Scalable ion trap quantum computing without moving ions

A hybrid quantum computing scheme is studied where thehybrid qubit is made of an ion trap qubit serving as theinformation storage and a solid-state charge qubit serving as thequantum processor, connected by a superconducting cavity. In thispaper, we extend our previous work [CITE] and study thedecoherence, coupling and scalability of the hybrid system. Wepresent our calculations of the decoherence of the coupled ion-charge system due to the charge fluctuations in the solid-statesystem and the dissipation of the superconducting cavity underlaser radiation. A gate scheme that exploits rapid state flips ofthe charge qubit to reduce decoherence by the charge noise isdesigned. We also study a superconducting switch that is insertedbetween the cavity and the charge qubit and provides tunablecoupling between the qubits. The scalability of the hybrid schemeis discussed together with several potential experimentalobstacles in realizing this scheme.