Fast quantum state control of a single trapped neutral atom

Abstract

We demonstrate the initialization, readout, and high-speed manipulation of a qubit stored in a single $^{87}\mathrm{Rb}$ atom trapped in a submicrometer-sized optical tweezer. Single-qubit rotations are performed on a time scale below $100\phantom{\rule{0.3em}{0ex}}\mathrm{ns}$ using two-photon Raman transitions. Using the spin-echo technique, we measure an irreversible dephasing time of $34\phantom{\rule{0.3em}{0ex}}\mathrm{ms}$. The readout of the single atom qubit is at the quantum projection noise limit when averaging up to 1000 individual events.