, Y; Leung, PH; Zhu, D; Linke, NM; Brown, KR; Duan, L; Monroe, C
    Ion trap quantum computers are based on modulating the Coulomb interaction between atomic ion qubits using external forces. However, the spectral crowding of collective motional modes could pose a challenge to the control of such interactions for large numbers of qubits. Here, we show that high-fidelity quantum gate operations are still possible with very large trapped ion crystals by using a small and fixed number of motional modes, simplifying the scaling of ion trap quantum computers. We present analytical work that shows that gate operations need not couple to the motion of distant ions, allowing parallel entangling gates with a crosstalk error that falls off as the inverse cube of the distance between the pairs. We also experimentally demonstrate high-fidelity entangling gates on a fully connected set of seventeen Yb+171 qubits using simple laser pulse shapes that primarily couple to just a few modes.