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 ⁸⁷Rb atom trapped in a submicrometer-sized optical tweezer. Single-qubit rotations are performed on a time scale below 1000.3em0exns using two-photon Raman transitions. Using the spin-echo technique, we measure an irreversible dephasing time of 340.3em0exms. The readout of the single atom qubit is at the quantum projection noise limit when averaging up to 1000 individual events.