Strong converses for classical information transmission and hypothesis testing
Nilanjana Datta, Milán Mosonyi, Min-Hsiu Hsieh, Fernando G. S. L. Brandão
Abstract
We obtain lower and upper bounds on the one-shot strong converse capacity for the transmission of classical information through quantum channels, in terms of a generalized relative entropy quantity, namely, the smoothed max-relative entropy. For the case of a memoryless channel, these bounds converge independently to the Holevo capacity, in the limit of asymptotically many uses. We also employ our one-shot result to obtain an upper bound to the strong converse capacity of a channel with long-term memory which can be shown to violate the strong converse property. Finally, we show bounds on the strong converse rate of hypothesis testing in the one-shot scenario, again in terms of the smoothed max-relative entropies.