A Generalized quantum Stein lemma on von Neumann algebras

Li Gao

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arXiv · 2610.02134

A Generalized quantum Stein lemma on von Neumann algebras

Li Gao

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Abstract

We prove a generalized quantum Stein lemma for i.i.d. normal states against convex, tensor-stable families on arbitrary von Neumann algebras. Assuming the existence of an alternative state with finite relative entropy from the null state, we show that, at every type-I error tolerance $\varepsilon\in (0,1)$, the worst case type-II error exponent is achieved with the regularized relative entropy with a strong converse. The proof combines the integral representation of relative entropy by hockey-stick divergences, a modular testing bound, and convex minimax argument.

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Li Gao. 2026-10-01. A Generalized quantum Stein lemma on von Neumann algebras. https://arxiv.org/abs/2610.02134

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