Abstract

The basic requirements for quantum computing have been demonstrated in many trapped ion experiments and work in the Oxford ion trap group towards scaling up the number of qubits in our system and increasing the fidelity of operations upon individual qubits will be presented. We are designing, fabricating, and testing multi-zone traps which should allow us to manipulate larger numbers of trapped ions. A further requirement for scability is protection against decoherence and we demonstrate the use of generalized spin echo pulses to guard against that caused by magnetic field fluctuations. Finally we have been studying high-fidelity readout using different detection methods. We have already reported high-fidelity readout for a single qubit (99.99% in 145us) using a photomultiplier, and we have now also demonstrated simultaneous high-fidelity readout of a register of 4 ions using a CCD camera.