Ultrafast Spin-Motion Entanglement and Interferometry with a Single Atom
Jonathan Mizrahi, Crystal Senko, Brian Neyenhuis, K. G. Johnson, Wesley C. Campbell, C. W. S. Conover, Christopher R. Monroe · Physical Review Letters · 2013
We report entanglement of a single atom's hyperfine spin state with its motional state in a time scale of less than 3 ns. We engineer a short train of intense laser pulses to impart a spin-dependent momentum transfer of ± 2 ħk. Using pairs of momentum kicks, we create an atomic interferometer and demonstrate collapse and revival of spin coherence as the motional wave packet is split and recombined. The revival after a pair of kicks occurs only when the second kick is delayed by an integer multiple of the harmonic trap period, a signature of entanglement and disentanglement of the spin with the motion. Such quantum control opens a new regime of ultrafast entanglement in atomic qubits.