  We report the first experimental realization of single-qubit manipulation for
single spinwaves stored in an atomic ensemble quantum memory. In order to have
high-fidelity gate operations, we make use of stimulated Raman transition and
controlled Lamor precession jointly. We characterize the gate performances with
quantum state tomography and quantum process tomography, both of which imply
that high-fidelity operations have been achieved. Our work complements the
experimental toolbox of atomic-ensemble quantum memories by adding the
capability of single-qubit manipulation, thus may have important applications
in future scalable quantum networks.

Quantum Physics