High-fidelity quantum cloning of two nonorthogonal quantum states via weak measurements
Minghao Wang, Qing-yu Cai · Physical Review A · 2019
We propose a scheme to enhance the fidelity of a symmetric quantum cloning machine via weak measurements. By adjusting the intensity of the weak measurement parameter $p$, we obtain copies of initial states with different values of fidelity. Choosing a proper value of $p$, we can obtain perfect copies. In this paper, we focus on $1\ensuremath{-}2$ quantum cloning for two nonorthogonal states. Sets containing more than two linear independent states are also briefly discussed. Due to the probabilistic nature of weak measurements, we obtain high-fidelity copies probabilistically. If the weak measurement is a success, we do subsequent operations to obtain high-fidelity copies; otherwise, the cloning process fails and we quit. From this perspective, the scheme we propose is economical for saving quantum resources and time. Our scheme may be very useful in quantum information processing.