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

In this study, we report the experimental reali-zation of seven-qubit Deutsch-Jozsa (D-J) algorithm and controlled phase-shift gates with improved precision using liquid state nuclear magnetic resonance (NMR). Theexperimental results have shown that transformations Uf in the seven-qubit D-J algorithm have been implemented with different pulse sequences, and whether f is constant orbalanced is determined by using only a single function call(Uf). Furthermore, we propose an experimental method tomeasure 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 ofsurmounting the difficulties of low signal-to-noise ratio(SNR) in multi-qubit NMR quantum computers, morecomplicated experimental techniques, and the increase ofgate errors due to using a large number of imperfect selec-tive pulses. These are also applied to more complicated quantum algorithms with more qubits, such as quantumFourier transformation and Shor抯 algorithm.

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

In this study, we report the experimental reali-zation 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 transformations Uf in the seven-qubit D-J algorithm have been implemented with different pulse sequences, and whether f is constant or balanced is determined by using only a single function call (Uf). 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 selec-tive pulses. These are also applied to more complicated quantum algorithms with more qubits, such as quantum Fourier transformation and Shor's algorithm.