Maximum confidence channel discrimination: Probe design, entanglement assistance, and sequential measurement
Phys. Rev. A 114, 042419 – Published 13 October, 2026
DOI: https://doi.org/10.1103/c2qc-34yl
Abstract
In this work, we study maximum confidence measurement for quantum channel discrimination and develop optimization-based algorithms for designing both the probe state and measurement operators. We show that entanglement-assisted strategies with pure probe states and bounded reference dimensions suffice to achieve optimal performance. We characterize the optimal probe as a weakly Pareto optimal point of the achievable confidence region, and illustrate the framework on complementary dephasing qubit channels for which this region, the minimax probe, and the sequential design are obtained in closed form. Finally, we extend the framework to sequential maximum confidence measurements, where multiple observers perform measurements sequentially while maintaining the same confidence guarantees.
