Quantum information processing and cavity QED experiments with trapped Ca+ ions

Single trapped Ca⁺ ions, stored in a linear Paul trap and laser-cooled to the ground state of their harmonic quantum motion are used for quantum information processing. As a demonstration, composite laser pulse sequences were used to implement phase gate and CNOT gate operation. For this, Stark shifts on the qubit transitions were precisely measured and compensated. With a single ion stored inside a high-finesse optical cavity, a cavity mode can be coherently coupled to the qubit transition.