



01180nas a2200157   4500008004100000245007300041210006900114490000800183520068500191100001800876700002900894700002400923700001600947700002200963856003700985       2018                        eng d00aOptimal Pure-State Qubit Tomography via Sequential Weak Measurements0 aOptimal PureState Qubit Tomography via Sequential Weak Measureme0 v1213 a<p>The spin-coherent-state positive-operator-valued-measure (POVM) is a fundamental measurement in quantum science, with applications including tomography, metrology, teleportation, benchmarking, and measurement of Husimi phase space probabilities. We prove that this POVM is achieved by collectively measuring the spin projection of an ensemble of qubits weakly and isotropically. We apply this in the context of optimal tomography of pure qubits. We show numerically that through a sequence of weak measurements of random directions of the collective spin component, sampled discretely or in a continuous measurement with random controls, one can approach the optimal bound.</p>1 aShojaee, Ezad1 aJackson, Christopher, S.1 aRiofrio, Carlos, A.1 aKalev, Amir1 aDeutsch, Ivan, H.  uhttps://arxiv.org/abs/1805.01012