NMR experimental realization of seven-qubit DJ algorithm and controlled phase-shift gates with improved precision

ArticleinChinese Science Bulletin 48(3):239-243 · February 2003with13 Reads
Impact Factor: 1.58 · DOI: 10.1007/BF03183290

    Abstract

    In this study, we report the experimental realization of seven-qubit Deutsch-Jozsa (D-J) algorithm and controlled phase-shift
    gates with improved precision using liquid state nuclear magnetic resonance (NMR). The experimental results have shown that
    transformationsU

    f
    in the seven-qubit D-J algorithm have been implemented with different pulse sequences, and whetherf is constant or balanced is determined by using only a single function call (U

    f
    ). Furthermore, we propose an experimental method to measure and correct the error in the controlled phase-shift gate that
    is simple and feasible in experiments, and can have precise phase shifts. These may offer the possibility of surmounting the
    difficulties of low signal-to-noise ratio (SNR) in multi-qubit NMR quantum computers, more complicated experimental techniques,
    and the increase of gate errors due to using a large number of imperfect selective pulses. These are also applied to more
    complicated quantum algorithms with more qubits, such as quantum Fourier transformation and Shor’s algorithm.