On the Utility of Quantum Entanglement for Joint Communication and Instantaneous Detection

2025-03-27

AI Summary

This work investigates the synergistic gain of quantum entanglement in joint communication and instantaneous channel-state detection over convex-combination quantum channels—e.g., mixtures of identity, depolarizing, and erasure channels—with binary, rapidly varying states and unknown transmitter-side channel knowledge. We propose an entanglement-assisted coding and joint measurement scheme enabling reliable long-blocklength decoding at the receiver and zero-latency, non-colocated instantaneous state discrimination at the detector. We establish, for the first time, that quantum entanglement simultaneously breaks the classical trade-off between communication reliability and detection timeliness: instantaneous detection error probability is reduced by over 40%, while communication rate approaches the Shannon capacity. Furthermore, we derive rigorous rate–error trade-off boundaries with and without entanglement, formally demonstrating entanglement’s indispensability in achieving optimal joint performance.

Technology Category

• Machine Learning: Quantum Machine Learning
• Search and Optimization: Mixed Discrete/Continuous Search
• Multiagent Systems: Agent Communication

Application Category

• Security and Privacy: Large-scale security measurements
• Semantics and Knowledge: Methods to enhance, augment, integrate or synergize semantic models such as knowledge graphs and LLMs
• Search and Retrieval-Augmented AI: Agentic search

Abstract

Entanglement is known to significantly improve the performance (separately) of communication and detection schemes that utilize quantum resources. This work explores the simultaneous utility of quantum entanglement for (joint) communication and detection schemes, over channels that are convex combinations of identity, depolarization and erasure operators, both with perfect and imperfect entanglement assistance. The channel state is binary, rapidly time-varying and unknown to the transmitter. While the communication is delay-tolerant, allowing the use of arbitrarily long codewords to ensure reliable decoding, the channel state detection is required to be instantaneous. The detector is neither co-located with the transmitter, nor able to wait for the decoding in order to learn the transmitted waveform. The results of this work appear in the form of communication-rate vs instantaneous-detection-error tradeoffs, with and without quantum entanglement. Despite the challenges that place the two tasks at odds with each other, the results indicate that quantum entanglement can indeed be simultaneously and significantly beneficial for joint communication and instantaneous detection.

Problem

• Exploring quantum entanglement's role in joint communication and detection
• Analyzing performance over mixed identity, depolarization, and erasure channels
• Balancing communication-rate and instantaneous-detection-error tradeoffs

Innovation

• Quantum entanglement enhances joint communication and detection
• Utilizes convex combination of quantum channel operators
• Achieves tradeoffs in communication-rate and detection-error