Universal gates based on targeted phase shifts in a 3D neutral atom   array
  Although the quality of quantum bits (qubits) and quantum gates has been steadily improving, the available quantity of qubits has increased quite slowly. To address this important issue in quantum computing, we have demonstrated arbitrary single qubit gates based on targeted phase shifts, an approach that can be applied to atom, ion or other atom-like systems. These gates are highly insensitive to addressing beam imperfections and have little crosstalk, allowing for a dramatic scaling up of qubit number. We have performed gates in series on 48 individually targeted sites in a 40% full $5\times 5\times 5$ 3D array created by an optical lattice. Using randomized benchmarking, we demonstrate an average gate fidelity of 0.9962(16), with an average crosstalk fidelity of 0.9979(2). 
Yang Wang, Aishwarya Kumar, Tsung-Yao Wu, David S. Weiss
quant-ph