Precision characterization of the D 5 / 2 2 state and the quadratic Zeeman coefficient in Yb + 171

We report measurements of the branching fraction, hyperfine constant, and second-order Zeeman coefficient of the ${D}_{5/2}$ level in $^{171}\\mathrm{Yb}^{+}$ with up to a two-orders-of-magnitude reduction in uncertainty compared to previously reported values. We estimate the electric quadrupole reduced matrix element of the ${S}_{1/2}\\phantom{\\rule{4pt}{0ex}}\\ensuremath{\\leftrightarrow}\\phantom{\\rule{4pt}{0ex}}{D}_{5/2}$ transition to be 12.5(4) $e{a}_{0}^{2}$. Furthermore, we determine the transition frequency of the ${F}_{7/2}\\phantom{\\rule{4pt}{0ex}}\\ensuremath{\\leftrightarrow}{\\phantom{\\rule{4pt}{0ex}}}^{1}D{[3/2]}_{3/2}$ at 760 nm with a $\\ensuremath{\\sim}$25-fold improvement in uncertainty. These measurements provide benchmarks for quantum-many-body atomic-physics calculations and provide valuable data for efforts to improve quantum information processors based on ${}^{171}{\\text{Yb}}^{+}$.