Quantized AC-Stark shifts and their use for multiparticle entanglement and quantum gatesF. Schmidt-Kaler, H. Häffner, S. Gulde, M. Riebe, G. Lancaster, J. Eschner, C. Becher and R. Blatt
Institut für Experimentalphysik - 6020 Innsbruck, Austria
(Received 5 September 2003; accepted 18 December 2003)
A single -ion is trapped and laser-cooled to its motional ground state. Laser radiation which couples off-resonantly to a motional sideband of the ion's S1/2 to D5/2 transition causes a phase shift proportional to the ion's motional quantum state . As the phase shift is conditional upon the ion's motion, we are able to demonstrate a universal 2-qubit quantum gate operation where the electronic target state is flipped depending on the motional qubit state . Finally, we discuss scaling properties of this universal quantum gate for linear ion crystals and present numerical simulations for the generation of a maximally entangled state of five ions.
03.67.Lx - Quantum computation.
03.65.Ud - Entanglement and quantum nonlocality (e.g., EPR paradox, Bell's inequalities, GHZ states, etc.).
© EDP Sciences 2004