Performance analysis of continuous-variable quantum key distribution using non-Gaussian states
This work addresses the challenge of secure quantum communication in non-ideal conditions for applications like cryptography, though it appears incremental as it builds on existing protocols with a specific state modification.
The study tackled the problem of improving quantum key distribution efficiency in noisy environments by analyzing a protocol using discrete-modulated non-Gaussian states (PASCS), finding that it always outperforms coherent states protocols, with performance gains increasing as noise levels rise.
In this study, we analyze the efficiency of a protocol with discrete modulation of continuous variable non-Gaussian states, the coherent states having one photon added and then one photon subtracted (PASCS). We calculate the secure key generation rate against collective attacks using the fact that Eve's information can be bounded based on the protocol with Gaussian modulation, which in turn is unconditionally secure. Our results for a four-state protocol show that the PASCS always outperforms the equivalent coherent states protocol under the same environmental conditions. Interestingly, we find that for the protocol using discrete-modulated PASCS, the noisier the line, the better will be its performance compared to the protocol using coherent states. Thus, our proposal proves to be advantageous for performing quantum key distribution in non-ideal situations.