title: Quantum computation with untunable couplings.
abstract: Most quantum computer realizations require the ability to apply local fields and tune the couplings between qubits, in order to realize single bit and two bit gates which are necessary for universal quantum computation. We present a scheme to remove the necessity of switching the couplings between qubits for two bit gates, which are more costly in many cases. Our strategy is to compute with encoded qubits in and out of carefully designed interaction free subspaces analogous to decoherence free subspaces. We give two examples to show how universal quantum computation is realized in our scheme with local manipulations to physical qubits only, for both diagonal and off diagonal interactions.
authors.affiliation: Superconducting Digital Electronics Lab, Electrical and Computer Engineering Department, University of Rochester, Rochester, New York 14627, USA.
authors.forename: Xingxiang
authors.initials: X
authors.lastname: Zhou
authors.forename: Zheng-Wei
authors.initials: ZW
authors.lastname: Zhou
authors.forename: Guang-Can
authors.initials: GC
authors.lastname: Guo
authors.forename: Marc J
authors.initials: MJ
authors.lastname: Feldman