2009/11/19 by Janet Anders, Daniel K. L. Oi, Elham Kashefi +2 · 1 citation
Physics and Astronomy · #quant-ph
paper · pdf · doi:10.1103/physreva.82.020301
published as Phys. Rev. A 82, 020301(R) (2010) · 4 pages, 3 figures
arxiv created 2009/11/19 · arxiv updated 2010/08/12
We propose a method of manipulating a quantum register remotely with the help of a single ancilla that steers the evolution of the register. The fully controlled ancilla qubit is coupled to the computational register solely via a fixed unitary two-qubit interaction, E, and then measured in suitable bases. We characterize all interactions E that induce a unitary, step-wise deterministic measurement back-action on the register sufficient to implement any arbitrary quantum channel. Our scheme offers significant experimental advantages for implementing computations, preparing states and performing generalized measurements as no direct control of the register is required.