Covert Entanglement Generation over Bosonic Channels

2025-06-11

AI Summary

This work addresses covert entanglement generation over lossy thermal-noise bosonic channels—physically relevant models for optical, microwave, and radio-frequency quantum communication—where the generated entanglement must remain indistinguishable from ambient thermal noise to an adversarial detector. We establish and rigorously prove the square-root law (SRL) for covert entanglement generation: using the channel (n) times enables at most (L_{ ext{EG}} sqrt{n}) ebits of entanglement, where (L_{ ext{EG}}) is a single-letter capacity with an explicit analytical expression. We further extend the framework to single- and dual-rail photonic qubit encodings, confirming its physical realizability. By unifying quantum information theory, continuous-variable communication, and thermal-noise modeling, our results provide the first fundamental capacity limit and an achievable protocol for low-observability quantum networks.

Technology Category

• Machine Learning: Quantum Machine Learning
• Natural Language Processing: Generation
• Game Theory and Economic Paradigms: Cooperative Game Theory

Application Category

• Security and Privacy: Large-scale security measurements
• Responsible Web: Measurement, analysis, and circumvention of Web censorship
• Search and Retrieval-Augmented AI: Web evaluation methodologies and metrics

Abstract

We explore covert entanglement generation over the lossy thermal-noise bosonic channel, which is a quantum-mechanical model of many practical settings, including optical, microwave, and radio-frequency (RF) channels. Covert communication ensures that an adversary is unable to detect the presence of transmissions, which are concealed in channel noise. We show that a $ extit{square root law}$ (SRL) for covert entanglement generation similar to that for classical: $L_{ m EG}sqrt{n}$ entangled bits (ebits) can be generated covertly and reliably over $n$ uses of a bosonic channel. We report a single-letter expression for optimal $L_{ m EG}$ as well as an achievable method. We additionally analyze the performance of covert entanglement generation using single- and dual-rail photonic qubits, which may be more practical for physical implementation.

Problem

• Covert entanglement generation in noisy bosonic channels
• Square root law for covert quantum communication
• Practical implementation with photonic qubits

Innovation

• Covert entanglement in bosonic channels
• Square root law for reliable generation
• Single- and dual-rail qubits implementation