Quantum hypothesis testing and sufficient subalgebras
نویسنده
چکیده
We introduce a new notion of a sufficient subalgebra for quantum states: a subalgebra is 2sufficient for a pair of states {ρ0, ρ1} if it contains all Bayes optimal tests of ρ0 against ρ1. In classical statistics, this corresponds to the usual definition of sufficiency. We show this correspondence in the quantum setting for some special cases. Furthermore, we show that sufficiency is equivalent to 2 sufficiency, if the latter is required for {ρ 0 , ρ ⊗ 1 }, for all n.
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