Quantum state betting, dependence measures, quantum R\'enyi divergences, and resource monotones: a four-way correspondence.
Andrés F. Ducuara, Paul Skrzypczyk
Abstract
We introduce the operational tasks of quantum state betting (QSB) played by gamblers with different risk tendencies. We do this by adapting to the quantum regime the task of horse betting with risk-aversion and side information. We prove that the advantage that informative measurements provide in QSB is exactly characterised by Arimoto's dependence measure, with the order $\alpha$ determining the risk aversion of the gambler. In limiting cases, we show that QSB recovers the tasks of quantum state discrimination when $\alpha \rightarrow \infty$, and quantum state exclusion when $\alpha \rightarrow -\infty$. In these respective limiting cases, Arimoto's dependence measure becomes equal to the accessible information and excludible information of the associated quantum-classical channels. Inspired by these connections, we introduce new quantum Renyi divergences for measurements, and derive a family of resource monotones for the quantum resource theory of measurement informativeness. This family of resource monotones recovers in the same limiting cases as above, the generalised robustness and the weight of informativeness. Altogether, these results establish a broad and continuous family of four-way correspondences between operational tasks, dependence measures, quantum Renyi divergences, and resource monotones, that can be seen to generalise two limiting correspondences that were recently discovered.