Quantum Reverse Shannon Theorem Simplified

Gilad Gour

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arXiv · 2510.04552

Quantum Reverse Shannon Theorem Simplified

Gilad Gour

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Abstract

We revisit the quantum reverse Shannon theorem, a central result in quantum information theory that characterizes the resources needed to simulate quantum channels when entanglement is freely available. We derive a universal additive upper bound on the smoothed max-information in terms of the sandwiched R\'enyi mutual information. This bound yields tighter single-shot results, eliminates the need for the post-selection technique, and leads to a conceptually simpler proof of the quantum reverse Shannon theorem. By consolidating and streamlining earlier approaches, our result provides a clearer and more direct understanding of the resource costs of simulating quantum channels.

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Gilad Gour. 2025-10-06. Quantum Reverse Shannon Theorem Simplified. https://arxiv.org/abs/2510.04552

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