Quantum-state tomography of a single nuclear spin qubit of an optically manipulated ytterbium atom
Atsushi Noguchi, Yujiro Eto, Masahito Ueda, Mikio Kozuma · Physical Review A · 2011
A single Yb atom is loaded into a high-finesse optical cavity with a moving lattice, and its nuclear spin state is manipulated using a nuclear magnetic resonance technique. A highly reliable quantum state control with fidelity and purity greater than 0.98 and 0.96, respectively, is confirmed by the full quantum state tomography; a projective measurement with high speed $(500\phantom{\rule{4pt}{0ex}}\ensuremath{\mu}\mathrm{s})$ and high efficiency $(0.98)$ is accomplished using the cavity QED technique. Because a hyperfine coupling is induced only when the projective measurement is operational, the long coherence times (${T}_{1}=0.49$ s and ${T}_{2}=0.10$ s) are maintained.