Storage and retrieval of von Neumann measurements via indefinite causal order structures
Storage and retrieval of von Neumann measurements via indefinite causal order structures
This work presents the problem of learning an unknown von Neumann measurement of dimension $d$ using indefinite causal structures. In the considered scenario, we have access to $N$ copies of the measurement. We use the formalism of process matrices to store information about the given measurement that later will be …