Quantum computing with a 2D array of Cs atom qubits*

We present recent progress on circuit model quantum computing with a 2D array of atomic qubits.   Atoms are loaded into blue-detuned optical lattices constructed from cross-hatched lines, each of a different frequency, which form optical traps, as well as other methods.  We examine and compare various methods for loading, cooling, and detecting atoms.  These techniques include creating a MOT using cooling on the second excited state transition (7p3/2), lambda grey molasses cooling, and cooling on a quadrupole line.  We also demonstrate atomic rearrangement using optical tweezers to create defect-free atomic arrays. 

The computational gate set uses microwaves for global operations, microwaves and a local Stark laser for site selected 1-qubit gates, and Rydberg interactions for 2-qubit gates. We perform CNOT gates between qubits based on Rydberg blockade using both sequential and simultaneous excitation of atoms.  We present results on gate fidelities as a function of system parameters including atom temperature, addressing beam focusing, laser noise, and choice of gate protocol.