Game-theoretic characterization of antidegradable channels

Abstract

We introduce a guessing game involving a quantum channel, three parties - the sender, the receiver and an eavesdropper, Eve - and a quantum public side channel. We prove that a necessary and sufficient condition for the quantum channel to be antidegradable, is that Eve wins the game. We thus obtain a complete operational characterization of antidegradable channels in a game-theoretic framework.Comment: v2: published version, 14 pages, 1 figure; v1: 13 pages, 1 figur