Assembly and coherent control of a register of nuclear spin qubits

We introduce an optical tweezer platform for assembling and individually manipulating a two-dimensional register of nuclear spin qubits. Each nuclear spin qubit is encoded in the ground \(^{1}S_{0}\) manifold of \(^{87}\)Sr and is individually manipulated by site-selective addressing beams. We observe that spin relaxation is negligible after 5 seconds, indicating that \(T_1\gg5\) s. Furthermore, utilizing simultaneous manipulation of subsets of qubits, we demonstrate significant phase coherence over the entire register, estimating \(T_2^\star = \left(21\pm7\right)\) s and measuring \(T_2^\text{echo}=\left(42\pm6\right)\) s.