Demonstration of microwave single-shot quantum key distribution

Area of Science:

• Quantum Information Science
• Quantum Communication Technology
• Applied Physics

Background:

• Classical data encryption faces threats from quantum computing.
• Quantum Key Distribution (QKD) offers a solution for secure information exchange.
• Microwave QKD is crucial for integrating with superconducting quantum processors and networks.

Purpose of the Study:

• To experimentally realize a continuous-variable QKD protocol using microwave frequencies.
• To demonstrate the feasibility and security of microwave QKD.
• To assess the performance of microwave QKD in different environments.

Main Methods:

• Utilized superconducting parametric devices for generating displaced squeezed microwave states.
• Employed single-shot quadrature detection for analyzing quantum states.
• Implemented a continuous-variable QKD protocol tailored for microwave frequencies.

Main Results:

• Achieved unconditional security in the experimental microwave QKD system.
• Demonstrated improved security performance by introducing trusted noise during preparation.
• Confirmed the feasibility of secure microwave quantum communication over 80m in open-air and over 1000m in cryogenic conditions.

Conclusions:

• The experimental realization validates the potential of microwave QKD for secure communication.
• Current technology enables practical microwave QKD for near-distance and networked applications.
• This work advances the development of robust quantum communication networks.