Proof-of-principle demonstration of a decoy state experiment based on the mirror protocol

Area of Science:

• Quantum Information Science
• Quantum Cryptography
• Experimental Physics

Background:

• Semi-quantum key distribution (SQKD) aims to improve security and performance in quantum key distribution.
• A gap exists between theoretical proposals for decoy state SQKD and experimental demonstrations.
• The mirror protocol is a specific scheme within SQKD.

Purpose of the Study:

• To propose and experimentally demonstrate a decoy state setting and scheme for the mirror protocol.
• To bridge the gap between theoretical decoy state SQKD and practical implementation.
• To lay the foundation for experimental security analysis of SQKD.

Main Methods:

• Development of a decoy state setting and experimental scheme tailored for the mirror protocol.
• Conducting proof-of-principle experiments under simulated and actual fiber channel conditions.
• Utilizing weak and vacuum decoy states for security enhancement.

Main Results:

• Simulations showed no key generation under Gottesman-Lo-Lütkenhaus-Preskill (GLLP) and one-decoy conditions.
• Valid key generation rates were achieved up to 19.1 km fiber transmission using weak and vacuum states.
• An experimental key generation rate of 406 bits/s was achieved over a 10 km fiber channel.

Conclusions:

• The first experimental demonstration of the decoy state mirror protocol was successfully achieved.
• The findings validate the feasibility of decoy state SQKD in practical scenarios.
• This work provides crucial experimental insights for advancing the security and verification of SQKD systems.