Discrete-modulation measurement-device-independent continuous-variable quantum key distribution with a quantum...

Area of Science:

• Quantum Information Science
• Quantum Cryptography
• Quantum Communication

Background:

• Continuous-variable quantum key distribution (CV-QKD) enables secure communication.
• Measurement-device-independent (MDI) protocols enhance security by removing detector vulnerabilities.
• Non-Gaussian states are crucial for advanced quantum protocols but pose implementation challenges.

Purpose of the Study:

• To investigate the impact of a novel quantum scissor on a non-Gaussian discrete-modulated MDI-CV-QKD protocol.
• To analyze how the quantum scissor affects key distribution performance, particularly fidelity and entanglement.
• To determine the potential range enhancement of the CV-QKD protocol with the proposed device.

Main Methods:

• Implementation of a quantum scissor at the receiver to truncate multi-photon states (≥4 photons) and amplify others probabilistically.
• Utilizing exact non-Gaussian calculations for precise analysis.
• Evaluating the protocol's performance under varying excess noise conditions.

Main Results:

• The quantum scissor significantly improves fidelity and entanglement between communicating parties (Alice and Bob) over long distances.
• The proposed quantum scissor effectively enhances the operational range of the CV-QKD protocol.
• The benefits of the quantum scissor diminish in the presence of high channel noise.

Conclusions:

• The developed quantum scissor is a promising technique for extending the reach of secure quantum key distribution.
• The protocol's robustness is limited in noisy environments, highlighting the need for noise mitigation strategies.
• This work contributes to the advancement of practical and secure long-distance quantum communication.