Rapid control and measurement of clock-state qubits in Yb and Sr

The optical clock-transitions in Yb and Sr are prime candidates for encoding qubits for quantum information processing. Electric dipole one- and two- photon transitions between the long-lived 1S0 and 3P0 states are dipole and parity forbidden, respectively. Although this results in a low-decoherence rate, it also represents the main problem for fast coherent manipulation and measurement of qubits. We examine the feasibility of using a coherent, recoil-free, three-photon transition [1] for single qubit operations, a collisional interaction for two qubit operations, and ultrafast readout of the 3P0 state via photo-ionization. Rapid control and measurement of atomic qubits are crucial for high-speed synchronization of quantum information processors. Furthermore, we explore the possibility of "loophole free" tests of Bell inequalities using spatially separated entangled qubits. [1] T. Hong, C. Cramer, W. Nagourney, E. N. Fortson, Phys. Rev. Lett. 94, 050801 (2005).