We characterize single qubit Clifford gate operations with randomized benchmarking in a 2D array of neutral atom qubits, and demonstrate global and site selected gates with high fidelity. An average fidelity of F 2 = 0.9983( 14) is measured for global microwave driven gates applied to a 49 qubit array. Single site gates are implemented with a focused laser beam to Stark shift the microwaves into resonance at a selected site. At Stark selected single sites we observe F 2 = 0.9923(7) and an average spin flip crosstalk error at other sites of 0.002(9).

We present experimental results on two-qubit Rydberg blockade quantum gates and entanglement in a two-dimensional qubit array. Without post selection against atom loss we achieve a Bell state fidelity of 0.73±0.05, the highest value reported to date. The experiments are performed in an array of single Cs atom qubits with a site to site spacing of 3.8 µm. Using the standard protocol for a Rydberg blockade CZ gate together with single qubit operations we create Bell states and measure their fidelity using parity oscillations. We analyze the role of AC Stark shifts that occur when using two-photon Rydberg excitation and show how to tune experimental conditions for optimal gate fidelity.

We describe a new type of blue detuned optical lattice for atom trapping which is intrinsically two dimensional, while providing three-dimensional atom localization. The lattice is insensitive to optical phase fluctuations since it does not depend on field interference between distinct optical beams. The array is created using a novel arrangement of weakly overlapping Gaussian beams that creates a two-dimensional array of dark traps which are suitable for magic trapping of ground and Rydberg states. We analyze the spatial localization that can be achieved and demonstrate trapping and detection of single Cs atoms in 6 and 49 site two-dimensional arrays.

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We present the direct measurements of electric-dipole moments for 5P 3/2 → nD 5/2 transitions with 20 < n < 48 for Rubidium atoms. The measurements were performed in an ultracold sample via observation of the Autler-Townes splitting in a three-level ladder scheme, commonly used for 2-photon excitation of Rydberg states. To the best of our knowledge, this is the first systematic measurement of the electric dipole moments for transitions from low excited states of rubidium to Rydberg states. Due to its simplicity and versatility, this method can be easily extended to other transitions and other atomic species with little constraints. Good agreement of the experimental results with theory proves the reliability of the measurement method.

Absolute total cross sections (TCSs) for electron scattering from boron trifluoride (BF(3)) and phosphorus trifluoride (PF(3)) molecules have been measured using a linear transmission method. The electron energy ranges from 0.6 to 370 eV for BF(3) and from 0.5 to 370 eV for PF(3). The TCS energy dependence for BF(3) exhibits two very pronounced enhancements: resonantlike narrow feature located near 3.6 eV with the maximum value of 19.2 x 10(-20) m(2), and intermediate energy very broad enhancement with two humps, one centered around 21 eV (18.8 x 10(-20) m(2) in the maximum) and the other near 45 eV (19.5 x 10(-20) m(2)). For PF(3) the TCS has quite different low-energy dependence: at 0.5 eV it has a high value of 70 x 10(-20) m(2) and decreases steeply towards higher energies. Beyond the minimum near 5.5 eV, the TCS reveals two distinct humps: the resonant one centered near 11 eV with the peak value of 32.9 x 10(-20) m(2) and the second one much broader around 35 eV (27.9 x 10(-20) m(2)). The present TCSs for trifluorides are compared to each other as well as to previous TCS data for selected perfluorides and to results for their perhydrided counterparts. The differences and similarities in the shape and magnitude of TCSs are pointed out.

We study the fidelity of single qubit quantum gates performed with two-frequency laser fields that have a Gaussian or super Gaussian spatial mode. Numerical simulations are used to account for imperfections arising from atomic motion in an optical trap, spatially varying Stark shifts of the trapping and control beams, and transverse and axial misalignment of the control beams. Numerical results that account for the three dimensional distribution of control light show that a super Gaussian mode with intensity I ∼ e −2(r/w0) n provides reduced sensitivity to atomic motion and beam misalignment. Choosing a super Gaussian with n = 6 the decay time of finite temperature Rabi oscillations can be increased by a factor of 60 compared to an n = 2 Gaussian beam, while reducing crosstalk to neighboring qubit sites.

An absolute total cross section (TCS) for electron scattering from phosphine (PH 3 ) molecules was obtained in a linear transmission experiment at energies ranging from low (0.5 eV) to intermediate (370 eV). The dominant behaviour of the TCS energy function is a very pronounced low-energy enhancement with two distinct resonant-like humps peaked at around 2.4 and 6 eV. Above 10 eV the TCS is a rather featureless, monotonically decreasing function of energy. Our experimental results are compared with the theoretical predictions and intermediate-energy measurements. The similarities and differences of experimental TCS data for isoelectronic hydrides containing third-period atoms (SiH 4 , PH 3 , H 2 S and HCl) are also pointed out and discussed.