Coherent manipulation of a 40Ca+ spin qubit in a micro ion trap

We demonstrate the implementation of a spin qubit with a single Ca-40(+) ion in a micro ion trap. The qubit is encoded in the Zeeman ground state levels m(J) = +1/2 and m(J) = -1/2 of the S-1/2 state of the ion. We show sideband cooling close to the vibrational ground state and demonstrate the initialization and readout of the qubit levels with 99.5% efficiency. We employ a Raman transition close to the S-1/2-P-1/2 resonance for coherent manipulation of the qubit. We observe single qubit rotations with 96% fidelity and gate times below 5 mu s. Rabi oscillations on the blue motional sideband are used to extract the phonon number distribution. The dynamics of this distribution is analysed to deduce the trap-induced heating rate of 0.3(1) phonons ms(-1).