Ancilla-driven universal quantum computation

Janet Anders, Daniel K. L. Oi, Elham Kashefi, Dan E. Browne, Erika Andersson

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We introduce a model of quantum computation intermediate between the gate-based and measurement-based models. A quantum register is manipulated remotely with the help of a single ancilla that "drives" the evolution of the register. The fully controlled ancilla qubit is coupled to the computational register only via a fixed unitary two-qubit interaction and then measured in suitable bases, driving both single- and two-qubit operations on the register. Arbitrary single- qubit operations directly on register qubits are not needed. We characterize all interactions E that induce a unitary, stepwise deterministic measurement back-action on the register sufficient to implement any quantum channel. Our scheme offers experimental advantages for computation, state preparation, and generalized measurements, since no tunable control of the register is required.

Original languageEnglish
Article number020301(R)
Number of pages4
JournalPhysical Review A
Issue number2
Publication statusPublished - 10 Aug 2010


  • ancilla qubit
  • quantum computation
  • quantum register

Cite this

Anders, J., Oi, D. K. L., Kashefi, E., Browne, D. E., & Andersson, E. (2010). Ancilla-driven universal quantum computation. Physical Review A, 82(2), [020301(R)].