Adaptive versus nonadaptive strategies for quantum channel discrimination
Aram W. Harrow, Avinatan Hassidim, Debbie Leung, John Watrous · Physical Review A · 2010
We provide a simple example that illustrates the advantage of adaptive over nonadaptive strategies for quantum channel discrimination. In particular, we give a pair of entanglement-breaking channels that can be perfectly discriminated by means of an adaptive strategy that requires just two channel evaluations, but for which no nonadaptive strategy can give a perfect discrimination using any finite number of channel evaluations.