Universal Gate Operations on Nuclear Spin Qubits in an Optical Tweezer Array of Yb-171 Atoms

Neutral atom arrays are a rapidly developing platform for quantum science. Recently, alkaline earth atoms (AEAs) have attracted interest because their unique level structure provides several opportunities for improved performance. In this work, we present the first demonstration of a universal set of quantum gate operations on a nuclear spin qubit in an AEA, using Yb-171. We implement narrow-line cooling and imaging using a newly discovered magic trapping wavelength at lambda = 486.78 nm. We also demonstrate nuclear spin initialization, readout, and single-qubit gates and observe long coherence times [T-1 approximate to 20 s and T*(2) = 1.24(5) s] and a single-qubit operation fidelity F-1Q = 0.99959(6). We also demonstrate two-qubit entangling gates using the Rydberg blockade, as well as coherent control of these gate operations using light shifts on the Yb+ ion core transition at 369 nm. These results are a significant step toward highly coherent quantum gates in AEA tweezer arrays.