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arXiv · 2601.20044

Quantum Channels on Graphs: a Resonant Tunneling Perspective

Giuseppe Catalano·Farzad Kianvash·Vittorio Giovannetti
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Abstract

Quantum transport on structured networks is strongly influenced by interference effects, which can dramatically modify how information propagates through a system. We develop a quantum-information-theoretic framework for scattering on graphs in which a full network of connected scattering sites is treated as a quantum channel linking designated input and output ports. Using the Redheffer star product to construct global scattering matrices from local ones, we identify resonant concatenation, a nonlinear composition rule generated by internal back-reflections. In contrast to ordinary channel concatenation, resonant concatenation can suppress noise and even produce super-activation of the quantum capacity, yielding positive capacity in configurations where each constituent channel individually has zero capacity. We illustrate these effects through models exhibiting resonant-tunneling-enhanced transport. Our approach provides a general methodology for analyzing coherent information flow in quantum graphs, with relevance for quantum communication, control, and simulation in structured environments.

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Giuseppe Catalano, Farzad Kianvash, Vittorio Giovannetti. 2026-01-27. Quantum Channels on Graphs: a Resonant Tunneling Perspective. https://arxiv.org/abs/2601.20044

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