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arXiv · 2606.17894

Demultiplexing Generalized Information via Quantum Transmission Lines

Soham Sau·Anna Jenčová·Tamal Guha
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Abstract

Demultiplexers are the fundamental primitives of network architecture, enabling perfect routing of an input classical signal to a designated one, among multiple output ports. Quantum transmission lines, having access to the quantum systems directly, are able to transmit both the classical and quantum information encoded in quantum systems. A natural question therefore emerges that whether the scrambled classical and quantum information in a quantum system can be perfectly demultiplexed in the designated classical and quantum output ports? Here we answer this question by introducing a quantum to quantum-classical device, namely the quantum demultiplexer (Q-DEMUX). We characterize the class of Q-DEMUXs enabling perfect routing of both the classical and the quantum information along with their simple circuit realizations. Our results highlight an explicit connection between the strength of a Q-DEMUX with the incompatibility of quantum instruments. Finally, we extend the notion in a stronger variant where the sender is oblivious regarding the nature of the data to be transmitted through the Q-DEMUX.

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Soham Sau, Anna Jenčová, Tamal Guha. 2026-06-16. Demultiplexing Generalized Information via Quantum Transmission Lines. https://arxiv.org/abs/2606.17894

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