Continuous-Variable Quantum Secret Sharing Based on Thermal Terahertz Sources in Inter-Satellite Wireless Links.

Area of Science:

• Quantum Information Science
• Satellite Communications
• Terahertz Technology

Background:

• Secure key distribution is crucial for satellite communication networks.
• Existing quantum key distribution methods face challenges in long-distance and multi-party scenarios.
• Terahertz (THz) frequencies offer potential for high-bandwidth inter-satellite links.

Purpose of the Study:

• To propose and analyze a continuous-variable quantum secret sharing (CVQSS) scheme tailored for inter-satellite wireless links.
• To leverage thermal terahertz (THz) sources for secure multi-party key sharing.
• To demonstrate the feasibility of a long-distance, multi-player THz-CVQSS system.

Main Methods:

• Preparation of thermal THz states via Gaussian modulation by each player.
• Coupling of THz states into a circulating spatiotemporal mode using a highly asymmetric beam splitter.
• Heterodyne detection by the dealer to measure quadrature components for key sharing.

Main Results:

• The proposed scheme ensures that secure keys are recoverable only through the collective knowledge of all group players.
• Neither individual players nor subsets of players can independently recover the secure key.
• Analysis confirms the feasibility of a long-distance inter-satellite THz-CVQSS scheme with multiple participants.

Conclusions:

• The developed THz-CVQSS scheme offers a robust solution for secure key distribution in inter-satellite networks.
• This work paves the way for building secure, long-distance quantum communication networks between satellites.
• The proposed method enhances the security and practicality of quantum communication in space.