Katherine Brown

University of Leeds

Using the qubus for quantum computing

The qubus is an ancilla based scheme of quantum computing. In this particular case a continuous variable field is used to mediate interactions between the qubits of the main system. Using such a scheme it is possible to generate a maximally entangling gate between two qubits and since we can perform local unitaries on the individual qubits this scheme is universal for quantum computation. In this talk we consider two systems that can be performed on the qubus; cluster state generation and simulating the BCS Hamiltonian. Since these two systems involve performing identical interactions on different qubits we show that it is possible to get a significant reduction in the number of operations needed to perform these systems by careful rearrangement of the gates involved. We also discuss other systems where a similar improvement may be found and show the limits of this technique.