Improving Continuous-Variable Quantum Key Distribution in a Turbulent Atmospheric Channel via Photon Subtraction

The transmission performance of continuous-variable quantum key distribution (CVQKD) in turbulent atmospheric channel is lower than CVQKD in fiber channel due to the large loss of quantum entanglement in turbulent atmospheric channel. In this paper, we propose a new approach to prolong the transmission performance of CVQKD in a turbulent atmospheric channel by using photon subtraction operation since the proposed approach can effectively enhance the entangled state between quantum. Simulation analysis shows that photon subtraction operation can effectively improve the security key rate of continuous-variable quantum key distribution, and the optimal performance can be achieved when only one photon is subtracted.