Fast quantum state control of a single trapped neutral atom

We demonstrate the initialization, readout, and high-speed manipulation of a qubit stored in a single Rb-87 atom trapped in a submicrometer-sized optical tweezer. Single-qubit rotations are performed on a time scale below 100 ns using two-photon Raman transitions. Using the spin-echo technique, we measure an irreversible dephasing time of 34 ms. The readout of the single atom qubit is at the quantum projection noise limit when averaging up to 1000 individual events.