Distinguishing Unitary Gates on the IBM Quantum Processor
An unknown unitary gates, which is secretly chosen from several known ones,
can always be distinguished perfectly. In this paper, we implement such a task
on IBM's quantum processor. More precisely, we experimentally demonstrate the
discrimination of two qubit unitary gates, the identity gate and the
$\frac{2}{3}\pi$-phase shift gate, using two discrimination schemes -- the
parallel scheme and the sequential scheme. We program these two schemes on the
\emph{ibmqx4}, a $5$-qubit superconducting quantum processor via IBM cloud,
with the help of the $QSI$ modules [S. Liu et al.,~arXiv:1710.09500, 2017]. We
report that both discrimination schemes achieve success probabilities at least
85%.
Shusen Liu Yinan Li Runyao Duan