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

Rapid control and measurement of clock-state qubits in Yb and Sr N. S. Babcock, R. Stock, B. C. Sanders Institute for Quantum Information Science, University of Calgary, Alberta 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 1S0 and 3P0 states are dipole and parity forbidden, respectively, resulting in extremely low decoherence rates for qubits stored using these states. To perform single-qubit operations, we propose a coherent, recoil-free, three-photon transition [1]. Single Yb or Sr atoms are stored in spatially-separated optical microtraps created by strongly focused laser beams. An entangling operation can be achieved via the collisional interaction between atoms as a pair of traps are brought together and separated adiabatically. Precise operation timing and symmetrization requirements ensure high gate fidelity. Qubit measurements are performed using fast readout of the 3P0 state via photo-ionization. The rapid control and measurement we describe are crucial for high-speed synchronization of atom-based quantum infor mation 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).